Encoder and decoder and methods thereof for encoding/decoding a picture of a video sequence
View Patent ↗An object of the embodiments is to achieve an improved reference picture handling. That is achieved by taking into account whether the reference pictures in the decoded picture buffer are long-term reference pictures or short-term reference pictures when determining how they should be marked when the information of the reference picture set is received. The reference pictures are marked as “used for short-term reference” or “used for long-term reference” in the Decoded Picture Buffer (DPB) depending on whether they are included as short-term pictures or long-term pictures in the RPS of a current picture.
1. A mobile device comprising a decoder for managing reference pictures to be used for decoding an encoded representation of a picture of a video sequence, the decoder configured to decode a reference picture set received from an encoder, wherein the reference picture set comprises information of the reference pictures to be kept in a decoded picture buffer and to decode a Picture Order Count (POC) value indicated in the reference picture set, the decoder comprising a processor configured to:
determine if the POC value indicated in the reference picture set corresponds to a short-term reference picture or to a long-term reference picture;
keep, when there is a long-term reference picture in the decoded picture buffer with a POC value corresponding to the POC value indicated in the reference picture set and the POC value indicated in the reference picture set corresponds to a long-term reference picture, the long-term reference picture in a decoded picture buffer as a long-term reference picture;
mark, when there is a short-term reference picture in the decoded picture buffer with a POC value corresponding to the POC value indicated in the reference picture set and the POC value indicated in the reference picture set corresponds to a long-term reference picture and there is not a long-term reference picture in the decoded picture buffer with a POC value corresponding to the POC value indicated in the reference picture set, the short-term reference picture in the decoded picture buffer as a long-term reference picture and keeping it in the decoded picture buffer; and
keep, when there is a short-term reference picture in the decoded picture buffer with a POC value corresponding to the POC value indicated in the reference picture set and the POC value indicated in the reference picture set corresponds to a short-term reference picture, the short-term reference picture in the decoded picture buffer as a short-term reference picture.
2. The mobile device of claim 1 , wherein the processor is configured to determine if the POC value indicated in the reference picture set corresponds to a short-term reference picture or to a long-term reference picture by determining if the POC value indicated in the reference picture set is included in one of the lists:
PocLtCurr or PocLtFoll, in which case the POC value corresponds to a long-term reference picture; and
PocStCurrBefore, PocStCurrAfter, or PocStFoll, in which case the POC value corresponds to a short-term reference picture.
3. The mobile device of claim 1 , wherein the processor is configured to mark the reference pictures in the decoded picture buffer by handling the long-term reference pictures in the reference picture set before the short-term reference pictures.
4. A display comprising a decoder for managing reference pictures to be used for decoding an encoded representation of a picture of a video sequence, the decoder configured to decode a reference picture set received from an encoder, wherein the reference picture set comprises information of the reference pictures to be kept in a decoded picture buffer and to decode a Picture Order Count (POC) value indicated in the reference picture set, the decoder comprising a processor configured to:
determine if the POC value indicated in the reference picture set corresponds to a short-term reference picture or to a long-term reference picture;
keep, when there is a long-term reference picture in the decoded picture buffer with a POC value corresponding to the POC value indicated in the reference picture set and the POC value indicated in the reference picture set corresponds to a long-term reference picture, the long-term reference picture in a decoded picture buffer as a long-term reference picture;
mark, when there is a short-term reference picture in the decoded picture buffer with a POC value corresponding to the POC value indicated in the reference picture set and the POC value indicated in the reference picture set corresponds to a long-term reference picture and there is not a long-term reference picture in the decoded picture buffer with a POC value corresponding to the POC value indicated in the reference picture set, the short-term reference picture in the decoded picture buffer as a long-term reference picture and keeping it in the decoded picture buffer; and
keep, when there is a short-term reference picture in the decoded picture buffer with a POC value corresponding to the POC value indicated in the reference picture set and the POC value indicated in the reference picture set corresponds to a short-term reference picture, the short-term reference picture in the decoded picture buffer as a short-term reference picture.
5. The display of claim 4 , wherein the processor is configured to determine if the POC value indicated in the reference picture set corresponds to a short-term reference picture or to a long-term reference picture by determining if the POC value indicated in the reference picture set is included in one of the lists:
PocLtCurr or PocLtFoll in which case the POC value corresponds to a long-term reference picture; and
PocStCurrBefore, PocStCurrAfter, or PocStFoll, in which case the POC value corresponds to a short-term reference picture.
6. The display of claim 4 , wherein the processor is configured to mark the reference pictures in the decoded picture buffer by handling the long-term reference pictures in the reference picture set before the short-term reference pictures.