Method and apparatus for video coding
Aspects of the disclosure provide methods and apparatuses for video encoding/decoding. In some examples, an apparatus for video decoding includes receiving circuitry and processing circuitry. For example, the processing circuitry decodes prediction information of a current block in a picture from a coded video bitstream, and determines, based on an intra block copy (IBC) prediction mode usage flag from the decoded prediction information, an IBC prediction mode that is separate from an inter prediction mode and an intra prediction mode. Further, the processing circuitry determines, a block vector that points to a reference area in the picture in response to the determination of the IBC prediction mode, and reconstructs the current block based on reference samples within the reference area in the picture.
1. A method for video decoding in a decoder, comprising:
decoding prediction information of a current block in a picture from a coded video bitstream;
determining whether the current block meets a size requirement;
in response to determining that the current block meets the size requirement,
determining an intra block copy (IBC) prediction mode usage flag for the current block based on (i) the decoded prediction information and (ii) a type of a tile group or slice to which the current block belongs;
determining, based on the IBC prediction mode usage flag, an IBC prediction mode that is separate from an inter prediction mode and an intra prediction mode;
determining, a block vector that points to a reference area in the picture in response to the determination of the IBC prediction mode; and
reconstructing the current block based on reference samples within the reference area in the picture.
2. The method of claim 1 , wherein the decoded prediction information includes an indicator that indicates whether the current block is enabled for the IBC prediction mode.
3. The method of claim 2 , wherein
the IBC prediction mode usage flag is determined to indicate the IBC prediction mode when the indicator indicates that the IBC prediction mode is enabled for the current block and the tile group or slice is I type.
4. The method of claim 2 , wherein when the tile group or slice type is I type, and the IBC prediction mode usage flag is not signaled in the coded video bitstream, a value of the IBC prediction mode usage flag is determined according to the indicator.
5. The method of claim 1 , wherein when the tile group or slice type is B or P type, and the IBC prediction mode usage flag is not signaled in the coded video bitstream, the IBC prediction mode usage flag is determined to be 0.
6. The method of claim 2 , wherein the indicator is a parameter of at least one of a video level, a sequence level, a picture level, and a tile group or slice level.
7. The method of claim 1 , further comprising at least one of:
decoding, from the coded video bitstream, a prediction mode flag; and
determining the prediction mode flag based on a skip flag and the type of the tile group or slice to which the current block belongs.
8. The method of claim 1 , further comprising:
determining, based on the decoded prediction information, a prediction mode flag, and the IBC prediction mode usage flag; and
selecting a prediction mode from the IBC prediction mode, the intra prediction mode and the inter prediction mode based on a combination of the prediction mode flag and the IBC prediction mode usage flag.
9. The method of claim 1 , further comprising:
in response to determining that the current block does not meet the size requirement, selecting the prediction mode from one of the intra prediction mode and the inter prediction mode.
10. A video decoder for video decoding, comprising:
processing circuitry configured to:
decode prediction information of a current block in a picture from a coded video bitstream,
determine whether the current block meets a size requirement, in response to a determination that the current block meets the size requirement,
determine an intra block copy (IBC) prediction mode usage flag for the current block based on (i) the decoded prediction information and (ii) a type of a tile group or slice to which the current block belongs,
determine, based on the IBC prediction mode usage flag, an IBC prediction mode that is separate from an inter prediction mode and an intra prediction mode,
determine, a block vector that points to a reference area in the picture in response to the determination of the IBC prediction mode, and
reconstruct the current block based on reference samples within the reference area in the picture.
11. The video decoder of claim 10 , wherein the decoded prediction information includes an indicator that indicates whether the current block is enabled for the IBC prediction mode.
12. The video decoder of claim 11 , wherein
the IBC prediction mode usage flag is determined to indicate the IBC prediction mode when the indicator indicates that the IBC prediction mode is enabled for the current block and the tile group or slice is I type.
13. The video decoder of claim 11 , wherein when the tile group or slice type is I type, and the IBC prediction mode usage flag is not signaled in the coded video bitstream, a value of the IBC prediction mode usage flag is determined according to the indicator.
14. The video decoder of claim 11 , wherein when the tile group or slice type is B or P type, and the IBC prediction mode usage flag is not signaled in the coded video bitstream, the IBC prediction mode usage flag is determined to be 0.
15. The video decoder of claim 11 , wherein the indicator is a parameter of at least one of a video level, a sequence level, a picture level, and a tile group or slice level.
16. The video decoder of claim 10 , wherein the processing circuitry is configured to:
decode, from the coded video bitstream, a prediction mode flag, and
determine the prediction mode flag based on a skip flag and the type of the tile group or slice to which the current block belongs.
17. The video decoder of claim 10 , wherein the processing circuitry is further configured to:
determine, based on the decoded prediction information, a prediction mode flag, and the IBC prediction mode usage flag, and
select a prediction mode from the IBC prediction mode, the intra prediction mode and the inter prediction mode based on a combination of the prediction mode flag and the IBC prediction mode usage flag.
18. The video decoder of claim 10 , wherein the processing circuitry is further configured to:
in response to a determination that the current block does not meet the size requirement, select the prediction mode from one of the intra prediction mode and the inter prediction mode.
19. A non-transitory computer readable medium having instructions stored therein, which when executed by a processor in a video decoder cause the processor to executed a method comprising:
decoding prediction information of a current block in a picture from a coded video bitstream;
determining whether the current block meets a size requirement;
in response to determining that the current block meets the size requirement,
determining an intra block copy (IBC) prediction mode usage flag for the current block based on (i) the decoded prediction information and (ii) a type of a tile group or slice to which the current block belongs;
determining, based on the IBC prediction mode usage flag, an IBC prediction mode that is separate from an inter prediction mode and an intra prediction mode;
determining, a block vector that points to a reference area in the picture in response to the determination of the IBC prediction mode; and
reconstructing the current block based on reference samples within the reference area in the picture.
20. The non-transitory computer readable medium of claim 19 , wherein the decoded prediction information includes an indicator that indicates whether the current block is enabled for the IBC prediction mode.