SEI message for film grain synthesis
A method and apparatus comprising computer code configured to cause a processor or processors to obtain video data comprising at least one coded picture, reconstruct a coded picture including a film grain characteristics SEI message, an alpha channel information SEI message, and at least a first sample and a second sample and at least a third alpha map sample and a fourth alpha map sample, wherein after reconstruction the first sample and the third alpha map sample, and the second sample and first sample are spatially co-located; apply film grain synthesis to the first sample based on a first value of the third sample; and determine to not applying film grain syntheses to the second sample based on a second value of the fourth sample, wherein the first value and second value are different from each other.
1 . A method for video decoding, the method comprising:
obtaining video data comprising at least one coded picture;
reconstructing a coded picture comprising a film grain characteristics SEI message, an alpha channel information SEI message, and at least a first sample and a second sample and at least a third alpha map sample and a fourth alpha map sample, after reconstruction the first sample and the third alpha map sample, and the second sample and the fourth alpha map sample are spatially co-located, and the film grain characteristics SEI message:
specifies coordinates of a top-left corner and a width and a height of a bounding box of an i-th region of a picture by any of an for region_top[i] syntax, an for region left[i] syntax, an for region width[i] syntax, and an for region height[i] syntax, and any of:
a value of the fgr_region_top[i] syntax is expressed in the film grain characteristics SEI message as in a range of 0 to PicWidthInLumaSamples−1, inclusive,
a value of the fgr_region left[i] syntax is expressed in the film grain characteristics SEI message as in a range of 0 to PicHeightInLumaSamples−1, inclusive,
a value of the fgr_region width[i] syntax is expressed in the film grain characteristics SEI message as in a range of 0 to PicWidthInLumaSamples−for region left[i], inclusive, and
a value of the for region height[i] syntax is expressed in the film grain characteristics SEI message as in a range of 0 to PicHeightInLumaSamples−fgr_region_top[i], inclusive;
applying film grain synthesis to the first sample based on a first value of the third sample; and
determining to not apply film grain synthesis to the second sample based on a second value of the fourth sample, wherein the first value and second value are different from each other.
2 . The method according to claim 1 , wherein each of:
the value of the fgr_region_top[i] syntax is expressed in the film grain characteristics SEI message as in the range of 0 to PicWidthInLumaSamples−1, inclusive,
the value of the fgr_region_left[i] syntax is expressed in the film grain characteristics SEI message as in the range of 0 to PicHeightInLumaSamples−1, inclusive,
the value of the for_region_width[i] syntax is expressed in the film grain characteristics SEI message as in the range of 0 to PicWidthInLumaSamples−fgr_region_left[i], inclusive, and
the value of the fgr_region_height[i] syntax is expressed in the film grain characteristics SEI message as in the range of 0 to PicHeightInLumaSamples−fgr_region_top[i], inclusive.
3 . The method according to claim 1 ,
wherein the first sample and the second sample are both rectangular.
4 . The method according to claim 1 ,
wherein the first sample and the second sample are at least partly overlapping each other.
5 . A method for video encoding, the method comprising:
obtaining video data comprising at least one picture; and
encoding the video data such that reconstructing the at least one picture comprises reconstructing the at least one picture based on a film grain characteristics SEI message, an alpha channel information SEI message, and at least a first sample and a second sample and at least a third alpha map sample and a fourth alpha map sample, after reconstruction the first sample and the third alpha map sample, and the second sample and the fourth alpha map sample are spatially co-located, and the film grain characteristics SEI message:
specifies coordinates of a top-left corner and a width and a height of a bounding box of an i-th region of a picture by any of an for region_top[i] syntax, an for region left[i] syntax, an for region width[i] syntax, and an for region height[i] syntax, and any of:
a value of the fgr_region_top[i] syntax is expressed in the film grain characteristics SEI message as in a range of 0 to PicWidthInLumaSamples−1, inclusive,
a value of the fgr_region left[i] syntax is expressed in the film grain characteristics SEI message as in a range of 0 to PicHeightInLumaSamples−1, inclusive,
a value of the fgr_region width[i] syntax is expressed in the film grain characteristics SEI message as in a range of 0 to PicWidthInLumaSamples−for region left[i], inclusive, and
a value of the for region height[i] syntax is expressed in the film grain characteristics SEI message as in a range of 0 to PicHeightInLumaSamples—fgr_region_top[i], inclusive,
wherein reconstructing the at least one picture further comprises applying film grain synthesis to the first sample based on a first value of the third sample and determining to not apply film grain synthesis to the second sample based on a second value of the fourth sample, wherein the first value and second value are different from each other.
