[0001]The present disclosure, the decoding device, method decoding, and a program, suitable decoding device, decoding method used in case of switching the output between the audio encoded bit stream reproducing timing are synchronized, and a program.
Background technique
[0002]For example, movies and news, in the content, such as sports coverage, more than one language to the video (for example, Japanese and English) while others voice of are prepared, in this case, the plurality of audio reproduction timing is synchronized the thing was.
[0003]
　Hereinafter, sound reproduction timing are synchronized, it is prepared as the audio encoded bit stream, respectively, the audio encoded bit stream, AAC containing at least MDCT (Modified Discrete Cosine Transform) processing (Advanced Audio Coding), etc. assuming that it is variable-length encoded by the encoding process. Incidentally, MPEG-2 AAC audio encoding method comprising the MDCT process is adopted in terrestrial digital television broadcasting (for example, see Non-Patent Document 1).
[0004]
　Figure 1 shows simplified examples of a conventional configuration of a decoding apparatus that performs decoding and encoding device that performs encoding processing with respect to sound source data, the audio encoded bit stream outputted from the encoding device ing.
[0005]
　Encoding device 10 includes a MDCT section 11, quantizer 12 and variable length coding unit 13,.
[0006]
　Source MDCT section 11 divides the source data for audio input from the previous stage into frames having a predetermined time width, by performing the MDCT process as the frame to the front and rear overlap, was a value in the time domain converts the data into a frequency-domain value is output to the quantization unit 12. Quantization unit 12 outputs to the variable length coding unit 13 inputs from the MDCT unit 11 quantizes. Variable length coding unit 13, generates an audio encoded bit stream by variable length coding the quantized value, and outputs.
[0007]
　Decoding unit 20, for example, the receiving apparatus that receives a content broadcast or distributed, is intended to be mounted on a playback device for reproducing content recorded on a recording medium, decoding unit 21, inverse quantization unit 22, and a IMDCT (Inverse MDCT) unit 23.
[0008]
　Decoding unit 21 corresponding to the variable length coding unit 13 performs a decoding process frame by frame to the audio encoded bit stream, and outputs the decoded result to the inverse quantization unit 22. Inverse quantization unit 22 corresponding to the quantization unit 12 performs inverse quantization on the decoded result, and outputs the processing result to the IMDCT unit 23. IMDCT unit 23 corresponding to the MDCT section 11 by performing the IMDCT process on the inverse quantization results to reconstruct the PCM data corresponding to the source before encoding data. It will be described in detail IMDCT process by the IMDCT unit 23.
[0009]
　Figure 2 shows an IMDCT process by the IMDCT unit 23.
[0010]
　As shown in the figure, the IMDCT unit 23, the two frames (Frame # 1 and Frame # 2) audio encoded bit stream (the inverse quantization result of) the BS1-1 and BS1-2 be around a target obtaining IMDCT-OUT # 1-1 as the inverse transformation result by performing IMDCT processing. The inverse conversion results by performing IMDCT processing two frames which overlap with the a (Frame # 2 and Frame # 3) Audio encoded bit stream (the inverse quantization result of) the BS1-2 and BS1-3 targeting obtain the IMDCT-OUT # 1-2 as. Further, IMDCT-OUT # 1-1 and by IMDCT-OUT # 1-2 to overlap-add the, Frame # PCM1-2 fully reconstructed is a PCM data corresponding to 2.
[0011]
　By the same method, PCM data 1-3 corresponding to Frame # 3 later, completely reconstructed also ....
[0012]
　However, the term "complete" as used herein is intended to mean that can reconfigure the PCM data, including the processing up to overlap-add, which means that the source data is reproduced 100% is not.
CITATION
Non-Patent Document
[0013]
Non-Patent Document 1: ARIB STD-B32 2.2 version Heisei 27 years July 29
Summary of the Invention
Problems that the Invention is to Solve
[0014]
　Here, the decode switches unless promptly as possible plurality of audio encoded bit stream reproduction timing is synchronized, considering that output.
[0015]
　3, by a conventional technique shows a state when switching from the first audio encoded bit stream reproduction timing is synchronized to the second audio encoded bit stream.
[0016]
　As shown in the figure, Frame # 2 and Frame # as boundary position switch between the 3, when switching from the first audio encoded bit stream to the second audio encoded bit stream, a first audio coding until PCM1-2 corresponding to Frame # 2 is decoded and output the bit-stream. Then, a second audio encoded bit stream after switching PCM2-3 later corresponding to Frame # 3 is decoded and output.
