Technical Field
[0002] The present technology relates to a transmitting apparatus, a transmitting method, a
receiving apparatus, and a receiving method and, in particular, relates to, for example,
a transmitting apparatus that transmits transmission video data obtained by applying a
predetermined opto-electrical transfer function to input video data.
Background Art
[0003] A High Dynamic Range (HDR) imaging service provides an image with a wide
luminance range to the receiving end and reproduces the image on the receiving end
while reflecting the creator' s intention on the image. This achieves display and r e
production of an image approaching the perception of the human eye in nature.
[0004] NPL 1 discloses, for example, a technique for transmitting a video stream generated
by encoding transmission video data obtained by applying a gamma curve to input
video data with luminance levels from 0 to 100% * N (the N is larger than one).
[0005] The levels of peak luminance of monitors (CE monitors) in receiving devices vary
depending on the device property, the placement of the backlight, or the design method
of a display panel. In comparison to the master monitor used for creating a program,
the CE monitor sometimes has too high or dark luminance. Thus, the CE monitor may
fail to correctly reproduce the luminance atmosphere that the creator intends.
Citation List
Non Patent Literature
[0006] NPL 1: High Efficiency Video Coding (HEVC) text specification draft 10 (for FDIS &
Last Call)
Summary of Invention
Technical Problem
[0007] It is desirable to excellently reproduce the luminance atmosphere that the creator
intends on the receiving end.
Solution to Problem
[0008] According to an embodiment of the present technology, there is provided a
transmitting apparatus including:
a processing unit configured to obtain transmission video data by applying a prede
termined opto-electrical transfer function to input video data, and
a transmitting unit configured to transmit the transmission video data together with
luminance conversion acceptable range information about a set region in a screen.
[0009] According to the present technology, a processing unit provides transmission video
data by applying a predetermined opto-electrical transfer function to the input video
data. For example, the input video data is video data including high dynamic range
(HDR) images having contrast ratios from 0% to 100% * N (the N is a number larger
than one) and having a brightness exceeding the brightness of the white peak value of
an existing low dynamic range (LDR) image.
[0010] A transmitting unit transmits the transmission video data with the luminance
conversion acceptable range information about a set region in the screen. For example,
the set region in the screen may be set in the unit of pixel or in the unit of block
including a predetermined number of pixels. Alternatively, for example, the
transmitting unit may transmit the video stream obtained by encoding transmission
video data, and may further include an information inserting unit configured to insert
the luminance conversion acceptable range information into a layer of the video
stream.
[001 1] According to the present technology, transmission video data is transmitted together
with the luminance conversion acceptable range information about a set region in the
screen as descried above. This enables the receiving end to excellently reproduce the
luminance atmosphere that the creator intends.
[0012] Note that, for example, the transmitting unit according to the present technology may
transmit the transmission video data together with the luminance conversion acceptable
range information about the entire screen in addition to the luminance conversion ac
ceptable range information about the set region in the screen. In such a case, the
receiving end can converts the luminance of the region other than the set region in the
screen in a luminance conversion process in accordance with the luminance conversion
acceptable range information about the entire screen.
[0013] According to an embodiment of the present technology, there is provided a receiving
apparatus including:
a receiving unit configured to receive transmission video data obtained by applying a
predetermined opto-electrical transfer function to input video data together with
luminance conversion acceptable range information about a set region in a screen; and
a processing unit configured to obtain output video data by applying an electrooptical
transfer function corresponding to the predetermined opto-electrical transfer
function to the transmission video data, and converting luminance of the transmission
video data in a luminance conversion process in accordance with the luminance
conversion acceptable range information.
[0014] A receiving unit receives the transmission video data together with the luminance
conversion acceptable range information about the set region in screen. The
transmission video data is obtained by applying a predetermined opto-electrical
transfer function to the input video data. For example, the input video data is video
data including High Dynamic Range (HDR) images having contrast ratios from 0% to
100% * N (the N is a number larger than one) and having a brightness exceeding the
brightness of the white peak value of an existing Low Dynamic Range (LDR) image.
[0015] For example, the set region in the screen may be set in the unit of pixel or in the unit
of block including a predetermined number of pixels. For example, the receiving unit
may receive the video stream obtained by encoding transmission video data, and the
luminance conversion acceptable range information may be inserted in a layer in the
video stream. Thus, the processing unit may applies, for example, an electro-optical
transfer function that is inverse to the predetermined opto-electrical transfer function to
the transmission video data, and outputs video data of which luminance is converted in
accordance with the luminance conversion acceptable range information in a
luminance conversion process.
[0016] According to the present technology, the transmission video data is received together
with the luminance conversion acceptable range information about the set region in the
screen such that the output video data is obtained by converting the luminance of the
received data in accordance with the luminance conversion acceptable range in
formation in a luminance conversion process as described above. This enables the
receiving end to excellently reproduce the luminance atmosphere that the creator
intends.
[0017] Note that, for example, the receiving unit according to the present technology may
receive the transmission video data together with the luminance conversion acceptable
range information about the entire screen in addition to the luminance conversion ac
ceptable range information about the set region in the screen such that the processing
unit can convert the luminance of the regions other than the set region in the screen in
accordance with the luminance conversion acceptable range information about the
entire screen in a luminance conversion process.
Advantageous Effects of Invention
[0018] The present technology enables a receiving end to excellently reproduce the
luminance atmosphere that the creator intends. Note that the effects described herein
are examples consistently. The present technology is not limited to the
examples. Furthermore, the present technology may include an additional effect.
Brief Description of Drawings
[0019] [fig. 1]Fig. 1 is a block diagram of an exemplary configuration of a transmitting and
receiving system as an embodiment.
[fig.2]Fig. 2 is a block diagram of an exemplary configuration of a transmitting
apparatus including the transmitting and receiving system.
[fig.3]Fig. 3 is a diagram of an exemplary display luminance characteristic of a master
monitor.
[fig.4]Fig. 4 is a diagram of an exemplary opto-electrical transfer function (OETF);
[fig.5]Fig. 5 is a diagram of the head access unit of a GOP when the data is encoded
with an HEVC encoding method.
[fig.6]Fig. 6 is a diagram of an access unit other than the head access unit of a GOP
when the data is encoded with an HEVC encoding method.
