UNIFIED INTRA-BLOCK COPY AND INTER-PREDICTION

• US 20160057420A1
• Filed: 08/20/2015
• Published: 02/25/2016
• Est. Priority Date: 08/22/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Rapaka, Krishnakanth, Wang, Ye-Kui, Sole Rojals, Joel, Karczewicz, Marta, Pang, Chao
• Granted Patent: US 10,412,387 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/513 Processing of motion vectors
• CPC Class Codes: H04N 19/52 by predictive encoding
• CPC Class Codes: H04N 19/523 with sub-pixel accuracy
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards

Abstract

A video coder may include a current picture and a reference picture in a reference picture list. The video coder may determine a co-located block of the reference picture. The co-located block is co-located with a current block of the current picture. Furthermore, the video coder derives a temporal motion vector predictor from the co-located block and may determine the temporal motion vector predictor has sub-pixel precision. The video coder may right-shift the temporal motion vector predictor determined to have sub-pixel precision. In addition, the video coder may determine, based on the right-shifted temporal motion vector predictor, a predictive block within the current picture.

Claims

1. A method of decoding video data using intra block copy mode, the method comprising:

including a current picture and a reference picture in a reference picture list, the reference picture being different from the current picture;

determining a co-located block of the reference picture, the co-located block being co-located with a current block of the current picture;

deriving a temporal motion vector predictor from the co-located block;

determining the temporal motion vector predictor has sub-pixel precision;

right-shifting the temporal motion vector predictor determined to have sub-pixel precision;

determining, based on the right-shifted temporal motion vector predictor, a predictive block within the current picture; and

forming a decoded video block by summing samples of a residual block and corresponding samples of the predictive block.

2. The method of claim 1, wherein the current picture is a first picture, the method further comprising:

decoding a first block of an I slice of a second picture using intra prediction; and

decoding a second block of the I slice using an intra block copy mode.

3. The method of claim 1, wherein the current picture is a first picture and the reference picture list is a first reference picture list, the method further comprising:

obtaining, from a bitstream, a syntax element indicating whether intra block copy is enabled for a second picture; and

as part of a decoding process for an I slice of the second picture, constructing, responsive to a determination based on the syntax element that intra block copy is enabled for the I slice, a second reference picture list, the second reference picture list including the second picture.

4. The method of claim 1, wherein including the current picture and the reference picture in the reference picture list comprises one of:

including, in the reference picture list, the current picture before long term pictures in the reference picture list; and

including, in the reference picture list, the current picture at a location in the reference picture list based on whether a slice is an I slice, a P slice, or a B slice.

5. The method of claim 1, further comprising generating a motion vector candidate list that includes at least one motion vector candidate for an intra block copy mode encoded block and at least one candidate for an inter-prediction mode encoded block.

6. A method of encoding video data using intra block copy mode, the method comprising:

including a current picture and a reference picture in a reference picture list, the reference picture being different from the current picture;

determining a co-located block of the reference picture, the co-located block being co-located with a current block of the current picture;

deriving a temporal motion vector predictor from the co-located block;

determining the temporal motion vector predictor has sub-pixel precision;

right-shifting the temporal motion vector predictor determined to have sub-pixel precision;

determining, based on the right-shifted temporal motion vector predictor, a predictive block within the current picture; and

generating residual data representing differences between the predictive block that was determined based on the right-shifted temporal motion vector predictor and the current block.

7. The method of claim 6, wherein the current picture is a first picture, the method further comprising:

encoding a first block of an I slice of a second picture using intra prediction; and

encoding a second block of the I slice using an intra block copy mode.

8. The method of claim 6, wherein the current picture is a first picture, the reference picture list is a first reference picture list, the method further comprising:

constructing a second reference picture list for a I slice of a second picture when intra block copy is enabled for the I slice, the second reference picture list including the second picture.

9. The method of claim 6, wherein including the current picture and the reference picture in the reference picture list comprises one of:

including, in the reference picture list, the current picture before long term pictures in the reference picture list; and

including, in the reference picture list, the current picture at a location in the reference picture list based on whether a slice is an I slice, a P slice, or a B slice.

10. The method of claim 6, further comprising generating a motion vector candidate list that includes at least one motion vector candidate for an intra block copy mode encoded block and at least one candidate for an inter-prediction mode encoded block.

11. A device for decoding video data using intra block copy mode, the device comprising:

a memory configured to store video data of a reference picture; and

one or more processors configured to;

include a current picture and the reference picture in a reference picture list, the reference picture being different from the current picture;

determine a co-located block of the reference picture, the co-located block being co-located with a current block of the current picture;

derive a temporal motion vector predictor from the co-located block;

determine the temporal motion vector predictor has sub-pixel precision;

right-shift the temporal motion vector predictor determined to have sub-pixel precision;

determine, based on the right-shifted temporal motion vector predictor, a predictive block within the current picture; and

form a decoded video block by summing samples of a residual block and corresponding samples of the predictive block.