[0017]
　Meanwhile, as described with reference to FIG. 2, in order to obtain a PCM1-2 requires a reverse conversion result IMDCT-OUT # 1-1 and IMDCT-OUT # 1-2. Similarly, in order to obtain a PCM2-3 requires a reverse conversion result IMDCT-OUT # 2-2 and IMDCT-OUT # 2-3. Therefore, in order to perform the switching illustrated in the figure, the period of Frame # 3 from Frame # 2 is in parallel decoding processing including IMDCT process on the first and second audio encoded bit stream It must be performed at the same time.
[0018]
　However, to run concurrently in parallel decoding processing including IMDCT processing, to realize a decoding process including an IMDCT processing in hardware, similarly configured hardware must be more than one, Ya of the circuit scale and the cost is high.
[0019]
　Also, if implemented by software decoding processing including IMDCT processing, sound interruption by the processing capability of the CPU, since problems such as abnormal noise can occur, it requires a high-performance CPU to prevent this, also cost it becomes high.
[0020]
　The present disclosure has been made in view of such circumstances, without causing the expansion and cost of the circuit scale, the decode switches unless promptly as possible plurality of audio encoded bit stream reproduction timing is synchronized it is intended to allow the output.
Means for Solving the Problems
[0021]
　Decoding apparatus according to the embodiment of the present disclosure includes an acquisition unit that acquires a plurality of audio encoded bit stream in which a plurality of source data reproduction timing is synchronized is coded after the MDCT processing in frame units respectively, determining the boundary position for switching the output of said plurality of audio encoded bit stream, selectively supplies to the decoding processing unit in accordance with one on the boundary position of the acquired plurality of audio encoded bit stream a selecting section for one of the plurality of audio encoded bit stream input via the selection unit, and the decoding processing unit for performing a decoding process including an IMDCT processing corresponding to the MDCT processing wherein the decoding unit is over in the IMDCT processing corresponding respectively to the front and rear of the frame of the boundary position Tsu omitted up addition.
[0022]
　Decoding apparatus according to the embodiment of the present disclosure, further include a fade processing unit to perform the fade processing on decoding results before and after the frame of the overlap-add is omitted the boundary position by the decoding unit it can.
[0023]
　The fade processing unit, performs fade-out processing on the decoding result of the previous frame of the boundary position where the overlap-add by the decoding processing unit is omitted, the decoding processing result of the frame following said boundary position it is possible to perform the fade-in process with respect to.
[0024]
　The fade processing unit, performs fade-out processing on the decoding result of the previous frame of the boundary position where the overlap-add by the decoding processing unit is omitted, the decoding processing result of the frame following said boundary position it is possible to perform the muting process on.
[0025]
　The fade processing unit performs muting processing for the decoding result of the previous frame of the boundary position where the overlap-add by the decoding processing unit is omitted, the decoding processing result of the frame following said boundary position it is possible to perform the fade-in process with respect to.
[0026]
　The selection unit may determine the boundary position based on the switching optimal position flag the set in the supply side of the plurality of audio encoded bit stream, it is added to each frame.
[0027]
　The switching optimum position flag, the supply side of the audio encoded bit stream can be as has been set based on the energy or the context of the source data.
[0028]
　The selection unit may determine the boundary position based on the information about the gain of the plurality of audio encoded bit stream.
[0029]
　Decoding method according to an aspect of the disclosure, in the decoding method of the decoding apparatus, according to the decoding device, a plurality of the plurality of sources data reproduction timing is synchronized is coded after the MDCT processing in frame units respectively an acquisition step of acquiring the audio encoded bit stream, a determination step of determining a boundary position for switching the output of said plurality of audio encoded bit stream, one of the acquired plurality of audio encoded bit stream a selecting step for selectively supplying the decoding step in accordance with the boundary position, relative to one of said plurality of audio encoded bit stream which is selectively supplied, IMDCT processing corresponding to the MDCT processing and a said decoding processing step of performing a decoding process including, wherein Decoding step is omitted overlap-add in the IMDCT processing corresponding respectively to the front and rear of the frame of the boundary position.
[0030]
　Program which is an aspect of the present disclosure, computer, acquiring portion in which a plurality of source data reproduction timing is synchronized to obtain a plurality of audio encoded bit stream is encoded after the MDCT processing in frame units respectively If, to determine the boundary position for switching the output of said plurality of audio encoded bit stream, the selectively decoding unit in accordance with one on the boundary position of the acquired plurality of audio encoded bit stream a selector for supplying, for one of the plurality of audio encoded bit stream input via the selection section, the decoding processing unit for performing a decoding process including an IMDCT processing corresponding to the MDCT processing to function as, the decoding processing unit corresponding respectively to the front and rear of the frame of the boundary position the IMD Omitted overlap-add in the CT processing.
[0031]
　In one aspect of the present disclosure, a plurality of audio encoded bit stream is obtained, the boundary position for switching the outputs of the plurality of audio encoded bit stream is determined, selectively supplied the in accordance with the boundary position for one of the plurality of audio encoded bit stream, decode processing including IMDCT processing corresponding to the MDCT processing is performed. In the decoding process, overlap-add in the IMDCT processing corresponding respectively to the front and rear of the frame of the boundary position is omitted.