[fig.7]Figs. 7A and 7B are diagrams to describe that set regions in a screen is set in the
unit of pixel or in the unit of block including a predetermined number of pixels;
[fig.8]Fig. 8 is a diagram of an exemplary configuration of a regional level mapping
SEI message.
[fig.9]Fig. 9 is a diagram of another exemplary configuration of a regional level
mapping SEI message.
[fig. 10] Fig. 10 is a diagram of the contents of primary information in an exemplary
configuration of a regional level mapping SEI message.
[fig. 1l]Fig. 11 is a block diagram of an exemplary configuration of a receiving
apparatus including a transmitting and receiving system.
[fig.l2]Fig. 12 is a diagram of an exemplary electro-optical transfer function (EOTF).
[fig.l3]Figs. 13A and 13B are diagrams of an exemplary display luminance char ac
teristic of a CE monitor when the highest luminance display capacity DP of the CE
monitor is higher than the highest luminance PL assumed in the master monitor
[fig. 14] Figs. 14A and 14B are diagrams of an exemplary display luminance char ac
teristic of a CE monitor when the highest luminance display capacity DP of the CE
monitor is lower than the highest luminance PL assumed in the master monitor.
[fig.l5]Figs. 15A and 15B are diagrams of another exemplary display luminance char
acteristic of a CE monitor when the highest luminance display capacity DP of the CE
monitor is lower than the highest luminance PL assumed in the master monitor
[fig. 16] Fig. 16 is a block diagram of another exemplary configuration of the
transmitting and receiving system.
Description of Embodiments
[0020] Hereinafter, a configuration to implement the present technology (hereinafter,
referred to as an "embodiment") will be described in the following order.
1. Embodiment
2. Variation
[0021] 1. Embodiment
(Exemplary Configuration of Transmitting and Receiving System)
Fig. 1 illustrates an exemplary configuration of a transmitting and receiving system
10 as an embodiment. The transmitting and receiving system 10 includes a
transmitting apparatus 100 and a receiving apparatus 200.
[0022] The transmitting apparatus 100 generates a transport stream TS in MPEG-2 as a
container to transmit the transport stream TS through broadcast waves or with packets
on a network. The transport stream TS includes a video stream obtained by encoding
transmission video data obtained by applying a predetermined opto-electrical transfer
function to input video data.
[0023] For example, the input video data includes High Dynamic Range (HDR) images
having contrast ratios from 0% to 100% * N (the N is a number larger than one) and
having a brightness exceeding the brightness of the white peak value of an existing
Low Dynamic Range (LDR) image. It is assumed herein that the level of 100% is a
luminance level corresponding to a white luminance value of 100cd/m2.
[0024] The luminance conversion acceptable range information about a set region in the
screen and the luminance conversion acceptable range information about the entire
screen is inserted in a layer of the video stream. The luminance conversion acceptable
range information will be described in detail below.
[0025] The receiving apparatus 200 receives the transport stream TS transmitted from the
transmitting apparatus 100 through broadcast waves or with packets on a network. The
transport stream TS includes a video stream including encoded video data. The
luminance conversion acceptable range information about a set region in the screen
and the luminance conversion acceptable range information about the entire screen is
inserted in the video stream as described above.
[0026] The receiving apparatus 200 obtains output video data by applying, for example, an
electro-optical transfer function that is in inverse to the predetermined opto-electrical
transfer function on the transmitting end to the transmission video data, and converting
the luminance of the data in accordance with the luminance conversion acceptable
range information in a luminance conversion process. In such a case, the luminance of
the data only in the luminance conversion acceptable range is converted, for example,
depending on the peak luminance of the monitor.
[0027] Exemplary Configuration of Transmitting Apparatus
Fig. 2 illustrates an exemplary configuration of the transmitting apparatus 100. The
transmitting apparatus 100 includes a control unit 101, an HDR camera 102, an HDR
opto-electrical transfer unit 103, a video encoder 104, a system encoder 105, and a
transmitting unit 106. The control unit 101 includes a central processing unit (CPU) to
control the operation of each of the components in the transmitting apparatus 100 in
accordance with a control program.
[0028] The HDR camera 102 captures an image of an object and outputs High Dynamic
Range (HDR) video data. The HDR video data has contrast ratios from 0 to 100% * N
(the N is a number larger than one), for example, from 0 to 1000% and has a brightness
exceeding the brightness of the white peak value of an existing Low Dynamic Range
(LDR) image. Note that herein the level of 100% corresponds, for example, to a white
luminance value of 100cd/m2. Note that the "cd/m2" indicates "cd/square meter".
[0029] The master monitor 103a is configured to grade the HDR video data obtained with
the HDR camera 102. The master monitor 103a includes the display luminance levels
appropriate to HDR video data, or appropriate for grading HDR video data.
[0030] Fig. 3 illustrates the display luminance characteristic of the master monitor 103a. In
the drawing, the input luminance level is shown on the horizontal axis, and the display
luminance level is shown on the vertical axis. When the input luminance level is at a
reference luminance RL, the display luminance level is at the reference level (%), for
example, of 100% that corresponds to the white luminance value of 100cd/m2. When
the input luminance level is at a peak luminance PL, the display luminance level is at
the peak level (%).
[0031] Note that a threshold luminance CL is newly defined in the present embodiment, and
indicates the boundary between the region of which input luminance corresponds to the
luminance when the region is displayed in the monitor (CE monitor) on the receiving
device, and the region of which luminance depends on the CE monitor. When the
monitor input luminance level is at the threshold luminance CL, the display luminance
level is at the threshold level (%).
[0032] With reference to Fig. 2 again, the HDR opto-electrical transfer unit 103 obtains
transmission video data VI by applying an opto-electrical transfer function for HDR
images (an HDR OETF curve) to the HDR video data obtained with the HDR camera
102.
[0033] Fig. 4 illustrates an exemplary opto-electrical transfer function (OETF). In the
drawing, the input luminance level is shown on the horizontal axis, similarly to the
horizontal axis of the display luminance characteristic of the master monitor (see Fig.
3), and a transmission code value is shown on the vertical axis. When the input
luminance level is at the reference luminance RL, the transmission code value is at a
reference level RP. When the input luminance level is at the peak luminance PL, the
transmission code value is at a peak level MP. When the input luminance level is at
the threshold luminance CL, the transmission code value is at a threshold level THP.
