The present technology relates to an information processing device, a method, and a program, and more particularly to an information processing device, a method, and a program capable of reducing the processing load on the distribution side while reducing the amount of information transmitted.
Background technology
[0002]
　The MPEG (Moving Picture Experts Group) -H coding standard, which is standardized as the conventional 3D Audio for fixed viewpoints, is based on the idea that the audio object moves in the space around the listener's position as the origin. (See, for example, Non-Patent Document 1).
[0003]
　Therefore, from a fixed viewpoint, the position information of each audio object seen from the listener at the origin is described by polar coordinates using the horizontal angle, the height angle, and the distance from the listener to each audio object. ing.
[0004]
　By using such an MPEG-H coding standard, it is possible to localize the sound image of each audio object in the space at the position of each audio object in the fixed viewpoint content, and the audio reproduction with a high sense of presence can be achieved. It is possible to achieve it.
Prior art literature
Non-patent literature
[0005]
Non-Patent Document 1: ISO / IEC 23008-3 Information technology － High efficiency coding and media delivery in heterogeneous environments － Part 3: 3D audio
Outline of the invention
Problems to be solved by the invention
[0006]
　On the other hand, there is also known free-viewpoint content that allows the listener to be positioned at any position in the space. From a free viewpoint, in addition to moving the audio object in space, the listener can also move. That is, the free viewpoint differs from the fixed viewpoint in that the listener can move.
[0007]
　Even in such a free viewpoint, as in the case of a fixed viewpoint, if the position information of the polar coordinates indicating the position of the audio object as seen by the listener can be obtained, the renderer of the polar coordinate system standardized by MPEG-H can be used. It is possible to realize audio reproduction. That is, it is possible to realize audio reproduction from a free viewpoint by the same rendering process as in the case of a fixed viewpoint.
[0008]
　In this case, for example, the audio data of each audio object and the position information indicating the position of those audio objects are provided from the server to the playback side. Then, rendering is performed for audio reproduction in which the sound image is localized at the position of the audio object in the space on the reproduction side.
[0009]
　However, when trying to realize free-viewpoint audio playback with the MPEG-H renderer, every time the position of the audio object or listener changes, the position of the audio object as seen by the listener is updated and information about the position of the audio object is obtained. Is required to be transmitted. Therefore, the amount of information transmitted and the processing load on the content distribution side such as the server may increase. Furthermore, when the number of listeners connected to the server increases, the processing load increases by a multiple of that number, and when the number reaches several thousand or tens of thousands, the load becomes excessive.
[0010]
　This technology was made in view of such a situation, and makes it possible to reduce the processing load on the distribution side while reducing the amount of information transmitted.
Means to solve problems
[0011]
　The information processing device of the first aspect of the present technology acquires low-precision position information of the first accuracy indicating the position of an object in the space in which the user is located, and indicates the position of the object in the space. Acquiring the acquisition unit for acquiring additional information for obtaining the position information of the second accuracy higher than the first accuracy according to the position of, and obtaining the position information based on the low-precision position information and the additional information. It is equipped with a position information calculation unit.
[0012]
　The information processing method or program of the first aspect of the present technology acquires low-precision position information of the first accuracy indicating the position of the object in the space in which the user is, and indicates the position of the object in the space. A step of acquiring additional information for obtaining position information having a second accuracy higher than the first accuracy according to the position of the user, and obtaining the position information based on the low-precision position information and the additional information. including.
[0013]
　In the first aspect of the present technology, the low-precision position information of the first accuracy indicating the position of the object in the space where the user is located is acquired, and the position of the user indicating the position of the object in the space is obtained. Additional information for obtaining position information with a second accuracy higher than the first accuracy according to the above is acquired, and the position information is obtained based on the low accuracy position information and the additional information.
[0014]
　The information processing device of the second aspect of the present technology transmits low-precision position information of the first accuracy indicating the position of an object in the space where the user is, and responds to a request from the transmission destination of the low-precision position information. The communication unit includes a communication unit that indicates the position of the object in the space and transmits additional information for obtaining position information having a second accuracy higher than the first accuracy according to the position of the user.
[0015]
　The information processing method or program of the second aspect of the present technology transmits low-precision position information of the first accuracy indicating the position of an object in the space where the user is, and requests from the destination of the low-precision position information. A step of transmitting additional information indicating the position of the object in the space to obtain position information having a second accuracy higher than the first accuracy according to the position of the user is included.
[0016]
　In the second aspect of the present technology, first-precision low-precision position information indicating the position of an object in the space in which the user is located is transmitted, and in response to a request from the destination of the low-precision position information, the above-mentioned Additional information indicating the position of the object in space to obtain position information with a second accuracy higher than the first accuracy according to the position of the user is transmitted.
The invention's effect
[0017]
　According to the first aspect and the second aspect of the present technology, it is possible to reduce the processing load on the distribution side while reducing the amount of information transmitted.
[0018]
　The effects described here are not necessarily limited, and may be any of the effects described in the present disclosure.
A brief description of the drawing
[0019]
[Fig. 1] Fig. 1 is a diagram showing a configuration example of a content reproduction system.
[Fig. 2] Fig. 2 is a diagram illustrating a processing sequence of a content reproduction system.
[Fig. 3] Fig. 3 is a diagram showing a configuration example of a content playback system.
[Fig. 4] Fig. 4 is a diagram showing a configuration example of a server.
[Fig. 5] Fig. 5 is a diagram showing a configuration example of a client.
[Fig. 6] Fig. 6 is a diagram illustrating a perceptual limit angle.
FIG. 7 is a flowchart illustrating a coding process and a file saving process.
[Fig. 8] Fig. 8 is a diagram showing an example of syntax of a high-precision position-coded data file.
FIG. 9 is a flowchart illustrating a position information acquisition process and a position information transmission process.
[Fig. 10] Fig. 10 is a diagram showing an example of syntax of header information.
[Fig. 11] Fig. 11 is a diagram showing a syntax example of a bit stream including low-precision quantized position information.
[Fig. 12] Fig. 12 is a diagram illustrating an example of coding of normalized position information.
FIG. 13 is a flowchart illustrating an additional bit information acquisition process and an additional bit information transmission process.
[Fig. 14] Fig. 14 is a diagram showing a syntax example of a request for transmitting additional bit information.
[Fig. 15] Fig. 15 is a diagram showing an example of syntax of difference data.
[Fig. 16] Fig. 16 is a diagram showing a configuration example of a computer.
Mode for carrying out the invention
[0020]
　Hereinafter, embodiments to which the present technology is applied will be described with reference to the drawings.
[0021]

　This technology transmits information by switching the quantization accuracy of position information indicating the position of an object according to the distance from the listener to the object. It is intended to reduce the processing load on the content distribution side such as a server while reducing the amount.
[0022]
　In the following, when the audio data of the audio object is rendered based on the information indicating the position of the audio object as seen by the listener on the playback side of the content, specifically, a free viewpoint is obtained by the MPEG-H renderer. An example of realizing audio reproduction will be described. However, the present technology can also be applied to the case of reproducing a content image including the object as a subject based on the information indicating the position of the object as seen by the listener.
[0023]
　In the following, the audio object will be simply referred to as an object.
[0024]
　For example, when the audio reproduction from a free viewpoint is performed by the MPEG-H renderer, it is conceivable to realize the audio reproduction by the content reproduction system shown in FIG.
[0025]
　The content reproduction system shown in FIG. 1 includes a listener position acquisition device 11, a polar coordinate position information encoder 12, a server 13, a client 14, and an MPEG-H renderer 15.
[0026]
　In this content reproduction system, the server-side user U11, who is the creator of the content, inputs, for each object in the space, object position information indicating the position of the object in the space to the polar coordinate position information encoder 12. The object position information may be in absolute coordinates or polar coordinates.
[0027]
　Further, on the client 14 side, there is a user who views the reproduced content, that is, a listener U12 of the voice of the content, and the listener position information indicating the position of the listener U12 in the space is the listener position acquisition device 11. Obtained by.
[0028]
　For example, the listener position acquisition device 11 acquires virtual position information of the listener U12 in a virtual space, a distance measuring device such as a GPS (Global Positioning System) or a gyro sensor that measures the position of the listener U12 in space. It consists of an input device, etc., and outputs the listener position information indicating the position of the listener U12.
[0029]
　Here, the listener position information is represented by the coordinates (x coordinate, y coordinate, and z coordinate) of the three-dimensional Cartesian coordinate system, that is, the xyz coordinate system, which indicates the absolute position of the listener U12 in space. It is regarded as absolute coordinate information. Hereinafter, the information indicating the absolute position in the space represented by the coordinates of the xyz coordinate system will also be referred to as an absolute coordinate.
[0030]
　The listener position information output by the listener position acquisition device 11 is received by the polar coordinate position information encoder 12 via the client 14 and the server 13.
[0031]
　The polar coordinate position information encoder 12 indicates the position of the object as seen from the listener U12 in the space based on the listener position information received from the listener position acquisition device 11 and the object position information input by the user U11. Generate polar coordinates as polar coordinate position information.
[0032]
　Then, the polar coordinate position information encoder 12 encodes (encodes) the polar coordinate position information obtained for each object, and transmits the encoded polar coordinate position information to the client 14 via the server 13.
