Spatial angular partitioned weighted intra prediction using intra prediction directional modes to determine applied weight
View Patent ↗A prediction method is disclosed. A weight derivation mode for a current block is determined. At least one of a first prediction mode or a second prediction mode for the current block is determined according to the weight derivation mode. A weight is determined according to the weight derivation mode. A prediction value is determined based on the first prediction mode, the second prediction mode, and the weight. A prediction list for a current block is determined, the prediction list containing at least one of an intra prediction mode or an inter prediction mode. At least one of a first prediction mode or a second prediction mode for the current block is determined according to the prediction list. A prediction value is determined based on the first prediction mode and the second prediction mode.
1. A prediction method, applied to a decoder, the method comprising:
parsing a bitstream to determine a weight derivation mode for a current block;
parsing the bitstream to obtain a first flag, the first flag indicating whether at least one of a first prediction mode or a second prediction mode belongs to an intra prediction mode, wherein at least one of the first prediction mode or the second prediction mode is an intra prediction mode or an inter prediction mode;
determining a type of each of the first prediction mode and the second prediction mode according to the first flag;
when at least one of the first prediction mode or the second prediction mode is an intra prediction mode, determining at least one of the first prediction mode or the second prediction mode based on the weight derivation mode;
determining a weight according to the weight derivation mode; and
determining a prediction value based on the first prediction mode, the second prediction mode, and the weight.
2. The method of claim 1 , wherein when at least one of the first prediction mode or the second prediction mode is an intra prediction mode, determining at least one of the first prediction mode or the second prediction mode based on the weight derivation mode comprises:
when at least one of the first prediction mode or the second prediction mode is an intra corresponding prediction mode, obtaining an intra prediction mode corresponding to the weight derivation mode; and
determining at least one of the first prediction mode or the second prediction mode according to the intra prediction mode corresponding to the weight derivation mode, wherein the intra prediction mode corresponding to the weight derivation mode comprises at least one of:
an intra prediction mode parallel to a boundary line of the weight, an intra prediction mode perpendicular to the boundary line, or a planar mode.
3. The method of claim 2 , wherein determining at least one of the first prediction mode or the second prediction mode according to the intra prediction mode corresponding to the weight derivation mode comprises at least one of:
when the first prediction mode is an intra prediction mode, parsing the bitstream to obtain a second flag and determining an intra prediction mode corresponding to the second flag in the intra prediction modes corresponding to the weight derivation mode as the first prediction mode, wherein the second flag indicates a correspondence between the first prediction mode and the intra prediction modes corresponding to the weight derivation mode; or
when the second prediction mode is an intra prediction mode, parsing the bitstream to obtain a third flag and determining an intra prediction mode corresponding to the third flag in the intra prediction modes corresponding to the weight derivation mode as the second prediction mode, wherein the third flag indicates a correspondence between the second prediction mode and the intra prediction modes corresponding to the weight derivation mode.
4. The method of claim 1 , wherein the first prediction mode is a first intra prediction mode and/or the second prediction mode is a second intra prediction mode, and determining at least one of the first prediction mode or the second prediction mode based on the weight derivation mode comprises:
determining at least one of the first intra prediction mode or the second intra prediction mode according to the weight derivation mode.
5. The method of claim 4 , wherein determining at least one of the first intra prediction mode or the second intra prediction mode according to the weight derivation mode comprises:
determining a mode list by using the weight derivation mode; and
determining at least one of the first intra prediction mode or the second intra prediction mode based on the mode list.
6. The method of claim 5 , wherein determining the mode list by using the weight derivation mode comprises:
determining an intra prediction mode corresponding to an adjacent block of the current block and determining the intra prediction mode corresponding to the adjacent block as a mode to-be-added;
when the mode to-be-added meets a preset adding condition, adding the mode to-be-added to the mode list;
when the mode list does not reach a preset list-length, determining a related intra prediction mode corresponding to the weight derivation mode and determining the related intra prediction mode corresponding to the weight derivation mode as the mode to-be-added;
when the mode to-be-added meets the preset adding condition, adding the mode to-be-added to the mode list.
7. The method of claim 6 , wherein determining the related intra prediction mode corresponding to the weight derivation mode comprises:
determining an intra prediction mode corresponding to the weight derivation mode; and
determining the related intra prediction mode according to a first index interval based on the intra prediction mode corresponding to the weight derivation mode.
