Method and system for transcoding video data

• US 7,133,452 B1
• Filed: 02/24/2003
• Issued: 11/07/2006
• Est. Priority Date: 02/24/2003
• Status: Active Grant

• Current Assignee: VIXS Systems Incorporated (Pixelworks Incorporated)
• Original Assignee: VIXS Systems Incorporated (Pixelworks Incorporated)
• Inventors: Rault, Patrick
• Primary Examiner(s): VO, TUNG T
• Application Number:
  US10/375,725
• Time in Patent Office: 1,352 Days
• Field of Search: 375/240.15, 375/240.16, 375/240.12, 375/240, 375/240.01, 375/240.08, 382/238
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/16 for a given display mode, e.g. for interlaced or progressive display mode
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• 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 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards

Abstract

A first method of transcoding video data is disclosed that generates a motion vector for a macroblock encoded as a dual prime macro block that has a direct motion vector, and differential motion vector for its two fields respectively. Another method of transcoding includes replacing a skipped P-macroblock that has been used to backward predict a B-Frame with a P-macroblock having a motion vector of zero. Another method of transcoding includes replacing a skipped B-Macroblock with a macroblock having a motion vector from a macroblock of the same frame of the skipped B-Macroblock that is not co-located.

Claims

1. A method of transcoding video data in a lossless manner, the method comprising:

receiving a first data stream having a first protocol;

determining if a first condition exists, wherein the first condition exists when the first data stream includes a first macroblock comprising a first motion vector and a differential motion vector;

when the first condition is determined to exist;

determining a second motion vector based upon adding the first motion vector and the differential motion vector;

encoding a second macroblock based upon the second motion vector; and

providing the second macroblock to a second data stream in place of the first macroblock, wherein the second macroblock is based on a second protocol different than the first protocol.

2. The method of claim 1 further comprising:

determining if a second condition exists, wherein the second condition exists when the first data stream includes a skipped P-macroblock and a first B-macroblock is forward predicted from image data associated with the skipped P-macroblock location;

when the second condition is determined to exist;

encoding a first P-macroblock based on a decoded image data of the first data stream representing an image for display at an image location of the skipped P-macroblock; and

providing the first P-macroblock to the second data stream to replace the skipped P-macroblock.

3. The method of claim 2 further comprising:

encoding the first P-macroblock based on a motion vector value of zero.

4. The method of claim 3 further comprising:

determining if a third condition exists, wherein the third condition exists when the first data stream includes a skipped B-macroblock;

when the third condition is determined to exist;

encoding a first B-macroblock based on a prediction error data set to zero;

providing the first B-macroblock to the second data stream to replace the skipped B-macroblock.

5. The method of claim 3 further comprising:

determining if a third condition exists, wherein the third condition exists when the first data stream includes a skipped B-macroblock;

when the third condition is determined to exist;

encoding a first B-macroblock based on a motion vector of a second B-macroblock in the same frame as the skipped B-macroblock; and

providing the first B-macroblock to the second data stream to replace the skipped B-macroblock.

6. The method of claim 2 further comprising:

determining if a third condition exists, wherein the third condition exists when the first data stream includes a skipped B-macroblock;

when the third condition is determined to exist;

encoding a first B-macroblock based on a prediction error data set to zero; and

providing the first B-macroblock to the second data stream to replace the skipped B-macroblock.

7. The method of claim 6 further comprising:

encoding the first B-macroblock based on a motion vector of a second B-macroblock in the same frame as the skipped B-macroblock.

8. The method of claim 7, wherein the second B-macroblock is a macroblock to be rendered prior to the first B-macroblock.

9. The method of claim 8, wherein the third B-macroblock comprises data to be displayed immediately adjacent to the first B-macroblock.

10. The method of claim 2 further comprising:

determining if a third condition exists, wherein the third condition exists when the first data stream includes a skipped B-macroblock;

when the third condition is determined to exist;

encoding a second B-macroblock based on a motion vector of a third B-macroblock in the same frame as the skipped B-macroblock; and

providing the second B-macroblock to the second data stream to replace the skipped B-macroblock.

11. The method of claim 1 further comprising:

determining if a second condition exists, wherein the second condition exists when the first data stream includes a skipped P-macroblock wherein a first B-macroblock is forward predicted from image data associated with the skipped P-macroblock location;

when the second condition is determined to exist;

encoding a first P-macroblock based upon a motion vector value of zero; and

providing the first P-macroblock to the second data stream to replace the skipped P-macroblock.