[0033]
　The client 14 decodes (decodes) the polar coordinate position information received from the polar coordinate position information encoder 12 by the polar coordinate position information decoder 21 provided in the client 14, and obtains the resulting polar coordinate position information in the MPEG-H renderer 15. Supply to.
[0034]
　The MPEG-H renderer 15 receives the polar coordinate position information of each object from the client 14, and also receives the audio data of each object from the server 13. The MPEG-H renderer 15 is a renderer of a polar coordinate system standardized by MPEG-H.
[0035]
　The MPEG-H renderer 15 renders based on the audio data of each object and the polar coordinate position information, generates playback audio data in which the sound image of the object is localized at each position in space, and outputs it to a playback system such as a speaker. do.
[0036]
　For example, when there are N objects in the space, the processing sequence in the content reproduction system is as shown in FIG.
[0037]
　In the example shown in FIG. 2, the client 14 first requests the server 13 to notify the number of objects in the space, that is, the number of objects, as shown by the arrow A11.
[0038]
　Then, the server 13 notifies the client 14 of the number of objects as shown by the arrow A12 in response to the request of the client 14.
[0039]
　Further, when the client 14 acquires the listener position information from the listener position acquisition device 11, the client 14 transmits the listener position information to the polar coordinate position information encoder 12 via the server 13 as shown by the arrow A13.
[0040]
　When the polar coordinate position information encoder 12 receives the listener position information, the polar coordinate position information encoder 12 calculates the position of the 0th object as seen from the listener U12 based on the listener position information and the object position information of the 0th object. , The polar coordinate position information indicating the calculation result is encoded. That is, the polar coordinate position information is encoded in a transmittable format and used as encoded data.
[0041]
　Then, as shown by the arrow A14, the polar coordinate position information encoder 12 transmits the coded polar coordinate position information, that is, the coded data of the polar coordinate position information, obtained for the 0th object to the client 14 via the server 13. And send.
[0042]
　On the client 14 side, the polar coordinate position information decoder 21 decodes the coded data of the received polar coordinate position information of the 0th object.
[0043]
　Similarly, the polar coordinate position information encoder 12 generates the polar coordinate position information encoded data for the first object, and as shown by the arrow A15, the polar coordinate position information encoded data of the first object is transmitted to the server 13. Is transmitted to the client 14 via. Further, on the client 14 side, the polar coordinate position information decoder 21 decodes the coded data of the received polar coordinate position information of the first object.
[0044]
　Then, even after that, the generation and transmission of the coded data of the polar coordinate position information and the decoding of the coded data of the polar coordinate position information are performed in order up to the N-1th object.
[0045]
　After the polar coordinate position information is obtained for N objects from the 0th to the N-1th by the above processing, rendering is performed based on the polar coordinate position information and the object data of each object by the MPEG-H renderer 15. Will be done.
[0046]
　By reproducing the sound based on the reproduced audio data obtained by the rendering process, the sound image of the object can be localized at the correct position when viewed from the listener U12.
[0047]
　For example, when playing back content from a free viewpoint, in order to render with the MPEG-H renderer 15, the polar coordinate position information of the polar coordinate representation indicating the position of the object as seen from the listener U12 is used as the input of the MPEG-H renderer 15. You will need it.
[0048]
　In the content reproduction system shown in FIG. 1, the MPEG-H renderer 15 for a fixed viewpoint can be used as it is in a free viewpoint. Further, since the polar coordinate position information is generated and transmitted in real time by the polar coordinate position information encoder 12, there is an advantage that it is not necessary to hold the polar coordinate position information on the server 13.
[0049]
　However, from a free viewpoint, in addition to the movement of the object in space, the listener U12 also moves in space, so each time either the object or the listener U12 moves, the polar coordinate position information is updated and transmitted. You will need it.
[0050]
　In particular, in the content reproduction system shown in FIG. 1, when there are a plurality of listeners U12, that is, when a plurality of clients 14 are connected to the server 13, the polar coordinate position information of all objects is obtained for all the listeners U12. Update (encoding) will be processed in real time. Then, the processing load of the polar coordinate position information encoder 12 on the content distribution side becomes high, and in some cases, it becomes impossible to supply the polar coordinate position information of the object required by the playback time to the client 14. It ends up.
[0051]
　On the other hand, it is also conceivable that the server 13 supplies the client 14 with the object position information indicating the position of the object expressed in absolute coordinates in the space, and the client 14 calculates the polar coordinate position information.
[0052]
　However, since the absolute coordinates originally do not depend on the position of the listener U12, they must be expressed with high accuracy, and it is preferable to transmit the object position information to the client 14 from the viewpoint of the transmission amount. No. That is, the amount of information (object position information) transmitted is larger when the object position information which is the absolute coordinate is transmitted as compared with the case where the polar coordinate position information which is the polar coordinate is transmitted.
[0053]
　Therefore, in this technology, information indicating the position of a low-precision object with a small amount of information is once transmitted to the client side, and low-precision information is provided so that sufficiently accurate information indicating the position of the object can be obtained. Information on the difference from the information with higher accuracy is additionally transmitted as needed. As a result, not only the amount of information transmitted can be reduced, but also the processing load on the content distribution side such as the polar coordinate position information encoder and the server can be reduced.
[0054]
　Such a content reproduction system to which the present technology is applied is configured as shown in FIG. 3, for example. In FIG. 3, the same reference numerals are given to the parts corresponding to the cases in FIG. 1, and the description thereof will be omitted as appropriate.
[0055]
　The content reproduction system shown in FIG. 3 includes an absolute coordinate position information encoder 51, a server 52, a listener position acquisition device 53, a client 54, and an MPEG-H renderer 55. In this content reproduction system, the client 54 calculates the polar coordinate position information of the polar coordinate representation indicating the position of the object as seen from the listener U12.
[0056]
　That is, on the content distribution side, the user U11 inputs normalized position information or the like indicating the position of each object in the space into the absolute coordinate position information encoder 51.
[0057]
　This normalized position information is normalized absolute coordinate information indicating the absolute position of an object in space represented by the coordinates of the three-dimensional Cartesian coordinate system, that is, the xyz coordinate system.
[0058]
　The absolute coordinate position information encoder 51 encodes the normalized position information and the like input by the user U11, and transmits the highest precision position coded data file obtained as a result to the server 52. Further, the server 52 is an information processing device having a recording unit 61, and records the highest precision position coded data file received from the absolute coordinate position information encoder 51 in the recording unit 61.
[0059]
　Here, in the highest-precision position-encoded data file, for each object, the normalized position information is quantized with the highest accuracy, that is, the highest-precision quantization obtained by quantization with a small quantization step width. Contains location information.
[0060]
　Hereinafter, the quantization accuracy when obtaining the highest precision quantization position information from the normalized position information will be referred to as the highest precision, and the position indicated by the highest precision quantization position information will also be referred to as the highest precision absolute position.
[0061]
　Although the details will be described later, by extracting a part of the highest precision quantization position information, it is possible to obtain the quantization position information obtained by quantizing the normalized position information with a quantization accuracy lower than the highest accuracy.
[0062]
　In the following, the quantization position information obtained by quantizing the normalized position information with a quantization accuracy lower than the highest accuracy will also be referred to as a low-precision quantization position information, and is particularly the lowest among the low-precision quantization position information. The low-precision quantization position information with quantization accuracy is also referred to as the lowest-precision quantization position information. Further, in the following, the position indicated by the low-precision quantized position information is also referred to as a low-precision absolute position, and the position indicated by the lowest-precision quantized position information is also referred to as a minimum-precision absolute position.
[0063]
　Furthermore, in the following, when it is not necessary to distinguish between the highest precision absolute position and the low precision absolute position, it is also simply referred to as the absolute position of the object, and it is necessary to particularly distinguish the highest precision quantized position information and the low precision quantized position information. If there is no, it is also simply referred to as the quantization position information of the object.
[0064]
　The low-precision quantized position information is information on absolute coordinates that represent the position of an object with a lower accuracy than the highest-precision quantized position information, but because the amount of information, that is, the number of bits, is smaller than that of the highest-precision quantized position information. It is possible to reduce the amount of information transmitted.
[0065]
　Further, on the client 54 side, the listener position acquisition device 53 corresponding to the listener position acquisition device 11 shown in FIG. 1 acquires the listener position information indicating the position of the listener U12 and supplies the listener position information to the client 54. .. The listener position acquisition device 53 is composed of, for example, a distance measuring device such as a GPS or a gyro sensor, an input device for acquiring virtual position information of the listener U12 in the virtual space, and the like.
[0066]
　The client 54 is an information processing device having an absolute coordinate position information decoder 71 and a coordinate conversion unit 72, and acquires the lowest precision quantized position information from the server 52. In the following, the case where the client 54 acquires the minimum precision quantization position information from the server 52 will be described as an example. However, the low-precision quantization position information of any quantization accuracy may be acquired as long as the quantization accuracy is lower than the highest precision, not limited to the lowest-precision quantization position information.
[0067]
　The absolute coordinate position information decoder 71 decodes the lowest precision quantized position information acquired from the server 52, and based on the listener position information, the position of the object indicated by the lowest precision quantized position information is sufficiently accurate. Determine if it is a thing.
