Method of intra picture block copy for screen content and video coding

• US 10,027,981 B2
• Filed: 08/26/2015
• Issued: 07/17/2018
• Est. Priority Date: 09/01/2014
• Status: Active Grant

• Current Assignee: HFI Innovation, Inc. (MediaTek, Inc.)
• Original Assignee: HFI Innovation, Inc. (MediaTek, Inc.)
• Inventors: Xu, Xiaozhong, Chuang, Tzu-Der, Liu, Shan
• Primary Examiner(s): Aghevli, Reza
• Application Number:
  US15/505,634
• Publication Number:
  US 20170280159A1
• Time in Patent Office: 1,056 Days
• Field of Search: None
• CPC Class Codes: H04N 19/11 among a plurality of spatial predictive coding modes
• CPC Class Codes: H04N 19/52 by predictive encoding
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques

Abstract

A method of screen content coding (SCC) and video coding using coding modes including IntraBC mode (Intra-block copy mode) is disclosed. In one embodiment, a Merge candidate list including one or more IntraBC Merge candidates and one or more Inter Merge candidates is derived. If an IntraBC Merge candidate is selected from the Merge candidate list for the current block, the current motion information of the current block is encoded or decoded by sharing candidate motion information of the selected IntraBC Merge candidate as the current motion information of the current block, and the current block is encoded or decoded using a coded block in the current picture located according to the current motion information as an IntraBC predictor. The candidate motion information or the current motion information may include one or more elements selected from a motion information group consisting of coding mode, displacement vector and reference picture information.

Claims

1. A method of screen content coding (SCC) and video coding using one or more coding modes including IntraBC mode (Intra-block copy mode) for a picture, wherein the picture is divided into multiple blocks, the method comprising:

receiving input data associated with a current block in a current picture;

deriving a first Merge candidate list including one or more IntraBC Merge candidates and one or more Inter Merge candidates, wherein candidate motion information of each of said one or more Inter Merge candidates identifies one temporal reference block in one temporal reference picture in one reference list; and

if one IntraBC Merge candidate is selected from the first Merge candidate list for the current block, encoding or decoding current motion information of the current block by sharing candidate motion information of the selected IntraBC Merge candidate as the current motion information of the current block, and encoding or decoding the current block using a coded block in the current picture located according to the candidate motion information of the selected IntraBC Merge candidate as an IntraBC predictor.

2. The method of claim 1, further comprising if one Inter Merge candidate is selected from the first Merge candidate list for the current block, encoding or decoding the current motion information of the current block by sharing candidate motion information of the selected Inter Merge candidate as the current motion information of the current block, and encoding or decoding the current block using a coded block in one temporal reference picture in one reference list located according to the current motion information as an Inter predictor.

3. The method of claim 1, wherein said deriving a first Merge candidate list is based on one or more spatial neighboring blocks, one or more temporal blocks, or both coded either in IntraBC mode or Inter mode.

4. The method of claim 3, wherein if the first Merge candidate list is not full after the first Merge candidate list is derived based on said one or more spatial neighboring blocks, said one or more temporal blocks, or both coded either in IntraBC mode or Inter mode, one or more pre-defined non-zero block vectors, one or more last coded block vectors, or both are added to the first Merge candidate list.

5. The method of claim 4, wherein said one or more non-zero block vectors correspond to one or more elements selected from a pre-defined block vector (BV) group consisting of (−

W,

     0), (−

2W,

     0), (0, −

H), (0, −

2H) and (−

W, −

H), and wherein W and H correspond to width and height of the current block respectively.

6. The method of claim 4, wherein part of or all of said one or more pre-defined non-zero block vectors, said one or more last coded block vectors, or both are added before one or more bi-predictive Merge candidates, or after said one or more bi-predictive Merge candidates and before one or more zero-valued Merge/AMVP (advanced motion vector predictor) candidates.