Effect of the invention
[0032]
　According to one aspect of the present disclosure, it can be switched quickly decoded to output as much as possible a plurality of audio encoded bit stream reproducing timing are synchronized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033]
Is a block diagram showing an example of the configuration of FIG. 1 encoding apparatus and decoding apparatus.
It is a diagram illustrating the FIG. 2] IMDCT processing.
It is a diagram showing a state of switching of FIG. 3 audio encoded bit stream.
Is a block diagram showing a configuration example of FIG. 4 has been applied the decoding apparatus of the present disclosure.
By [5] decoding apparatus of FIG. 4 is a diagram illustrating a first method of switching audio encoded bit stream.
6 is a flowchart illustrating the audio switching process.
Is a flowchart illustrating a FIG. 7 Switching optimal position flag setting process.
Is a diagram showing a state of FIG. 8 switching optimal position flag setting process.
Is a flowchart illustrating a FIG. 9 switching boundary position determination process.
It is a diagram showing a state of FIG. 10 switching boundary position determination process.
[11] according to the decoding apparatus of FIG. 4 is a diagram illustrating a second method of switching audio encoded bit stream.
By [12] the decoding apparatus of FIG. 4 is a diagram illustrating a third method of switching audio encoded bit stream.
13 is a block diagram showing a configuration example of a general-purpose computer.
DESCRIPTION OF THE INVENTION
[0034]
　Hereinafter, best mode for carrying out the present disclosure (hereinafter, referred to as embodiments) will be described in detail with reference to the drawings.
[0035]
　
　Fig. 4 shows a configuration example of a decoding apparatus according to an embodiment of the present disclosure.
[0036]
　The decoding device 30 includes, for example, the receiving apparatus that receives a content broadcast or distributed, a reproducing apparatus for reproducing the content recorded on the recording medium is mounted on a like. Further, the decoding device 30 is capable of outputting the decoded promptly switch the first and second audio encoded bit stream reproducing timing are synchronized.
[0037]
　The first and second audio encoded bit stream is assumed to source data of voice are variable length coded by the encoding process including at least MDCT processing. Further, hereinafter, the first and second audio encoded bit stream, simply also referred to as first and second coded bit stream.
[0038]
　Decoding unit 30, the demultiplexing unit 31, the decoding unit 32-1 and 32-2 has a selection unit 33, decoding unit 34 and the fade processing unit 37.
[0039]
　Demultiplexer 11, from the multiplexed stream input from the previous stage, separating the first coded bit stream and the second encoded stream reproduction timing is synchronized. Further, the multiplexing unit 11, a first encoded bit stream and outputs to the decoding unit 32-1, and outputs the second encoded stream to the decoding unit 32-2.
[0040]
　Decoding unit 32-1 performs decoding process for decoding the variable-length code the first coded bit stream as an object, a processing result (hereinafter, referred to as quantized data) to the selector 33 a. Decoding unit 32-2 performs decoding process for decoding the variable length code of the second coded bit stream as an object, and outputs the quantized data of the processing result to the selection unit 33.
[0041]
　Selection unit 33, the switching boundary position determined based on the audio switching instruction from the user, in accordance with the determined switching boundary position, to the decoding unit 34 the quantized data from the decoding unit 32-1 or the decoding unit 32-2 Output.
[0042]
　The selection unit 33 may also determine the switching boundary position based on the switching optimum position flag added to each frame to first and second coded bit stream. This will be described later with reference to FIGS. 7-10.
[0043]
　Decoding unit 34 includes an inverse quantization unit 35 and the IMDCT unit 36. Inverse quantization unit 35 performs inverse quantization on the quantized data inputted through the selector 33, the inverse quantization results (hereinafter referred to as MDCT data) to the IMDCT unit 36. IMDCT unit 36, by performing the IMDCT process on MDCT data, reconstructs the PCM data corresponding to the source before encoding data.
[0044]
　However, IMDCT 36, not completely reconstruct the PCM data corresponding respectively to all the frames, also it outputs PCM data reconstructed by incomplete for a frame in the vicinity of the switching boundary position.
[0045]
　Fade processing section 37, fade-out processing on the PCM data near the switching boundary position input from the decode processing unit 34, fade-in processing, or performs mute processing for the subsequent stage.
[0046]
　In the configuration example shown in FIG. 4, but with respect to the decoding device 30 shows a case where multiplexed streams first and second coded bit stream are multiplexed is input, multiple of more encoded bit stream may be multiplexed into the stream. In that case, may increase the number of the decoding unit 32 in accordance with the number of encoded bit stream are multiplexed.