[0068]
　At this time, the client 54 acquires additional bit information from the server 52 for obtaining the quantization position information with sufficient accuracy for the object determined to be not sufficiently accurate. The additional bit information is the difference information between the quantized position information with sufficient accuracy and the quantized position information with the lowest accuracy. By adding the additional bit information to the quantized position information with the lowest accuracy, the quantized position with sufficient accuracy Information can be obtained. In some cases, the quantized position information with sufficient accuracy may be the highest accuracy quantized position information.
[0069]
　When the quantization position information with sufficient accuracy is obtained for each object, the coordinate conversion unit 72 converts the quantization position information into polar coordinates indicating the relative position of each object as seen from the listener U12 in space. Converted to polar coordinate position information.
[0070]
　The coordinate conversion unit 72 supplies the polar coordinate position information of each object to the MPEG-H renderer 55, and the MPEG-H renderer 55 is based on the supplied polar coordinate position information and the audio data of each object acquired from the server 52. And render.
[0071]
　Then, the MPEG-H renderer 55 outputs the reproduced audio data obtained by rendering, in which the sound image of the object is localized at each position in the space, to a reproduction system such as a speaker, and reproduces the sound. The MPEG-H renderer 55 is a polar coordinate system renderer standardized by MPEG-H, like the MPEG-H renderer 15 in FIG. 1.
[0072]
　In the content reproduction system as described above, the information indicating the position of the object exchanged between the server 52 and the client 54 is regarded as the minimum precision quantization position information which is an absolute coordinate. Therefore, it is not necessary to consider the position of the listener U12 in the space, and there is an advantage that the minimum precision quantization position information needs to be encoded and transmitted to the client 54 only for the moving object.
[0073]

　Next, a more detailed configuration example of the server 52 and the client 54 shown in FIG. 3 will be described. First, a configuration example of the server 52 will be described.
[0074]
　The server 52 is configured, for example, as shown in FIG. In FIG. 4, the same reference numerals are given to the parts corresponding to the cases in FIG. 3, and the description thereof will be omitted as appropriate.
[0075]
　The server 52 shown in FIG. 4 has a communication unit 101, a control unit 102, and a recording unit 61.
[0076]
　The communication unit 101 transmits various information supplied from the control unit 102 to the client 54, and receives various information transmitted from the absolute coordinate position information encoder 51 and the client 54 and supplies the information to the control unit 102. Or
[0077]
　The control unit 102 controls the operation of the entire server 52. The control unit 102 has a communication control unit 111 and a transmission information generation unit 112.
[0078]
　The communication control unit 111 controls the communication with the absolute coordinate position information encoder 51 and the client 54 by the communication unit 101 by controlling the communication unit 101. The transmission information generation unit 112 generates various information to be transmitted to the client 54 by using the information such as the highest precision position-encoded data file recorded in the recording unit 61 as needed.
[0079]
Further
　, the client 54 is configured as shown in FIG. 5, for example. In FIG. 5, the parts corresponding to the case in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted as appropriate.
[0080]
　The client 54 shown in FIG. 5 has a communication unit 141, a control unit 142, and an output unit 143.
[0081]
　The communication unit 141 transmits various information supplied from the control unit 142 to the server 52, or receives various information transmitted from the server 52 and supplies the information to the control unit 142.
[0082]
　The control unit 142 controls the operation of the entire client 54. The control unit 142 includes a communication control unit 151, an absolute coordinate position information decoder 71, and a coordinate conversion unit 72.
[0083]
　The communication control unit 151 controls the communication with the server 52 by the communication unit 141 by controlling the communication unit 141. For example, the communication control unit 151 functions as an acquisition unit that controls the communication unit 141 to acquire the minimum precision quantization position information and additional bit information from the server 52.
[0084]
　The absolute coordinate position information decoder 71 decodes the encoded normalized position information by calculating information indicating the absolute position of the object based on the lowest precision quantization position information and additional bit information. It functions as a position information calculation unit to perform.
[0085]
　The output unit 143 outputs the polar coordinate position information of each object obtained by the coordinate conversion by the coordinate conversion unit 72 to the MPEG-H renderer 55.
[0086]

　Next, the coding (quantization) of the normalized position information of each object will be described.
[0087]
　For example, suppose that the space that is the target of the content, that is, the space where the user U12 and the object exist is a cube-shaped space, and at a certain time, the listener U12 is located at the center position in the space as shown in FIG. Suppose you were there. In FIG. 6, the same reference numerals are given to the parts corresponding to the cases in FIG. 3, and the description thereof will be omitted as appropriate.
[0088]
　FIG. 6 is a view in which the region R11 inside the outer square is a bird's-eye view of the three-dimensional space in which the listener U12 and the object exist from the positive direction to the negative direction of the z-axis of the xyz coordinate system. The center position of the dimensional space is the origin O of the xyz coordinate system. Also, here, the listener U12 is at the position of the origin O.
[0089]
　Further, it is assumed that the absolute distance is the absolute distance, which is half the length of one side of the cube, which is the space represented by the region R11, that is, the actual length from the origin O to the end of the cube. Here, the unit of the length of the absolute distance absoluteDistance is, for example, meters (m), and in the following, the information indicating the absolute distance absoluteDistance will also be described as the absolute distance information absoluteDistance.
[0090]
　There is a finding that the horizontal direction is recognized by human hearing as the same angle as the front angle if the angle is within a certain range on the left and right with respect to the front object, and this angle is called the perceptual limit angle θ. There is. Here, it is assumed that the perception limit angle θ is, for example, 1.5 degrees.
[0091]
　Therefore, for example, assuming that the angle formed by the straight line L11 and the straight line L12 is the perceptual limit angle θ, when the sound image is localized at an arbitrary position between the points PT11 and the point PT12, where is the sound image position? However, the listener U12 at the origin O perceives that the sound is being heard from the same direction. Therefore, in this case, for the object between the points PT11 and the point PT12, the normalized position information of the object is quantized with the distance from the point PT11 to the point PT12 as the quantization step width, and at that time. If the representative quantization value is a value indicating the position PtQ, the number of bits of the quantization position information can be reduced without making the sound image position shift.
[0092]
　In addition, since the horizontal tolerance of the listener U12 with respect to the direction of arrival of the sound is the perceptual limit angle θ, which is the angle information, the case where the distance between the listener U12 and the object is farther than when the distance between the listener U12 and the object is within 0.75 degrees to the left and right. The absolute width of the margin of error is larger.
[0093]
　In this technology, by using the human perception limit angle θ, the quantization accuracy of the quantization position information, that is, the quantization step width is changed according to the distance from the listener U12 to the object, so that the original sound image direction is obtained. The amount of information transmitted can be suppressed without feeling a difference in perception.
[0094]
　Specifically, the user U11 inputs the number of objects nObj, the absolute distance information absoluteDistance, the minimum distance information, the normalized position information of each object, and the perceptual limit angle θ to the absolute coordinate position information encoder 51.
[0095]
　Here, the number of objects nObj is the number of objects existing in the space. In the following, it is assumed that the space targeted for the content has a cube shape, and the center position of the cube is the origin O of the xyz coordinate system.
[0096]
　The minimum distance information is information indicating the minimum possible distance MinDist as the distance from the listener U12 to the object.
[0097]
　The unit of the minimum distance MinDist is, for example, the same meter (m) as the absolute distance absolute Distance. Such a minimum distance MinDist is determined so that the listener U12 and the object do not overlap, for example, in consideration of the size of the head of the listener U12. Of course, it is also possible to localize the sound image of the object at the position of the listener U12 with the minimum distance MinDist = 0. In the following, the minimum distance information indicating the minimum distance MinDist will also be referred to as the minimum distance information MinDist.
[0098]
　Further, the normalized position information of the object consists of the x-coordinate, the y-coordinate, and the z-coordinates Px (i), Py (i), and Pz (i) indicating the absolute position of the object in the xyz coordinate system. It is information, and i (where 0 ≤ i
　Next, specific processing performed in the content reproduction system will be described.
[0131]
　First, the coding process by the absolute coordinate position information encoder 51 and the file saving process by the server 52 will be described with reference to the flowchart of FIG. 7.
[0132]
　When the coding process is started, the absolute coordinate position information encoder 51 sets the number of objects nObj, the absolute distance information absoluteDistance, the minimum distance information MinDist, the normalized position information of each object, and the perception input by the user U11 in step S11. Obtain the limit angle θ.
[0133]
　In step S12, the absolute coordinate position information encoder 51 calculates the equation (1), and calculates the exponential index exp_index_high when the distance from the listener U12 to the object is the minimum distance MinDist.
[0134]
　In step S13, the absolute coordinate position information encoder 51 calculates the equation (2) for each object based on the normalized position information, the exponent index exp_index_high, the absolute distance information absoluteDistance, and the perceptual limit angle θ, and obtains the highest precision quantum. Calculate the mantissa parts Qpx_high (i), Qpy_high (i), and Qpz_high (i) of the quantized position information.
[0135]
　In step S14, the absolute coordinate position information encoder 51 encodes the sign bit of the normalized position information of each object and obtains the sign bit information sign_x (i), sign_y (i), and sign_z (i).
[0136]
　By obtaining the mantissa part and the sign bit information of the highest precision quantization position information by the above processing, the normalized position information of the object is encoded (quantized) with the highest precision.
[0137]
　In step S15, the absolute coordinate position information encoder 51 generates the highest precision position coding data file including the highest precision quantization position information of each object.
