Reference picture lists modification
Systems, methods, and instrumentalities are disclosed relating to modifications to reference picture lists used for multiple layer video coding. A bitstream that may include a reference picture list of a slice may be received. An indication to reposition a reference picture within the reference picture list from a first position to a second position may be received. An indication to insert a reference picture within the reference picture list at a position may be received. The reference picture may be repositioned and/or inserted in the reference picture list in response to receiving the indication. A reference picture previously associated with the position may be shifted in the reference picture list according to the indication to reposition and/or insert the reference picture, although an indication to reposition the reference picture previously associated with the position may not be received. The slice may be decoded using the reference picture list.
1. A method comprising:
receiving a video signal;
determining encoding statistics related to the video signal during a first encoding pass using one or more reference picture lists;
reordering, prior to a second encoding pass, pictures in the one or more reference picture lists based on the encoding statistics determined from the first encoding pass, wherein the encoding statistics comprise motion-compensated distortion information such that the pictures with smaller motion-compensated distortion are assigned lower indices in the one or more reference picture lists; and
encoding the video signal during the second encoding pass using the one or more reordered reference picture lists.
2. The method of claim 1 , further comprising:
encoding the video signal during the first encoding pass using the one or more reference picture lists;
comparing a video bitstream generated during the first encoding pass to a video bitstream generated during the second encoding pass; and
sending the video bitstream that is characterized by a lower Lagrangian rate-distortion (RD) cost.
3. The method of claim 1 , wherein the encoding statistics further comprise reference usage information, and wherein the pictures in the one or more reference picture lists are reordered such that the pictures with higher usage frequency are assigned lower indices.
4. The method of claim 3 , wherein the reference usage information is based on a number of smallest prediction units (SPUs) in an encoded picture or slice that refer to a reference picture.
5. The method of claim 1 , wherein the motion-compensated distortion information is determined based on one or more of sum of square error (SSE), sum of absolute difference (SAD), or sum of absolute transformed differences (SATD).
6. The method of claim 1 , wherein the motion-compensated distortion information is determined based on motion-compensated distortion of smallest prediction units (SPUs) and prediction blocks of the pictures in the one or more reference picture lists.
7. The method of claim 1 , wherein one or more of the first encoding pass and the second encoding pass comprise a complete encoding pass of the video signal.
8. The method of claim 1 , wherein the pictures in the one or more reference picture lists that are reordered comprise at least one of temporal reference pictures or inter-layer reference pictures.
9. The method of claim 1 , further comprising:
performing one or more encoding passes after the first encoding pass and before the second encoding pass.
10. An encoder comprising:
a processor configured to:
receive a video signal;
determine encoding statistics related to the video signal during a first encoding pass using one or more reference picture lists;
reorder, prior to a second encoding pass, pictures in the one or more reference picture lists based on the encoding statistics determined from the first encoding pass, wherein the encoding statistics comprise motion-compensated distortion information such that the pictures with smaller motion-compensated distortion are assigned lower indices in the one or more reference picture lists; and
encode the video signal during the second encoding pass using the one or more reordered reference picture lists.
11. The encoder of claim 10 , wherein the processor is further configured to:
encode the video signal during the first encoding pass using the one or more reference picture lists;
compare a video bitstream generated during the first encoding pass to a video bitstream generated during the second encoding pass; and
send the video bitstream that is characterized by a lower Lagrangian rate-distortion (RD) cost.
12. The encoder of claim 10 , wherein the encoding statistics further comprise reference usage information, and wherein the pictures in the one or more reference picture lists are reordered such that the pictures with higher usage frequency are assigned lower indices.
13. The encoder of claim 12 , wherein the reference usage information is based on a number of smallest prediction units (SPUs) in an encoded picture or slice that refer to a reference picture.
14. The encoder of claim 10 , wherein the motion-compensated distortion information is determined based on one or more of sum of square error (SSE), sum of absolute difference (SAD), or sum of absolute transformed differences (SATD).
15. The encoder of claim 10 , wherein the motion-compensated distortion information is determined based on motion-compensated distortion of smallest prediction units (SPUs) and prediction blocks of the pictures in the one or more reference picture lists.
16. The encoder of claim 10 , wherein one or more of the first encoding pass and the second encoding pass comprise a complete encoding pass of the video signal.
17. The encoder of claim 10 , wherein the pictures in the one or more reference picture lists that are reordered comprise at least one of temporal reference pictures or inter-layer reference pictures.
18. The encoder of claim 10 , wherein the encoder is further configured to perform one or more encoding passes after the first encoding pass and before the second encoding pass.