Method and apparatus of harmonizing triangular merge mode with weighted prediction
The present disclosure relates to moving picture processing, and in particular, to cases where non-rectangular partitioning modes are used for inter-prediction in a combination with weighted prediction (WP) for coding fades. Non-rectangular modes refer to those inter-prediction modes, in which case a current block is partitioned/sliced in a non-rectangular way (slices). Such modes may be triangular (TMP) or geometric (GEO) prediction. The aim of the disclosure is to harmonize non-rectangular partitioning modes with WP by way of disabling TMP/GEO when WP is applied. This may be accomplished by checking whether all reference pictures for a current slice are disabled, and if this is the case to disable the slice-level WP for non-rectangular prediction units. Whether the reference pictures are disabled may be determined based on conditions applied on set values, for example, of luma/chroma flags, which refer to the reference pictures.
1. An inter prediction method, comprising:
determining whether reference pictures in a preset reference picture set of a current slice are disabled for a slice-level weighted prediction of the current slice;
determining that non-rectangular prediction units for the current slice are disabled for the slice-level weighted prediction, when the reference pictures are determined to be disabled; and
predicting the current slice in accordance with a determination result.
2. The method of claim 1 , wherein the disabling of the reference pictures is indicated by one or more flags.
3. The method of claim 2 , wherein the one or more flags include at least one of one or more luma-weighted flags or one or more chroma-weighted flags.
4. The method of claim 3 , wherein the one or more luma-weighted flags and the one or more chroma-weighted flags each refer to a list0 and a list1 of the reference pictures, wherein the list0 includes reference pictures of a first predictor P 0 of the current slice and the list1 includes reference pictures of a second predictor P 1 of the current slice.
5. The method of claim 4 , wherein the disabling of the reference pictures is indicated when all the following conditions are true:
the luma-weighted flags of the list0 are 0;
the luma-weighted flags of the list1 are 0;
the chroma-weighted flags of the list0 are 0; and
the chroma-weighted flags of the list1 are 0.
6. The method of claim 1 , wherein the slice-level weighted prediction is enabled in the event that any one of the reference pictures is enabled for the weighted prediction.
7. The method according to claim 6 , wherein the slice-level weighted prediction is a triangle prediction mode (TPM) or a geometric prediction mode (GEO).
8. An inter prediction method, comprising:
parsing an indicator from a bitstream corresponding to a current slice;
determining whether a slice-level weighted prediction for non-rectangular prediction units of the current slice is enabled for the current slice according to a value of the indicator; and
predicting the current slice in accordance with a determination result.
9. The method of claim 8 , wherein the indicator is a flag.
10. The method of claim 9 , wherein the flag is based on a type of the current slice.
11. The method of claim 8 , wherein the slice-level weighted prediction is determined to be enabled when the value is a first value.
12. The method of claim 11 , wherein the slice-level weighted prediction is disabled when the value is a second value different from the first value.
13. The method according to claim 8 , wherein the slice-level weighted prediction is a non-rectangular prediction mode.
14. The method according to claim 13 , wherein the non-rectangular prediction mode is a triangle prediction mode (TPM) or a geometric prediction mode (GEO).
15. An inter prediction method, comprising:
determining whether weighing factors of reference pictures of a current block are carried by a bitstream when the current block is processed by a sub-block based prediction mode for non-rectangular prediction units of the current block; and
obtaining a prediction value of the current block by blending weighted parameters when the weighing factors are not carried by the bitstream.
16. The method of claim 15 , further comprising:
obtaining the prediction value of the current block according to the weighing factors when the weighing factors are carried by the bitstream.
17. The method of claim 15 , wherein the sub-block based prediction mode is a non-rectangular prediction mode.
18. The method of claim 17 , wherein the non-rectangular prediction mode comprises a triangle prediction mode (TPM) or a geometric prediction mode (GEO).