[0047]
　Also, rather than multiplexed stream is input to the decoding device 30, a plurality of coded bit streams may be each be individually entered. In that case, the demultiplexer 31 can be omitted.
[0048]
　
　Next, FIG. 5 shows a first switching method of the coded bit stream by the decoding apparatus 30.
[0049]
　As shown in the figure, as the boundary position switching between Frame # 2 and Frame # 3, when switching from the first encoded bit stream to the second coded bit stream, the first coded bit stream is up to Frame # 2 immediately before switching boundary position subject to IMDCT processing. In this case, although until PCM1-1 corresponding to Frame # 1 can be completely reconstructed, reconstruction of PCM1-2 corresponding to Frame # 2 becomes incomplete.
[0050]
　On the other hand, the second coded bit stream, and from Frame # 3 immediately after the switching boundary position subject to IMDCT processing. In this case, reconstruction of PCM2-3 corresponding to Frame # 3 becomes incomplete, so as to completely reconstructed from PCM2-4 later corresponding to Frame # 4.
[0051]
　Here, the "imperfect reconstruction", without performing overlap-add refers to the use by the intact PCM data early or late IMDCT-OUT.
[0052]
　In the present case, the PCM1-2 corresponding to Frame # 2 of the first coded bit stream, the may be used as the second half of the MDCT-OUT # 1-1. Similarly, the PCM2-3 corresponding to Frame # 3 of the second coded bit stream, the first half of the MDCT-OUT # 2-3 may be used as it is. Needless to say, PCM1-2 and PCM2-3 incompletely reconstructed becomes that sound quality is deteriorated as compared with the case where fully reconstructed.
[0053]
　Then, when the output of the PCM data, until PCM1-1 was completely reconstructed corresponding to Frame # 1 outputs a normal volume. Switching boundary position immediately before the Frame # incomplete corresponding to 2 PCM1-2 gradually reduces the volume by fade-out process, the fade-in process for PCM2-3 incomplete corresponding to Frame # 3 immediately after the switching boundary position gradually to increase the volume by. Then, Frame # 4 and later was completely reconstructed PCM2-4, so as to output the ... at normal volume.
[0054]
　Thus, by outputting the PCM data incompletely reconstituted just after changing the boundary position, it is possible to eliminate the need to perform in parallel the two decoding. Also, by connecting the incomplete PCM data in fade-out process and the fade-in process, from the switching of voice, it is possible to suppress the volume of annoying glitch noise due to discontinuous frames.
[0055]
　The switching method of the coded bit stream by the decoding device 30 is not limited to the first switching method described above, it is also possible to employ a second or third switching method will be described later.
[0056]
　
　Next, FIG. 6 corresponds to the first switching method shown in FIG. 5 is a flowchart illustrating an audio switching processing.
[0057]
　Given the voice switching process, in the decoding apparatus 30, the demultiplexer 11, are first and second coded bit stream is separated from the multiplexed stream, each decoding unit 32-1 or 31-2 It is assumed to be decoded by. Further, the selection unit 33, it is assumed that one of the quantized data from the decoding unit 32-1 and 31-2 are inputted is selected in the decoding unit 34.
[0058]
　Hereinafter, the selection unit 33, the case where the quantized data from the decoding unit 32-1 is selected and is input to the decoding unit 34. Thus, currently, from the decoding unit 30 in a state of PCM data based on the first encoded bit stream is output at normal volume.
[0059]
　In step S1, the selector 33 determines whether or not there is an audio switching instruction from the user waits until the audio switching instruction. During this waiting, selective output by the selector 33 is maintained. That is, the decoding device 30 PCM data based on the first encoded bit stream is continued to output at normal volume.
[0060]
　If there is audio switching instruction from the user, the process proceeds to step S2. In step S2, the selecting unit 33 determines the switching boundary position of the sound. For example, to determine after a predetermined number of frames has elapsed since a voice switching instruction to switch the boundary position of the sound. However, it may be determined based on the switching optimum position flag included in the encoded bit stream (described in detail later).
[0061]
　Case, as shown in FIG. 5, it is assumed that during Frame # 2 and Frame # 3 is determined to switch the boundary position.
[0062]
　Thereafter, in step S3, the selection unit 33, the quantized data corresponding to the immediately preceding frame of the determined switching boundary position to be output to the decoding unit 34 maintains the current selection. That, and outputs the quantized data from the decoding unit 32-1 in the subsequent stage.
[0063]
　In step S4, the inverse quantization unit 35 of the decoding processing unit 34 performs inverse quantization of the quantized data based on the first coded bit stream, and outputs the resulting MDCT data in the IMDCT unit 36. IMDCT unit 36, by performing the IMDCT process as a target up MDCT data corresponding to the immediately preceding frame of the switching boundary position, to reconstruct the PCM data corresponding to the source before encoding data to output to the fade processing unit 37 .