6 . The method according to claim 5 , wherein each of:
the value of the fgr_region_top[i] syntax is expressed in the film grain characteristics SEI message as in the range of 0 to PicWidthInLumaSamples−1, inclusive,
the value of the fgr_region_left[i] syntax is expressed in the film grain characteristics SEI message as in the range of 0 to PicHeightInLumaSamples−1, inclusive,
the value of the fgr_region_width[i] syntax is expressed in the film grain characteristics SEI message as in the range of 0 to PicWidthInLumaSamples−fgr_region_left[i], inclusive, and
the value of the fgr_region_height[i] syntax is expressed in the film grain characteristics SEI message as in the range of 0 to PicHeightInLumaSamples−fgr_region_top[i], inclusive.
7 . The method according to claim 5 ,
wherein the first sample and the second sample are both rectangular.
8 . The method according to claim 5 ,
wherein the first sample and the second sample are at least partly overlapping each other.
9 . A method of processing visual media data, the method comprising:
performing a conversion between a visual media file and a bitstream of a visual media data according to a format rule indicating to
obtain video data comprising at least one coded picture;
reconstruct a coded picture comprising a film grain characteristics SEI message, an alpha channel information SEI message, and at least a first sample and a second sample and at least a third alpha map sample and a fourth alpha map sample, wherein after reconstruction the first sample and the third alpha map sample, and the second sample and the fourth alpha map sample are spatially co-located, and the film grain characteristics SEI message:
specifies coordinates of a top-left corner and a width and a height of a bounding box of an i-th region of a picture by any of an for region_top[i] syntax, an for region left[i] syntax, an for region width[i] syntax, and an fgr_region height[i] syntax, and any of:
a value of the for region_top[i] syntax is expressed in the film grain characteristics SEI message as in a range of 0 to PicWidthInLumaSamples−1, inclusive,
a value of the for region left[i] syntax is expressed in the film grain characteristics SEI message as in a range of 0 to PicHeightInLumaSamples−1, inclusive,
a value of the for region width[i] syntax is expressed in the film grain characteristics SEI message as in a range of 0 to PicWidthInLumaSamples−for region left[i], inclusive, and
a value of the for region height[i] syntax is expressed in the film grain characteristics SEI message as in a range of 0 to PicHeightInLumaSamples−fgr_region_top[i], inclusive;
apply film grain synthesis to the first sample based on a first value of the third sample; and
determine to not apply film grain synthesis to the second sample based on a second value of the fourth sample, wherein the first value and second value are different from each other.
10 . The method according to claim 9 , wherein each of:
the value of the fgr_region_top[i] syntax is expressed in the film grain characteristics SEI message as in the range of 0 to PicWidthInLumaSamples−1, inclusive,
the value of the fgr_region_left[i] syntax is expressed in the film grain characteristics SEI message as in the range of 0 to PicHeightInLumaSamples−1, inclusive,
the value of the fgr_region_width[i] syntax is expressed in the film grain characteristics SEI message as in the range of 0 to PicWidthInLumaSamples−fgr_region_left[i], inclusive, and
the value of the fgr_region_height[i] syntax is expressed in the film grain characteristics SEI message.
11 . The method according to claim 9 ,
wherein the first sample and the second sample are both rectangular.
12 . The method according to claim 2 , wherein applying the film grain synthesis to the first sample based on the first value of the third sample comprises simulating film grain in a chroma format 4:4:4.
13 . The method according to claim 2 , wherein applying the film grain synthesis to the first sample based on the first value of the third sample comprises simulating film grain in a chroma format 4:2:0.
14 . The method according to claim 2 , wherein applying the film grain synthesis to the first sample based on the first value of the third sample comprises simulating film grain in a chroma format 4:2:2.
15 . The method according to claim 6 , wherein applying the film grain synthesis to the first sample based on the first value of the third sample comprises simulating film grain in a chroma format 4:4:4.
16 . The method according to claim 6 , wherein applying the film grain synthesis to the first sample based on the first value of the third sample comprises simulating film grain in a chroma format 4:2:0.
17 . The method according to claim 6 , wherein applying the film grain synthesis to the first sample based on the first value of the third sample comprises simulating film grain in a chroma format 4:2:2.
18 . The method according to claim 6 , wherein applying the film grain synthesis to the first sample based on the first value of the third sample comprises simulating film grain in a chroma format 4:4:4.
19 . The method according to claim 6 , wherein applying the film grain synthesis to the first sample based on the first value of the third sample comprises simulating film grain in a chroma format 4:2:0.
20 . The method according to claim 10 , wherein applying the film grain synthesis to the first sample based on the first value of the third sample comprises simulating film grain in a chroma format 4:2:2.