Method and system for transcoding video data
View Patent ↗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.
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.