US-20230283787-A1 - LOCAL ILLUMINATION COMPENSATION FOR VIDEO ENCODING AND DECODING USING STORED PARAMETERS

Abstract

A Local illumination compensation system for video encoding and decoding uses memory for storing illumination compensation parameters and does not require access to reconstructed pixels of neighboring blocks. A set of illumination compensation parameters is stored in a dedicated buffer, which is of limited size, and which is decoupled from the coding unit level storage of information. The buffer contains a set of illumination compensation parameters, which may be, for example, computed (or determined in some other manner) on the fly or determined beforehand (for example for example obtained from the video signal or from a device).

Inventors

• LE LÉANNEC FABRICE
• POIRIER TANGI
• CHEN YA
• BORDES PHILIPPE

Assignees

• INTERDIGITAL VC HOLDINGS INC

Dates

Publication Date

20230907

Application Date

20230515

Priority Date

20180919

Claims (20)

1. 1 - 16 . (canceled)
2. 17 . A method for video decoding, the method comprising: obtaining local illumination compensation (LIC) information; selecting a first LIC parameter set for a first coding block based on the LIC information; and decoding the first coding block based on the determined LIC parameter set.
3. 18 . The method of claim 17 , wherein the LIC information comprises an LIC parameter candidate list and an LIC parameter index associated with the LIC parameter candidate list, wherein the first LIC parameter set is selected from the LIC parameter candidate list based on the LIC parameter index.
4. 19 . The method of claim 17 , wherein the LIC information comprises an LIC parameter candidate list, and the method further comprises: obtaining, for the first coding block, an LIC parameter index associated with the LIC parameter candidate list, wherein the first LIC parameter set is further selected based on the LIC parameter index and the LIC parameter candidate list.
5. 20 . The method of claim 17 , wherein the LIC information comprises an LIC parameter candidate list, and the method further comprises: selecting a third LIC parameter set, for a second coding block, from the LIC parameter candidate list based on the LIC parameter candidate list; decoding the second coding block based on the selected third LIC parameter set.
6. 21 . The method of claim 20 , wherein the third LIC parameter set is the second LIC parameter set.
7. 22 . The method of claim 17 , wherein the LIC information comprises an LIC parameter candidate list, and the method further comprises: obtaining a reconstructed sub-block of the first coding block; determining a second LIC parameter set based on the reconstructed sub-block of the first coding block; and adding the second LIC parameter set to the LIC parameter candidate list.
8. 23 . The method of claim 22 , wherein the LIC information further comprises an LIC parameter index associated with the LIC candidate list, wherein the reconstructed sub-block of the first coding block is a right-hand vertical sub-block of the first coding block, and wherein the second LIC parameter set is indexed in the LIC parameter candidate list as a function of a vertical position associated with the sub-block of the first coding block.
9. 24 . The method of claim 22 , wherein the LIC information further comprises an LIC parameter index associated with the LIC candidate list, wherein the reconstructed sub-block is a lower horizontal sub-block of the first coding block, and wherein the second LIC parameter set is indexed in the LIC parameter candidate list as a function of a horizontal position associated with the sub-block of the first coding block.
10. 25 . The method of claim 22 , wherein determining the second LIC parameter set further comprises: determining a vertical LIC parameter set based on a right-hand vertical sub-block of the first coding block; and determining a horizontal LIC parameter set based on a lower-horizontal sub-block of the first coding block, wherein the vertical LIC parameter set is indexed in the LIC parameter candidate list as a function of a vertical position of the sub-block associated with the right-hand vertical sub-block of the first coding block, and wherein the horizontal LIC parameter set is indexed in the LIC parameter candidate list as a function of a horizontal position associated with the lower-horizontal sub-block of the first coding block.
11. 26 . The method of claim 17 , wherein the method further comprises: receiving an indication to perform LIC on the first coding block.
12. 27 . A method for video encoding, the method comprising: obtaining local illumination compensation (LIC) information; selecting an LIC parameter set for a first coding block based on the LIC information; and encoding the first coding block based on the selected LIC parameter set; and including in video data, an indication of an index of the first LIC parameter set for the first coding block.
13. 28 . The method of claim 27 , wherein the LIC information comprises an LIC parameter candidate list and an LIC parameter index associated with the LIC parameter candidate list, wherein the first LIC parameter set is selected from the LIC parameter candidate list based on the LIC parameter index.
14. 29 . The method of claim 27 , wherein the LIC information comprises an LIC parameter candidate list, and the method further comprises: obtaining, for the first coding block, an LIC parameter index associated with the LIC parameter candidate list, wherein the first LIC parameter set is further selected based on the LIC parameter index and the LIC parameter candidate list.
15. 30 . The method of claim 27 , wherein the LIC information comprises an LIC parameter candidate list, and wherein the method further comprises: selecting a third LIC parameter set, for a second coding block, from the LIC parameter candidate list based on the LIC parameter candidate list; encoding a second coding block based on the third LIC parameter set; and including, in video data, an index of the third LIC parameter set for the second coding block.
16. 31 . The method of claim 30 , wherein the third LIC parameter set is the second LIC parameter set.
17. 32 . The method of claim 27 , wherein the LIC information comprises an LIC parameter candidate list, and the method further comprises: obtaining a reconstructed sub-block of the first block; determining a second LIC parameter set based on the reconstructed sub-block of the first block; adding the second LIC parameter set to the LIC parameter candidate list; and including, in video data, an indication of an index of the second LIC parameter set.
18. 33 . The method of claim 32 , wherein the LIC information comprises an LIC parameter candidate list, wherein the reconstructed sub-block of the first block is a right-hand vertical sub-block of the first coding block, and wherein the second LIC parameter set is indexed in the LIC parameter candidate list as a function of a vertical position associated with the sub-block of the first coding block.
19. 34 . The method of claim 32 , wherein the LIC information comprises an LIC parameter candidate list, wherein the reconstructed sub-block of the first block is a lower horizontal sub-block of the first coding block, and wherein the second LIC parameter set is indexed in the LIC parameter candidate list as a function of a horizontal position associated with the sub-block of the first coding block.
20. 35 . The method of claim 32 , wherein determining the second LIC parameter set further comprises: determining a vertical LIC parameter set based on a right-have vertical sub-block of the first block; and determining a horizontal LIC parameter set based on a lower-horizontal sub-block of the first coding block, wherein the vertical LIC parameter set is indexed in the LIC parameter candidate list as a function of a vertical position of the sub-block associated with the right-hand vertical sub-block of the first coding block, and wherein the horizontal LIC parameter set is indexed in the LIC parameter candidate list as a function of a horizontal position associated with the lower-horizontal sub-block of the first coding block.

