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CA-3152472-C - SIGNALING OF PICTURE HEADER IN VIDEO CODING

CA3152472CCA 3152472 CCA3152472 CCA 3152472CCA-3152472-C

Abstract

A method of decoding is provided. The method includes receiving a video bitstream including a picture unit (PU), where a gradual decoding refresh (GDR) flag in a picture header (PH) of the PU has a first value to specify that a picture associated with the PH is a GDR picture; and decoding the GDR picture from the PU to obtain a decoded picture.

Inventors

  • Fnu HENDRY
  • Ye-Kui Wang
  • Jianle Chen

Assignees

  • HUAWEI TECHNOLOGIES CO., LTD.

Dates

Publication Date
20260505
Application Date
20200805
Priority Date
20190924

Claims (20)

  1. CLAIMS What is claimed is: 1. A method of decoding implemented by a video decoder, comprising: receiving, by the video decoder, a video bitstream including a picture unit (PU), wherein a gradual decoding refresh (GDR) flag in a picture header (PH) of the PU has a first value to specify that a picture associated with the PH is a GDR picture; and decoding, by the video decoder, the GDR picture from the PU to obtain a decoded picture.
  2. 2. The method of claim 1, wherein the first value is one.
  3. 3. The method according to any one of claims 1 to 2, wherein the GDR flag is designated as ph gdr pie_ flag.
  4. 4. The method according to any one of claims 1 to 3, wherein the PH contains a picture order count (POC) identifying a recovery point picture corresponding to the GDR picture in the PU.
  5. 5. The method according to any one of claims 1 to 4, wherein the PH is contained within a PH network abstraction layer (NAL).
  6. 6. The method according to any one of claims 1 to 5, wherein the PH contains syntax elements that apply to all slices of the GDR picture.
  7. 7. The method of claim 6, wherein a slice of the GDR picture is contained in a video coding layer (VCL) NAL unit.
  8. 8. The method of claim 6, wherein the PH NAL unit immediately precedes a first video coding layer (VCL) NAL unit in the PU.
  9. 9. The method according to any one of claims 1 to 8, further comprising displaying the decoded picture on a display of an electronic device. 67 Date re~ue/date received 2024-06-03
  10. 10. A method of encoding implemented by a video encoder, the method comprising: generating, by the video encoder, a picture unit (PU) having a gradual decoding refresh (GDR) flag in a picture header (PH), wherein the GDR flag has a first value to specify that a picture associated with the PH is a GDR picture; encoding, by the video encoder, the PU into a video bitstream; and storing, by the video encoder, the video bitstream for communication toward a video decoder.
  11. 11. The method of claim 10, wherein the first value is one.
  12. 12. The method of claim 11, wherein the GDR flag is designated as ph_gdr_pic_flag.
  13. 13. The method according to any one of claims 11 to 12, wherein the PH contains a picture order count (POC) identifying a recovery point picture corresponding to the GDR picture in the PU.
  14. 14. A decoding device, comprising: a receiver configured to receive a video bitstream including a picture unit (PU), wherein a gradual decoding refresh (GDR) flag in a picture header (PH) of the PU has a first value to specify that a picture associated with the PH is a GDR picture; a memory coupled to the receiver, the memory storing instructions; and a processor coupled to the memory, the processor configured to execute the instructions to cause the decoding device to: decode the GDR picture from the PU to obtain a decoded picture.
  15. 15. The decoding device of claim 14, wherein the first value is one.
  16. 16. The decoding device of claim 15, wherein the GDR flag is designated as ph_gdr_pic_flag.
  17. 17. The decoding device according to any one of claims 15 to 16, wherein the PH contains a picture order count (POC) identifying a recovery point picture corresponding to the GDR picture in the PU. 68 Date re~ue/date received 2024-06-03
  18. 18. An encoding device, comprising: a memory containing instructions; a processor coupled to the memory, the processor configured to implement the instructions to cause the encoding device to: generate a picture unit (PU) having a gradual decoding refresh (GDR) flag in a picture header (PH), wherein the GDR flag has a first value to specify that a picture associated with the PH is a GDR picture; encode the PU into a video bitstream; and a transmitter coupled to the processor, the transmitter configured to transmit the video bitstream toward a video decoder.
  19. 19. The encoding device of claim 18, wherein the first value is one.
  20. 20. The encoding device of claim 19, wherein the GDR flag is designated as ph_gdr_pic_flag, wherein the first value is one, and wherein the PH contains a picture order count (POC) identifying a recovery point picture corresponding to the GDR picture in the PU.

