Method and system for constraining tile processing overhead in video coding
A method for encoding a picture of a video sequence in a bit stream that constrains tile processing overhead is provided. The method includes computing a maximum tile rate for the video sequence, computing a maximum number of tiles for the picture based on the maximum tile rate, and encoding the picture wherein a number of tiles used to encode the picture is enforced to be no more than the maximum number of tiles.
1. A method for encoding a picture of a video sequence in a bit stream, the method comprising:
determining, by one or more processors, a level for the video sequence, wherein the level specifies values for MaxLumaSR, MaxLumaPS, MaxTileCols, and MaxTileRows
computing, by the one or more processor circuits, a maximum tile rate for the video sequence;
setting, by the one or more processor circuits, a value of a maximum number of tiles for the picture as a minimum of (a) a maximum number of tiles per picture specified for the video sequence and (b) the maximum tile rate divided by a frame rate of the video sequence, wherein the maximum number of tiles per picture is specified independently of the maximum tile rate divided by the frame rate; and
encoding, by the one or more processor circuits, the picture wherein a number of tiles used to encode the picture is enforced to be no more than the value of the maximum number of tiles.
2. A method comprising:
decoding, one or more processors, a bitstream such that a removal time of access unit 0 satisfies the following constraint:
the number of tiles in picture 0 is less than or equal to a minimum value of a first value and a second value,
the first value being a function of a sum of a third value and a fourth value,
the third value being a function of MaxTileCols*MaxTileRows*(t r (0)−t r,n (0)),
the fourth value being equal to
MaxTileCols*MaxTileRows*PicSizeInSamples Y /MaxLumaPS,
the second value being equal to MaxTileCols*MaxTileRows,
where MaxTileCols, MaxTileRows, and MaxLumaPS are specified values that apply to picture 0, and where:
MaxTileCols represents a maximum number of tile columns,
MaxTileRows represents a maximum number of tile rows,
MaxLumaPS represents a maximum luma picture size, t r (0) represents the removal time of access unit 0, and
t r,n (0) represents a nominal removal time of access unit 0, the method further comprising:
displaying, by a display, video data obtained from the decoded bitstream.
3. The method of claim 2 , wherein the third value is equal to:
MaxTileCols*MaxTileRows* K *( t r (0) −t r,n (0)).
4. The method of claim 3 , wherein the third value is equal to:
wherein K=120.
5. The method of claim 3 , wherein K=MaxLumaSR/MaxLumaPS, where MaxLumaSR is a maximum luma sample rate.
6. A device comprising:
one or more processors configured to decode a bitstream such that a removal time of access unit 0 satisfies the following constraint:
the number of tiles in picture 0 is less than or equal to a minimum value of a first value and a second value,
the first value being a function of a sum of a third value and a fourth value,
the third value being a function of MaxTileCols*MaxTileRows*(t r (0)−t r,n (0)),
the fourth value being equal to
MaxTileCols*MaxTileRows*PicSizeInSamples Y /MaxLumaPS,
the second value being equal to MaxTileCols*MaxTileRows,
where MaxTileCols, MaxTileRows, and MaxLumaPS are specified values that apply to picture 0, and where:
MaxTileCols represents a maximum number of tile columns,
MaxTileRows represents a maximum number of tile rows,
MaxLumaPS represents a maximum luma picture size,
t r (0) represents the removal time of access unit 0, and
t r,n (0) represents a nominal removal time of access unit 0, the method further comprising:
a display configured to display video data obtained from the decoded bitstream.
7. The device of claim 6 , wherein the third value is equal to:
MaxTileCols*MaxTileRows* K *( t r (0) −t r,n (0)).
8. The device of claim 7 , wherein the third value is equal to:
wherein K=120.
9. The device of claim 7 , wherein K=MaxLumaSR/MaxLumaPS, where MaxLumaSR is a maximum luma sample rate.
10. A method comprising:
decoding, by one or more processors, a bitstream based on a removal time of access unit 0, wherein the removal time of access unit 0 satisfies the following constraint:
the number of tiles in picture 0 is less than or equal to a minimum value of a first value and a second value,
the first value being a function of a sum of a third value and a fourth value,
the third value being a function of MaxTileCols*MaxTileRows*(t r (0)−t r,n (0)),
the fourth value being equal to
MaxTileCols*MaxTileRows*PicSizeInSamples Y /MaxLumaPS,
the second value being equal to MaxTileCols*MaxTileRows,
where MaxTileCols, MaxTileRows, and MaxLumaPS are specified values that apply to picture 0, and where:
MaxTileCols represents a maximum number of tile columns,
MaxTileRows represents a maximum number of tile rows,
MaxLumaPS represents a maximum luma picture size,
t r (0) represents the removal time of access unit 0, and
t r,n (0) represents a nominal removal time of access unit 0, the method further comprising:
displaying, by a display, video data obtained from the decoded bitstream.