[0064]
　For now, until PCM1-1 corresponding to Frame # 1 can be completely reconstructed, reconstruction of PCM1-2 corresponding to Frame # 2 becomes incomplete.
[0065]
　In step S5, the fade processing unit 37 (in this case, corresponding to Frame # 2 PCM1-2) incomplete PCM data corresponding to the immediately preceding frame of the switching boundary position input from the decode processing section 34 with respect to and outputs it to the subsequent stage performs fade-out process Te.
[0066]
　Next, in step S6, the selection unit 33 switches the output to the decoding processing unit 34. That, and outputs the quantized data from the decoding unit 32-2 in the subsequent stage.
[0067]
　In step S7, the inverse quantization unit 35 of the decoding processing unit 34 performs inverse quantization of the quantized data based on the second coded bit stream, and outputs the resulting MDCT data in the IMDCT unit 36. IMDCT unit 36, by performing the IMDCT process as a target from MDCT data corresponding to the immediately following frame of the switching boundary position, to reconstruct the PCM data corresponding to the source before encoding data to output to the fade processing unit 37 .
[0068]
　In the present case, reconstruction of PCM2-3 corresponding to Frame # 3 becomes imperfect since PCM2-4 corresponding to Frame # 4 is completely reconstructed.
[0069]
　In step S8, the fade processing unit 37 (in this case, corresponding to Frame # 3 PCM2-3) incomplete PCM data corresponding to a frame immediately after the switching boundary position input from the decode processing section 34 with respect to to output to the subsequent stage performing the fade-in processing Te. Thereafter, the processing is returned to step S1, and the subsequent repeated.
[0070]
　This concludes the description of the audio switching processing performed by the decoding apparatus 30. According to the above audio switching processing without executing in parallel the two decoding, it is possible to switch the audio encoded bit stream. Further, from the switching to the voice, it is possible to suppress the volume of annoying glitch noise due to discontinuous frames.
[0071]
　
　In the above-described audio switching processing in response to the audio switching instruction from the user, then was determined after a predetermined number of frames has passed the switching boundary position of the sound. However, switching Considering that executes the fade-out process and the fade-in processing to the vicinity of the boundary position, the switching boundary position, or the voice is possible positions of the state close to silence, or temporarily volume depending on the context even when the lower it is desirable means of a series of words or conversation is a position which satisfies.
[0072]
　Accordingly, next, a state sound as close as possible to the silence at the supply side of the content (i.e., the state gain or energy is smaller source data) to detect, there make a changeover optimum position flag processing (hereinafter, switching optimum position flag setting process) will be described.
[0073]
　Figure 7 is a flowchart explaining the optimum position flag setting process executed by the supply side of the content. Figure 8 shows how the switching optimum position flag setting processing.
[0074]
　In step S21, the first and second source data (first and second coded bit stream Each respective original playback timing is synchronized) is divided into frame units is input from the previous stage, step in S22, the energy in each frame, separated is measured.
[0075]
　In step S23, the energy of the first and second source data for each frame is equal to or less than a predetermined threshold value. If the energy of the first and second source data is both less than a predetermined threshold value, the processing is advanced to step S24, switching the optimum position flag for the frame is meant to be a switching optimum position "1" It is set to.
[0076]
　Conversely, if at least one of the energy of the first or second source data is larger than a predetermined threshold value, the processing is advanced to step S25, switching the optimum position flag for the frame is that it is not a switch optimum position It is set in meaning to "0".
[0077]
　In step S26, the input of the first and second source data is determined whether or not completed, when the input of the first and second source data is continued, the process thereafter is returned to step S21 It is repeated. If the input of the first and second source data is completed, switching the optimum position flag setting process ends.
[0078]
　Next, FIG. 9 corresponds to the case where the switching optimum position flag is set for each frame of the first and second coded bit stream by the above-mentioned switching optimum position flag setting processing, in the decoding device 30, the voice it is a flowchart illustrating a switching boundary position decision processing. Figure 10 is a diagram showing a state of the switching boundary position determination process.
[0079]
　This switching boundary position determination process may be executed instead of steps S1 and S2 of the audio switching process described with reference to FIG.
[0080]
　In step S31, the selection unit 33 of the decoding apparatus 30 determines whether or not there is audio switching instruction from the user waits until the audio switching instruction. During this waiting, selective output by the selector 33 is maintained. That is, the decoding device 30 PCM data based on the first encoded bit stream is continued to output at normal volume.
