Method of reference view selection for 3D video coding
A method of deriving VSP (View Synthesis Prediction) Merge candidates with aligned inter-view reference pictures is disclosed. The method generates a second Disparity Vector (DV) using a scaled DV derived from Neighboring Block Disparity Vector (NBDV) of the current block. A method of deriving one or more inter-view DV Merge candidates with aligned DV and associated inter-view reference pictures is also disclosed. The inter-view reference picture pointed by the DV derived from Depth oriented NBDV (DoNBDV) is used as the reference picture and the DV derived from DoNBDV is used as the DV for inter-view DV Merge candidate. Furthermore, a method of deriving temporal DV for NBDV is disclosed, where if the temporal neighboring block has a DV existing, the DV is used as an available DV for the current CU only if the associated inter-view reference picture exists in the reference lists of the current CU.
1. A method of a three-dimensional (3D) or multi-view coding system using a VSP (View Synthesis Prediction) Merge candidate, the method comprising:
receiving input data associated with a current block in a dependent view;
determining a derived DV (Disparity Vector) for the current block, wherein the derived DV is in a first reference list and the derived DV points to a first-list inter-view reference picture in the first reference list with a first view index;
identifying a second-list inter-view reference picture in a second reference list with a second view index, wherein the second reference list is different from the first reference list and the second view index is different from the first view index;
deriving a second DV pointing to the second-list inter-view reference picture as a bi-directional VSP Merge candidate when the second-list inter-view reference picture exists, wherein the second DV is derived based on the derived DV according to a DV conversion process; and
encoding or decoding the current block using bi-directional Merge candidates including the bi-directional VSP Merge candidate, wherein bi-directional VSP is allowed.
2. The method of claim 1 , wherein the DV conversion process corresponds to DV scaling, wherein the second DV is derived based on the derived DV according to view order distance associated with the first view index and the second view index.
3. The method of claim 1 , wherein the DV conversion process corresponds to depth-to-disparity vector (depth-to-DV) conversion, wherein the second DV is converted from a maximum depth value selected from a depth block in a reference view, wherein the depth block is located using the derived DV.
4. The method of claim 1 , wherein the derived DV is determined using a NBDV (Neighboring Block Disparity Vector) process, wherein the derived DV is determined based on disparity vectors of neighboring blocks of the current block.
5. The method of claim 1 , wherein the derived DV is determined using a DoNBDV (Depth oriented Neighboring Block Disparity Vector) process, wherein a NBDV (Neighboring Block Disparity Vector) process is used to derive a first DV from disparity vectors of neighboring blocks of the current block, the first DV is used to access a depth block in a reference view, a converted DV is converted from a maximum depth value selected from the depth block, and the converted DV is provided as an output of the DoNBDV process.
6. The method of claim 1 , wherein the second DV is stored as the bi-directional VSP Merge candidate.
7. A method of a three-dimensional (3D) or multi-view coding system using an inter-view DV (disparity vector) Merge candidate, the method comprising:
receiving input data associated with a current block in a dependent view;
determining a derived DV (Disparity Vector) based on a DV derivation process, wherein the derived DV is in a first reference list and the derived DV points to a first-list inter-view reference picture in the first reference list with a first view index;
deriving a first inter-view DV Merge candidate using a disparity value of the derived DV and an inter-view reference picture pointed by the derived DV; and
encoding or decoding the current block using Merge candidates including the first inter-view DV Merge candidate.
8. The method of claim 7 , wherein the DV derivation process corresponds to a NBDV (neighboring block disparity vector) process, wherein the derived DV is determined based on disparity vectors of neighboring blocks of the current block.
9. The method of claim 7 , wherein the DV derivation process corresponds to a DoNBDV (Depth oriented NBDV) process, wherein the derived DV is determined using a DoNBDV (Depth oriented Neighboring Block Disparity Vector) process, wherein a NBDV (Neighboring Block Disparity Vector) process is used to derive a first DV from disparity vectors of neighboring blocks of the current block, the first DV is used to access a depth block in a reference view, a converted DV is converted from a maximum depth value selected from the depth block, and the converted DV is provided as an output of the DoNBDV process.
10. The method of claim 7 , wherein the derived DV is stored as a uni-directional inter-view DV candidate.
11. The method of claim 7 , further comprising:
when the current block is coded using bi-prediction, identifying a second-list inter-view reference picture in a second reference list with a second view index, wherein the second reference list is different from the first reference list;
deriving a second DV pointing to the second-list inter-view reference picture combining a first DV pointing to the first-list inter-view reference picture as a second inter-view DV Merge candidate, wherein the second DV is derived based on the derived DV according to a DV conversion process; and
wherein the Merge candidates including the second inter-view DV Merge candidate.
12. The method of claim 11 , wherein the second view index is different from the first view index.
13. The method of claim 11 , wherein the second DV is stored as a bi-directional inter-view DV candidate.
14. The method of claim 11 , wherein the DV conversion process corresponds to DV scaling, wherein the second DV is derived based on the derived DV according to view order distance associated with the first view index and the second view index.
15. The method of claim 11 , wherein the DV conversion process corresponds to depth-to-DV conversion, wherein the second DV is converted from a maximum depth value selected from a depth block in a reference view, wherein the depth block is located using the derived DV.
16. A method of a three-dimensional (3D) or multi-view coding system using a DV (Disparity Vector) derived according to NBDV (Neighboring Block Disparity Vector) process, the method comprising:
receiving input data associated with a current block in a dependent view;
determining one or more collocated blocks in a temporal reference picture corresponding to the current block;
searching for an available DV from said one or more collocated blocks;
determining whether the available DV points to an inter-view reference picture in a reference list of the current block;
designating the available DV as a temporal NBDV if said determining whether the available DV points to the inter-view reference picture in the reference list of the current block is asserted; and
encoding or decoding the current block using the temporal NBDV.