11. The method of claim 10 , wherein the third value is equal to:
MaxTileCols*MaxTileRows*K*(t r (0)−t r,n (0)).
12. The method of claim 11 , wherein the third value is equal to:
wherein K=120.
13. The method of claim 11 , wherein K=MaxLumaSR/MaxLumaPS, where MaxLumaSR is a maximum luma sample rate.
14. A device comprising:
one or more processors configured to decode a bitstream based on a removal time of access unit 0, wherein the removal time of access unit 0 satisfies the following constraint:
the number of tiles in picture 0 is less than or equal to a minimum value of a first value and a second value,
the first value being a function of a sum of a third value and a fourth value,
the third value being a function of MaxTileCols*MaxTileRows*(t r (0)−t r,n (0)),
the fourth value being equal to
MaxTileCols*MaxTileRows*PicSizeInSamples Y /MaxLumaPS,
the second value being equal to MaxTileCols*MaxTileRows,
where MaxTileCols, MaxTileRows, and MaxLumaPS are specified values that apply to picture 0, and where:
MaxTileCols represents a maximum number of tile columns,
MaxTileRows represents a maximum number of tile rows,
MaxLumaPS represents a maximum luma picture size,
t r (0) represents the removal time of access unit 0, and
t r,n (0) represents a nominal removal time of access unit 0, the method further comprising:
a display configured to display video data obtained from the decoded bitstream.
15. The device of claim 14 , wherein the third value is equal to:
MaxTileCols*MaxTileRows* K *( t r (0) −t r,n (0)).
16. The device of claim 15 , wherein the third value is equal to:
wherein K=120.
17. The device of claim 15 , wherein K=MaxLumaSR/MaxLumaPS, where MaxLumaSR is a maximum luma sample rate.
18. A method comprising:
decoding, by one or more processors, a bitstream that is encoded based on a removal time of access unit 0 satisfying the following constraint:
the number of tiles in picture 0 is less than or equal to a minimum value of a first value and a second value,
the first value being a function of a sum of a third value and a fourth value,
the third value being a function of MaxTileCols*MaxTileRows*(t r (0)−t r,n (0)),
the fourth value being equal to
MaxTileCols*MaxTileRows*PicSizeInSamples Y /MaxLumaPS,
the second value being equal to MaxTileCols*MaxTileRows,
where MaxTileCols, MaxTileRows, and MaxLumaPS are specified values that apply to picture 0, and where:
MaxTileCols represents a maximum number of tile columns,
MaxTileRows represents a maximum number of tile rows,
MaxLumaPS represents a maximum luma picture size,
t r (0) represents the removal time of access unit 0, and
t r,n (0) represents a nominal removal time of access unit 0, the method further comprising:
displaying, by a display, video data obtained from the decoded bitstream.
19. The method of claim 18 , wherein the third value is equal to:
MaxTileCols*MaxTileRows* K *( t r (0) −t r,n (0)).
20. The method of claim 19 , wherein the third value is equal to:
wherein K=120.
21. The method of claim 19 , wherein K=MaxLumaSR/MaxLumaPS, where MaxLumaSR is a maximum luma sample rate.
22. A device comprising:
one or more processors configured to decode a bitstream that is encoded based on a removal time of access unit 0 satisfying the following constraint:
the number of tiles in picture 0 is less than or equal to a minimum value of a first value and a second value,
the first value being a function of a sum of a third value and a fourth value,
the third value being a function of MaxTileCols*MaxTileRows*(t r (0)−t r,n (0)),
the fourth value being equal to
MaxTileCols*MaxTileRows*PicSizeInSamples Y /MaxLumaPS,
the second value being equal to MaxTileCols*MaxTileRows,
where MaxTileCols, MaxTileRows, and MaxLumaPS are specified values that apply to picture 0, and where:
MaxTileCols represents a maximum number of tile columns,
MaxTileRows represents a maximum number of tile rows,
MaxLumaPS represents a maximum luma picture size,
t r (0) represents the removal time of access unit 0, and
t r,n (0) represents a nominal removal time of access unit 0, the method further comprising:
a display configured to display video data obtained from the decoded bitstream.
23. The device of claim 22 , wherein the third value is equal to:
MaxTileCols*MaxTileRows* K *( t r (0) −t r,n (0)).
24. The device of claim 23 , wherein the third value is equal to:
wherein K=120.
25. The device of claim 23 , wherein K=MaxLumaSR/MaxLumaPS, where MaxLumaSR is a maximum luma sample rate.