[0081]
　If there is audio switching instruction from the user, the process proceeds to step S32. In step S32, the selection unit 33, first and second switching optimum position flag added to each frame of the encoded bit stream (the quantization data which is decoded result of) sequentially input from the preceding stage 1 to wait until. During this waiting also selectively output by the selector 33 is maintained. Then, when it becomes 1 switching optimal position flag, processing advances to step S33 and the switching optimum position flag during the next frame as the frame 1, to determine the switching boundary position of the sound. Thus, the switching boundary position determination process is ended.
[0082]
　Above the switching optimum position flag setting process described, and according to the switching boundary position determination process, it is possible to determine the boundary position switches the position of the sound is as close as possible to the silent state. Thus, possible to prevent the effect of executing the fade-out process and the fade-in process.
[0083]
　Further, even when the switching optimum position flag is not added, such as in the selection unit 33 in the decoding apparatus 30, with reference to the information related to the gain of the encoded bit stream, the following volume specified threshold position may be detected and to determine the switching boundary position. The information relating to the gain, for example, can utilize information such as scale factors in the encoding method such as AAC, MP3.
[0084]
　
　Next, FIG. 11 shows a second method of switching the coded bit stream by the decoding apparatus 30.
[0085]
　As shown in the figure, as the boundary position switching between Frame # 2 and Frame # 3, when switching from the first encoded bit stream to the second coded bit stream, the first coded bit stream is up to Frame # 2 immediately before switching boundary position subject to IMDCT processing. In this case, although until PCM1-1 corresponding to Frame # 1 can be completely reconstructed, reconstruction of PCM1-2 corresponding to Frame # 2 becomes incomplete.
[0086]
　On the other hand, the second coded bit stream, and from Frame # 3 immediately after the switching boundary position subject to IMDCT processing. In this case, reconstruction of PCM2-3 corresponding to Frame # 3 becomes incomplete, so as to completely reconstructed from PCM2-4 later corresponding to Frame # 4.
[0087]
　Then, when the output of the PCM data, until PCM1-1 was completely reconstructed corresponding to Frame # 1 outputs a normal volume. Switching boundary position immediately before the Frame # incomplete corresponding to 2 PCM1-2 gradually reduces the volume by fade-out process, the mute processing for PCM2-3 incomplete corresponding to Frame # 3 immediately after the switching boundary position the silent interval. Also, completely for PCM2-4 reconstituted to raise gradually the volume by fade-in processing, so that the PCM2-5 later corresponding to Frame # 5 outputted by the normal volume.
[0088]
　Thus, by outputting the PCM data incompletely reconstituted just after changing the boundary position, it is possible to eliminate the need to perform in parallel the two decoding. Further, fade-out process incomplete PCM data, by connecting in mute processing, and fade-in processing, from the switching of voice, it is possible to suppress the volume of annoying glitch noise due to discontinuous frames.
[0089]
　
　Next, FIG 12 shows a third switching method of the coded bit stream by the decoding apparatus 30.
[0090]
　As shown in the figure, as the boundary position switching between Frame # 2 and Frame # 3, when switching from the first encoded bit stream to the second coded bit stream, the first coded bit stream is up to Frame # 2 immediately before switching boundary position subject to IMDCT processing. In this case, although until PCM1-1 corresponding to Frame # 1 can be completely reconstructed, reconstruction of PCM1-2 corresponding to Frame # 2 becomes incomplete.
[0091]
　On the other hand, the second coded bit stream, and from Frame # 3 immediately after the switching boundary position subject to IMDCT processing. In this case, reconstruction of PCM2-3 corresponding to Frame # 3 becomes incomplete, so as to completely reconstructed from PCM2-4 later corresponding to Frame # 4.
[0092]
　Then, when the output of the PCM data, Frame # before the corresponding PCM1-1 to 1 outputs a normal volume, gradually lowering the volume by fadeout process for PCM1-1, switching boundary position immediately before the Frame # for incomplete PCM1-2 corresponding to 2 and silent section by muting. Also, gradually to increase the volume by fade-in processing for PCM2-3 incomplete corresponding to Frame # 3 immediately after the switching boundary position, since PCM2-4 corresponding to Frame # 4 outputs a normal volume so as to.
[0093]
　Thus, by outputting the PCM data incompletely reconstituted just after changing the boundary position, it is possible to eliminate the need to perform in parallel the two decoding. Further, fade-out process incomplete PCM data, by connecting in mute processing, and fade-in processing, from the switching of voice, it is possible to suppress the volume of annoying glitch noise due to discontinuous frames.
[0094]
　
　The present disclosure is also applicable to other switching applications first and second coded bit stream reproduction timing is synchronized, for example, in switching applications between objects in 3D Audio coding can do. Applications More specifically, when such switch to another group (Switch Group) collectively what object data is grouped, for switching a simultaneously multiple objects for reasons such as the switching of the viewpoint position in the playback scene and free viewpoint It can be applied to.
