Method and Apparatus for Detection and Concealment of Reference and Non-Reference Video Frames

• US 20090175344A1
• Filed: 06/06/2006
• Published: 07/09/2009
• Est. Priority Date: 07/25/2005
• Status: Active Grant

• Current Assignee: InterDigital Madison Patent Holdings (InterDigital, Inc.)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Landais, Frederic, Boyce, Jill MacDonald, Pandit, Purvin Bibhas, Wu, Zhenyu
• Granted Patent: US 8,428,147 B2
• Time in Patent Office: Days
• US Class Current: 375/240.160
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/895 in combination with error concealment

Abstract

There are provided method and apparatus for detecting and concealing reference and non-reference video frames. A video decoder includes an entropy decoder, an error detector, and an error concealer. The entropy decoder is for decompressing a video bitstream intended to have a fixed frame rate and parsing the decompressed video bitstream to find picture order counts for frames of the decompressed video bitstream. The error detector is for determining that a particular frame of the decompressed video bitstream is missing based upon the picture order counts. The error concealer is for concealing the particular frame. The method is accomplished by decompressing and parsing the video bitstream to find picture order counts for frames of the decompressed video bitstream and then determining that a particular frame of the decompressed video bitstream is missing based upon comparison of their associated picture order counts, and then concealing that particular frame.

Claims

1. A video decoder, comprising:

an entropy decoder for decompressing a video bitstream and parsing the decompressed video bitstream to find picture order counts for frames of the decompressed video bitstream;

an error detector for determining that a particular frame of the decompressed video bitstream is missing based upon comparison of the picture order counts; and

an error concealer for concealing the particular frame.

2. The video decoder of claim 1, wherein said error detector determines that the particular frame is lost based on a gap in the picture order counts between temporally adjacent frames of the decompressed video bitstream.

3. The video decoder of claim 1, wherein said error detector determines that the particular frame is lost by determining a picture order count gap between temporally adjacent frames, and indicating the particular frame as lost when the picture order count gap is greater than a threshold.

4. The video decoder of claim 1, wherein said error concealer conceals the particular frame using a frame repeat procedure.

5. The video decoder of claim 1, wherein said error concealer conceals the particular frame by deriving motion information for a block in the particular frame from a co-located block in a previously coded frame.

6. The video decoder of claim 5, wherein said error concealer derives a reference index for use for the block in the particular frame from a reference index of the co-located block in the previously decoded frame.

7. The video decoder of claim 5, wherein said error concealer conceals the particular frame by instead deriving the motion information for the block in the particular frame from motion vectors of spatially available neighbors of the co-located block in the previously coded frame, when the co-located block in the previously coded frame is intra coded.

8. The video decoder of claim 7, wherein said error concealer derives the motion information for the block in the particular frame by applying a median filter to the motion vectors of the spatially available neighbors of the co-located block in the previously coded frame.

9. The video decoder of claim 7, wherein the motion information for the block in the particular frame is obtained using SKIP mode decoding.

10. The video decoder of claim 8, wherein the SKIP mode decoding is performed according to the International Telecommunication Union, Telecommunication Sector (ITU-T) H.264 standard.

11. The video decoder of claim 1, wherein said error detector updates a picture order count of the particular frame.

12. A method for decoding a video bitstream comprising:

decompressing the video bitstream;

parsing the decompressed video bitstream to find picture order counts for frames of the decompressed video bitstream;

determining that a particular frame of the decompressed video bitstream is missing based upon comparison of their associated picture order counts; and

concealing the particular frame.

13. The method of claim 12, wherein said determining step determines that the particular frame is lost based on a gap in the picture order counts between temporally adjacent frames of the decompressed video bitstream.

14. The method of claim 12, wherein said determining step determines that the particular frame is lost by determining a picture order count gap between temporally adjacent frames, and indicating the particular frame as lost when the picture order count gap is greater than a threshold.

15. The method of claim 12, wherein said concealing step conceals the particular frame using a frame repeat procedure.

16. The method of claim 12, wherein said concealing step conceals the particular frame by deriving motion information for a block in the particular frame from a co-located block in a previously coded frame.

17. The method of claim 16, wherein said concealing step derives a reference index for use for the block in the particular frame from a reference index of the co-located block in the previously decoded frame.

18. The method of claim 16, wherein said concealing step conceals the particular frame by instead deriving the motion information for the block in the particular frame from motion vectors of spatially available neighbors of the co-located block in the previously coded frame, when the co-located block in the previously coded frame is intra coded.

19. The method of claim 18, wherein said concealing step derives the motion information for the block in the particular frame by applying a median filter to the motion vectors of the spatially available neighbors of the co-located block in the previously coded frame.

20. The method of claim 18, wherein the motion information for the block in the particular frame is obtained using SKIP mode decoding.

21. The method of claim 20, wherein the SKIP mode decoding is performed according to the International Telecommunication Union, Telecommunication Sector (ITU-T) H.264 standard.

22. The method of claim 12, further comprising updating a picture order count of the particular frame.