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WO-2026096703-A1 - SELECTIVE REFERENCE RANGE FOR ADAPTIVE VIDEO SAMPLE CLIPPING

WO2026096703A1WO 2026096703 A1WO2026096703 A1WO 2026096703A1WO-2026096703-A1

Abstract

A coder (e.g., an encoder or decoder) is configured to set a first reference range for reconstructed samples of a picture. The coder obtains at least one first indicator from a bitstream indicating whether: a first difference is in relation to the maximum of the first reference range or to the maximum of a second reference range for the reconstructed samples of the picture; and a second difference is in relation to the minimum of the first reference range or to the minimum of the second reference range. The coder further obtains the first and second differences from the bitstream and derives, using the obtained differences and based on the at least one first indicator, a target range. The coder clips the reconstructed samples of the picture to be within the target range, thereby improving reconstruction consistency and coding efficiency.

Inventors

  • Ruiz Coll, Damian
  • LEE, JUNG KYUNG

Assignees

  • OFINNO, LLC

Dates

Publication Date
20260507
Application Date
20251030
Priority Date
20241030

Claims (20)

  1. 1. A method, comprising: determining a range of actual values of original samples in a picture; comparing the range of actual values to a first reference range for the samples of the picture; setting, based on the comparing, a second indicator indicating whether a target range for reconstructed samples of the picture matches the first reference range; based on the target range not matching the first reference range: determining a first difference between the range of actual values and at least one of the first reference range or a second reference range for samples of the picture; and setting at least one first indicator indicating whether the first difference relates to the first reference range or to the second reference range; and signaling, in a bitstream, the second indicator, the at least one first indicator, and the first difference in association with the picture.
  2. 2. A method, comprising: setting, based on a status of a third indicator in a bitstream, a first reference range for reconstructed samples of a picture; obtaining, from the bitstream, a second indicator indicating that the first reference range does not match a target range; obtaining, from the bitstream and based on the second indicator indicating the first reference range does not match the target range, at least one first indicator indicating whether a first difference is specified in relation to the first reference range or in relation to a second reference range for the reconstructed samples of the picture; obtaining the first difference from the bitstream; deriving, using the first difference and based on the at least one first indicator, the target range; clipping the reconstructed samples of the picture to be in the target range; and reconstructing the picture comprising the clipped reconstructed samples.
  3. 3. A method, comprising: setting a first reference range for reconstructed samples of a picture; determining a range of actual values of original samples in a picture; determining a first difference in relation to the maximum of a first reference range or to the maximum of a second reference range for reconstructed samples of the picture; determining a second difference in relation to the minimum of the first reference range or to the minimum of the second reference range; Docket No.: 24-2054PCT setting at least one first indicator each indicating whether the first difference relates to the first reference range or to the second reference range or whether the second difference relates to the first reference range or to the second reference range; and signaling, in a bitstream, the at least one third indicator, the first difference, and the second difference in association with the picture.
  4. 4. A method, comprising: setting a first reference range for reconstructed samples of a picture; obtaining, from a bitstream, at least one first indicator indicating whether: a first difference is in relation to the maximum of the first reference range or to the maximum of a second reference range for the reconstructed samples of the picture; and a second difference is in relation to the minimum of the first reference range or to the minimum of the second reference range; obtaining the first difference and the second difference from the bitstream; deriving, using the first and second differences and based on the at least one first indicator, a target range; and clipping the reconstructed samples of the picture to be in the target range.
  5. 5. The method of any one of claim 1-4, wherein the at least one first indicator comprises one indication indicating whether: the first difference is in relation to the maximum of the first reference range and the second difference is in relation to the minimum of the first reference range for the reconstructed samples of the picture; or the first difference is in relation to the maximum of the second reference range and the second difference is in relation to the minimum of the second reference range for the reconstructed samples of the picture.
  6. 6. The method of any one of claims 1-5, wherein the at least one first indicator comprises: a first reference indicator indicating whether the first difference is in relation to the maximum of the first reference range or to the maximum of the second reference range; and a second reference indicator indicating whether the second difference is in relation to the minimum of the first reference range or to the minimum of the second reference range.
  7. 7. The method of any one of claims 2, or 4-6, wherein the setting the first reference range comprises: setting the first reference range to a first video range of a bit depth if the third indicator comprises a first value, or setting the reference range to a second video range of the bit depth if the third indicator comprises a second value; or if the third indicator is not detected from a parameter set obtained from the bitstream for the picture, setting the first reference range to the second video range if a type of a current slice in the picture is a first type or setting the first reference range to the first video range or the second video range in accordance with a collocated picture if the type of the current slice is not the first type. Docket No.: 24-2054PCT
  8. 8. The method of any one of claims 2, 4, 5, or 7, wherein the at least one first indicator comprises: a first reference indicator indicating whether the first difference is in relation to the maximum of the first reference range or to the maximum of the second reference range; and a second reference indicator indicating whether the second difference is in relation to the minimum of the first reference range or to the minimum of the second reference range.
  9. 9. The method of any one of claims 1 , 3, or 5-8, wherein the determining the first difference in relation to the maximum of the first reference range or to the maximum of the second reference range comprises comparing the maximum of the range of actual values to a threshold between the maximum of the first reference range and the maximum of the second reference range.
  10. 10. The method of claim 9, wherein the threshold between the maximum of the first reference range and the maximum of the second reference range is calculated based on the first reference range and the second reference range.
  11. 11. The method of claim 9, wherein the threshold between the maximum of the first reference range and the maximum of the second reference range is calculated based on a coding efficiency of the first difference.
  12. 12. The method of any one of claims 1, 3, or 5-11 , wherein the signaling the first difference in the bitstream comprises: quantizing the first difference; and signaling the quantized first difference in the bitstream.
  13. 13. The method of claim 12, wherein the quantizing is based on a quantization step determined according to a type of a current slice of the picture.
  14. 14. The method of any one of claims 1, 3, or 5-13, wherein the first difference is included In a header of the picture in the bitstream.
  15. 15. The method of any one of claims 1, 3, or 5-14, wherein the first difference comprises a range maximum first difference and a range minimum first difference, wherein the at least one first indicator comprises only one of a first reference indicator indicating that the range maximum first difference relates to one of the first reference range or the second reference range, or a second reference indicator indicating that the range minimum first difference relates to the other of the first reference range or the second reference range.
  16. 16. The method of any one of claims 1, 3, or 5-14, wherein the first difference comprises a range maximum first difference and a range minimum first difference, wherein the at least one first indicator indicates that the range maximum first difference relates to one of the first reference range or the second reference range and that the range minimum first difference relates to the one of the first reference range or the second reference range.
  17. 17. The method of any one of claims 1 , 3, or 5-16, wherein each of the reconstructed samples comprises a luma value of a pixel.
  18. 18. The method of any one of claims 1, 3, or 5-16, wherein each of the reconstructed samples comprises a chroma value of a pixel. Docket No.: 24-2054PCT
  19. 19. The method of any one of claims 3 or 5-18, wherein the determining the second difference in relation to the minimum of the first reference range or to the minimum of the second reference range comprises comparing the minimum of the range of actual values to a threshold between the minimum of the first reference range and the minimum of the second reference range.
  20. 20. The method of claim 19, wherein the threshold between the minimum of the first reference range and the minimum of the second reference range is calculated based on the first reference range and the second reference range.