[0095]
　In addition, and if you switch the channel environment in surround sound, such as 5.1ch from 2ch stereo sound, even in the operation, such as switching in accordance with the movement of the seat in a stream with a surround in each seat of a free viewpoint video, the present disclosure it is possible to apply.
[0096]
　The series of processing by the decoding device 30 described above can be executed by hardware or can be executed by software. When executing the series of processing by software, a program constituting the software is installed into a computer. Here, the computer includes a computer incorporated in dedicated hardware, by installing various programs, which can execute various functions include, for example, such as a general-purpose personal computer.
[0097]
　Figure 13 is a block diagram showing a configuration example of hardware of a computer that executes the series of processes described above.
[0098]
　In the computer 100, CPU (Central Processing Unit) 101, ROM (Read Only Memory) 102, RAM (Random Access Memory) 103 are connected to each other via a bus 104.
[0099]
　The bus 104 further input and output interface 105 is connected. Output interface 105, an input unit 106, output unit 107, storage unit 108, a communication unit 109, and a drive 110 are connected.
[0100]
　Input unit 106 includes a keyboard, a mouse, and a microphone. The output unit 107 includes a display and a speaker. Storage unit 108 includes a hard disk and a nonvolatile memory. The communication unit 109 includes a network interface. The drive 110 drives a magnetic disk, an optical disk, a magneto-optical disk, or a removable medium 111 such as a semiconductor memory.
[0101]
　In configured computer 100 as described above, CPU 101 is, for example, a program stored in the storage unit 108, output interface 105 and the bus 104, and executes the program loaded into the RAM 103, the above-described a series of processing is performed.
[0102]
　The program which the computer 100 executes may be a program processed in time-series is performed in the order described herein, the necessary timing such as when parallel or call is made in the process it may be a program to be performed.
[0103]
　Embodiments of the present disclosure is not intended to be limited to the embodiments described above, but various modifications are possible without departing from the scope of the present disclosure.
[0104]
　The present disclosure can also be configured as below.
(1)
　an acquisition unit reproduction timing to obtain a plurality of audio encoded bit stream in which a plurality of source data being synchronized is coded after the MDCT processing in frame units respectively,
　said plurality of audio encoded bit stream determining the boundary position for switching the output of a selector for selectively supplying the decoding unit in accordance with one on the boundary position of the acquired plurality of audio encoded bit stream,
　said selection portion for one of the plurality of audio encoded bit stream input via, and a the decoding processing unit for performing a decoding process including an IMDCT processing corresponding to the MDCT processing,
　the decoding processing unit, overlap-add is omitted in the IMDCT processing corresponding respectively to the front and rear of the frame of the boundary position
　decoding instrumentation .
(2)
　a fade processing unit that performs a fade process on decoding results before and after the frame of the overlap-add is been said boundary position is omitted by the decoding unit
　decoding apparatus according to further comprising the (1).
(3)
　the fade processing unit, performs fade-out processing on the decoding result of the previous frame of the boundary position where the overlap-add by the decoding processing unit is omitted, the frame after the boundary position performing fade-in processing with respect to the decoding processing results
　Decoding apparatus according to (2).
(4)
　the fade processing unit, performs fade-out processing on the decoding result of the previous frame of the boundary position where the overlap-add by the decoding processing unit is omitted, the frame after the boundary position It performs mute processing for decoding processing result
　the decoding apparatus according to (2).
(5)
　the fade processing unit performs muting processing for the decoding result of the previous frame of the boundary position where the overlap-add by the decoding processing unit is omitted, the frame after the boundary position performing fade-in processing with respect to the decoding processing result
　decoding apparatus according to (2).
(6)
　the selection unit was set at the feed side of the plurality of audio encoded bit stream, determines the boundary position based on the switching optimum position flag added to each frame
　from said (1) ( decoding apparatus according to any one of 5).
(7)
　wherein the switching optimum position flag, the audio in the supply side of the encoded bit stream is set based on the energy or the context of the source data
　decoding apparatus according to (6).
(8)
　the selection unit determines the boundary position based on the information about the gain of the plurality of audio encoded bit stream
　Decoding apparatus according to any one of (1) to (5).
(9)
　In the decoding method of the decoding apparatus,
　according to the decoding device,
　　a plurality of source data reproduction timing is synchronized to obtain a plurality of audio encoded bit stream is encoded after the MDCT processing in frame units respectively an acquisition step,
　　a determination step of determining a boundary position for switching the output of said plurality of audio encoded bit stream,
　　selectively one of the acquired plurality of audio encoded bit stream in response to said boundary position a selecting step for supplying the decoding step,
　　the decoding with respect to one of the selectively supplied the plurality of audio encoded bit stream, performs a decoding process including an IMDCT processing corresponding to the MDCT processing and a processing step,
　the decoding step, the boundary Omitted overlap-add in the IMDCT processing corresponding respectively to the front and rear frames of the field position
　decoding method.
