Grouping of image frames in video coding

• US 20060120451A1
• Filed: 01/25/2006
• Published: 06/08/2006
• Est. Priority Date: 01/23/2002
• Status: Active Grant

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Hannuksela, Miska
• Granted Patent: US 8,050,321 B2
• Time in Patent Office: Days
• US Class Current: 375/240.120
• CPC Class Codes: H04N 19/105 Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
• CPC Class Codes: H04N 19/114 Adapting the group of pictures [GOP] structure, e.g. number of B-frames between two anchor frames H04N19/107 takes precedence
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/142 Detection of scene cut or scene change
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/31 in the temporal domain
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/587 involving temporal sub-sampling or interpolation, e.g. decimation or subsequent interpolation of pictures in a video sequence
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/65 using error resilience
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/895 in combination with error concealment

Abstract

A method for encoding a video sequence comprising an independent sequence of image frames, wherein at least one reference image frame is predictable from at least one previous image frame that is earlier than the previous reference image frame in decoding order. An indication of at least one image frame is encoded into the video sequence, which indicated image frame is the first image frame, in decoding order, of the independent sequence, said at least one reference image frame being included in the sequence. In the decoding phase, the indication of at least one image frame is decoded from the video sequence, and the decoding of the video sequence is started from said first image frame of the independent sequence, whereby the video sequence is decoded without prediction from any image frame decoded prior to said first image frame.

Claims

1. A method for encoding a video sequence comprising an independent sequence of image frames, wherein at least one reference image frame is predictable from at least one previous image frame that is earlier than the previous reference image frame in decoding order, the method comprising:

encoding into the video sequence an indication of at least one image frame, which is the first image frame, in decoding order, of the independent sequence, said at least one reference image frame being included in the sequence.

2. A method according to claim 1, further comprising:

encoding the indication into the video sequence as a separate flag included in the header of a slice.

3. A method according to claim 1, further comprising:

encoding identifier values for image frames according to a numbering scheme, and

resetting the identifier value for the indicated first image frame of an independent sequence.

4. A method according to claim 1, further comprising:

encoding into the video sequence an identifier value for the independent sequence.

5. A video encoder for encoding a video sequence comprising an independent sequence of image frames, wherein at least one reference image frame is predictable from at least one previous image frame that is earlier than the previous reference image frame in decoding order, the video encoder being arranged to

encode into the video sequence an indication of at least one image frame, which is the first image frame, in decoding order, of the independent sequence, said at least one reference image frame being included in the sequence.

6. A video encoder according to claim 5, wherein the video encoder is arranged to

encode the indication into the video sequence as a separate flag included in the header of a slice.

7. A video encoder according to claim 5, wherein the video encoder is arranged to

encode identifier values for image frames according to a numbering scheme, and

reset the identifier value for the indicated first image frame of an independent sequence.

8. A video encoder according to claim 5, wherein the video encoder is arranged to

encode into the video sequence an identifier value for the independent sequence.

9. A computer program product, stored on a computer readable medium and executable in a data processing device, for encoding a video sequence comprising an independent sequence of image frames, wherein at least one reference image frame is predictable from at least one previous image frame that is earlier than the previous reference image frame in decoding order, the computer program product comprising:

a computer program code for encoding into the video sequence an indication of at least one image frame, which is the first image frame, in decoding order, of the independent sequence, said at least one reference image frame being included in the sequence.

10. A method for decoding a compressed video sequence, wherein at least one reference image frame is predictable from at least one previous image frame that is earlier than the previous reference image frame in decoding order, the method comprising

decoding from the video sequence an indication of at least one image frame, which is the first image frame, in decoding order, of an independent sequence, said sequence including the at least one reference image frame;

and

starting the decoding of the video sequence from said first image frame of the independent sequence, whereby the video sequence is decoded without prediction from any image frame decoded prior to said first image frame.

11. A method according to claim 10, wherein the indication is a separate flag included in the header of a slice.

12. A method according to claim 10, further comprising:

decoding identifier values for image frames according to a numbering scheme, and

resetting the identifier value for the indicated first image frame of an independent sequence.

13. A video decoder for decoding a compressed video sequence, wherein at least one reference image frame is predictable from at least one previous image frame that is earlier than the previous reference image frame in decoding order, the video decoder being arranged to

decode from the video sequence an indication of at least one image frame, which is the first image frame, in decoding order, of an independent sequence, said sequence including the at least one reference image frame;

and

start the decoding of the video sequence from said first image frame of the independent sequence, whereby the video sequence is decoded without prediction from any image frame decoded prior to said first image frame.

14. A computer program product, stored on a computer readable medium and executable in a data processing device, for decoding a compressed video sequence, wherein at least one reference image frame is predictable from at least one previous image frame that is earlier than the previous reference image frame in decoding order, the computer program product comprising:

a computer program code for decoding from the video sequence an indication of at least one image frame, which is the first image frame, in decoding order, of an independent sequence, said sequence including the at least one reference image frame; and

a computer program code for starting the decoding of the video sequence from said first image frame of the independent sequence, whereby the video sequence is decoded without prediction from any image frame decoded prior to said first image frame.

15. A video signal comprising a compressed video sequence including an independent sequence of image frames, wherein at least one reference image frame is predictable from at least one previous image frame that is earlier than the previous reference image frame in decoding order, the video signal further comprising:

an indication of at least one image frame, which is the first image frame, in decoding order, of the independent sequence, said at least one reference image frame being included in the sequence.

16. A video signal according to claim 15, the video signal further comprising an identifier value for the independent sequence.