EP-4736431-A1 - SYNTAX COST REDUCTION FOR ADAPTIVE LOOP FILTERS

Abstract

Systems, devices, and methods are described herein for reducing syntax cost associated with adaptive loop filters. An example method may involve identifying a filter comprising a coefficient. The method may involve determining an encoding procedure based on context information associated with at least one of: a location of the coefficient associated with the filter or a size of the filter. The method may involve encoding the coefficient using the determined encoding procedure. The method may involve including, in video data, the encoded coefficient.

Inventors

• GALPIN, FRANCK
• BOISSON, GUILLAUME
• BORDES, PHILIPPE
• LEFEBVRE, FREDERIC

Assignees

• InterDigital CE Patent Holdings, SAS

Dates

Publication Date

20260506

Application Date

20240612

Claims (16)

1. 1 . A method for video encoding, the method comprising: identifying a filter and a coefficient associated with the filter; determining an encoding procedure based on context information associated with at least one of: a location of the coefficient associated with the filter or a size of the filter; encoding the coefficient using the determined encoding procedure; and including, in video data, the encoded coefficient.
2. 2. The method of claim 1 , wherein determining the encoding procedure based on the context information comprises determining an order of an exponential Golomb equation based on the location of the coefficient associated with the filter, and encoding the coefficient using the determined encoding procedure comprises encoding the coefficient using the exponential Golomb equation of the determined order.
3. 3. The method of claim 1 , wherein determining the encoding procedure based on the context information comprises determining an order of an exponential Golomb equation based on the location of the coefficient associated with the filter, and wherein the order of the exponential Golomb equation increases as a distance between the coefficient and a center of the filter decreases.
4. 4. The method of claim 1 , wherein the method further comprises receiving an indication of the size of the filter, and determining the encoding procedure based on the context information comprises determining the encoding procedure based on the size of the filter.
5. 5. The method of claim 1 , wherein the coefficient is a first coefficient associated with the filter, the method further comprises identifying a second coefficient associated with the filter, the second coefficient neighbors the first coefficient and is earlier in a decoding order than the first coefficient, and encoding the first coefficient using the determined encoding procedure comprises encoding the first coefficient based on a difference between a first value associated with the first coefficient and a second value associated with the second coefficient.
6. 6. The method of claim 1 , wherein encoding the coefficient using the determined encoding procedure comprises encoding the coefficient using an entropy encoder.
7. 7. The method of claim 1 , wherein the coefficient is a first coefficient, and the method further comprises: determining a first sign associated with the first coefficient based on a second sign associated with a second coefficient, wherein the second coefficient neighbors the first coefficient; and encoding the first sign associated with the first coefficient.
8. 8. A video encoding device comprising a processor, wherein the processor is configured to implement the steps of the method according to any one of claims 1-7.
9. 9. A method for video decoding, the method comprising: identifying a filter and a coefficient associated with the filter; determining a decoding procedure based on context information associated with at least one of: a location of the coefficient associated with the filter or a size of the filter; decoding the coefficient using the determined decoding procedure; and decoding a coding block based on the coefficient.
10. 10. The method of claim 9, wherein determining the decoding procedure based on the context information comprises determining an order of an exponential Golomb equation based on the location of the coefficient associated with the filter, and decoding the coefficient using the determined decoding procedure comprises decoding the coefficient using the exponential Golomb equation of the determined order.
11. 11 . The method of claim 9, wherein determining the decoding procedure based on the context information comprises determining an order of an exponential Golomb equation based on the location of the coefficient associated with the filter, and wherein the order of the exponential Golomb equation increases as a distance between the coefficient and a center of the filter decreases.
12. 12. The method of claim 9, wherein the method further comprises receiving an indication of the size of the filter, and determining the decoding procedure based on the context information comprises determining the decoding procedure based on the size of the filter.
13. 13. The method of claim 9, wherein the coefficient is a first coefficient associated with the filter, the method further comprises identifying a second coefficient associated with the filter, the second coefficient neighbors the first coefficient and is earlier in a decoding order than the first coefficient, and decoding the first coefficient using the determined decoding procedure comprises decoding the first coefficient based on a difference between a first value associated with the first coefficient and a second value associated with the second coefficient.
14. 14. The method of claim 9, wherein decoding the coefficient using the determined decoding procedure comprises decoding the coefficient using an entropy encoder.
15. 15. The method of claim 9, wherein the coefficient is a first coefficient, and the method further comprises: determining a first sign associated with the first coefficient based on a second sign associated with a second coefficient, wherein the second coefficient neighbors the first coefficient; and decoding the first sign associated with the first coefficient.
16. 16. A video decoding device comprising a processor, wherein the processor is configured to implement the steps of the method according to any one of claims 9-15.