(10)
　a computer,
　an acquisition unit having a plurality of source data reproduction timing is synchronized to obtain a plurality of audio encoded bit stream is encoded after the MDCT processing in frame units respectively,
　Determining the boundary position for switching the output of said plurality of audio encoded bit stream, selectively supplies to the decoding processing unit in accordance with one on the boundary position of the acquired plurality of audio encoded bit stream a selecting unit,
　to one of the plurality of audio encoded bit stream input via the selection section, functions as the decoding processing unit for performing a decoding process including an IMDCT processing corresponding to the MDCT processing is allowed,
　the decoding section omits overlap-add in the IMDCT processing corresponding respectively to the front and rear of the frame of the boundary position
　program.
DESCRIPTION OF SYMBOLS
[0105]
　30 decoding unit, 31 demultiplexer, 32-1 and 32-2 decode unit, 33 selecting unit, 34 decoding section, 35 inverse quantization unit, 36 IMDCT unit, 37 fade processing section, 100 computer, 101 CPU

claims

[Claim 1]An acquisition unit reproduction timing to obtain a plurality of audio encoded bit stream in which a plurality of source data being synchronized is coded after the MDCT processing in frame units respectively,
　the outputs of the plurality of audio encoded bit stream determining the boundary position of switching, a selection unit for selectively supplying the decoding unit in accordance with one on the boundary position of the acquired plurality of audio encoded bit stream,
　input via the selector for one of the plurality of audio encoded bit stream, and a the decoding processing unit for performing a decoding process including an IMDCT processing corresponding to the MDCT processing,
　the decoding processing unit, the boundary position omitted overlap-add in the corresponding said IMDCT processing each before and after the frame of the
　decoding device.
[Claim 2]
　Fade processing section for performing fade processing on decoding results before and after the frame of the overlap-add is abbreviated said boundary position by the decoding unit
　decoding apparatus according to claim 1, further comprising.
[Claim 3]
　The fade processing unit, performs fade-out processing on the decoding result of the previous frame of the boundary position where the overlap-add by the decoding processing unit is omitted, the decoding processing result of the frame following said boundary position performing fade-in processing with respect to
　the decoding apparatus according to claim 2.
[Claim 4]
　The fade processing unit, performs fade-out processing on the decoding result of the previous frame of the boundary position where the overlap-add by the decoding processing unit is omitted, the decoding processing result of the frame following said boundary position It performs mute processing for
　decoding apparatus according to claim 2.
[Claim 5]
　The fade processing unit performs muting processing for the decoding result of the previous frame of the boundary position where the overlap-add by the decoding processing unit is omitted, the decoding processing result of the frame following said boundary position performing fade-in processing with respect to
　the decoding apparatus according to claim 2.
[Claim 6]
　The selection unit may determine that the boundary position based on the switching optimal position flag the set in the supply side of the plurality of audio encoded bit stream, is added to each frame
　decoding apparatus according to claim 2.
[Claim 7]
　The switching optimum position flag, the supply side of the audio encoded bit stream is set based on the energy or the context of the source data
　decoding apparatus according to claim 6.
[8.]
　The selection unit determines the boundary position based on the information about the gain of the plurality of audio encoded bit stream
　decoding apparatus according to claim 2.
[Claim 9]
　In the decoding method of the decoding apparatus,
　according to the decoding device,
　　an acquisition step in which a plurality of source data reproduction timing is synchronized to obtain a plurality of audio encoded bit stream is encoded after the MDCT processing in frame units respectively ,
　　a determination step of determining a boundary position for switching the output of said plurality of audio encoded bit stream,
　　selectively decoding one of the acquired plurality of audio encoded bit stream in response to said boundary position a selecting step for supplying to a step,
　　for one of the plurality of audio encoded bit stream which is selectively supplied, said decoding processing step of performing a decoding process including an IMDCT processing corresponding to the MDCT processing wherein the
　said decoding step, said boundary position Omitted overlap-add in the IMDCT processing corresponding to the frames before and after the
　decoding process.
[Claim 10]
　The computer,
　an acquisition unit that acquires a plurality of audio encoded bit stream in which a plurality of source data reproduction timing is synchronized is coded after the MDCT processing in frame units respectively,
　said plurality of audio encoded bit stream determining the boundary position for switching the output of a selector for selectively supplying the decoding unit in accordance with one on the boundary position of the acquired plurality of audio encoded bit stream,
　said selection portion for one of the plurality of audio encoded bit stream input via, to function as the decoding processing unit for performing a decoding process including an IMDCT processing corresponding to the MDCT processing,
　the decoding processing unit, saving the overlap-add in the IMDCT processing corresponding respectively to the front and rear of the frame of the boundary position The