[0034] Note that the range of the transmission code value on the vertical axis corresponds to
the input pixel data range (Encoder input pixel data range) of the video encoder
104. For example, when data is encoded in 10-bit encoding, the range is from "64" to
"940", or from "4" to "1019" using the expanded region.
[0035] With reference to Fig. 2 again, the video encoder 104 obtains encoded video data by
encoding the transmission video data VI, for example, with MPEG-4 AVC encoding,
MPEG-2 video encoding, or high Efficiency Video Coding (HEVC) encoding. The
video encoder 104 includes a stream formatter (not illustrated) at the latter part to
generate a video stream (video elementary stream) including the encoded video
data. At that time, the video encoder 104 inserts the luminance conversion acceptable
range information about a set region in the screen and the luminance conversion ac
ceptable range information about the entire screen into a layer of the video stream.
[0036] (Insertion of Luminance Conversion Acceptable Range Information)
The insertion of the luminance conversion acceptable range information will be
described in detail. According to the present embodiment, a regional level mapping
SEI message (Regional_Level_mapping SEI message) that is newly defined is inserted
in the part of "SEIs" in an access unit (AU).
[0037] Fig. 5 illustrates the head access unit of a Group Of Pictures (GOP) when the data is
encoded with an HEVC encoding method. Fig. 6 illustrates an access unit other than
the head access unit of a GOP when the data is encoded with an HEVC encoding
method. When data is encoded with an HEVC encoding method, an SEI message
group "Prefix_SEIs" for decoding is placed before slices in which pixel data is
encoded, and an SEI message group "Suffix_SEIs" for displaying is placed after the
slices. As illustrated in Figs. 5 and 6, the regional level mapping SEI message is
places as an SEI message group "Suffix_SEIs".
[0038] A set region in a screen is set in the unit of pixel or in the unit of block including a
predetermined number of pixels. Fig. 7A illustrates an example of set regions set in
the unit of pixel. In the illustrated example, a line MR is the ridge of a mountain, and
regions Rl and R3 including stars and a region R2 including a neon-light sign are set
as set regions. The thing that the creator intends about the regions Rl and R3 is to
merely display the twinkle of the stars. Meanwhile, the creator intends to maintain the
texture of the neon-light sign in the region R2 although the region R2 has a high
luminance.
[0039] Each of the set regions has a rectangle shape and is identified with the pixel co
ordinates on the top left and the pixel coordinates on the bottom right. In other words,
the region Rl is identified with pixel coordinates (xls, yls) on the top left and pixel
coordinates (xle, yle) on the bottom right. The region R2 is identified with pixel co
ordinates (x2s, y2s) on the top left and pixel coordinates (x2e, y2e) on the bottom
right. The region R3 is identified with pixel coordinates (x3s, y3s) on the top left and
pixel coordinates (x3e, y3e) on the bottom right.
[0040] Fig. 7B illustrates an example of set regions set in the unit of block. The screen is
divided into a plurality of blocks in horizontal directions and vertical directions. For
example, a block has a size of 8 * 8 pixels, 16 * 16 pixels, 32 * 32 pixels, or another
size. Each of the blocks is denoted with a block ID. In the illustrated example, regions
Rl 1, R12, and R13 are set as set regions.
[0041] Each of the set regions has a rectangle shape and is identified with the block ID on
the top left and the block ID on the bottom right. In other words, the region Rl 1 is
identified with a block ID (ID Is) on the top left and a block ID (IDle) on the bottom
right. The region R12 is identified with a block ID (ID2s) on the top left and a block
ID (ID2e) on the bottom right. The region R13 is identified with a block ID (ID3s) on
the top left and a block ID (ID3e) on the bottom right.
[0042] Fig. 8 illustrates exemplary formation (Syntax) of a regional level mapping SEI
message when the set regions are set in the unit of pixel. Fig. 9 illustrates exemplary
formation (Syntax) of a regional level mapping SEI message when the set regions are
set in the unit of block. Fig. 10 illustrates the contents (Semantics) of the primary in
formation in the exemplary formation.
[0043] The "level_mapping_cancel_flag" is flag information of a bit. The "1" indicates the
cancelation of the previous state of the level mapping (Level_mapping) message. The
"0" indicates that each element is transmitted and the previous state is refreshed with
the element.
[0044] The eight-bit field of the "coded_data_bit_depth" indicates the bit length of the
encoded data, and is, for example, a length of 8 to 14 bits. The 16-bit field of the
"reference_white_level" is the input luminance value when the display luminance is at
100% in the master monitor 103a, namely, the reference luminance RL. The 16-bit
field of the "reference_white_level_code_value" indicates the level code value is at the
luminance of 100% and the value with the bit precision indicated in the
"coded_data_bit_depth", namely, the reference level RP.
[0045] The eight-bit field of the "number_of_regions" indicates the number of set regions in
a screen. The 16-bit field of the "global_compliant_threshold_level" is a mapping
display threshold for the entire screen. The mapping display threshold is the highest
luminance value in CE display that the creator assumes when the creator intends to
make the luminance in the CE display correspond to the input luminance. The
mapping display threshold is used to indicate that the luminance at a level exceeding
the mapping display threshold is displayed depending on the display capacity of the
CE monitor. The 16-bit field of the "global_compliant_threshold_level_value"
indicates the transmission value (transmission code value) of the mapping display
threshold for the entire screen.
[0046] The 16-bit field of the "position_start_x" and the 16-bit field of the "position_start_y"
indicate the pixel coordinates on the top left identifying a set region. In other words,
the "position_start_x" indicates the horizontal start position of a set region with the
number of pixels when the top left of an effective display region is set at zero. The
"position_start_y" indicates the vertical start position of a set region with the number
of pixels when the top left of an effective display region is set at zero.
[0047] The 16-bit field of the "position_end_x" and the 16-bit field of the "position_end_y"
indicate the pixel coordinates on the bottom right identifying a set region. In other
words, the "position_end_x" indicates the horizontal end position of a set region with
the number of pixels when the top left of an effective display region is set at zero. The
"position_end_y" indicates the vertical end position of a set region with the number of
pixels when the top left of an effective display region is set at zero.