Description

Docket No.: 24-2054PCT TITLE Selective Reference Range for Adaptive Video Sample Clipping CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 63/714,093, filed October 30, 2024, which is hereby incorporated by reference in its entirety. BRIEF DESCRIPTION OF THE DRAWINGS [0002] Some features are shown by way of example, and not by limitation, in the accompanying drawings. In the drawings, like numerals reference similar elements. [0003] FIG. 1 shows an example video coding/decoding system in which embodiments of the present disclosure may be implemented. [0004] FIG. 2 shows an example encoder in which embodiments of the present disclosure may be implemented. [0005] FIG. 3 shows an example decoder in which embodiments of the present disclosure may be implemented. [0006] FIG. 4 shows an example quadtree partitioning of a coding tree block (CTB). [0007] FIG. 5 shows an example quadtree corresponding to the example quadtree partitioning of the CTB in FIG. 4. [0008] FIG. 6 show examples of binary tree and ternary tree partitions. [0009] FIG. 7A shows an example of combined quadtree and multi-type tree partitioning of a CTB. [0010] FIG. 7B shows an example tree corresponding to the combined quadtree and multi-type tree partitioning of the CTB shown in FIG. 7A. [0011] FIG. 8 shows an example of partitioning modes in AV1. [0012] FIG. 9 shows an example set of reference samples determined for intra prediction of a current block. [0013] FIG. 10A, FIG. 10B, and FIG. 10C show example intra prediction modes. [0014] FIG. 11 shows an example of a current block and corresponding reference samples. [0015] FIG. 12 shows an example of applying an intra prediction mode (e.g., an angular mode) for prediction of a current block. [0016] FIG. 13A shows an example of inter prediction performed for a current block in a current picture. [0017] FIG. 13B shows an example motion vector. [0018] FIG. 14 shows an example of bi-prediction performed for a current block. [0019] FIG. 15A shows example spatial candidate neighboring blocks relative to a current block being coded. [0020] FIG. 15B shows example locations of two temporal, co-located blocks relative to a current block. [0021] FIG. 16 shows an example of intra block copy (IBC). [0022] FIG. 17 shows an example of intra template matching prediction (IntraTMP) for predicting or determining a current block, according to some embodiments. [0023] FIG. 18 shows the video ranges (the full video range and the narrow video range) in relation to the range provided by the internal bit depth, according to some embodiments. Docket No.: 24-2054PCT [0024] FIG. 19A shows an example of differences determined between the reference range and the range of actual pixel values, according to some embodiments. [0025] FIG. 19B shows a flowchart of an example conventional method of adaptive quantization for use in clipping, according to some embodiments. [0026] FIG. 20 shows an example of a target range for clipping in relation to the reference range and the video ranges when the reference range is set to the narrow video range, according to some embodiments. [0027] FIG. 21 shows an example of a target range for clipping in relation to the reference range and the video ranges when the reference range is set to the full video range, according to some embodiments. [0028] FIG. 22 shows an example of a threshold range for signaling a target range for clipping in relation to the reference range and another reference range, according to some embodiments. [0029] FIG. 23 shows a flowchart of an example selective reference range determination for improved adaptive clipping, according to some embodiments. [0030] FIG. 24A and FIG. 24B show an example of the improvement in delta values signaled in accordance with an embodiment. [0031] FIG. 25 shows a flowchart of an example method for selective reference range determination for improved adaptive quantization performed at an encoder, according to some embodiments. [0032] FIG. 26 shows a flowchart of an example method for selective reference range determination for improved adaptive quantization performed at an decoder, according to some embodiments. [0033] FIG. 27 illustrates a block diagram of an example computer system in which embodiments of the present disclosure may be implemented. DETAILED DESCRIPTION [0034] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the disclosure. However, it will be apparent to those skilled in the art that the disclosure, including structures, systems, and methods, may be practiced without these specific details. The description and representation herein are the common means used by those experienced or skilled in the art to most effectively convey the substance of their work to others skilled in the art. In other instances, well-known methods, procedures, components, and circuitry have not been described