[0138]
　As a result, for example, the highest precision position-coded data file in the format shown in FIG. 8 is generated. That is, FIG. 8 is a diagram showing an example of the syntax of the highest precision position-coded data file.
[0139]
　In this example, the absolute distance information absoluteDistance is placed at the beginning of the highest-precision position-coded data file, followed by the exponential index exp_index_high. Further, following the exponential exponential index exp_index_high, information indicating the number of objects nObj indicated by the character "Num_of_Object" is arranged.
[0140]
　Furthermore, after the information indicating the number of objects nObj, the sign bit information sign_x (i), sign_y (i), and sign_z (i) of the highest precision quantization position information of each object are added by the number of objects nObj. The mantissa parts Qpx_high (i), Qpy_high (i), and Qpz_high (i) are arranged.
[0141]
　In the example of FIG. 8, ceil () indicating the number of bits of the mantissa part of the highest precision quantization position information indicates a ceiling function that outputs the minimum integer value equal to or greater than the argument.
[0142]
　In this way, the absolute distance information absoluteDistance, the power exponent index exp_index_high, the number of objects nObj, the sign bit information of the highest precision quantization position information of each object, and the mantissa part of the highest precision quantization position information of each object are included. Once the precision position-encoded data file is obtained, the process then proceeds to step S16 of FIG.
[0143]
　In step S16, the absolute coordinate position information encoder 51 transmits the generated highest-precision position-coded data file to the server 52 by wireless or wired communication or the like, and the coding process ends.
[0144]
　As will be described later, when the highest precision position-encoded data file is correctly saved in the server 52, a save completion notification to that effect is transmitted from the server 52, so that the absolute coordinate position information encoder 51 has been transmitted. Receive the save completion notification and display it as appropriate.
[0145]
　Further, when the highest precision position-coded data file is transmitted, the server 52 starts the file saving process.
[0146]
　That is, in step S31, the communication unit 101 of the server 52 receives the highest-precision position-coded data file transmitted from the absolute coordinate position information encoder 51 under the control of the communication control unit 111, and supplies it to the control unit 102.
[0147]
　In step S32, the control unit 102 supplies the highest precision position-coded data file supplied from the communication unit 101 to the recording unit 61 and stores it. As a result, the highest precision position-coded data file is stored (recorded) in the recording unit 61.
[0148]
　After that, the communication control unit 111 controls the communication unit 101 to send a save completion notification to the effect that the highest precision position-coded data file has been correctly saved to the absolute coordinate position information encoder 51, and the file saving process ends. ..
[0149]
　As described above, the absolute coordinate position information encoder 51 encodes the normalized position information of the object with the highest accuracy, and the server 52 outputs the highest precision position coded data file including the highest precision quantized position information obtained as a result. Send to. Further, the server 52 stores the highest accuracy position-coded data file received from the absolute coordinate position information encoder 51.
[0150]
　By doing so, the server 52 can generate the quantization position information of arbitrary quantization accuracy from the highest precision quantization position information in response to the request of the client 54 and transmit it to the client 54.
[0151]
　As a result, the client 54 obtains the polar coordinate position information of each object to reduce the processing load on the content distribution side such as the server 52 and the absolute coordinate position information encoder 51, and the highest precision quantization position information is directly transmitted to the client 54. The amount of information transmitted can be reduced as compared with the case of transmission.
[0152]
When the
　highest precision position coded data file is saved in the server 52, the client 54 receives the quantized position information of each object for the content from the server 52. Will be able to. Hereinafter, the processing performed when the client 54 acquires the quantization position information from the server 52 will be described. That is, the position information acquisition process by the client 54 and the position information transmission process by the server 52 will be described below with reference to the flowchart of FIG.
[0153]
　When the position information acquisition process is started by the client 54, in step S61, the communication unit 141 transmits the object number transmission request to the server 52 by wireless or wired communication or the like under the control of the communication control unit 151.
[0154]
　Here, the object number transmission request is information to request the transmission of the object number notification information indicating the number of objects constituting the content, that is, the number of objects existing in the space.
[0155]
　When the object number transmission request is transmitted, the server 52 starts the position information transmission process. That is, in step S81, the communication unit 101 receives the object number transmission request transmitted from the client 54 according to the control of the communication control unit 111, and supplies it to the control unit 102.
[0156]
　Then, the transmission information generation unit 112 refers to the highest precision position-encoded data file recorded in the recording unit 61 to generate object number notification information indicating the number of objects nObj, and the communication control unit 111 is generated. The number of objects notification information is supplied to the communication unit 101.
[0157]
　In step S82, the communication unit 101 transmits the object number notification information supplied from the communication control unit 111 to the client 54 under the control of the communication control unit 111.
[0158]
　On the other hand, in the client 54, in step S62, the communication unit 141 receives the object number notification information transmitted from the server 52 according to the control of the communication control unit 151, and supplies the information to the control unit 142.
[0159]
　As a result, the client 54 can grasp the number of objects nObj in the content, and can prepare for the processing to be performed in the future according to the number of objects nObj.
[0160]
　The object number notification information can be, for example, a frame including header information in the format (syntax) shown in FIG.
[0161]
　In the example of FIG. 10, the header information includes absolute distance information absoluteDistance and information indicating the number of objects nObj indicated by the character "Num_of_Object". The header information shown in FIG. 10 may be added to all the signals transmitted from the server 52 to the client 54, may be transmitted to the client 54 at an appropriate timing such as at the time of initialization, or may be periodically transmitted. May be transmitted to the client 54.
[0162]
　When the number of objects nObj is specified, the communication control unit 151 generates a transmission request requesting the server 52 to transmit the minimum precision quantization position information, and supplies the transmission request to the communication unit 141.
[0163]
　Here, an example in which the low-precision quantization position information first acquired from the server 52 by the client 54 is the lowest-precision quantization position information will be described, but what if the quantization accuracy is lower than the highest precision? It may be low-precision quantization position information with high quantization accuracy.
[0164]
　In step S63, the communication unit 141 transmits the transmission request of the lowest precision quantized position information supplied from the communication control unit 151 to the server 52 according to the control of the communication control unit 151.
[0165]
　Then, in the server 52, in step S83, the communication unit 101 receives the transmission request of the minimum precision quantization position information transmitted from the client 54 and supplies it to the control unit 102 according to the control of the communication control unit 111.
[0166]
　In step S84, the transmission information generation unit 112 refers to the highest precision position-coded data file recorded in the recording unit 61 in response to the transmission request supplied from the communication unit 101, and refers to the lowest precision quantization position information. Generate the mantissa part of.
[0167]
　Specifically, for example, the transmission information generation unit 112 may use the mantissas Qpx_high (i), Qpy_high (i), and Qpz_high (i) of the highest-precision quantized position information included in the highest-precision position-encoded data file for each object. ) Is extracted.
[0168]
　Then, the transmission information generation unit 112 increases the mantissa part Qpx_high (i), Qpy_high (i), by the difference between the power exponential part index exp_index_high and the lowest precision power exponential part index exp_index = 0, which has the lowest quantization accuracy. And Qpz_high (i) are shifted to Qpx_low (i), Qpy_low (i), and Qpz_low (i), which are the mantissas of the x-coordinate, y-coordinate, and z-coordinate indicating the lowest precision absolute position.
[0169]
　In other words, by extracting information for the number of bits corresponding to the exponential index exp_index, which should be the lowest precision, from the MSB (Most Significant Bit) side (most significant bit side) of the mantissa part of the highest precision quantization position information. , The mantissa part of the lowest precision quantization position information can be obtained.
[0170]
　For example, if the value of the exponential exponential index exp_index_high is 9, the information obtained by removing the information for the lower 9 bits in the mantissa Qpx_high (i) by the shift process for the mantissa Qpx_high (i) is the lowest. It is the mantissa part Qpx_low (i) of the x-coordinate of the accuracy absolute position.
[0171]
　Further, the transmission information generation unit 112 keeps the sign bit information sign_x (i), sign_y (i), and sign_z (i) of the highest precision quantization position information included in the highest precision position coding data file as they are at least. It is the sign bit information of the precision quantization position information. This is because the sign bit is the same regardless of the quantization accuracy.
[0172]
　In step S85, the transmission information generation unit 112 includes the mantissa parts Qpx_low (i), Qpy_low (i), and Qpz_low (i) obtained in the process of step S84, and the sign bit information sign_x (i), sign_y (i). , And sign_z (i) to generate the lowest precision quantized position information.
[0173]
　As a result, for example, the lowest precision quantization position information shown in FIG. 11 can be obtained. More specifically, FIG. 11 shows an example of a bitstream syntax that includes the least accurate quantization position information for each object.
[0174]
　In this example, for each object for the number of objects nObj, the sign bit information sign_x (i), sign_y (i), and sign_z (i) of the minimum precision quantization position information and each coordinate of the minimum precision quantization position information The mantissa Qpx_low (i), Qpy_low (i), and Qpz_low (i) are stored in the bitstream.
[0175]
　When the minimum precision quantization position information is obtained in this way, the communication control unit 111 supplies the minimum precision quantization position information of each object to the communication unit 101.
[0176]
　In step S86, the communication unit 101 transmits the minimum precision quantization position information of each object supplied from the communication control unit 111 to the client 54 under the control of the communication control unit 111, and the position information transmission process ends.