[0048] The 16-bit field of the "block_start" indicates the block ID on the top left identifying
a set region. In other words, the "block_start" indicates the ID (block ID) of a start
block from which the set regions are scanned in a direction from the top left to the
bottom right block by block. The 16-bit field of the "block_end" indicates the block
ID on the bottom right identifying a set region. In other words, the "block_end"
indicates the ID (block ID) of an end block to which the set regions are scanned in a
direction from the top left to the bottom right block by block. The eight-bit field of the
"block_size" indicates the size of the block that is the unit to designate a set
region. For example, the block size is designated in the range of 8 ' 8 pixels when the
value is "0x01", the block size is designated in the range of 16 ' 16 pixels when the
value is "0x02", or the block size is designated in the range of 32 ' 32 pixels when the
value is "0x03".
[0049] The 16-bit field of the "region_compliant_threshold_level" is a mapping display
threshold for the set region. The mapping display threshold is the highest luminance
value in the set region in CE display that the creator assumes when the creator intends
to make the luminance in the set region in the CE display correspond to the input
luminance. The mapping display threshold is used to indicate that the luminance in the
set region at a level exceeding the mapping display threshold is displayed depending
on the display capacity of the CE monitor. The 16-bit field of the
"region_compliant_threshold_level_value" indicates a transmission value
(transmission code value) of the mapping display threshold in the set region.
[0050] The eight-bit field of the "peak_percentage" indicates a value of the percent of the
highest luminance level to 100%. The value is indicated by the creator. For example,
the "peak_percentage" of the peak luminance of 1000 cd/m2 is 1000%. In that case,
the 100% is indicated as a value 1, and the 1000% is 10 times the 100% and is
indicated as a value 10. The 16-bit field of the "peak_percentage_value" indicates the
largest code value of the "peak_percentage" when the data is transmitted with the bit
precision indicated in the "coded_data_bit_depth", namely, the peak level MP. For
example, when the "peak_percentage" is 1000%, the highest value "1019" in 10-bit
transmission indicates the 1000%.
[0051] The information of the "global_compliant_threshold_level" and
"global_compliant_threshold_level_value" in the regional level mapping SEI message
is included in the luminance conversion acceptable range information about the entire
screen. The information of the "region_compliant_threshold_level" and
"region_compliant_threshold_level_value" is included in the luminance conversion ac
ceptable range information about a set region in the screen. This enables the receiving
end to detect the luminance conversion acceptable range information about a set region
and detect also the luminance conversion acceptable range information about the other
regions from the regional level mapping SEI message.
[0052] In such a case, the luminance conversion acceptable range information may be
designated picture by picture, scene by scene, or program by program. Note that the
type of the OETF (opto-electrical transfer function) to be used is transmitted in video
usability information (VUI) to the NAL unit of a sequence parameter set (SPS).
[0053] With reference to Fig. 2 again, the system encoder 105 generates the transport stream
TS including the video stream VS generated with the video encoder 104. The
transmitting unit 106 transmits the transport stream TS through broadcast waves or
with packets on a network to the receiving apparatus 200.
[0054] The operation of the transmitting apparatus 100 illustrated in Fig. 2 will be described
briefly. The HDR video data obtained by the capture with the HDR camera 102 is
supplied to the HDR opto-electrical transfer unit 103. The HDR video data obtained
with the HDR camera 102 is graded with the master monitor 103a. The HDR optoelectrical
transfer unit 103 obtains the transmission video data VI by applying the
opto-electrical transfer function for HDR images (HDR OETF curve) to the HDR
video data. The transmission video data VI is supplied to the video encoder 104.
[0055] The video encoder 104 obtains encoded video data by encoding the transmission
video data VI, for example, with MPEG-4 AVC encoding, MPEG-2 video encoding,
or HEVC encoding.
[0056] The video encoder 104 includes a stream formatter (not illustrated) at the latter part
to generate a video stream (video elementary stream) VS including the encoded video
data. At that time, the video encoder 104 inserts the luminance conversion acceptable
range information about a set region in the screen and the luminance conversion ac
ceptable range information about the entire screen into a layer of the video stream.
[0057] The video stream VS generated with the video encoder 104 is supplied to the system
encoder 105. The system encoder 105 generates an MPEG-2 transport stream TS
including the video stream. The transport stream TS is transmitted through broadcast
waves or with packets on a network to the receiving apparatus 200 with the
transmitting unit 106.
[0058] Exemplary Configuration of Receiving Apparatus
Fig. 11 illustrates an exemplary configuration of the receiving apparatus 200. The
receiving apparatus 200 includes a control unit 201, a receiving unit 202, a system
decoder 203, a video decoder 204, an HDR electro-optical transfer unit 205, a display
mapping unit 206, and a CE monitor 207. The control unit 201 includes a Central
Processing Unit (CPU) to control the operation of each of the components in the
receiving apparatus 200 in accordance with a control program.
[0059] The receiving unit 202 receives the transport stream TS through broadcast waves or
with packets on a network from the transmitting apparatus 100. The system decoder
203 extracts the video stream (elementary stream) VS from the transport stream
TS. The system decoder 203 further extracts various types of information inserted in
the layers of the container (transport stream) to transmit the information to the control
unit 201.
[0060] The video decoder 204 decodes the video stream VS extracted with the system
decoder 203 in a decoding process, and outputs the transmission video data VI. The
video decoder 204 extracts the parameter set or SEI message inserted in each of the
access units included in the video stream VS to transmit the parameter set or SEI
message to the control unit 201.
[0061] The control unit 201 recognizes the OETF (opto-electrical transfer function) used on
the transmitting end from the designation of the type of OETF in the video usability in
formation (VUI) of the SPS to set an EOTF (electro-optical transfer function), for
example, that is inverse to the OETF in the HDR electro-optical transfer unit 205.
[0062] The regional level mapping SEI message is one of the SEI messages extracted with
the video decoder 204 and transmitted to the control unit 201. The control unit 201
may obtain the information of the "global_compliant_threshold_level" and
"global_compliant_threshold_level_value" included in the luminance conversion ac
ceptable range information about the entire screen from the regional level mapping SEI
message. The control unit 201 may obtain also the information of the
"region_compliant_threshold_level" and "region_compliant_threshold_level_value"
included in the luminance conversion acceptable range information about a set region
together with the information about the set region from the regional level mapping SEI
message.
[0063] The HDR electro-optical transfer unit 205 obtains output video data for display an
HDR image by applying, for example, an EOTF (electro-optical transfer function) that
is inverse to the OETF (opto-electrical transfer function) in the HDR opto-electrical
transfer unit 103 of the transmitting apparatus 100 to the transmission video data VI
output from the video decoder 204.