Description

Signaling of Picture Header in Video Coding CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This patent application claims the benefit of U.S. Provisional Patent Application No. 62/905,150 filed September 24, 2019, by FnuHendry, et al., and titled "Signalling of Picture Header in Video Coding". TECHNICAL FIELD [0002] fu general, this disclosure describes techniques for determining the starting point of a picture in a bitstream in video coding. More specifically, this disclosure ensures that the starting point of the picture may be accurately determined within a multi-layer bitstream in video coding. BACKGROUND [0003] The amount of video data needed to depict even a relatively short video can be substantial, which may result in difficulties when the data is to be streamed or otherwise communicated across a communications network with limited bandwidth capacity. Thus, video data is generally compressed before being communicated across modem day telecommunications networks. The size of a video could also be an issue when the video is stored on a storage device because memory resources may be limited. Video compression devices often use software and/or hardware at the source to code the video data prior to transmission or storage, thereby decreasing the quantity of data needed to represent digital video images. The compressed data is then received at the destination by a video decompression device that decodes the video data. With limited network resources and ever increasing demands of higher video quality, improved compression and decompression techniques that improve compression ratio with little to no sacrifice in image quality are desirable. SUMMARY [0004] A first aspect relates to a method of decoding implemented by a video decoder, comprising: receiving, by the video decoder, a video bitstream including a picture unit (PU), wherein a gradual decoding refresh (GDR) flag in a picture header (PH) of the PU has a first value to specify that a picture associated with the PH is a GDR picture; and decoding, by the video decoder, the GDR picture from the PU to obtain a decoded picture. 1 Date Re9ue/Date Received 2023-08-04 [0005] The method provides techniques that utilize a gradual decoding refresh (GDR) flag in a picture header (PH) of a picture unit (PU) to indicate that all slices of a picture correspond to a GDR picture. Thus, the GDR picture can be identified based on the GDR flag instead of being identified by type of network abstraction layer (NAL) unit type (e.g., GDR NAL unit type (GDR _ NUT)) carrying the slices. Moreover, the GDR flag supports signaling a picture order count (POC) corresponding to the recovery picture once in the PH instead of signaling the POC in each slice header. Including the POC corresponding to the recovery picture in the picture header instead of the slice header reduces redundant signaling. Hence, the POC corresponding to the recovery picture is signaled once per GDR picture and not in every slice of the GDR picture. This increases coding efficiency. Thus, the coder / decoder (a.k.a., "codec") in video coding is improved relative to current codecs. As a practical matter, the improved video coding process offers the user a better user experience when videos are sent, received, and/or viewed. [0006] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the first value is one. [0007] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the GDR flag is designated as ph gdr _pie_ flag. [0008] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the PH contains a picture order count (POC) identifying a recovery point picture corresponding to the GDR picture in the PU. [0009] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the PH is contained within a PH network abstraction layer (NAL). [0010] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the PH contains syntax elements that apply to all slices of the GDR picture. [0011] Optionally, in any of the preceding aspects, another implementation of the aspect provides that a slice of the GDR picture is contained in a video coding layer (VCL) NAL unit. [0012] Optionally, in any of the preceding aspects, another implementation of the aspect provides that the PH NAL unit immediately precedes a first video coding layer (VCL) NAL unit in the PU. [0013] Optionally, in any of the preceding aspects, another implementation of the aspect provides that displaying the decoded picture on a display of an electronic device. 2 Date Regue/Date Received 2022-04-22 [0014] A second aspect relates to a method of encoding implemented by a video encoder, the method comprising: generating, by the video encoder, a picture unit (PU) having a gradual decoding refresh (GDR) flag in a picture header (PH), wherein the GDR flag has a first value to s