[0177]
　Here, FIG. 12 shows a specific example in which the coordinates of one axis of the normalized position information of a certain object are encoded.
[0178]
　In FIG. 12, the perceptual limit angle θ is 1.5 degrees, and the permissible error angle determined by the perceptual limit angle θ is 0.75 degrees. The absolute distance absolute Distance is 30 m, and the coordinates of the normalized position information are 0.1.
[0179]
　In the example of FIG. 12, the binary value and the like of the mantissa corresponding to each quantization accuracy of the coordinate value 0.1, that is, the binary value and the like are shown.
[0180]
　That is, the "1/2 exponential index" indicates the exponential exponential index exp_index, and the larger the value of the exponential exponential index exp_index, the higher the quantization accuracy.
[0181]
　In particular, here, the value of the exponent index exp_index_high, which should have the highest quantization accuracy, is "9", and the value of the exponent index exp_index, which should have the lowest quantization accuracy, is "0". ing.
[0182]
　In addition, the "distance from the listener to the object" is such that the two positions separated by the quantization step width of the quantization accuracy corresponding to the power exponent index exp_index are separated by the perceptual limit angle θ when viewed from the listener U12. It shows the distance from the listener U12 to the object when it is in position.
[0183]
　The "quantization step width" indicates the quantization step width corresponding to the exponential exponential index exp_index.
[0184]
　The "real number quantization value" is a real value when the coordinate value "0.1" of the normalized position information is quantized by the quantization step width corresponding to the power exponent index exp_index.
[0185]
　The "quantized bit number" indicates the number of bits of the mantissa part of the normalized normalized position information, and the "binary binary" indicates the binary value of the mantissa part of the normalized normalized position information (binary binary value). Binary binary value) is shown, and "integerized quantization value" shows the value of the mantissa part (integer value). That is, the value indicated by the "integerized quantization value" is the value of the mantissa part of the quantized normalized position information, and the binary value of that value is the value indicated by the "binary binary".
[0186]
　In particular, here, when the value of the exponent index exp_index is 9, the integer of the value indicated by the "real quantized value" is the integer of the mantissa of the quantized normalized position information. It is said to be a quantized value.
[0187]
　On the other hand, for those with a power exponential index exp_index value of 8 to 0, those mantissas extract a part of the binary value of the mantissa with a power exponential index exp_index value of 9. It has become the one obtained.
[0188]
　For example, the value obtained by extracting the upper 7 bits of the binary value of the mantissa part where the value of the exponent exponent index exp_index is 9 is the binary value of the mantissa part where the value of the exponential exponent index exp_index is 0. ..
[0189]
　Here, in order to make the figure easier to see, "0000" on the MSB side is omitted in the binary value part of the mantissa.
[0190]
　Further, "Position after decoding" indicates the coordinate value of the normalized position information obtained by decoding based on the mantissa part of the quantized normalized position information, that is, the value indicated by the "binary binary". ing.
[0191]
　In this example, since the coordinate value of the normalized position information to be quantized (encoded) is "0.1", it is ideal that the coordinate value of the normalized position information after decoding is "0.1". However, here, the smaller the exponential index exp_index is, the lower the quantization accuracy is. Therefore, the lower the quantization accuracy is, the larger the error is in the coordinate values ​​after decoding.
[0192]
　At the time of coding (quantization) of normalized position information, the number of quantization bits is determined for the exponential exponent index exp_index, and the mantissa part of the number of quantization bits, that is, the binary binary value of the quantization value of the coordinate value is can get.
[0193]
　Comparing the mantissa in each exponent index exp_index, the number of quantization bits increases as the value of the exponent index exp_index increases, and the mantissa has a value in the LSB (Least Significant Bit) direction, that is, in the least significant bit direction. You can see that it will be added.
[0194]
　This means that the larger the exponential exponential index exp_index, the higher the quantization accuracy of the mantissa. Then, if only the information with high quantization accuracy, that is, the formal part of the highest-precision quantization position information is retained, only the information on the LSB side of the formal part is removed, and no new quantization calculation is performed. It is also possible to obtain the improper part of the low-precision quantization position information.
[0195]
　Here, the quantization step width step corresponding to the exponential exponential index exp_index is as shown in the following equation (6).
[0196]
[Number 6]

[0197]
　Further, the number of quantization bits of the mantissa corresponding to the exponential exponential index exp_index can be obtained by calculating ceil (log2 (1 / step + 1)) using the quantization step width step. Note that ceil () is a ceiling function.
[0198]
　Therefore, for example, when the value of the exponential exponential index exp_index is "0", the number of quantization bits is 7 bits.
[0199]
　Now, for example, assume that the value of the exponential exponential index exp_index_high is "9". In this case, the difference between the highest precision exponential index exp_index_high = 9 and the lowest precision exponential index exp_index = 0 is 9.
[0200]
　Therefore, the mantissa part of the coordinates of the lowest precision quantization position information is obtained by removing the lower bits of the mantissa part "0000110100111011" of the coordinates of the highest precision quantization position information by 9 bits, which is the difference between the exponent index parts. The 7-bit value "0000110" is obtained.
[0201]
　In other words, when the exponent index exp_index, which should be the lowest precision, is 0, the number of quantization bits is 7, so if the upper 7 bits of the mantissa part of the coordinates of the highest precision quantization position information are extracted. , The mantissa part of the coordinates of the lowest precision quantization position information will be obtained.
[0202]
　Returning to the description of the flowchart of FIG. 9, when the minimum precision quantization position information is transmitted by the server 52, the client 54 performs the process of step S64.
[0203]
　In step S64, the communication unit 141 receives the minimum precision quantization position information transmitted from the server 52 according to the control of the communication control unit 151, and supplies it to the control unit 142. That is, the communication control unit 151 acquires the minimum precision quantization position information.
[0204]
　When the minimum precision quantization position information is received, the absolute coordinate position information decoder 71 selects each object for the number of objects nObj one by one as the object to be processed, and selects the minimum precision absolute position of those objects. calculate.
[0205]
　That is, in step S65, the absolute coordinate position information decoder 71 has the equation (4) based on the known perception limit angle θ and the absolute distance information absolute Distance included in the header information such as the frame received from the server 52. Perform the same calculation to calculate the quantization step width. Here, since the value of the exponential exponential index exp_index with the lowest accuracy is 0, the quantization step width is calculated by substituting 0 for the value of the exponential exponential index exp_index_sel in equation (4).
[0206]
　In step S66, the absolute coordinate position information decoder 71 decodes the sign bit information sign_x (i), sign_y (i), and sign_z (i) of the minimum precision quantization position information received in step S64 for the object to be processed. do. As a result, the sign bit information sign_x_val (i), sign_y_val (i), and sign_z_val (i) after decoding are obtained.
[0207]
　In step S67, the absolute coordinate position information decoder 71 describes the quantization step width obtained in step S65 and the sign bit information sign_x_val (i), sign_y_val (i), and sign_z_val obtained in step S66 for the object to be processed. The lowest precision absolute position is calculated based on (i) and the mantissas Qpx_low (i), Qpy_low (i), and Qpz_low (i) of the lowest precision quantized position information received in step S64.
[0208]
　That is, the absolute coordinate position information decoder 71 performs the same calculation as the above-mentioned equation (5), and indicates the decoded minimum accuracy absolute position, the x-coordinate Dtx (i), the y-coordinate Dty (i), and the z-coordinate. Obtain the decoding minimum accuracy normalized position information consisting of Dtz (i).
[0209]
　Specifically, in the equation (5), the quantization step width obtained in step S65 is substituted for the quantization step width step_dec, and the Qpx_sel (i), Qpy_sel (i), and Qpz_sel (i) are replaced. The mantissa parts Qpx_low (i), Qpy_low (i), and Qpz_low (i) are substituted. Further, as the absolute distance information absolute Distance, the one received from the server 52 is used. As a result, the x-coordinate Dpx (i), the y-coordinate Dpy (i), and the x-coordinate Dtx (i), the y-coordinate Dty (i), and the z-coordinate Dtz (i) corresponding to the z-coordinate Dpz (i) are obtained. Be done.
[0210]
　The decoding minimum accuracy normalized position information including the x-coordinate Dtx (i), the y-coordinate Dty (i), and the z-coordinate Dtz (i) obtained in this manner is provisional decoding normalized position information. The process of steps S65 to S67 described above is a process of decoding the lowest-precision quantization position information.
[0211]
　In step S68, the absolute coordinate position information decoder 71 determines whether or not all the objects have been processed as the objects to be processed.
[0212]
　If it is determined in step S68 that all the objects have not been processed yet, the process returns to step S66, and the above-described process is repeated. In this case, an object that has not yet been processed is selected as the next object to be processed, and the minimum decoding accuracy normalized position information is obtained.
[0213]
　On the other hand, if it is determined in step S68 that all the objects have been processed, the position information acquisition process ends.
[0214]
　As described above, the client 54 receives the minimum precision quantization position information from the server 52, performs decoding processing, and obtains the decoding minimum accuracy normalized position information. Further, the server 52 generates the minimum precision quantization position information in response to the request of the client 54 and transmits it to the client 54.
[0215]
　By doing so, it is possible to reduce the amount of information transmitted between the server 52 and the client 54 as compared with the case where the highest-precision quantized position information is exchanged.