12. The method of claim 1 further comprising:

determining if a second condition exists, wherein the second condition exists when the first data stream includes a skipped B-macroblock;

when the second condition is determined to exist;

encoding a first B-macroblock based on a prediction error data set to zero; and

providing the first B-macroblock to the second data stream to replace the skipped B-macroblock.

13. The method of claim 12 further comprising:

encoding the first B-macroblock based on a motion vector of a second B-macroblock in the same frame as the skipped B-macroblock.

14. The method of claim 13, wherein the second B-macroblock is a macroblock to be rendered prior to the first B-macroblock.

15. The method of claim 14 wherein the second B-macroblock comprises data to be displayed immediately adjacent to the second B-macroblock.

16. The method of claim 1 further comprising:

determining if a second condition exists, wherein the second condition exists when the first data stream includes a skipped B-macroblock;

when the second condition is determined to exist;

encoding a first B-macroblock based on a motion vector of a second B-macroblock in the same flame as the skipped B-macroblock; and

providing the first B-macroblock to the second data stream to replace the skipped B-macroblock.

17. A method of transcoding video data in a lossless manner, the method comprising:

receiving a first data stream having a first protocol;

determining if a first condition exists, wherein the first condition exists when the first data stream includes a skipped B-macroblock vector;

when the first condition is determined to exist;

encoding a first B-macroblock based on a prediction error data set to zero; and

providing the first B-macroblock to a second data stream to replace the skipped B-macroblock, wherein the second macroblock is based on a second protocol different than the first protocol.

18. The method of claim 17 further comprising:

determining if a second condition exists, wherein the second condition exists when the first data stream includes a skipped P-macroblock wherein a second B-macroblock is forward predicted from image data associated with the skipped P-macroblock location;

when the second condition is determined to exist;

encoding a first P-macroblock based on a decoded image data of the first data stream representing an image for display at an image location of the skipped P-macroblock; and

providing the first P-macroblock to the second data stream to replace the skipped P-macroblock.

19. The method of claim 18 further comprising:

encoding the first P-macroblock based on a motion vector value of zero.

20. The method of claim 17 further comprising:

determining if a second condition exists, wherein the second condition exists when the first data stream includes a skipped P-macroblock wherein a second B-macroblock is forward predicted from image data associated with the skipped P-macroblock location;

when the second condition is determined to exist;

encoding a first P-macroblock based on a motion vector value of zero; and

providing the first P-macroblock to the second data stream to replace the skipped P-macroblock.

21. A method of transcoding video data in a lossless manner, the method comprising:

receiving a first data stream having a first protocol;

determining if a first condition exists, wherein the first condition exists when the first data stream includes a skipped P-macroblock wherein a first B-macroblock is forward predicted from image data associated with the skipped P-macroblock location;

when the first condition is determined to exist;

encoding a first P-macroblock based on a decoded image data of the first data stream representing an image for display at an image location of the skipped P-macroblock; and

providing the first P-macroblock to a second data stream to replace the skipped P-macroblock, wherein the second macroblock is based on a second protocol different than the first protocol.

22. A system comprising:

means for receiving a first data stream having a first protocol;

means for determining if a first condition exists, wherein the first condition exists when the first data stream includes a first macroblock comprising a first motion vector and a differential motion vector;

when the first condition is determined to exist;

means for determining a second motion vector based upon adding the first motion vector and the differential motion vector;

means for encoding a second macroblock based upon the second motion vector; and

means for providing the second macroblock to a second data stream in place of the first macroblock wherein the second macroblock is based on a second protocol different than the first protocol.

23. The system of claim 22, further comprising:

means for determining if a second condition exists, wherein the second condition exists when the first data stream includes a skipped P-macroblock and a first B-macroblock is forward predicted from image data associated with the skipped P-macroblock location;

when the second condition is determined to exist;

means for encoding a first P-macroblock based on a decoded image data of the first data stream representing an image for display at an image location of the skipped P-macroblock; and

means for providing the first P-macroblock to the second data stream to replace the skipped P-macroblock.

24. The system of claim 23 further comprising:

means for determining if a third condition exists, wherein the third condition exists when the first data stream includes a skipped B-macroblock;

when the third condition is determined to exist;

means for encoding a first B-macroblock based on a prediction error data set to zero; and

means for providing the first B-macroblock to the second data stream to replace the skipped B-macroblock.

25. The system of claim 23 further comprising:

means for determining if a third condition exists, wherein the third condition exists when the first data stream includes a skipped B-macroblock;

when the third condition is determined to exist;

means for encoding a first B-macroblock based on a motion vector of a second B-macroblock in the same frame as the skipped B-macroblock; and

means for providing the first B-macroblock to the second data stream to replace the skipped B-macroblock.