INTRARANDOM ACCESS POINTS FOR IMAGE ENCODING

Abstract

Methods and devices for video processing are described, including encoding and decoding. An example of a video processing method includes performing a conversion between a video and a video bitstream according to a format rule, where the bitstream includes one or more output layer sets (OLS), each OLS comprises one or more encoded layer video sequences, and where the format rule specifies that a set of video parameters indicates, for each of the one or more OLS, a maximum allowable value of a chroma format indicator and / or a maximum allowable value of a bit depth used to represent video pixels.

Claims

CLAIMS 1. A video processing method, comprising performing a conversion between a video having one or more video layers comprising one or more video images and a video bitstream according to a format rule, and wherein the format rule specifies that a first video image being an intra-random access point image associated with a second image and the second image are restricted to belonging to the same video layer.

2. The method according to claim 1, wherein, between the first video image and the second image in decoding order, there is no gradual decoding refresh image in the same video layer.

3. The method according to claim 1, wherein the first video image and the second image have the same identifier of a layer to which a network abstraction layer unit of the video encoding layer belongs or the same identifier of a layer to which a network abstraction layer unit that is not video encoding is applied.

4. The method according to any of claims 1 to 3, wherein, between the first video image and the second image in decoding order, there is no gradual decoding refresh image with the same identifier.

5. The method according to claim 1, wherein the formatting rule further specifies that a drag image follows an associated intra-random hotspot image or a gradual decoding refresh image in an output order.

6. A video processing method, comprising performing a conversion between a video having one or more video layers comprising one or more video frames and a video bitstream according to a format rule, wherein the format rule specifies that a drag frame in the bitstream is allowed to be associated with a gradually decoding refresh frame 7. The method according to claim 6, wherein the drag image is an image for which each network abstraction layer unit of the video encoding layer has a type of drag network abstraction layer unit.

8. The method according to claim 6 or 7, wherein the drag image is permitted to be associated with an intra-random hotspot image.

9. The method according to any of claims 6 to 8, wherein the tracking image associated with an intra-random hotspot image or a gradual decoding refresh image follows the intra-random hotspot image or the gradual decoding refresh image in the decoding order.

10. The method according to any of claims 6 to 8, wherein images following the associated intra-random access point image in the output order and preceding the associated intra-random access point image in the decoding order are not permitted.

11. The method of claim 6, wherein the format rule further specifies that, for each layer, each layer image, except the first layer image in the bitstream, is associated with a nearest one from a previous intra-random access point or a gradual refresh image of the same layer's decoder in the decoding order.

12. The method of claim 6 or 11, wherein the subsequent image is required to follow the associated intra-random access point or the gradual decoder refresh image in the output order.

13. A video processing method, comprising performing a conversion between a video having one or more video layers comprising one or more video images and a video bitstream according to a format rule, and wherein the format rule specifies that a restriction for an output order of images preceding an intra-random access point in a decoding order is applicable to images of the same video layer.

14. The method of claim 13, wherein the restriction specifies that any image having a NAL (Network Abstraction Layer) unit header identifier equal to a particular value and preceding, in a decoding order, an intra-random access point image with the NAL unit header layer identifier equal to the particular value is required to precede, in an output order, the intra-random access point image and all associated decodable random access head images.

15. The method of claim 14, wherein the unit NAL (network abstraction layer) header layer identifier is nuh layer id.

16. The method of claim 14, wherein the header layer identifier of the NAL (network abstraction layer) unit specifies the identifier of a layer to which a video encoding network abstraction layer unit belongs or the identifier of a layer to which a non-video encoding network abstraction layer unit is applied.

17. A video processing method, comprising performing a conversion between a video having one or more video layers comprising one or more video frames and a video bitstream according to a format rule, and wherein the format rule specifies a restriction that (1) a trace frame follows an associated intra-random access point frame or a gradual decoder refresh frame in an output order, or (2) a frame having the same NAL (Network Abstraction Layer) header identifier as the gradual decoder refresh frame precedes, in the output order, the gradual decoder refresh frame and all associated frames of the gradual decoder refresh frame.

18. A video processing method, comprising performing a conversion between a video having one or more video layers comprising one or more video images and a video bitstream according to a rule, and wherein the rule specifies applying a restriction on a decoding order of an image associated with an intra-random access point image and a non-leading image if and only if the image, the intra-random access point image, and the non-leading image are in the same layer.

19. The method according to claim 18, wherein the restriction specifies that if a field sequence indicator value is equal to 0 and the image with a NAL (Network Abstraction Layer) unit header identifier equal to a particular value is a prime image associated with the intra-random access point image, the image precedes, in the decoding order, all non-prime images that are associated with the intra-random access point image.

20. The method according to claim 19, wherein the field sequence flag value equal to 0 indicates that a layer-coded video sequence transmits images representing frames.

21. The method according to claim 18, wherein the restriction specifies that if a field sequence flag value is equal to 0 and the image is a principal image associated with the intra-random access point image, the image precedes, in the decoding order, all non-principal images that are associated with the intra-random access point image.

22. A video processing method, comprising performing a conversion between a video having one or more video layers comprising one or more video frames and a video bitstream according to a rule, and wherein the rule specifies an order of a master frame, a random-access decodable master frame, and a random-access skipped master frame associated with a gradual-decoding refresh frame.

23. The method according to claim 22, wherein the main image associated with the gradual decoding refresh image follows the gradual decoding refresh image in the decoding order and precedes the gradual decoding refresh image in the output order.

24. The method according to claim 22, wherein the random-access decodable main image associated with the step-down decoding refresh image is the main image associated with the step-down decoding refresh image and has a NAL (network abstraction layer) unit type corresponding to an encoded portion of the random-access decodable main image.

25. The method according to claim 22, wherein the random-access decodable main image associated with the step-down decoding refresh image is the main image associated with the step-down decoding refresh image and has a NAL (network abstraction layer) unit type corresponding to an encoded portion of the random-access decodable main image.

26. A video processing method, comprising performing a conversion between a video having one or more video layers comprising one or more video images and a video bitstream according to a rule, and wherein the rule specifies that a restriction for a reference image list for a portion of a clean random-access image is limited to one layer.

27. The method according to claim 26, wherein the restriction specifies that, for a layer having the clear random access image, a preceding intra-random access point image in a decode or output order is not referenced by an entry in the reference image list.

28. The method according to any of claims 1 to 27, wherein the conversion includes encoding the video in the bitstream.

29. The method according to any of claims 1 to 27, wherein the conversion includes decoding the video from the bitstream.

30. The method of claims 1 to 27, wherein the conversion includes generating the bitstream from the video, and the method further comprises: storing the bitstream on a computer-readable non-transient recording medium.

31. A video processing apparatus comprising a processor configured to implement a method recited in one or more of claims 1 to 30.

32. A method of storing a video bitstream, comprising a method described in any one of claims 1 to 30, and further comprising storing the bitstream on a computer-readable, non-transient recording medium.

33. A computer-readable medium that stores program code that, when executed, causes a processor to implement a method recited in one or more of claims 1 to 30.

34. A computer-readable medium that stores a bit stream generated according to any of the methods described above.

35. A video processing apparatus for storing a bitstream representation, wherein the video processing apparatus is configured to implement a method recited in one or more of claims 1 to 30.

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