[0064] Fig. 12 illustrates an exemplary electro-optical transfer function (EOTF). In the
drawing, the transmission code value corresponding to the vertical axis in Fig. 4 is
shown on the horizontal axis. The output luminance level (display luminance level)
corresponding to the horizontal axis in Fig. 4 is shown on the vertical axis. In the
drawing, a solid line a is the EOTF curve. When the transmission code value is at the
peak level MP, the output luminance level is PL. When the transmission code value is
at the threshold level THP, the output luminance level is CL.
[0065] When the highest luminance display capacity of the CE monitor 207 is higher than
the highest luminance PL assumed in the master monitor 103a in that case, the output
luminance levels among which the transmission code values are higher than the
threshold level THP are assigned to the range up to the display highest luminance level
DPI of the CE monitor 207 in a process in the display mapping unit 206 (luminance
increasing process). In the drawing, an alternate long and two short dashes line b is an
exemplary luminance conversion process in such a case.
[0066] On the other hand, when the highest luminance display capacity of the CE monitor
207 is lower than the highest luminance PL assumed in the master monitor 103a, the
output luminance levels among which the transmission code values are higher than the
threshold level THP are assigned to the range up to the display highest luminance level
DP2 of the CE monitor 207 in a process in the display mapping unit 206 (luminance
decreasing process). In the drawing, an alternate long and short dash line c is an
exemplary luminance conversion process in such a case.
[0067] With reference to Fig. 11 again, the display mapping unit 206 converts the output
luminance levels in the HDR electro-optical transfer unit 205 that exceed the threshold
luminance CL in accordance with the highest luminance display capacity of the CE
monitor 207, as described above. In that case, the display mapping unit 206 uses the
luminance CL appropriate to the set region in the set region of a screen, and uses the
luminance CL appropriate to the entire screen in the other regions of the screen.
[0068] In such a case, when the transmission code value is at the threshold level THP or
lower, in other words, when the output luminance level is equal to or lower than the
threshold luminance CL, the luminance is reproduced with fidelity to the luminance at
the received level without depending on the CE monitor 207. Thus, for example, the
texture of an object is represented correctly in accordance with the creator's
intention. The CE monitor 207 displays an HDR image in accordance with the output
video data from the display mapping unit 206.
[0069] When the highest luminance display capacity DP of the CE monitor 207 is higher
than the highest luminance PL assumed in the master monitor 103a, in other words,
when DP > PL holds, the display mapping unit 206 assigns the levels exceeding the
threshold luminance CL to the range up to the peak luminance DP with a prede
termined algorithm in a luminance increasing process.
[0070] Each of Figs. 13A and 13B illustrates the display luminance characteristic of the CE
monitor 207 when DP > PL holds. The characteristic includes the luminance
conversion characteristic of the display mapping unit 206. In each of the drawings, the
input luminance level is shown on the horizontal axis, and the display luminance level
is shown on the vertical axis. Fig. 13A illustrates that the threshold luminance CL is
set at a relatively small value CL (1). Fig. 13B illustrates that the threshold luminance
CL is set at a relatively large value CL (2).
[0071] When the input luminance level is at the threshold luminance CL (1), the display
luminance level is at the threshold level THP1. When the input luminance level is at
the threshold luminance CL (2), the display luminance level is at the threshold level
THP2. In other words, when the input luminance level is at a level up to the threshold
luminance CL (1) or CL (2), the display luminance level is at the level that the creator
intends. When the input luminance level is at the peak luminance PL, the display
luminance level is at the peak level DP of the CE monitor 207. In other words, when
the input luminance level is between the threshold luminance CL (1) or CL (2) and the
peak luminance PL, a luminance increasing process is performed as denoted with a
solid line LI or L2.
[0072] When the highest luminance display capacity DP of the CE monitor 207 is lower
than the highest luminance PL assumed in the master monitor 103a, in other words,
when DP < PL holds, the display mapping unit 206 assigns the levels exceeding the
threshold luminance CL to the range up to the peak luminance DP with a prede
termined algorithm in a luminance decreasing process.
[0073] Each of Figs. 14A and 14B illustrates the display luminance characteristic of the CE
monitor 207 when DP < PL holds and the highest luminance display capacity DP is
relatively high. The display luminance characteristic includes the luminance
conversion characteristic of the display mapping unit 206. In each of the drawings, the
input luminance level is shown on the horizontal axis, and the display luminance level
is shown on the vertical axis.
[0074] Fig. 14A illustrates that the threshold luminance CL is set at a relatively small value
CL (3). Fig. 14B illustrates that the threshold luminance CL is set at a relatively large
value CL (4). When the input luminance level is at the threshold luminance CL (3),
the display luminance level is at the threshold level THP3. When the input luminance
level is at the threshold luminance CL (4), the display luminance level is at the
threshold level THP4. In other words, when the input luminance level is at a level up
to the threshold luminance CL (3) or CL (4), the display luminance level is at the level
that the creator intends. When the input luminance level is at the peak luminance PL,
the display luminance level is at the peak level DP of the CE monitor 207. In other
words, when the input luminance level is between the threshold luminance CL (3) or
CL (4) and the peak luminance PL, a luminance decreasing process is performed as
denoted with a solid line L31 or L41.
[0075] Each of Figs. 15A and 15B illustrates the display luminance characteristic of the CE
monitor 207 when DP < PL holds and the highest luminance display capacity DP is
relatively low. The display luminance characteristic includes the luminance
conversion characteristic of the display mapping unit 206. In each of the drawings, the
input luminance level is shown on the horizontal axis, and the display luminance level
is shown on the vertical axis.
[0076] Fig. 15A illustrates that the threshold luminance CL is set at a relatively small value
CL (3) and the threshold level THP3 is lower than the peak level DP of the CE monitor
207. When the input luminance level is at the threshold luminance CL (3), the display
luminance level is at the threshold level THP3. In other words, when the input
luminance level is at a level up to the threshold luminance CL (3), the display
luminance level is at the level that the creator intends. When the input luminance level
is at the peak luminance PL, the display luminance level is at the peak level DP of the
CE monitor 207. In other words, when the input luminance level is between the
threshold luminance CL (3) and the peak luminance PL, a luminance decreasing
process is performed as denoted with a solid line L32.
