Methods and systems for extended spatial scalability with picture-level adaptation

• US 7,961,963 B2
• Filed: 02/07/2006
• Issued: 06/14/2011
• Est. Priority Date: 03/18/2005
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Sun, Shijun
• Primary Examiner(s): Bali; Vikkram
• Assistant Examiner(s): YEH, EUENG NAN
• Application Number:
  US11/350,000
• Publication Number:
  US 20060209959A1
• Time in Patent Office: 1,953 Days
• Field of Search: 382/240, 341/50, 375/240.08, 375/240.16
• US Class Current: 382/240
• 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 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/139 Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/156 Availability of hardware or computational resources, e.g. encoding based on power-saving criteria
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• 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 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/187 the unit being a scalable video layer
• CPC Class Codes: H04N 19/33 in the spatial domain
• CPC Class Codes: H04N 19/34 Scalability techniques involving progressive bit-plane based encoding of the enhancement layer, e.g. fine granular scalability [FGS]
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/513 Processing of motion vectors
• CPC Class Codes: H04N 19/523 with sub-pixel accuracy
• CPC Class Codes: H04N 19/543 using regions
• CPC Class Codes: H04N 19/56 Motion estimation with initialisation of the vector search, e.g. estimating a good candidate to initiate a search
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/61 : in combination with predictive coding
• CPC Class Codes: H04N 19/70 : characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/80 : Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation H04N19/635, H04N19/86 take precedence
• CPC Class Codes: H04N 19/82 : involving filtering within a prediction loop
• CPC Class Codes: H04N 19/86 : involving reduction of coding artifacts, e.g. of blockiness

Abstract

Embodiments of the present invention comprise systems and methods for modification of motion vectors in spatial scalable video coding. Some embodiments of the present invention comprise methods and systems designed for use with the Scalable Video Coding extension of H.264/MPEG-4 AVC.

Claims

1. A method for picture-level adaptation in a spatially-scalable video codec, said method comprising:

a) receiving a definition of a first cropping window at a first location in a first picture of an input video sequence;

b) generating a first base layer corresponding to said first cropping window;

c) receiving a definition of a second cropping window at a second location, not coincident to said first location, in a second picture of said input video sequence; and

d) generating a second base layer corresponding to said second cropping window; and

e) predicting an area of said second picture in said second cropping window by adjusting a motion vector to account for the difference between said first location of said first cropping window and said second location of said second cropping window.

2. A method as described in claim 1 further comprising predicting an enhancement layer for said second picture based on said second base layer.

3. A method as described in claim 2 wherein said predicting comprises use of a scaled motion vector having an image motion vector component and a cropping window motion vector component.

4. A method as described in claim 2 wherein said predicting comprises a motion vector mv=(d_x, d_y) that is scaled in the vector mv_s=(d_sx, d_sy) using the following equations:

5. A method as described in claim 2 wherein said first picture and said second picture are texture pictures.

6. A method as described in claim 2 wherein said first picture and said second picture are residual pictures.

7. A method for predicting an enhancement layer area, defined by a user-defined, cropping window, from a base layer in a spatially-scalable video codec, said method comprising:

a) receiving a first location for a user-defined, cropping window in said enhancement layer of a frame of said spatially-scalable video codec;

b) calculating a base-layer motion vector in a direction for an image block in said base layer;

c) scaling said base-layer motion vector based on the ratio of a dimension of said cropping window in said direction to a dimension of said base layer in said direction; and

d) adjusting said scaled motion vector to account for said location of said cropping window relative to said base layer.

8. A method as described in claim 7 further comprising predicting said enhancement layer using said adjusted, scaled motion vector.

9. A method as described in claim 7 wherein said scaling and said adjusting are performed in two orthogonal directions.

10. A method as described in claim 7 wherein said scaling and said adjusting are performed on a motion vector mv=(d_x, d_y) that is adjusted and scaled in the vector mv_s=(d_sx, d_sy) using the following equations:

11. A method as described in claim 7 wherein said prediction comprises textural prediction.

12. A method as described in claim 7 wherein said prediction comprises residual prediction.

13. A method as described in claim 7 wherein said scaling and said adjusting are applied to a all motion vectors of a prediction macroblock MB_pred.

14. A system for predicting an enhancement layer area, defined by a user-defined cropping window, from a base layer in a spatially-scalable video codec, said system comprising:

a) a computing device for calculating a base-layer motion vector in a direction for an image block in said base layer;

b) said computing device further comprising a scaling function for scaling said base-layer motion vector based on the ratio of a dimension of said user-defined, image-content-independent cropping window in said direction to a dimension of said base layer in said direction; and

c) said computing device further comprising an adjusting function for adjusting said scaled motion vector to account for motion of said user-defined, cropping window from a location of a second user-defined, cropping window in a reference picture from which said predicting is being performed.

15. A method as described in claim 14 further comprising a predictor for predicting an enhancement layer using said adjusted, scaled motion vector.

16. A method as described in claim 14 wherein said scaling and said adjusting are each performed in two orthogonal directions.

17. A method as described in claim 14 wherein said scaling and said adjusting are performed on a motion vector mv=(d_x, d_y) that is adjusted and scaled in the vector mv_s=(d_sx, d_sy) using the following equations:

18. A method as described in claim 14 wherein said prediction comprises textural prediction.

19. A method as described in claim 14 wherein said prediction comprises residual prediction.

20. A method as described in claim 14 wherein said scaling and said adjusting are applied to a all motion vectors of a prediction macroblock MB_pred.