[0216]
　Here, an example in which only the highest-precision quantized position information is recorded in the server 52 in advance, and the lowest-precision quantized position information to be transmitted (transmitted) to the client 54 is generated based on the highest-precision quantized position information. Was explained. However, the quantization position information of each quantization accuracy may be held in advance in the server 52, and the required quantization position information of the quantization accuracy may be read out and transmitted to the client 54.
[0217]

　By the way, when the position information acquisition process described with reference to FIG. 9 is performed, the decoding minimum accuracy normalized position information can be obtained for each object. ..
[0218]
　Whether or not the minimum precision quantization position information, that is, the decoding minimum precision normalized position information is sufficiently accurate as the quantization position information indicating the absolute position of the object in the space, is determined from the listener U12. It can be specified by the distance to the position indicated by the normalized position information.
[0219]
　Here, the quantized position information with sufficient accuracy is the direction of the position indicated by the normalized position information seen from the listener U12 and the direction of the position indicated by the quantized position information seen from the listener U12. The angle of formation is θ / 2 or less. In other words, from the perspective of the listener U12, the position indicated by the quantized position information is located within the range of the perceptual limit angle θ centered on the position indicated by the normalized position information.
[0220]
　Since the decryption minimum accuracy normalized position information indicates the position of the object in space, although it is not accurate, if the decoding minimum accuracy normalized position information is used, the listener U12 to the object in space is large. You can get another distance.
[0221]
　Therefore, the client 54 has sufficient quantization accuracy for the minimum accuracy quantization position information for each object based on the highly accurate listener position information measured by GPS or the like and the decoding minimum accuracy normalized position information. It is possible to specify whether or not the quantization position information is sufficient and the quantization position information is sufficient.
[0222]
　When the minimum precision quantization position information is not sufficient quantization accuracy, the client 54 acquires additional bit information from the server 52 to obtain decoding normalization position information with sufficient accuracy. Hereinafter, the processing performed by the client 54 and the server 52 in such a case will be described. That is, the additional bit information acquisition process by the client 54 and the additional bit information transmission process by the server 52 will be described below with reference to the flowchart of FIG.
[0223]
　When the additional bit information acquisition process is started in the client 54, the absolute coordinate position information decoder 71 calculates the distance ObjectDistance from the listener U12 to the object for each object in step S121.
[0224]
　Specifically, the Euclidean distance from the listener U12 to the object in the space is calculated as the distance Object Distance based on the listener position information supplied from the listener position acquisition device 53 and the decoding minimum accuracy normalized position information. Will be done.
[0225]
　In step S122, the absolute coordinate position information decoder 71 compares the distance distance determined with respect to the power exponential index exp_index with the distance ObjectDistance while changing the value of the power exponential index exp_index from 0 to a larger value. ..
[0226]
　That is, for example, the absolute coordinate position information decoder 71 calculates the distance distance corresponding to the exponential exponential index exp_index by calculating the following equation (7) based on the exponential exponential index exp_index and the absolute distance information absoluteDistance.
[0227]
[Number 7]

[0228]
　Then, the absolute coordinate position information decoder 71 compares the obtained distance distance with the distance ObjectDistance, and determines whether or not the distance distance is equal to or less than the distance ObjectDistance.
[0229]
　The absolute coordinate position information decoder 71 specifies the smallest exponential index exp_index whose distance distance is less than or equal to the distance ObjectDistance while increasing the value of the exponential exponential index exp_index by 1 until the distance distance becomes less than or equal to the distance ObjectDistance. ..
[0230]
　Hereinafter, the smallest exponential index exp_index in which the distance distance is equal to or less than the distance ObjectDistance is also referred to as a power exponential index exp_index_cover.
[0231]
　The exponential exponential index exp_index_cover is the smallest value of the exponential exponential index exp_index of the above-mentioned sufficiently accurate quantization position information.
[0232]
　When the exponential exponential index exp_index_cover is specified for each object, the process proceeds to step S123.
[0233]
　In step S123, the absolute coordinate position information decoder 71 compares the exponential index exp_index_cover for each object with the exponential index exp_index for the lowest precision quantization position information, and identifies the objects with insufficient quantization accuracy. conduct.
[0234]
　Here, the exponential exponential index exp_index_cover is the exponential exponential index exp_index with the minimum required quantization accuracy. Therefore, an object whose exponential exponential index exp_index of the lowest precision quantization position information is less than the exponential exponential index exp_index_cover is considered to have insufficient quantization accuracy.
[0235]
　In particular, since the value of the exponent index exp_index of the lowest precision quantization position information is 0 here, the object having the exponent index exp_index_cover value of 1 or more has insufficient quantization accuracy and additional bits. It is said to be an object that requires information.
[0236]
　By such identification processing, an object whose quantization accuracy is insufficient and requires additional bit information is identified, and such an object is required from among a plurality of predetermined quantization accuracys. Quantization accuracy has been determined (specified). The required quantization accuracy here is the quantization accuracy (quantization step width) corresponding to the exponential exponential index exp_index_cover.
[0237]
　In step S124, the absolute coordinate position information decoder 71 finally decodes and normalizes the decoding minimum accuracy normalization position information obtained for the minimum accuracy quantization position information whose exponential exponential index exp_index is equal to or greater than the exponential index exp_index_cover. Use as location information.
[0238]
　That is, for an object whose exponential exponential index exp_index is equal to or greater than the exponential exponential index exp_index_cover, the decoding minimum accuracy normalized position information with sufficient quantization accuracy has been obtained. Therefore, the x-coordinate Dtx (i), y-coordinate Dty (i), and z-coordinate Dtz (i) of the decoding minimum accuracy normalized position information are directly used as the x-coordinate Dpx (i), y-coordinate Dpy of the decoding normalized position information. (i) and z coordinate Dpz (i).
[0239]
　In step S125, the communication unit 141 transmits a transmission request for additional bit information for an object whose exponential exponential index exp_index is less than the exponential index exp_index_cover, that is, an object for which additional bit information is determined to be required.
[0240]
　For example, the absolute coordinate position information decoder 71 generates a transmission request for additional bit information, including the number of objects requesting transmission of additional bit information, the index extend_object_index (j) of the objects, and the exponent index extend_exp_index (j). ..
[0241]
　Here, the index extend_object_index (j) of the object is an index i that identifies an object that requests transmission of additional bit information, that is, an object whose exponential exponential index exp_index is less than the exponential exponential index exp_index_cover.
[0242]
　The exponential exponential index extend_exp_index (j) is the exponential exponential index exp_index with the final quantization accuracy required for the object indicated by the index extend_object_index (j). In this case, the value of the exponential exponential index exp_index_cover is used as it is as the value of the exponential index extend_exp_index (j).
[0243]
　As a result, for example, a transmission request in the format (syntax) shown in FIG. 14 can be obtained.
[0244]
　In this example, information indicating the number of objects requesting transmission of additional bit information indicated by the character "num_of_resend_objects" is placed at the beginning of the transmission request.
[0245]
　After that, the index end_object_index (j) of the object and the exponential index end_exp_index (j) of the power are arranged as many as shown in num_of_resend_objects.
[0246]
　Returning to the description of FIG. 13, the communication control unit 151 supplies the transmission request of the additional bit information generated in this manner to the communication unit 141 and causes the communication unit 141 to transmit the transmission request.
[0247]
　When the request for transmitting the additional bit information is transmitted, the server 52 starts the process of transmitting the additional bit information.
[0248]
　That is, in step S161, the communication unit 101 receives the transmission request for the additional bit information transmitted from the client 54 according to the control of the communication control unit 111, and supplies it to the control unit 102.
[0249]
　In step S162, the transmission information generation unit 112 is requested to transmit in response to the transmission request supplied from the communication unit 101, that is, in response to the request from the client 54, which is the transmission destination of the lowest precision quantized position information. Generate additional bit information for the object.
[0250]
　Specifically, for example, the transmission information generation unit 112 describes the mantissa part Qpx_high (i), Qpy_high (i) of the highest precision quantized position information included in the highest precision position coding data file for the object indicated by the index extend_object_index (j). i) and Qpz_high (i) are extracted.
[0251]
　Then, the transmission information generation unit 112 shifts the mantissas Qpx_high (i), Qpy_high (i), and Qpz_high (i) by the difference between the exponential exponential index exp_index_high and the exponential exponential index extend_exp_index (j).
[0252]
　This removes the bits of the difference between the exponential exponential index exp_index_high on the lower bit side of the mantissa Qpx_high (i), Qpy_high (i), and Qpz_high (i) and the exponential exponential index extend_exp_index (j). , The mantissa part of the quantization position information of the exponential part index extend_exp_index (j) will be obtained.
[0253]
　The transmission information generation unit 112 removes as many bits as the number of bits of the mantissa part of the lowest precision quantization position information on the upper bit side from the mantissa part of the quantization position information of the exponential part index extend_exp_index (j) to be obtained. And use it as additional bit information.
[0254]
　This additional bit information is the difference information of the mantissa part of each of the x-coordinate, y-coordinate, and z-coordinate of the quantization position information of the power exponent index extend_exp_index (j) and the lowest precision quantization position information. Bit information Consists of Qpx_diff (j), Qpy_diff (j), and Qpz_diff (j).
[0255]
　For example, the additional bit information Qpx_diff (j) is the difference between the x-coordinate mantissa part of the quantization position information of the exponent index extend_exp_index (j) and the x-coordinate mantissa part Qpx_low (i) of the lowest precision quantization position information. Is.
