Coding schemes for virtual reality (vr) sequences

A method of coding a video containing virtual reality (VR) pictures that includes indexing of reference subpictures relative to current subpictures, the method comprising:

• defining a current VR picture in the VR pictures as six subpictures;
• defining a reference picture and reference subpictures for the current VR picture
• building a reference list and index for the current VR picture and subpictures relative to the reference picture and subpictures;
• indexing the subpictures of the reference picture to the subpictures in the current picture according to temporal and spatial distances to a current block in a current one of the subpictures to a reference block in the reference subpictures;
• and
• using the reference list and index in coding that is sent to the decoder.

A method of coding a video containing virtual reality (VR) pictures that includes the ability to change subpicture orientation, the method comprising:

• defining a current VR picture as six subpictures;
• identifying subpictures in a reference picture for the current VR picture;
• identifying a current subpicture of the current VR picture;
• and
• rotating the subpictures of the reference picture to match the orientation of the subpictures of the current VR picture.

A decoder that provides for temporal motion vector prediction for inter block coding in High Efficiency Video Coding (HEVC) that relies on a block based translational model, the encoder comprising:

• a processor;
• and
• a memory storing code executable by the processor to cause the processor to perform the following steps:
• identifying a current VR picture in the VR pictures as six subpictures;
• receiving at least one reference list for the current VR picture, wherein the at least one reference list holds a reference picture made from a past-coded version of the VR picture as well reference pictures made from past-coded subpictures of the current VR picture;
• wherein the past-coded pictures are included in a first reference list;
• wherein the past-coded subpictures are included in a second reference list;
• receiving motion vector prediction blocks using reference subpictures from the first and second reference list for the current VR picture;
• and
• using the motion vector prediction blocks in decoding.