Description

TECHNICAL FIELD At least one of the present embodiments generally relates to the field of video compression. At least one embodiment particularly aims at Local Illumination Compensation and more particularly to using a stored set of parameters for the Local Illumination Compensation. BACKGROUND To achieve high compression efficiency, image and video coding schemes usually employ prediction and transform to leverage spatial and temporal redundancy in the video content. Generally, intra or inter prediction is used to exploit the intra or inter frame correlation, then the differences between the original block and the predicted block, often denoted as prediction errors or prediction residuals, are transformed, quantized, and entropy coded. To reconstruct the video, the compressed data are decoded by inverse processes corresponding to the entropy coding, quantization, transform, and prediction. SUMMARY One or more of the present embodiments relates to a Local Illumination Compensation (LIC) system that uses stored illumination compensation (IC) parameters and does not require access to reconstructed pixels of neighboring blocks. According to a first aspect of at least one embodiment, a video encoding method for encoding picture data of a block in a picture comprises encoding the picture data with signaling information comprising at least information representative of the use of a local illumination compensation function and an index of local illumination compensation parameters to be used. According to a second aspect of at least one embodiment, a video decoding method for encoding picture data of a block in a picture comprises obtaining an index of local illumination compensation parameters to be used; and decoding the picture data and when the use of local illumination compensation function is signaled in signaling information corresponding to the block, use a local illumination compensation function with local illumination compensation parameters obtained according to the index. According to a third aspect of at least one embodiment, an apparatus comprises an encoder for encoding picture data for at least one block in a picture or video wherein the encoder is configured to encode the picture data with signaling information comprising at least information representative of the use of local illumination compensation function and an index of the local illumination compensation parameters to be used. According to a fourth aspect of at least one embodiment, an apparatus comprises a decoder for decoding picture data for at least one block in a picture or video wherein the decoder is configured to obtain an index of local illumination compensation parameters to be used from the buffer; and decode the picture data and when the use of local illumination compensation is signaled in signaling information corresponding to the block, use a local illumination compensation function with local illumination compensation parameters obtained from a buffer according to the index. According to a fifth aspect of at least one embodiment, a computer program comprising program code instructions executable by a processor is presented, the computer program implementing the steps of a method according to at least the first or second aspect. According to an eighth aspect of at least one embodiment, a computer program product which is stored on a non-transitory computer readable medium and comprises program code instructions executable by a processor is presented, the computer program product implementing the steps of a method according to at least the first or second aspect. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a block diagram of an example of video encoder 100, such as a High Efficiency Video Coding (HEVC) encoder. FIG. 2 illustrates a block diagram of an example of video decoder 200, such as an HEVC decoder. FIG. 3 illustrates a block diagram of an example of a system in which various aspects and embodiments are implemented. FIG. 4A illustrates an example of coding tree unit and coding tree in the compressed domain. FIG. 4B illustrates an example of division of a CTU into coding units, prediction units and transform units. FIG. 5 illustrates samples used for reconstruction of a block of picture in Inter mode. FIG. 6 illustrates the motion vector between the current block and the reference block. FIG. 7 illustrates an example of Bi-Prediction using two references. FIG. 8 illustrates an example of overall coding process to signal the coding parameters of a CU. FIG. 9 illustrates an example of overall entropy decoding process of a CU. FIG. 10 illustrates an example of coding of the INTER prediction information associated to a CU in AMVP mode. FIG. 11 illustrates an example of process used to decode the motion information associated to an AMVP Coding Unit. FIG. 12 illustrates a first example embodiment where LIC parameters are computed after a CU is reconstructed on a decoder and computed based on a right-hand sub-portion