[0077] Fig. 15B illustrates that the threshold luminance CL is set at a relatively large value
CL (4) and the threshold level THP4 is higher than the peak level DP of the CE
monitor 207. When the input luminance level is at a value CLa smaller than the
threshold luminance CL (4), the display luminance level is at the peak level DP of the
CE monitor 207. In other words, when the input luminance level is at a level up to the
threshold luminance CLa, the display luminance level is at the level that the creator
intends in such a case. When the input luminance level is between the value CLa and
the peak luminance PL, the display luminance level is, for example, at the peak level
DP of the CE monitor 207 as denoted with solid line L42. Note that a display
luminance conversion may be performed in such a case so as to vary the display
luminance level smoothly on the high luminance side, for example, as denoted with a
dashed line L42'.
[0078] The operation of the receiving apparatus 200 illustrated in Fig. 11 will be described
briefly. The receiving unit 202 receives the transport stream TS from the transmitting
apparatus 100 through broadcast waves or with packets on a network. The transport
stream TS is supplied to the system decoder 203. The system decoder 203 extracts the
video stream (elementary stream) VS from the transport stream TS.
[0079] The video stream VS extracted with the system decoder 203 is supplied to the video
decoder 204. The video decoder 204 decodes the video stream VS extracted with the
system decoder 203 in a decoding process to obtain the transmission video data
VI. The video decoder 204 extracts the parameter set or SEI message inserted in each
of the access units included in the video stream VS to transmit the extracted parameter
set or SEI message to the control unit 201.
[0080] The control unit 201 obtains the information of "global_compliant_threshold_level"
and "global_compliant_threshold_level_value" included in the luminance conversion
acceptable range information about the entire screen from the regional level mapping
SEI message. The control unit 201 further obtains the information of
"region_compliant_threshold_level" and "region_compliant_threshold_level_value"
included in the luminance conversion acceptable range information about each of the
set regions together with the information about the set region from the regional level
mapping SEI message.
[0081] The transmission video data VI obtained with the video decoder 204 is supplied to
the HDR electro-optical transfer unit 205. The HDR electro-optical transfer unit 205
obtains output video data for displaying an HDR image by applying, for example, an
EOTF (electro-optical transfer function) that is inverse to the OETF (opto-electrical
transfer function) of the HDR opto-electrical transfer unit 103 in the transmitting
apparatus 100 to the transmission video data VI. The output video data is supplied to
the display mapping unit 206.
[0082] The display mapping unit 206 coverts the output luminance levels exceeding the
luminance CL in the HDR electro-optical transfer unit 205 in accordance with the
highest luminance display capacity of the CE monitor 207. At that time, the display
mapping unit 206 uses the luminance CL appropriate to the set region in the set regions
of the screen, and uses the luminance CL appropriate to the entire screen in the other
regions of the screen. The output video data is supplied from the display mapping unit
206 to the CE monitor 207. The CE monitor 207 displays an HDR image.
[0083] As described above, the transmission video data VI obtained from opto-electrical
transferred HDR video data is transmitted together with the luminance conversion ac
ceptable range information about the set region in the screen in the transmitting and
receiving system 10 illustrated in Fig. 1. Thus, the luminance of each of the set
regions is independently converted in the luminance conversion acceptable range in ac
cordance with the display luminance capacity of the CE monitor 207 on the receiving
end. This can excellently reproduce the luminance atmosphere that the creator intends.
[0084] In the example in Fig. 7A, even when the luminance of the stars in the regions Rl
and R3, and the neon-light sign in the region R2 are set at the same luminance level,
the threshold level CL of the regions Rl and R3 is lower than the luminance level and
the threshold level CL of the region R2 is higher than the luminance level.
[0085] In such a case, the luminance of the stars is included in the luminance conversion ac
ceptable range and is to be display mapped, while the luminance of the neon-light sign
is not included in the luminance conversion acceptable range and is not to be display
mapped. Thus, the creator intentions to merely display the twinkle of the stars in the
regions Rl and R3 and to maintain the texture of the neon-light sign even in the region
R2 having a high luminance can excellently be reproduced on the receiving end.
[0086] The transmission video data VI is transmitted together with the luminance
conversion acceptable range information about the entire screen in addition to the
luminance conversion acceptable range information about the set region in the screen
in the transmitting and receiving system 10 illustrated in Fig. 1. This enables the
receiving end to convert the luminance of the regions other than the set region in the
screen in accordance with the luminance conversion acceptable range information
about the entire screen in a luminance conversion process.
[0087] 2. Variation
Note that, according to the embodiment, the luminance conversion acceptable range
information about a predetermined number of set regions and the luminance
conversion acceptable range information about the entire screen is placed in the
regional level mapping SEI messages to transmit the information to the receiving
end. However, only the luminance conversion acceptable range information about a
predetermined number of set regions may be transmitted to the receiving end. In such
a case, for example, prescribed luminance conversion acceptable range information is
used in the regions other than the set regions in the screen on the receiving end.
[0088] The HDR electro-optical transfer unit 205 performs an electro-optical transfer
process while the display mapping unit 206 performs a luminance conversion process
in accordance with the highest luminance display capacity of the CE monitor 207 in
the receiving apparatus 200 according to the embodiment. However, reflecting the
luminance conversion characteristic on the electro-optical transfer function (EOTF)
enables the HDR electro-optical transfer unit 205 to singly perform an electro-optical
process and a luminance conversion process simultaneously.
[0089] The transmitting and receiving system 10 according to the embodiment includes the
transmitting apparatus 100 and the receiving apparatus 200. However, the con
figuration of the transmitting and receiving system to which the present technology
may be applied is not limited to the embodiment. For example, a television 200 may
include a set top box 200A and a monitor 200B connected to each other via a digital
interface such as a High-Definition Multimedia Interface (HDMI) as illustrated in Fig.
16. Note that the "HDMI" is a registered trademark.
[0090] In such a case, the set top box 200A may determine the highest luminance level of
the monitor 200B in accordance with the information in EDID of the monitor 200B
while obtaining the information via the HDMI when the set top box 200A performs a
display mapping process. Alternatively, when the monitor 200B performs a display
mapping process, the set top box 200A and the monitor 200B can share the in
formation by defining the level mapping SEI message, the type of EOTF, and the in
formation about VUI in meta data such as the "Vender Specific Info Frame".