[0256]
　For example, in the example shown in FIG. 12, it is assumed that the value of the exponential exponential index extend_exp_index (j) is 7.
[0257]
　In this case, since the exponential index exp_index_high of the highest precision quantized position information is 9, the difference between 9 and the exponential index extend_exp_index (j) = 7 is 2.
[0258]
　Also, by removing the lower 2 bits from the mantissa part "0000110100111011" of the highest precision quantized position information, the mantissa part "00001101001110" of the low precision quantized position information with a power exponent index extend_exp_index (j) = 7 Is obtained.
[0259]
　Further, since the number of bits of the mantissa part of the lowest precision quantization position information is 7 bits, the additional bit information "1001110" can be obtained by removing the upper 7 bits from the mantissa part "00001101001110". On the client 54 side, the additional bit information "1001110" obtained in this way is finally required by adding it to the lower bit side of the mantissa part "0000110" of the lowest precision quantization position information. The mantissa part "00001101001110" of the low-precision quantized position information in which the exponent part index extend_exp_index (j) = 7 is obtained.
[0260]
　When additional bit information is obtained for the object indicated by each index extend_object_index (j) by the above processing, the transmission information generation unit 112 generates difference data including the additional bit information.
[0261]
　As a result, for example, difference data in the format (syntax) shown in FIG. 15 can be obtained. In this example, the diff data contains as many additional bit information Qpx_diff (j), Qpy_diff (j), and Qpz_diff (j) as the number shown in num_of_resend_objects above.
[0262]
　In FIG. 15, the number of bits of each additional bit information is the number of bits for extend_exp_index (j).
[0263]
　Returning to the description of FIG. 13, the communication control unit 111 supplies the difference data including the additional bit information to the communication unit 101, and controls the transmission to the client 54.
[0264]
　In step S163, the communication unit 101 transmits the difference data including the additional bit information supplied from the communication control unit 111 to the client 54 under the control of the communication control unit 111, and the additional bit information transmission process ends.
[0265]
　Further, when the difference data is transmitted, the client 54 performs the process of step S126.
[0266]
　In step S126, the communication unit 141 receives the difference data transmitted from the server 52 and supplies the difference data to the control unit 142 under the control of the communication control unit 151. That is, the communication control unit 151 acquires the difference data including the additional bit information.
[0267]
　In step S127, the absolute coordinate position information decoder 71 calculates the equation (4) with the value of the exponential exponential index extend_exp_index (j) as the exponential exponential index exp_index_sel for the object indicated by each index extend_object_index (j). Calculate the quantization step width step_dec.
[0268]
　In step S127, the quantization step width step_dec is calculated for each object for which the quantization accuracy is determined to be insufficient in step S123, that is, for each object indicated by the index extend_object_index (j).
[0269]
　In step S128, the absolute coordinate position information decoder 71 uses the difference data supplied from the communication unit 141 for the object indicated by each index extend_object_index (j) to obtain the quantized position information of the power exponent index end_exp_index (j). Generate the mantissa.
[0270]
　That is, the absolute coordinate position information decoder 71 adds bit information included in the difference data on the lower bit side of the mantissa part Qpx_low (i), Qpy_low (i), and Qpz_low (i) of the lowest precision quantization position information. Add Qpx_diff (j), Qpy_diff (j), and Qpz_diff (j).
[0271]
　As a result, the mantissa part of each coordinate of the quantization position information of the exponential exponential index extend_exp_index (j) is obtained, and the mantissa part Qpx_sel (i), Qpy_sel (i), and Qpz_sel in which those mantissa parts are finally determined are obtained. It is said to be (i).
[0272]
　In step S129, the absolute coordinate position information decoder 71 calculates the decoding normalized position information of the object for the object indicated by each index extend_object_index (j).
[0273]
　Specifically, the quantization step width step_dec obtained in step S127, the absolute distance information absoluteDistance, the code bit information after decoding obtained in step S66 of FIG. 9, and the final determination obtained in step S128. Equation (5) is calculated based on the mantissa, and decoding normalization position information is calculated.
[0274]
　The process of steps S127 to S129 described above is a process of decoding the quantized position information obtained from the lowest precision quantized position information and the additional bit information. Further, by the above processing, the decoding normalization position information is obtained for all the objects corresponding to the number of objects nObj.
[0275]
　In step S130, the coordinate conversion unit 72 of the object as seen from the listener U12 in the space based on the decoding normalized position information and the listener position information supplied from the listener position acquisition device 53 for each object. Calculate polar coordinate position information indicating the position.
[0276]
　Then, the coordinate conversion unit 72 supplies the obtained polar coordinate position information to the output unit 143, and the output unit 143 outputs the polar coordinate position information to the MPEG-H renderer 55. When the output unit 143 outputs the polar coordinate position information of all the objects to the MPEG-H renderer 55, the additional bit information acquisition process ends.
[0277]
　When the additional bit information acquisition process is completed, the MPEG-H renderer 55 renders. That is, the MPEG-H renderer 55 renders based on the audio data of each object acquired from the server 52 or the like and the polar coordinate position information supplied from the output unit 143, and the sound image of the object is displayed at each position in the space. Generates localized playback audio data and outputs it to a playback system such as a speaker.
[0278]
　As described above, the client 54 acquires (receives) additional bit information from the server 52 for the object having insufficient quantization accuracy, and calculates the decoding normalization position information with sufficient accuracy. Further, the server 52 generates additional bit information in response to the request of the client 54 and transmits the additional bit information to the client 54.
[0279]
　By doing so, the client 54 can obtain the decoding normalized position information with sufficient accuracy with a smaller amount of information transmission than the case where the highest precision quantization position information is acquired from the server 52 from the beginning.
[0280]
　Moreover, since the processing for obtaining the required quantization accuracy and the processing for calculating the polar coordinate position information are all performed by the client 54, it is possible to reduce the processing load on the content distribution side such as the server 52 and the absolute coordinate position information encoder 51. can. In particular, the effect of reducing the processing load increases as the number of clients 54 connected to the server 52 increases.
[0281]
　In the client 54, the polar coordinate position information changes every time the position of the object or the listener U12 in the space changes during the reproduction of the content.
[0282]
　Therefore, the client 54 updates the polar coordinate position information when, for example, the listener position information of the listener U12 changes.
[0283]
　However, if the object is not moving in space and the listener U12 moves away from the object, it is not necessary to update the decoding normalization position information for that object. This is because, in addition to the object not moving, the accuracy required is less when the object is closer to the listener U12. That is, there is already sufficient accuracy of decoding normalization position information.
[0284]
　In such a case, for example, the communication control unit 151 of the client 54 controls the communication unit 141 to set the index i of the moving object and the object whose distance from the listener U12 is shortened. The server 52 is made to transmit the transmission request of the minimum precision quantization position information including the object. Then, in step S64 of FIG. 9, the communication unit 141 receives only the lowest precision quantization position information of the object of the index i of those objects from the server 52, and the client 54 performs the subsequent processing, and the polar coordinates. Location information is updated.
[0285]
　In addition, for non-moving objects whose distance from the listener U12 is short, the decryption normalized position information obtained by the previous processing and the new listener position information of the listener U12 are used. , The required quantization accuracy can be specified.
[0286]
　Therefore, in this case, if the client 54 performs the additional bit information acquisition processing of FIG. 13 for the object that does not move and the distance from the listener U12 is short, the minimum precision quantization position information is newly obtained. Decoding normalization position information with sufficient accuracy can be obtained without acquisition.
[0287]
　As described above, according to the present technology, it is possible to avoid the unilateral processing load on the content distribution side that occurs in 3D Audio from a free viewpoint and transmit information indicating the position of an object. In addition, since the appropriate quantization accuracy is specified according to the distance from the listener U12 to the object and the human perception limit angle θ, the difference from the original sound image direction is equal to or less than the perception limit. It is possible to transmit position information while suppressing the amount of transmission.
[0288]

　By the way, the series of processes described above can be executed by hardware or software. When a series of processes are executed by software, the programs that make up the software are installed on the computer. Here, the computer includes a computer embedded in dedicated hardware and, for example, a general-purpose personal computer capable of executing various functions by installing various programs.
[0289]
　FIG. 16 is a block diagram showing a configuration example of hardware of a computer that executes the above-mentioned series of processes programmatically.
[0290]
　In a computer, a CPU (Central Processing Unit) 501, a ROM (Read Only Memory) 502, and a RAM (Random Access Memory) 503 are connected to each other by a bus 504.
[0291]
　An input / output interface 505 is further connected to the bus 504. An input unit 506, an output unit 507, a recording unit 508, a communication unit 509, and a drive 510 are connected to the input / output interface 505.
[0292]
　The input unit 506 includes a keyboard, a mouse, a microphone, an image sensor, and the like. The output unit 507 includes a display, a speaker, and the like. The recording unit 508 includes a hard disk, a non-volatile memory, and the like. The communication unit 509 includes a network interface and the like. The drive 510 drives a removable recording medium 511 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory.
[0293]
　In the computer configured as described above, the CPU 501 loads the program recorded in the recording unit 508 into the RAM 503 via the input / output interface 505 and the bus 504 and executes the above-described series. Is processed.
