Decoder and encoder and methods for coding of a video sequence using least significant bits of picture order count

摘要

An encoder calculates an indication to a previous reference picture having temporal identity of zero. The encoder creates a first set of indicators to the previous reference picture, to all reference pictures in a first reference picture set of the previous reference picture, and to all pictures following the previous reference picture in decoding order and precede the current picture in decoding order. The encoder sets a flag for picture order count cycle, when a long term reference picture (LTRP) has least significant bits (LSBs) of a picture order count, for which more than one picture in the first set share same value of the LSBs of picture order count as the LTRP. The decoder obtains LSB of a picture order count for a LTRP in a reference picture set of the current picture. The decoder concludes non-compliant bitstream based on indications provided by the flag.

主权项

1. A method, performed by an encoder, for encoding a video sequence into a bitstream, wherein the bitstream is a High Efficiency Video Coding “HEVC” compliant bitstream, wherein the method comprises, when encoding a current picture of the video sequence:
calculating an indication to a previous reference picture, wherein the previous reference picture is located before the current picture in decoding order, wherein the previous reference picture is, relatively to the current picture, a closest previous reference picture, in decoding order, that has a temporal identity equal to zero; creating a first set of indicators to previous pictures, wherein the first set comprises:
the indication to the previous reference picture,a second set of indicators to all reference pictures included in a first reference picture set, “RPS”, of the previous reference picture, anda third set of indicators to all pictures that follow the previous reference picture in decoding order and precede the current picture in decoding order; and based on a long term reference picture in a second RPS of the current picture having least significant bits of a picture order count, for which more than one picture indicated by the indication to the previous reference picture in the first set share the same value of the least significant bits of picture order count as the long term reference picture, setting a flag for the long term reference picture, wherein the flag indicates use of a picture order count cycle and least significant bits of the picture order count to indicate the long term reference picture in the second RPS.