Apparatus, a method and a computer program for video coding and decoding

Patent metadata

Field	Value
Publication number	US-9800893-B2
Application number	US-201414254120-A
Country	US
Kind code	B2
Filing date	Apr 16, 2014
Priority date	Apr 17, 2013
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A method and related apparatus for decoding an image sequence from a bitstream, wherein an identifier indicating if all output pictures are decodable with a predefined set of reference pictures is decoded; an indication of required reference pictures for a given output picture is decoded; the indicated at least one reference picture for the given output picture is decoded; and the at least one output picture is decoded.

First claim

The invention claimed is:

1. A method for decoding an image sequence from a bitstream, the method comprising:
decoding an identifier indicating that all output pictures from the encoded image sequence are decodable with a predefined set of independently decodable reference pictures, wherein the identifier signals that the predefined set of independently decodable reference pictures can be stored in a reference picture buffer such all the output pictures of the encoded image sequence can be decoded with the predefined set of independently decodable reference pictures, wherein the predefined set of independently decodable reference pictures does not change during the decoding of the encoded image sequence;
decoding an indication of required independently decodable reference pictures from the predefined set of reference pictures for a given output picture;
decoding an indication that all inter coded pictures of the encoded image sequence use only intra pictures as reference pictures from the predefined set of independently decodable reference pictures;
decoding the required independently decodable reference pictures for the given output picture; and
decoding the at least one output picture.

2. The method according to claim 1 , further comprising
decoding an indication from one or more syntax elements and/or syntax elements values whether a picture is a reference picture or a non-reference picture.

3. The method according to claim 1 , further comprising
decoding an indication that the bitstream comprises only one temporal sub-layer, wherein temporal sub-layer non-reference pictures are regarded as non-reference pictures and all other pictures are regarded as reference pictures.

4. The method according to claim 1 , further comprising
decoding an indication that the bitstream comprises two or more temporal sub-layers, wherein all pictures with TemporalId equal to 0 are considered reference pictures, and all pictures with TemporalId greater than 0 are considered non-reference pictures.

5. An apparatus comprising:
at least one processor and at least one memory, said at least one memory storing code thereon, which when executed by said at least one processor, causes an apparatus to perform at least
decoding an identifier from a bitstream, the identifier indicating that all output pictures from an encoded image sequence are decodable with a predefined set of independently decodable reference pictures, wherein the identifier signals that the predefined set of independently decodable reference pictures can be stored in a reference picture buffer such that all the output pictures of the encoded image sequence can be decoded with the predefined set of independently decodable reference pictures, wherein the predefined set of independently decodable reference pictures does not change during the decoding of the encoded image sequence;
decoding an indication of required independently decodable reference pictures from the predefined set of independently reference pictures for a given output picture;
decoding an indication that all inter coded pictures of the encoded image sequence use only intra pictures as reference pictures from the predefined set of independently decodable reference pictures;
decoding the required independently decodable reference pictures for the given output picture; and
decoding the at least one output picture.

6. The apparatus according to claim 5 , wherein said apparatus is further caused to perform
decoding an indication from one or more syntax elements and/or syntax elements values whether a picture is a reference picture or a non-reference picture.

7. The apparatus according to claim 5 , wherein said apparatus is further caused to perform
decoding an indication that the bitstream comprises only one temporal sub-layer, wherein temporal sub-layer non-reference pictures are regarded as non-reference pictures and all other pictures are regarded as reference pictures.

8. The apparatus according to claim 5 , wherein said apparatus is further caused to perform
decoding an indication that the bitstream comprises two or more temporal sub-layers, wherein all pictures with TemporalId equal to 0 are considered reference pictures, and all pictures with TemporalId greater than 0 are considered non-reference pictures.

9. A non-transitory computer readable storage medium storing code thereon for use by an apparatus, which when executed by a processor, causes the apparatus to perform:
decoding an identifier from a bitstream, the identifier indicating that all output pictures from an encoded image sequence are decodable with a predefined set of independently decodable reference pictures, wherein the identifier signals that the predefined set of independently decodable reference pictures can be stored in a reference picture buffer such that all the output pictures of the encoded image sequence can be decoded with the predefined set of independently decodable reference pictures, wherein the predefined set of independently decodable reference pictures does not change during the decoding of the encoded image sequence;
decoding an indication of required independently decodable reference pictures from the predefined set of independently reference pictures for a given output picture;
decoding an indication that all inter coded pictures of the encoded image sequence use only intra pictures as reference pictures from the predefined set of independently decodable reference pictures;
decoding the required independently decodable reference pictures for the given output picture; and
decoding the at least one output picture.

10. A method for encoding an image sequence in a bitstream, the method comprising:
encoding a set of independently decodable reference pictures;
storing said set of independently decodable reference pictures in an initial reference picture buffer;
encoding a set of pictures from the image sequence without changing the content of the initial reference picture buffer;
encoding an indication in the bitstream indicating that all the set of encoded pictures from the image sequence are decodable using said set of independently decodable reference pictures, wherein the identifier signals to a decoder that the set of independently decodable reference pictures can be stored in a reference picture buffer such that all the output pictures of the encoded image sequence can be decoded with the set of independently decodable reference pictures, wherein the set of independently decodable reference pictures does not change during the decoding of the encoded image sequence; and
encoding an indication that all inter coded pictures of the encoded image sequence use only intra pictures as reference pictures from the set of independently decodable reference pictures.

11. The method according to claim 10 , further comprising
encoding an indication in one or more syntax elements and/or syntax elements values whether a picture is an independently decodable reference picture or a non-reference picture.

12. The method according to claim 10 , further comprising
encoding an indication that the bitstream comprises only one temporal sub-layer, wherein temporal sub-layer non-reference pictures are regarded as non-reference pictures and all other pictures are regarded as reference pictures.

13. An apparatus comprising:
at least one processor and at least one memory, said at least one memory stored with code thereon, which when executed by said at least one processor, causes an apparatus to perform at least:
encoding a set of independently decodable reference pictures in a bitstream;
storing said set of independently decodable reference pictures in an

Assignees

• Nokia Technologies Oy

Inventors

• Lainema Jani
• Hannuksela Miska Matias
• Ugur Kemal
• Malamal Vadakital Vinod Kumar

Classifications

• H04N19/58

  Motion compensation with long-term prediction, i.e. the reference frame for a current frame not being the temporally closest one (H04N19/23 takes precedence) · CPC title

• H04N19/187

  the unit being a scalable video layer · CPC title

• H04N19/31

  in the temporal domain · CPC title

• H04N19/70

  characterised by syntax aspects related to video coding, e.g. related to compression standards · CPC title

• H04N19/573 Primary

  Motion compensation with multiple frame prediction using two or more reference frames in a given prediction direction · CPC title