7. The method of claim 4, wherein the first Merge candidate list is pruned to remove one or more redundant Merge candidates before or after said one or more pre-defined non-zero block vectors, said one or more last coded block vectors, or both are added to the first Merge candidate list.

8. The method of claim 3, wherein said one or more spatial neighboring blocks coded in the IntraBC mode are restricted to be within a current CTU (coding tree unit) of the current block, or within the current CTU and an above-CTU above the current block.

9. The method of claim 8, wherein block vectors associated with said one or more spatial neighboring blocks coded in the IntraBC mode are stored in a compressed form by storing one block vector for each target block size larger than a minimum block size.

10. The method of claim 1, wherein the candidate motion information or the current motion information includes one or more elements selected from a motion information group consisting of a coding mode, a displacement vector and reference picture information, and wherein the coding mode comprises IntraBC mode and Inter mode, the displacement vector corresponds to one block vector or one motion vector, and the reference picture information includes one reference picture index, one reference picture list or both.

11. The method of claim 1, wherein block vectors associated with said one or more IntraBC Merge candidates are stored by re-using Inter motion vector buffer used to store motion vectors associated with Inter coded blocks.

12. The method of claim 1, further comprising signaling or parsing a first syntax corresponding to a Merge candidate index to select said one IntraBC Merge candidate from the first Merge candidate list when the current block is coded using IntraBC mode.

13. The method of claim 12, when the current block is coded using Inter mode, further comprising signaling or parsing the first syntax corresponding to the Merge candidate index to select one Inter Merge candidate from the first Merge candidate list.

14. The method of claim 1, wherein a syntax related to a maximum number of IntraBC Merge candidates in the first Merge candidate list is incorporated in slice header, PPS (picture parameter set), SPS (sequence parameter set), VPS (video parameter set), slice header SCC (screen content coding) extensions, PPS SCC extensions, SPS SCC extensions, or VPS SCC extensions.

15. A method of screen content coding (SCC) and video coding for a picture, wherein the picture is divided into multiple blocks, the method comprising:

receiving input data associated with a current block in a current picture;

if the current block is coded in Inter mode, signaling or parsing a current motion vector for the current block at an encoder side or a decoder side respectively, and storing the current motion vector in an Inter motion vector buffer, and wherein the current motion vector is used to locate a first coded block in a temporal reference picture and the first coded block is used as an Inter predictor for the current block;

if the current block is coded in IntraBC mode, signaling or parsing a current block vector for the current block at the encoder side or the decoder side respectively, and storing the current block vector by reusing the Inter motion vector buffer, and wherein the current block vector is used to locate a second coded block in the current picture and the second coded block is used as an IntraBC predictor; and

providing one or more motion vectors and one or more block vectors stored in the Inter motion vector buffer for encoding or decoding one or more subsequent blocks.

16. The method of claim 15, wherein when the current block vector is stored in the Inter motion vector buffer, reusing the Inter motion vector buffer by the current block vector is indicated by setting a reference picture index for the current block to −

1, unavailable, or a value equal to or larger than a number of reference pictures in a reference list, or setting Inter prediction direction, interDir to zero.

17. An apparatus for screen content coding (SCC) and video coding using one or more coding modes including IntraBC mode (Intra-block copy mode) for a picture, wherein the picture is divided into multiple blocks, the apparatus comprising one or more electronic circuits configured to:

receive input data associated with a current block in a current picture;

derive a first Merge candidate list including one or more IntraBC Merge candidates and one or more Inter Merge candidates, wherein candidate motion information of each of said one or more Inter Merge candidates identifies one temporal reference block in one temporal reference picture in one reference list; and

if one IntraBC Merge candidate is selected from the first Merge candidate list for the current block, encode or decode current motion information of the current block by sharing candidate motion information of the selected IntraBC Merge candidate as the current motion information of the current block, and encode or decode the current block using a coded block in the current picture located according to the candidate motion information of the selected IntraBC Merge candidate as an IntraBC predictor.