[0091] According to the embodiment, the transport stream (MPEG-2 TS) is used as a
container. However, the present technology does not limit the transport stream to the
transport stream TS. Even when another packet, for example, in ISO BMFF or MMT
is used, the layers of video data can be implemented in the same manner as according
to the embodiment.
[0092] Thus, the present technology may be applied to a system that distributes data to a
receiving terminal via a network such as the Internet as well. When data is distributed
via the Internet, a container in MP4 or another format is often used to distribute the
data. In other words, containers in various format, for example, a transport stream
(MPEG-2 TS) used as a digital broadcast standard, or MP4 used for distribution via the
Internet may be used for the container according to the present technology.
[0093] The present technology can also be adopted the following configuration.
(1) A transmitting apparatus including:
a processing unit configured to obtain transmission video data by applying a prede
termined opto-electrical transfer function to input video data, and
a transmitting unit configured to transmit the transmission video data together with
luminance conversion acceptable range information about a set region in a screen.
(2) The transmitting apparatus according to (1), wherein the transmitting unit
transmits the transmission video data together with luminance conversion acceptable
range information about an entire screen in addition to the luminance conversion ac
ceptable range information about the set region in the screen.
(3) The transmitting apparatus according to (1) or (2), wherein the set region in the
screen is set in a unit of pixel or in a unit of block including a predetermined number of
pixels.
(4) The transmitting apparatus according to any of (1) to (3), further including:
an information inserting unit configured to insert the luminance conversion ac
ceptable range information into a layer of a video stream obtained by encoding the
transmission video data,
wherein the transmitting unit transmits the video stream.
(5) A transmitting method including:
obtaining transmission video data by applying a predetermined opto-electrical
transfer function to input video data, and
transmitting, with a transmitting unit, the transmission video data together with
luminance conversion acceptable range information about a set region in a screen.
(6) A receiving apparatus including:
a receiving unit configured to receive transmission video data obtained by applying a
predetermined opto-electrical transfer function to input video data together with
luminance conversion acceptable range information about a set region in a screen; and
a processing unit configured to obtain output video data by applying an electro-optical
transfer function corresponding to the predetermined opto-electrical transfer function
to the transmission video data, and converting luminance of the transmission video
data in a luminance conversion process in accordance with the luminance conversion
acceptable range information.
(7) The receiving apparatus according to (6), wherein the receiving unit receives the
transmission video data together with luminance conversion acceptable range in
formation about an entire screen in addition to the luminance conversion acceptable
range information about the set region in the screen, and
the processing unit performs a luminance conversion process in a region other than the
set region in the screen in accordance with the luminance conversion acceptable range
information about the entire screen.
(8) The receiving apparatus according to (6) or (7), wherein the set region in the screen
is set in a unit of pixel or in a unit of block including a predetermined number of
pixels.
(9) The receiving apparatus according to any of (6) to (8),
wherein the receiving unit receives video stream obtained by encoding the
transmission video data, and
the luminance conversion acceptable range information is inserted in a layer of the
video stream.
(10) A receiving method including:
receiving, with a receiving unit, transmission video data obtained by applying a prede
termined opto-electrical transfer function to input video data together with luminance
conversion acceptable range information about a set region in a screen; and
obtaining output video data by applying an electro-optical transfer function corre
sponding to the predetermined opto-electrical transfer function to the transmission
video data, and converting luminance of the transmission video data in a luminance
conversion process in accordance with the luminance conversion acceptable range in
formation.
(ID
A transmitter comprising:
circuitry configured to implement
a processor that applies a predetermined opto-electrical transfer function to input
image data to obtain output image data, and
store the output image data in association with context-determined luminance
conversion range information regarding a sub-region of an image to be displayed.
(12)
The transmitter of 11, wherein the circuitry is further configured to transmit the
output image data in association with the context-determined luminance conversion
range information.
(13)
The transmitter of 11, wherein the output image data is video data, and the subregion
being a smaller region than a region covered by an entirety of a video frame.
(14)
The transmitter according to 12, wherein the transmitter transmits the output image
data together with the context-determined luminance conversion range information
about an entire image area of the image to be displayed in addition to the contextdetermined
luminance conversion range information about the sub-region of the image
to be displayed.
(15)
The transmitter according to 11, wherein the sub-region is defined in units of a
pixel or in a pixel block that includes a predetermined number of pixels.
(16)
The transmitter according to 12, wherein the circuitry is further configured to insert
the context-determined luminance conversion range information into a layer of a video
stream obtained by encoding the output image data, and transmit the video stream via
the transmitter.
(17)
A transmitting method comprising:
applying with circuitry a predetermined opto-electrical transfer function to input
image data to obtain output image data, and
store the output image data in association with a context-determined luminance
conversion range information regarding a sub-region of an image to be displayed.
(18)
The transmitting method of 17, further comprising:
inserting the context-determined luminance conversion range information into a
layer of a video stream obtained by encoding the output image data, and transmitting
the video stream.
The transmitting method of 17, wherein the image data is video data, and the subregion
being a smaller region than a region covered by an entirety of a video frame of a
video image to be displayed.
(20)
A receiver comprising:
circuitry configured to
receive image data from another device that applied a predetermined opto-electrical
transfer function to input image data and stored output image data in association with a
context-determined luminance conversion range for a sub-region of an image to be
displayed, and
apply an electro-optical transfer function, which corresponds to the predetermined
opto-electrical transfer function, to the output image data received from the another
device, and convert a luminance of the output image data received from the another
device in a luminance conversion process in accordance with the context-determined
luminance conversion range information.
(21)
The receiver of 20, wherein the output image data is video data, and the sub-region
being a smaller region than a region covered by an entirety of a video frame.
(22)
The receiver according to 20, wherein the circuitry is further configured to receive
the output image data together with context-determined luminance conversion range
information for an entire image area in addition to the context-determined luminance
conversion range information for the sub-region of the entire image area, and
the circuitry is further configured to perform a luminance conversion process in a
region other than the sub-region in accordance with the context-determined luminance
conversion range information for the entire image area.
(23)
The receiver according to 22, wherein the sub-region is defined in units of a pixel
or in a pixel block that includes a predetermined number of pixels.
(24)
The receiver according to 22,
wherein the circuitry is configured to receive a video stream that includes the
output image data, and
the context-determined luminance conversion range information.
