Decoding variable coded resolution video with native range/resolution post-processing operation

• US 20060072673A1
• Filed: 04/29/2005
• Published: 04/06/2006
• Est. Priority Date: 10/06/2004
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Lin, Chih-Lung, Srinivasan, Sridhar, Hsu, Pohsiang, Holcomb, Thomas W.
• Granted Patent: US 8,243,820 B2
• Time in Patent Office: Days
• US Class Current: 375/240.250
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/156 Availability of hardware or computational resources, e.g. encoding based on power-saving criteria
• CPC Class Codes: H04N 19/164 Feedback from the receiver or from the transmission channel
• CPC Class Codes: H04N 19/174 the region being a slice, e.g. a line of blocks or a group of blocks
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/177 the unit being a group of pictures [GOP]
• CPC Class Codes: H04N 19/179 the unit being a scene or a shot
• 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 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• 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

Abstract

A video codec provides for encoding and decoding pictures of a video sequence at various coded resolutions, such that pictures can be encoded at lower coded resolutions based on bit rate or other constraints while maintaining a consistent display resolution. The video codec further provide for encoding and decoding pictures of the video sequence at ranges lower than that used for display, and then expanding the range after decoding for display. The video codec applies post-processing operations, such as de-blocking, de-ringing, and color conversion, at the native resolution and range of the decoded video, prior to range expansion and upsampling for display.

Claims

1. A method of decoding video, comprising:

extracting a video bit stream from a carrying channel container, where a sequence header is integral to the video bit stream;

decoding a unit of the video bit stream, the unit having a native range less than a range for display;

applying one or more post-processing operations on the decoded unit at its native range; and

expanding range of the unit to the range for display of the video.

2. The method of claim 1 wherein the unit further has a native resolution less than a resolution of display, the method further comprising:

applying said one or more post-processing operations on the decoded unit at its native resolultion; and

up-sampling the unit to the maximum coded resolution for display of the video.

4. The method of claim 1 further comprising:

decoding at least one syntax element signaling whether the one or more post-processing operations are to be applied for the unit; and

applying the post-processing operations as signaled by the decoded post-processing operation-signaling syntax element.

5. The method of claim 4 wherein the post-processing operation signaling syntax element is encoded at least in part at a frame level of the video bit stream.

6. The method of claim 4 wherein the at least one syntax element signals to optionally apply one or more post-processing operations from a group comprising de-blocking, de-ringing, range remapping, and color conversion.

7. The method of claim 4 wherein the at least one syntax element signals to optionally apply de-blocking, de-ringing, or a combination of de-blocking and de-ringing.

8. The method of claim 7 comprising in the case that the at least one syntax element signals to apply de-blocking and de-ringing in combination, applying de-blocking before de-ringing.

9. The method of claim 1 wherein the one or more post-processing operations comprise one or more de-blocking filter stages.

10. The method of claim 1 wherein the one or more post-processing operations comprise one or more de-ringing filter stages.

11. The method of claim 1 wherein the one or more post-processing operations comprise an artifact removal operation.

12. The method of claim 1 wherein the one or more post-processing operations comprise a range re-mapping operation.

13. The method of claim 1 wherein the one or more post-processing operations comprise a color conversion operation.

3. (canceled)

14. A video decoder, comprising:

means for reading elements specifying a maximum coded resolution for a video sequence from a sequence header of the video sequence in a compressed video bit stream;

means for reading a flag indicative of whether at least one picture of a segment in the video sequence is encoded at a lower coded resolution;

means for reading elements specifying the lower coded resolution when indicated for the segment by the flag;

means for decoding the at least one picture of the segment;

means for optionally applying a post-processing operation to the at least one decoded picture while at the lower coded resolution; and

means for up-sampling the at least one picture of the segment from the lower coded resolution to the maximum coded resolution of the video sequence.

15. The video decoder of claim 14, further comprising:

means for reading elements in the compressed video bit stream specifying whether the post-processing operation is to be performed for the at least one picture of the segment;

wherein the means for optionally applying the post-processing operation applies the post-processing operation in accordance with the elements specifying whether the post-processing operation is to be performed.

16. The video decoder of claim 15 wherein the elements specifying whether post-processing is to be performed comprise bits encoding whether to perform de-blocking, de-ringing, de-blocking and de-ringing, or neither.

17. The video decoder of claim 14 wherein the post-processing operation comprises any one or more of de-blocking, de-ringing, range remapping, and color conversion.

18. At least one computer-readable program carrying medium having a software module thereon that is executable by a processing unit to perform a method of decoding a video bit stream coded using variable coded resolution, the method comprising:

extracting a video bit stream from a carrying channel container, where a sequence header is integral to the video bit stream;

decoding at least one syntax element from a sequence header carried in the video bit stream specifying a maximum coded resolution;

decoding at least one syntax element specifying a coded resolution of a unit of the video bit stream;

decoding the unit of the video bit stream;

applying one or more post-processing operations on the decoded unit at its coded resolution; and

in a case where the coded resolution of the unit is less than the maximum coded resolution, up-sampling the unit to the maximum coded resolution for display of the video.

19. The at least one computer-readable program carrying medium of claim 18, wherein the method further comprises:

decoding at least one syntax element signaling whether the one or more post-processing operations are to be applied for the unit; and

applying the post-processing operations as signaled by the decoded post-processing operation-signaling syntax element.

20. The at least one computer-readable program carrying medium of claim 18, wherein the at least one syntax element signals to optionally apply one or more post-processing operations from a group comprising de-blocking, de-ringing, range remapping, and color conversion.

21. The at least one computer-readable program carrying medium of claim 19, wherein the post-processing operation signaling syntax element is encoded at least in part at a frame level of the video bit stream.