Method and apparatus for video encoding

• US 7,844,000 B2
• Filed: 07/09/2001
• Issued: 11/30/2010
• Est. Priority Date: 07/11/2000
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Dolbear, Catherine Mary, Hobson, Paola Marcella
• Primary Examiner(s): RAO, ANAND SHASHIKANT
• Application Number:
  US10/070,069
• Publication Number:
  US 20030016752A1
• Time in Patent Office: 3,431 Days
• Field of Search: 37524001-24029
• US Class Current: 375/240.25
• 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 enhancement layer is determined with reference to a corresponding characteristic of pictures in another layer of layers, such as a base layer, of the video bit stream and the peak signal to noise ration of the B picture is matched to that of the pictures in the layer below. By endeavouring to align the characteristics of the bidirectionally predicted picture or pictures with the existing picture or pictures 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 as claimed in claim 1, wherein the peak signal-to-noise ratios are made similar.

5. A method as claimed claim 1, wherein the other layer is a base layer.

6. A method as claimed in claim 1, wherein characteristics of more than one picture in another layer are considered.

7. A method as claimed in claim 1, 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.

8. A method as claimed in claim 1, 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.

9. An apparatus which implements a method according to claim 1, 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.

10. An apparatus as claimed in claim 9, which is adapted to encode video signal 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 bidirectionally predicted pictures in an enhancement layer are determined to be spaced evenly with reference to temporal positions of pictures in other layers.