Reference picture lists modification

Abstract

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 - 20 . (canceled) 
     
     
         21 . A method comprising:
 determining whether a slice of a video bitstream is a P slice or a B slice;   wherein, based on determining that the slice is a P slice, the method further comprises inserting one or more inter-layer reference pictures in List_0 for the slice, the one or more reference pictures inserted at the end of List_0; and   wherein, based on determining that the slice is a B slice, the method further comprises inserting the one or more inter-layer reference pictures in List_0 and List_1 of the slice, the one or more reference pictures placed at the end of List_0 and at the end of List_1.   
     
     
         22 . An encoder comprising:
 a processor configured to:   determine whether a slice of a video bitstream is a P slice or a B slice;   wherein, based on determining that the slice is a P slice, the processor is further configured to insert one or more inter-layer reference pictures in List_0 for the slice, the one or more reference pictures inserted at the end of List_0; and   wherein, based on determining that the slice is a B slice, the processor is further configured to insert the one or more inter-layer reference pictures in List_0 and List_1 of the slice, the one or more reference pictures placed at the end of List_0 and at the end of List_1.   
     
     
         23 . A method comprising:
 receiving a bitstream comprising a base layer and an enhancement layer, the bitstream further comprising a reference picture list of a slice, the reference picture list comprising a plurality of reference pictures that comprise inter-layer reference pictures and temporal reference pictures;   receiving an indication to reposition a reference picture of the plurality of reference pictures within the reference picture list from a first position to a second position;   receiving a first index indicating the first position and a second index indicating the second position;   repositioning the reference picture within the reference picture list from the first position to the second position, wherein an indication to reposition a reference picture previously associated with the second position is not received and the reference picture previously associated with the second position is shifted in the reference picture list according to the indication to reposition the reference picture; and   decoding the slice of the bitstream using the reference picture list.   
     
     
         24 . The method of  claim 23 , wherein the reference picture is an inter-layer reference picture, and wherein the inter-layer reference picture is repositioned in front of a temporal reference picture within the reference picture list. 
     
     
         25 . The method of  claim 23 , wherein the reference picture previously associated with the second position and reference pictures previously associated with positions between the first position and the second position are shifted in the reference picture list according to the indication to reposition the reference picture. 
     
     
         26 . The method of  claim 25 , wherein indications are not received for the reference picture previously associated with the second position or the reference pictures previously associated with positions between the first position and the second position. 
     
     
         27 . The method of  claim 23 , wherein the indication to reposition the reference picture is a variable in a slice header of the slice. 
     
     
         28 . The method of  claim 23 , wherein the first position is after the second position in the reference picture list. 
     
     
         29 . A decoder comprising:
 a processor configured to:   receive a bitstream comprising a base layer and an enhancement layer, the bitstream further comprising a reference picture list of a slice, the reference picture list comprising a plurality of reference pictures that comprise inter-layer reference pictures and temporal reference pictures;   receive an indication to reposition a reference picture of the plurality of reference pictures within the reference picture list from a first position to a second position;   receive a first index indicating the first position and a second index indicating the second position;   reposition the reference picture within the reference picture list from the first position to the second position, wherein an indication to reposition a reference picture previously associated with the second position is not received and the reference picture previously associated with the second position is shifted in the reference picture list according to the indication to reposition the reference picture; and   decode the slice of the bitstream using the reference picture list.   
     
     
         30 . The decoder of  claim 29 , wherein the reference picture is an inter-layer reference picture, and wherein the inter-layer reference picture is repositioned in front of a temporal reference picture within the reference picture list. 
     
     
         31 . The decoder of  claim 29 , wherein the reference picture previously associated with the second position and reference pictures previously associated with positions between the first position and the second position are shifted in the reference picture list according to the indication to reposition the reference picture. 
     
     
         32 . The decoder of  claim 31 , wherein indications are not received for the reference picture previously associated with the second position or the reference pictures previously associated with positions between the first position and the second position. 
     
     
         33 . The decoder of  claim 29 , wherein the indication to reposition the reference picture is a variable in a slice header of the slice. 
     
     
         34 . The decoder of  claim 29 , wherein the first position is after the second position in the reference picture list.