Coding and decoding methods of a picture block, corresponding devices and data stream

Patent metadata

Field	Value
Publication number	US-12445635-B2
Application number	US-202418743536-A
Country	US
Kind code	B2
Filing date	Jun 14, 2024
Priority date	Feb 22, 2013
Publication date	Oct 14, 2025
Grant date	Oct 14, 2025

Abstract

A method for decoding a picture block is disclosed. The decoding method comprises: decoding ( 10 ) at least one stream S_diff into decoded data and into one information for identifying a reconstructed reference picture in a decoder picture buffer; reconstructing ( 12 ) a special reference picture from at least the identified reconstructed reference picture and from the decoded data; reconstructing ( 16 ) the picture block from at least the special reference picture, wherein the at least the special reference picture is not displayed.

First claim

The invention claimed is:

1. A decoding method comprising:
decoding a plurality of pictures from a first bitstream, including a first and second picture, and storing the first picture and the second picture;
switching from the first bitstream to a second bitstream, the second bitstream including a third picture;
in response to the switching, obtaining a plurality of difference pictures including a first difference picture and a second difference picture;
modifying the stored first picture based on the first difference picture and modifying the second stored picture based on the second difference picture; and
reconstructing the third picture from the modified first picture and the modified second picture.

2. The method of claim 1 , wherein the first bitstream is provided in a first layer of a scalable video, the second bitstream is provided in a second layer of the scalable video, and the plurality of difference pictures are provided in the second layer.

3. The method of claim 1 , wherein the modified first picture and the modified second picture are not displayed.

4. The method of claim 1 , wherein the first bitstream and the second bitstream have different bitrates.

5. The method of claim 1 , wherein switching from the first bitstream to the second bitstream comprises requesting a switch from the first bitstream to the second bitstream.

6. An encoding method comprising:
encoding a plurality of pictures in a first bitstream, including a first and second picture;
encoding a plurality of pictures in a second bitstream, including a third picture, a fourth picture, and a fifth picture, wherein the fifth picture is predicted from the third picture and the fourth picture; and
encoding a plurality of difference pictures including a first difference picture and a second difference picture, the first difference picture representing a difference between the first picture and the third picture, and the second difference picture representing a difference between the second picture and the fourth picture.

7. The method of claim 6 , wherein the first bitstream is provided in a first layer of a scalable video, the second bitstream is provided in a second layer of the scalable video, and the plurality of difference pictures are provided in the second layer.

8. The method of claim 6 , wherein the first bitstream and the second bitstream have different bitrates.

9. The method of claim 6 , further comprising:
providing the first and second picture to a decoder; and
switching from the first bitstream to a second bitstream by providing the first difference picture, the second difference picture, and the fifth picture to the decoder without providing the third picture or the fourth picture to the decoder.

10. The method of claim 9 , wherein switching from the first bitstream to the second bitstream is performed in response to a request form the decoder.

11. A decoding apparatus comprising one or more processors configured to perform at least:
decoding a plurality of pictures from a first bitstream, including a first and second picture, and storing the first picture and the second picture;
switching from the first bitstream to a second bitstream, the second bitstream including a third picture;
in response to the switching, obtaining a plurality of difference pictures including a first difference picture and a second difference picture;
modifying the stored first picture based on the first difference picture and modifying the second stored picture based on the second difference picture; and
reconstructing the third picture from the modified first picture and the modified second picture.

12. The apparatus of claim 11 , wherein the first bitstream is provided in a first layer of a scalable video, the second bitstream is provided in a second layer of the scalable video, and the plurality of difference pictures are provided in the second layer.

13. The apparatus of claim 11 , wherein the modified first picture and the modified second picture are not displayed.

14. The apparatus of claim 11 , wherein the first bitstream and the second bitstream have different bitrates.

15. The apparatus of claim 11 , wherein switching from the first bitstream to the second bitstream comprises requesting a switch from the first bitstream to the second bitstream.

16. An encoding apparatus comprising one or more processors configured to perform at least:
encoding a plurality of pictures in a first bitstream, including a first and second picture;
encoding a plurality of pictures in a second bitstream, including a third picture, a fourth picture, and a fifth picture, wherein the fifth picture is predicted from the third picture and the fourth picture; and
encoding a plurality of difference pictures including a first difference picture and a second difference picture, the first difference picture representing a difference between the first picture and the third picture, and the second difference picture representing a difference between the second picture and the fourth picture.

17. The apparatus of claim 16 , wherein the first bitstream is provided in a first layer of a scalable video, the second bitstream is provided in a second layer of the scalable video, and the plurality of difference pictures are provided in the second layer.

18. The apparatus of claim 16 , wherein the first bitstream and the second bitstream have different bitrates.

19. The apparatus of claim 16 , further comprising:
providing the first and second picture to a decoder; and
switching from the first bitstream to a second bitstream by providing the first difference picture, the second difference picture, and the fifth picture to the decoder without providing the third picture or the fourth picture to the decoder.

20. The apparatus of claim 19 , wherein switching from the first bitstream to the second bitstream is performed in response to a request form the decoder.

Assignees

• Interdigital Vc Holdings Inc

Inventors

• Bordes Philippe
• Hiron Franck
• Andrivon Pierre
• Lopez Patrick
• Salmon Philippe

Classifications

• H04N19/50

  using predictive coding (H04N19/61 takes precedence) · CPC title

• H04N19/176

  the region being a block, e.g. a macroblock · CPC title

• H04N19/30 Primary

  using hierarchical techniques, e.g. scalability (H04N19/63 takes precedence) · CPC title

• H04N19/573

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

• H04N21/2358

  for generating different versions, e.g. for different recipient devices · CPC title