12. The device of claim 11, wherein the current picture is a first picture, the one or more processors being further configured to:

decode a first block of an I slice of a second picture using intra prediction; and

decode a second block of the I slice using an intra block copy mode.

13. The device of claim 11, wherein the current picture is a first picture, the reference picture list is a first reference picture list, the one or more processors being further configured to:

obtain, from a bitstream, a syntax element indicating whether intra block copy is enabled for a second picture; and

as part of a decoding process for an I slice of the second picture, construct, responsive to a determination based on the syntax element that intra block copy is enabled for the I slice, a second reference picture list, the second reference picture list including the second picture.

14. The device of claim 11, wherein the one or more processors being configured to perform one of:

include, in the reference picture list, the current picture before long term pictures in the reference picture list; and

include, in the reference picture list, the current picture at a location in the reference picture list based on whether a slice is an I slice, a P slice, or a B slice.

15. The device of claim 11, wherein the one or more processors are further configured to generate a motion vector candidate list that includes at least one motion vector candidate for an intra block copy mode encoded block and at least one candidate for an inter-prediction mode encoded block.

16. The device of claim 11, wherein the device comprises at least one of:

an integrated circuit;

a microprocessor;

or

a wireless communication device comprising one or both of a display configured to display the current picture or a camera configured to capture the current picture.

17. The device of claim 11, wherein the device further comprises a display configured to display decoded video data.

18. The device of claim 11, wherein the one or more processors are further configured to encode the video data, the device further comprising a camera configured to capture the video data.

19. A device for encoding video data using intra block copy mode, the device comprising:

a memory configured to store video data of a reference picture; and

one or more processors configured to;

include a current picture and the reference picture in a reference picture list, the reference picture being different from the current picture;

determine a co-located block of the reference picture, the co-located block being co-located with a current block of the current picture;

derive a temporal motion vector predictor from the co-located block;

determine the temporal motion vector predictor has sub-pixel precision;

right-shift the temporal motion vector predictor determined to have sub-pixel precision;

determine, based on the right-shifted temporal motion vector predictor, a predictive block within the current picture; and

generate residual data representing differences between the predictive block that was determined based on the right-shifted temporal motion vector predictor and the current block.

20. The device of claim 19, wherein the current picture is a first picture, the one or more processors being further configured to:

encode a first block of an I slice of a second picture using intra prediction; and

encode a second block of the I slice using an intra block copy mode.

21. The device of claim 19, wherein the current picture is a first picture, the reference picture list is a first reference picture list, the one or more processors being further configured to:

construct a second reference picture list for a I slice of a second picture when intra block copy is enabled for the I slice, the second reference picture list including the second picture.

22. The device of claim 19, wherein the one or more processors being configured to perform one of:

include, in the reference picture list, the current picture before long term pictures in the reference picture list; and

include, in the reference picture list, the current picture at a location in the reference picture list based on whether a slice is an I slice, a P slice, or a B slice.

23. The device of claim 19, wherein the one or more processors are further configured to generate a motion vector candidate list that includes at least one motion vector candidate for an intra block copy mode encoded block and at least one candidate for an inter-prediction mode encoded block.

24. The device of claim 19, wherein the device comprises at least one of:

an integrated circuit;

a microprocessor;

or

a wireless communication device comprising one or both of a display configured to display the current picture or a camera configured to capture the current picture.

25. The device of claim 19, wherein the device further comprises a display configured to display decoded video data.

26. The device of claim 19, wherein the one or more processors are further configured to decode video data.

27. An apparatus for coding video data using intra block copy mode, the apparatus comprising:

means for including a current picture and a reference picture in a reference picture list, the reference picture being different from the current picture;

means for determining a co-located block of the reference picture, the co-located block being co-located with a current block of the current picture;

means for deriving a temporal motion vector predictor from the co-located block;

means for determining the temporal motion vector predictor has sub-pixel precision;

means for right-shifting the temporal motion vector predictor determined to have sub-pixel precision; and

means for determining, based on the right-shifted temporal motion vector predictor, a predictive block within the current picture.

28. A non-transitory computer-readable storage medium having instructions stored thereon that, when executed, cause one or more processors of a computing device configured to code video data to:

include a current picture and a reference picture in a reference picture list, the reference picture being different from the current picture;

determine a co-located block of the reference picture, the co-located block being co-located with a current block of the current picture;

derive a temporal motion vector predictor from the co-located block;

determine the temporal motion vector predictor has sub-pixel precision;

right-shift the temporal motion vector predictor determined to have sub-pixel precision; and

determine, based on the right-shifted temporal motion vector predictor, a predictive block within the current picture.