(25)
A receiving method comprising:
receiving, with a receiver, image data from another device that applied a prede
termined opto-electrical transfer function to input image data and stored the image data
in association with a context-determined luminance conversion range for a sub-region
of an image to be displayed; and
obtaining with circuitry output video data by applying an electro-optical transfer
function corresponding to the predetermined opto-electrical transfer function to the
image data, and converting luminance of the image data in a luminance conversion
process in accordance with the context-determined luminance conversion range in
formation.
(26)
The method of 25, wherein the image data is video data, and the sub-region being a
smaller region than a region covered by an entirety of a video frame.
(27)
The method according to 25, further comprising:
receiving the image data together with context-determined luminance conversion
range information for an entire image area in addition to the context-determined
luminance conversion range information for the sub-region of the entire image area,
and
performing with the circuitry a luminance conversion process in a region other than
the sub-region in accordance with the context-determined luminance conversion range
information for the entire image area.
(28)
The method according to 25, wherein the sub-region is defined in units of a pixel or
in a pixel block that includes a predetermined number of pixels.
(29)
The method according to 25,
further comprising:
receiving a video stream that includes the image data, the context-determined
luminance conversion range information.
[0094] According to a primary feature of the present technology, the transmission video data
obtained from electro-optical transferred HDR video data is transmitted together with
the luminance conversion acceptable range information about the set regions in the
screen, and the luminance of each of the set regions in a screen is independently
converted only in the luminance conversion acceptable range on the receiving
end. This can excellently reproduce the luminance atmosphere that the creator intends
(See Figs. 5 to 9).
[0095] It should be understood by those skilled in the art that various modifications, com
binations, sub-combinations and alterations may occur depending on design re
quirements and other factors insofar as they are within the scope of the appended
claims or the equivalents thereof.
Reference Signs List
10, 10A Transmitting and receiving system
100 Transmitting apparatus
101 Control unit
102 HDR camera
103 HDR opto-electrical transfer unit
103a Master monitor
104 Video encoder
105 System encoder
106 Transmitting unit
200 Receiving apparatus
200A Set top box
200B Monitor
201 Control unit
202 Receiving unit
203 System decoder
204 Video decoder
205 HDR electro-optical transfer unit
206 Display mapping unit
207 CE monitor
PCT/JP2015/003866
Claims
A transmitter comprising:
circuitry configured to implement
a processor that applies a predetermined opto-electrical transfer
function to input image data to obtain output image data, and
store the output image data in association with context-determined
luminance conversion range information regarding a sub-region of an
image to be displayed.
The transmitter of claim 1, wherein the circuitry is further
configured to transmit the output image data in association with the
context-determined luminance conversion range information.
The transmitter of claim 1, wherein the output image data is video
data, and the sub-region being a smaller region than a region covered
by an entirety of a video frame.
The transmitter according to claim 2, wherein the transmitter
transmits the output image data together with the context-determined
luminance conversion range information about an entire image area of
the image to be displayed in addition to the context-determined
luminance conversion range information about the sub-region of the
image to be displayed.
The transmitter according to claim 1, wherein the sub-region is
defined in units of a pixel or in a pixel block that includes a prede
termined number of pixels.
The transmitter according to claim 2, wherein the circuitry is further
configured to insert the context-determined luminance conversion
range information into a layer of a video stream obtained by encoding
the output image data, and transmit the video stream via the transmitter.
A transmitting method comprising:
applying with circuitry a predetermined opto-electrical transfer
function to input image data to obtain output image data, and
store the output image data in association with a context-determined
luminance conversion range information regarding a sub-region of an
image to be displayed.
The transmitting method of claim 7, further comprising:
inserting the context-determined luminance conversion range in
formation into a layer of a video stream obtained by encoding the
output image data, and transmitting the video stream.
PCT/JP2015/003866
The transmitting method of claim 7, wherein the image data is
video data, and the sub-region being a smaller region than a region
covered by an entirety of a video frame of a video image to be
displayed.
A receiver comprising:
circuitry configured to
receive image data from another device that applied a prede
termined opto-electrical transfer function to input image data and stored
output image data in association with a context-determined luminance
conversion range for a sub-region of an image to be displayed, and
apply an electro-optical transfer function, which corresponds to the
predetermined opto-electrical transfer function, to the output image
data received from the another device, and convert a luminance of the
output image data received from the another device in a luminance
conversion process in accordance with the context-determined
luminance conversion range information.
The receiver of claim 10, wherein the output image data is video
data, and the sub-region being a smaller region than a region covered
by an entirety of a video frame.
The receiver according to claim 10, wherein the circuitry is further
configured to receive the output image data together with contextdetermined
luminance conversion range information for an entire
image area in addition to the context-determined luminance conversion
range information for the sub-region of the entire image area, and
the circuitry is further configured to perform a luminance
conversion process in a region other than the sub-region in accordance
with the context-determined luminance conversion range information
for the entire image area.
The receiver according to claim 12, wherein the sub-region is
defined in units of a pixel or in a pixel block that includes a prede
termined number of pixels.
The receiver according to claim 12,
wherein the circuitry is configured to receive a video stream that
includes the output image data, and
the context-determined luminance conversion range information.
A receiving method comprising:
receiving, with a receiver, image data from another device that
applied a predetermined opto-electrical transfer function to input image
WO 2016/031144 PCT/JP2015/003866
data and stored the image data in association with a context-determined
luminance conversion range for a sub-region of an image to be
displayed; and
obtaining with circuitry output video data by applying an electrooptical
transfer function corresponding to the predetermined optoelectrical
transfer function to the image data, and converting luminance
of the image data in a luminance conversion process in accordance with
the context-determined luminance conversion range information.
[Claim 16] The method of claim 15, wherein the image data is video data, and
the sub-region being a smaller region than a region covered by an
entirety of a video frame.
[Claim 17] The method according to claim 15, further comprising:
receiving the image data together with context-determined
luminance conversion range information for an entire image area in
addition to the context-determined luminance conversion range in
formation for the sub-region of the entire image area, and
performing with the circuitry a luminance conversion process in a
region other than the sub-region in accordance with the context-de
termined luminance conversion range information for the entire image
area.
[Claim 18] The method according to claim 15, wherein the sub-region is
defined in units of a pixel or in a pixel block that includes a prede
termined number of pixels.
[Claim 19] The method according to claim 15,
further comprising:
receiving a video stream that includes the image data, the contextdetermined
luminance conversion range information.