Method and apparatus for video encoding

• US 20030016752A1
• Filed: 03/04/2002
• Published: 01/23/2003
• Est. Priority Date: 07/11/2000
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola Solutions, Inc.
• Inventors: Dolbear, Catherine Mary, Hobson, Paola Marcella
• Granted Patent: US 7,844,000 B2
• Time in Patent Office: Days
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/29 involving scalability at the object level, e.g. video object layer [VOL]
• CPC Class Codes: H04N 19/31 in the temporal domain
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures

Abstract

A method of enchancing a video bit stream using temporal scalability, wherein the number of bits or a temporal position of a bidirectionally predicted picture in an enhncement layer is determined with reference to a corresponding characteristic of pictures in another layer of layers, such as a base layer, of the video hit stream and the peak signal to noise ration of the B picture is mathched to that of the pictures in the layer below. By endeavouring to align the characteristics of the bidirectially predicted picture or pictures with the existing picture or pictur4es in the lower layer or layers, and improved video sequence can be encoded and decoded for viewing by a user.

Claims

1. A method of enhancing a video bit stream using temporal scalability, wherein peak signal-to-noise ratios of bidirectionally predicted pictures in an enhancement layer are determined with reference to the peak signal-to-noise ratios of pictures in another layer.

4. A method according to any two or more of claims 1 to 3.

5. A method as claimed in claim 1 or claim 4, wherein the peak signal-to-noise ratios are made similar.

6. A method as claimed in any preceding claim, wherein the other layer is a base layer.

7. A method as claimed in any preceding claim, wherein characteristics of more than one picture in another layer are considered.

8. A method as claimed in any preceding claim, wherein:

(i) a first enhancement layer uses SNR scalability to produce enhanced pictures; and

(ii) a second enhancement layer uses temporal scalability to produce enhanced pictures, based on temporal positions of pictures in the first lower enhancement layer.

9. A method as claimed in any preceding claim, wherein an average number of bits used to define a predicted picture and an average number of bits used to define a picture in the another layer are used to define a weighting value

10. An apparatus which implements a method according to any preceding claim, the apparatus including:

means for selecting temporal position, PSNR and/or number of bits of a bidirectionally predicted picture based on information relating to a picture in another layer.

11. An apparatus as claimed in claim 10, which is adapted to encode video signals for transmission via a mobile communications system

2. A method of enhancing a video bit stream using temporal scalability, wherein the number of bits allocated to encode a bidirectionally predicted picture of an enhancement layer is determined with reference to the number of bits used to encode a picture of another layer.

3. A method of enhancing a video bit stream using temporal scalability, wherein temporal positions of predicted pictures in an enhancement layer are determined to be spaced evenly with reference to temporal positions of pictures in other layers.