8. The method of claim 6 , further comprising:
when the mode list does not reach the preset list-length, determining an associated intra prediction mode corresponding to the mode list according to a second index interval based on any prediction mode in the mode list, and determining the associated intra prediction mode as the mode to-be-added; and
when the mode to-be-added meets the preset adding condition, adding the mode to-be-added to the mode list.
9. The method of claim 5 , further comprising:
setting an alternate intra prediction mode; and
determining at least one of the first intra prediction mode or the second intra prediction mode based on the mode list comprises:
determining one prediction mode in the mode list as the first intra prediction mode; and/or
removing the one prediction mode from the mode list and adding the alternate intra prediction mode to the mode list to obtain an updated mode list; and
selecting one prediction mode from the updated mode list as the second intra prediction mode.
10. The method of claim 5 , further comprising:
setting a length parameter of the mode list as (N+1), where N is a positive integer, and
determining at least one of the first intra prediction mode or the second intra prediction mode based on the mode list comprises:
when the first intra prediction mode is determined using the mode list, determining one prediction mode from first N prediction modes in the mode list as the first intra prediction mode; and/or
determining the second intra prediction mode using remaining N prediction modes in the mode list except for the first intra prediction mode; and
when the first intra prediction mode is determined without using the mode list, determining one prediction mode from first N prediction modes in the mode list as the second intra prediction mode.
11. The method of claim 4 , wherein determining at least one of the first intra prediction mode or the second intra prediction mode according to the weight derivation mode comprises at least one of:
establishing a reference set of first intra prediction modes corresponding to the weight derivation mode, and determining the first intra prediction mode based on the reference set of first intra prediction modes; or
establishing a reference set of second intra prediction modes corresponding to the weight derivation mode, and determining the second intra prediction mode based on the reference set of second intra prediction modes.
12. The method of claim 4 , further comprising:
when a size parameter of the current block is less than a first size threshold, determining the weight derivation mode according to a first mode index range, wherein the first mode index range limits an index number of the weight derivation mode, and the first mode index range comprises a first lower threshold and a first upper threshold;
when the index number of the weight derivation mode is less than the first lower threshold, setting the index number of the weight derivation mode to the first lower threshold; and
when the index number of the weight derivation mode is greater than the first upper threshold, setting the index number of the weight derivation mode to the first upper threshold.
13. The method of claim 4 , further comprising:
when a size parameter of the current block is less than a second size threshold, determining the first intra prediction mode and the second intra prediction mode according to a second mode index range, wherein the second mode index range limits index numbers of the intra prediction modes, and the second mode index range comprises a second lower threshold and a second upper threshold;
determining a first index number of the first intra prediction mode and a second index number of the second intra prediction mode;
setting both the first index number and the second index number to be greater than the second lower threshold; and
setting both the first index number and the second index number to be less than the second upper threshold.
14. The method of claim 4 , wherein when the second prediction mode is the second intra prediction mode, the method further comprises:
determining a first initial mode and a second initial mode for the current block according to a mode list for the current block;
determining an offset mode parameter;
when the offset mode parameter indicates performing an offset process:
determining an offset parameter of the current block, wherein the offset parameter comprises an offset manner and an offset amount;
determining the first intra prediction mode by offsetting the first initial mode according to the offset manner and the offset amount, and determining the second intra prediction mode by offsetting the second initial mode according to the offset manner and the offset amount; and
when the offset mode parameter indicates not performing an offset process:
determining the first intra prediction mode and the second intra prediction mode according to the mode list; and
determining the prediction value based on the first intra prediction mode and the second intra prediction mode.
15. A prediction method, applied to an encoder, the method comprising:
determining a weight derivation mode for a current block;
obtaining a first flag, the first flag indicating whether at least one of a first prediction mode or a second prediction mode belongs to an intra prediction mode, wherein at least one of the first prediction mode or the second prediction mode is an intra prediction mode or an inter prediction mode;
determining a type of each of the first prediction mode and the second prediction mode according to the first flag;
when at least one of the first prediction mode or the second prediction mode is an intra prediction mode, determining at least one of the first prediction mode or the second prediction mode based on the weight derivation mode;
determining a weight according to the weight derivation mode; and
determining a prediction value based on the first prediction mode, the second prediction mode, and the weight.