[0294]
　The program executed by the computer (CPU 501) can be recorded and provided on a removable recording medium 511 as a package medium or the like, for example. Programs can also be provided via wired or wireless transmission media such as local area networks, the Internet, and digital satellite broadcasts.
[0295]
　In a computer, the program can be installed in the recording unit 508 via the input / output interface 505 by mounting the removable recording medium 511 in the drive 510. Further, the program can be received by the communication unit 509 and installed in the recording unit 508 via a wired or wireless transmission medium. In addition, the program can be pre-installed in the ROM 502 or the recording unit 508.
[0296]
　The program executed by the computer may be a program that is processed in chronological order according to the order described in this specification, or may be a program that is processed in parallel or at a necessary timing such as when a call is made. It may be a program in which processing is performed.
[0297]
　Further, the embodiment of the present technology is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present technology.
[0298]
　For example, the present technology can have a cloud computing configuration in which one function is shared by a plurality of devices via a network and jointly processed.
[0299]
　Further, each step described in the above-mentioned flowchart can be executed by one device or can be shared and executed by a plurality of devices.
[0300]
　Further, when a plurality of processes are included in one step, the plurality of processes included in the one step can be executed by one device or shared by a plurality of devices.
[0301]
　Further, the present technology can also have the following configurations.
[0302]
(1)
　The first accuracy according to the position of the user, which acquires the low-precision position information of the first accuracy indicating the position of the object in the space where the user is and indicates the position of the object in the space. An
　information
　processing device including an acquisition unit for acquiring additional information for obtaining position information having a higher second accuracy, and a position information calculation unit for obtaining the position information based on the low-precision position information and the additional information. ..
(2) The
　position information calculation unit identifies the object that requires the additional information based on the user position information indicating the user's position and the low-precision position information, and the
　acquisition unit is 1 or
　The information processing apparatus according to (1), wherein the additional information is acquired for the object specified by the position information calculation unit among the plurality of objects .
(3) The
　position information calculation unit is based on the user position information and the low-precision position information for each object that requires the additional information, and the second position information of the position information is selected from a plurality of accuracy.
　The information processing apparatus according to (2), which determines the accuracy .
(4) The
　low-precision position information and the position information are information indicating the absolute coordinates of the position of the object in the space, and the
　user position information indicates the absolute coordinates of the position of the user in the space. Information
　The information processing device according to (2) or (3).
(5) The
　information according to
　(4), further comprising a conversion unit that converts the position information into polar coordinate information indicating the relative position of the object as seen by the user based on the position information and the user position information. Processing equipment.
(6) 　The information processing apparatus according to any one of (1) to (5),
　wherein the additional information is information on a difference between the position information and the low-precision position information
.
(7) 　The information processing device according to any one of (1) to (6),
　wherein the object is an audio object
.
(8) The
　information processing device
　acquires the first-precision low-precision position information indicating the position of the object in the space in which the user is located, and indicates the position of the object in the
　space according to the position of the user. An
　information
　processing method for acquiring additional information for obtaining position information having a second accuracy higher than the first accuracy, and obtaining the position information based on the low-precision position information and the additional information .
(9)
　Acquire the first-precision low-precision position information indicating the position of the object in the space where the user is, and obtain the first-precision low-precision position information.
　Obtaining additional information indicating the position of the object in the space to obtain the position information of the second accuracy higher than the first accuracy according to the position of the user, the
　low-precision position information and the said.
　A program that causes a computer to execute a process including a step of obtaining the position information based on additional information .
(10)
　The position of the object in the space is transmitted in response to a request from the destination of the low-precision position information by transmitting the low-precision position information of the first accuracy indicating the position of the object in the space where the user is. An information
　processing device including a communication unit for transmitting additional information for obtaining position information having a second accuracy higher than the first accuracy according to the position of the user .
(11) 　The information processing apparatus according to (10),
　wherein the low-precision position information and the position information are information indicating absolute coordinates of the position of the object in the space
.
(12)
　The information
　processing apparatus according to (10) or (11), wherein the additional information is information on a difference between the position information and the low-precision position information .
(13) 　By extracting a part of the highest-precision position information
　and a recording unit that records the highest-precision position information obtained by quantizing the information indicating the position of the object with the highest-precision quantization step width.
With a transmission information generator that generates the low-precision position information or the additional information
　The information processing apparatus according to (12).
(14) 　The information processing apparatus
　according to
(13), wherein the quantization step width is a value obtained by multiplying a power value of 1/2 by a constant .
(15) 　The information processing device according to any one of (10) to (14),
　wherein the object is an audio object
.
(16) The
　information processing device
　transmits first-precision low-precision position information indicating the position of an object in the space in which the user is located, and
　in response to a request from the destination of the low-precision position information , the information processing device in the space. An
　information processing method for transmitting additional information indicating the position of the object in order to obtain position information having a second accuracy higher than the first accuracy according to the position of the user .
(17)
　The first-precision low-precision position information indicating the position of the object in the space where the user is located is transmitted, and
　the position of the object in the space is received in response to a request from the destination of the low-precision position information.
　A program for causing a computer to execute a process including a step of transmitting additional information for obtaining position information having a second accuracy higher than the first accuracy according to the position of the user .
Code description
[0303]
　52 Server, 54 Client, 61 Recording unit, 71 Absolute coordinate position information decoder, 72 Coordinate conversion unit, 101 Communication unit, 102 Control unit, 141 Communication unit, 142 Control unit
The scope of the claims
[Claim 1]
　It is higher than the first accuracy according to the position of the user, which acquires the low-precision position information of the first accuracy indicating the position of the object in the space where the user is and indicates the position of the object in the space. An
　information
　processing device including an acquisition unit for acquiring additional information for obtaining a second -precision position information, and a position information calculation unit for obtaining the position information based on the low-precision position information and the additional information .
[Claim 2]
　The position information calculation unit identifies the object that requires the additional information based on the user position information indicating the user's position and the low-precision position information, and the
　acquisition unit may be one or more of the above- mentioned objects.
　The information processing device according to claim 1, wherein the additional information is acquired for the object specified by the position information calculation unit among the objects .
[Claim 3]
　The position information calculation unit determines the second accuracy of the position information from among a plurality of accuracy based on the user position information and the low-precision position information for each object that requires the additional information.
　The information processing device according to claim 2.
[Claim 4]
　The low-precision position information and the position information are information indicating the absolute coordinates of the position of the object in the space, and the
　user position information is information indicating the absolute coordinates of the position of the user in the space.
　The information processing device according to claim 2.
[Claim 5]
　The information
　processing apparatus according to claim 4, further comprising a conversion unit that converts the position information into polar coordinate information indicating the relative position of the object as seen by the user based on the position information and the user position information .
[Claim 6]
　The information
　processing apparatus according to claim 1, wherein the additional information is information on a difference between the position information and the low-precision position information .
[Claim 7]

　The information processing device according to claim 1, 　wherein the object is an audio object .
[Claim 8]
　The information processing device
　acquires low-precision position information of the first accuracy indicating the position of the object in the space in which the user is located, and indicates the position of the object in the
　space. An
　information
　processing method for acquiring additional information for obtaining position information having a second accuracy higher than the accuracy of the above , and obtaining the position information based on the low-precision position information and the additional information .
[Claim 9]
　It
　is higher than the first accuracy according to the position of the user , which acquires the low-precision position information of the first accuracy indicating the position of the object in the space where the user is and indicates the position of the object in the space. 　A program that acquires additional information for obtaining second
　-precision position information, and
causes a computer to execute a process including a step of obtaining the low-precision position information and the position information based on the additional information .
[Claim 10]
　First-precision low-precision position information indicating the position of an object in the space in which the user is located is transmitted, and the position of the object in the space is indicated in response to a request from the destination of the low-precision position information. An information
　processing device including a communication unit that transmits additional information for obtaining position information having a second accuracy higher than the first accuracy according to the position of the user .
[Claim 11]

　The information processing apparatus according to claim 10, 　wherein the low-precision position information and the position information are information indicating absolute coordinates of the position of the object in the space .
[Claim 12]
　The information
　processing device according to claim 10, wherein the additional information is information on a difference between the position information and the low-precision position information .
[Claim 13]
　The low precision is obtained by
　extracting a part of the highest precision position information and a recording unit that records the highest precision position information obtained by quantizing the information indicating the position of the object with the highest precision quantization step width. The information
　processing apparatus according to claim 12, further comprising a transmission information generation unit that generates location information or the additional information .
[Claim 14]

　The information processing apparatus 　according to claim 13, wherein the quantization step width is a value obtained by multiplying a power value of 1/2 by a constant .
[Claim 15]

　The information processing device according to claim 10, 　wherein the object is an audio object .
[Claim 16]
　The information processing device
　transmits first-precision low-precision position information indicating the position of an object in the space in which the user is located, and
　in response to a request from the destination of the low-precision position information, the object in the space. An
　information processing method for transmitting additional information indicating the position of the user to obtain position information having a second accuracy higher than the first accuracy according to the position of the user .
[Claim 17]
　First-precision low-precision position information indicating the position of an object in the space in which the user is located is transmitted, and
　the position of the object in the space is indicated in response to a request from the destination of the low-precision position information.
　A program that causes a computer to perform a process including a step of transmitting additional information for obtaining position information having a second accuracy higher than the first accuracy according to the position of the user .