Description

SYNTAX COST REDUCTION FOR ADAPTIVE LOOP FILTERS CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of European Provisional Patent Application No. EP23306024.3, filed June 27, 2023, the contents of which are hereby incorporated by reference herein. BACKGROUND [0002] Video coding systems may be used to compress digital video signals, e.g., to reduce the storage and/or transmission bandwidth needed for such signals. Video coding systems may include, for example, block-based, wavelet-based, and/or object-based systems. SUMMARY [0003] Systems, devices, and methods are described herein for reducing the syntax cost associated with adaptive loop filters. An example method (e.g., for video encoding) may involve identifying a filter and a coefficient associated with the filter. The method may involve determining an encoding procedure based on context information associated with at least one of: a location of the coefficient associated with the filter or a size of the filter. The method may involve encoding the coefficient using the determined encoding procedure. The method may involve including, in video data, the encoded coefficient. [0004] Determining the encoding procedure based on the context information may involve determining an order of an exponential Golomb equation based on the location of the coefficient associated with the filter. Encoding the coefficient using the determined encoding procedure may involve encoding the coefficient using the exponential Golomb equation of the determined order. [0005] Determining the encoding procedure based on the context information may involve determining an order of an exponential Golomb equation based on the location of the coefficient associated with the filter. The order of the exponential Golomb equation may increase as a distance between the coefficient and a center of the filter decreases. [0006] An indication of the size of the filter may be received. Determining the encoding procedure based on the context information may involve determining the encoding procedure based on the size of the filter. [0007] The coefficient may be a first coefficient associated with the filter. A second coefficient associated with the filter may be identified. The second coefficient may neighbor the first coefficient and be earlier in a decoding order than the first coefficient. Encoding the first coefficient using the determined encoding procedure may involve encoding the first coefficient based on a difference between a first value associated with the first coefficient and a second value associated with the second coefficient. [0008] Encoding the coefficient using the determined encoding procedure may involve encoding the coefficient using an entropy encoder. [0009] The method may involve determining a first sign associated with the first coefficient based on a second sign associated with a second coefficient. The second coefficient may neighbor the first coefficient. The first sign associated with the first coefficient may be encoded. [0010] A video decoding device may include a processor that is configured to implement any of the actions described herein. [0011] An example method (e.g., for video decoding) may involve identifying a filter and a coefficient associated with the filter. The method may involve determining a decoding procedure based on context information associated with at least one of: a location of the coefficient associated with the filter or a size of the filter. The method may involve decoding the coefficient using the determined decoding procedure. The method may involve decoding a coding block based on the coefficient. [0012] Determining the decoding procedure based on the context information may involve determining an order of an exponential Golomb equation based on the location of the coefficient associated with the filter. Decoding the coefficient using the determined decoding procedure may involve decoding the coefficient using the exponential Golomb equation of the determined order. [0013] Determining the decoding procedure based on the context information may involve determining an order of an exponential Golomb equation based on the location of the coefficient associated with the filter. The order of the exponential Golomb equation may increase as a distance between the coefficient and a center of the filter decreases. [0014] An indication of the size of the filter may be received. Determining the decoding procedure based on the context information may involve determining the decoding procedure based on the size of the filter. [0015] The coefficient may be a first coefficient associated with the filter. A second coefficient associated with the filter may be identified. The second coefficient may neighbor the first coefficient and be earlier in a decoding order than the first coefficient. Decoding the first coefficient using the determined decoding procedure may involve decoding the first coefficient based on a differenc