International organisation for standardisation organisation internationale de normalisation
Yüklə 8,2 Mb.
|
RCE4 related (palette mode) (44)14.1.97.1.1.1.1.1.214JCTVC-P0298 BoG report on Palette mode [C. Rosewarne] Discussed in JCT-VC plenary Sunday 01-12 a.m. (JRO & GJS). Candidate software and reference configuration(s) for TE or AHG testing were discussed. The following recommendations were made by the BoG: Options recommended are either to have one or two basis softwares. Two basis software option: New test 1: P0108 also with previous coded palette reuse [P0153]. New test 2: P0231 + previous CU palette prediction [P0114] and the copy-from-above syntax [P0116, P0095] and removal of the copy-from-above for first line [P0116, P0179]. One basis software option: P0198 less prediction of escape pixel with throughput issue scheme [an aspect of P0231] + previous CU palette prediction [P0114, P0153] and the copy-from-above syntax [P0116, P0095] and removal of the copy-from-above for first line [P0116, P0179] + adaptive bit lengths to code the quantized escape value [aspect of P0231] + escape pixel index signalling [an aspect of P0108]. No consensus on selecting whether to have one or two basis software codebases. As a conclusion, it was discussed in the plenary that the investigation of palette mode coding shall be further conducted in an AHG on investigation of palette mode coding tools with mandates to perform further investigation of P0108, P0198 and related technology, define test conditions for investigating the compression performance, investigate the complexity. 14.1.97.1.1.1.1.1.215JCTVC-P0090 Non-RCE4: Advanced copy mode for palette coding [Erh-Chung Ke, Jih-Sheng Tu, Chao-Hsiung Hung (ITRI)] Discussed 01-10 p.m. (JRO). In the 14th JCT-VC meeting, the contribution JCTVC-N0249 proposed a palette-based coding method for screen contents. This method was implemented on top of the Range Extension software HM-12.0+RExt-4.1 for the 15th JCT-VC meeting, and the performance evaluation was provided in contribution JCTVC-O0218. In this contribution, an extended modification is proposed. Relates to group of “test 2” of RCE4. Extends the method of O0218 into a more general copy mode, including three more neighbour positions as candidates. As the original method, it uses only data from current CU. The copy index is coded in bypass mode (not context coded). Performance for screen content slightly better than P0198, but probably also more complex. The size of the candidate list is fixed. 14.1.97.1.1.1.1.1.216JCTVC-P0251 Crosscheck of JCTVC-P0090 on advanced copy mode for palette coding [Y.-C. Sun, Y.-W. Huang (MediaTek)] [late]
Discussed 01-10 p.m. (JRO). In this contribution, palette update restriction options are presented for pair performance comparison between two palette coding proposals in RCE4 and other possible proposals. This restriction is also asserted to be useful to solve memory and bandwidth problems. In this contribution, five options are presented: no palette update, left-only palette update, palette update within the current CTU, palette update within the current and left CTUs, and palette update within current slice. For current palette coding proposals, left-only palette update and palette update within the current and left CTUs are asserted to be the most preferable because very small or no BD-BR drop is expected and the maximum memory size for palette update is limited. Some results:
It is proposed to add a picture-layer flag to disable palette update. Yüklə 8,2 Mb. Dostları ilə paylaş:
|