Method and apparatus for MPEG-2 to VC-1 video transcoding

• US 20070030906A1
• Filed: 08/05/2005
• Published: 02/08/2007
• Est. Priority Date: 08/05/2005
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: LSI Logic Corporation (Broadcom, Inc.)
• Inventors: Cote, Guy, Joch, Anthony Peter, Winger, Lowell
• Granted Patent: US 8,045,618 B2
• Time in Patent Office: Days
• US Class Current: 375/240.160
• CPC Class Codes: H04N 19/112 according to a given display mode, e.g. for interlaced or progressive display mode
• CPC Class Codes: H04N 19/16 for a given display mode, e.g. for interlaced or progressive display mode
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• 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 19/42 characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation H04N19/635 takes precedence
• CPC Class Codes: H04N 19/513 Processing of motion vectors
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

A method for transcoding from an MPEG-2 format to a VC-1 format is disclosed. The method generally comprises the steps of (A) decoding an input video stream in the MPEG-2 format to generate a picture; (B) determining a mode indicator for the picture; and (C) coding the picture into an output video stream in the VC-1 format using one of (i) a VC-1 field mode coding and (ii) a VC-1 frame mode coding as determined from the mode indicator.

Claims

1. A method for transcoding from an MPEG-2 format to a VC-1 format, comprising the steps of:

(A) decoding an input video stream in said MPEG-2 format to generate a picture;

(B) determining a mode indicator for said picture; and

(C) coding said picture into an output video stream in said VC-1 format using one of (i) a VC-1 field mode coding and (ii) a VC-1 frame mode coding as determined from said mode indicator.

2. The method according to claim 1, further comprising the step of:

for inter-coded blocks, determining one of (i) a VC-1 8×

8 transform, (ii) a VC-1 8×

4 transform, (iii) a VC-1 4×

8 transform and (iv) a VC-1 4×

4 transform from a magnitude of an MPEG-2 DC coded coefficient.

3. The method according to claim 1, further comprising the step of:

for inter-coded blocks, determining one of (i) a VC-1 8×

8 transform, (ii) a VC-1 8×

4 transform, (iii) a VC-1 4×

8 transform and (iv) a VC-1 4×

4 transform from a magnitude of an MPEG-2 AC coded coefficient.

4. The method according to claim 1, further comprising the step of:

partitioning at least one of a plurality of macroblocks decoded from said input video stream into a plurality of VC-1 partitions in said output video stream.

5. The method according to claim 4, further comprising the step of:

mapping an MPEG-2 16×

16 macroblock partition in said picture to at least one of (i) a VC-1 16×

16 partition and (ii) a plurality of VC-1 8×

8 partitions.

6. The method according to claim 4, further comprising the step of:

mapping an MPEG-2 16×

8 macroblock partition in said picture to at least one of (i) a VC-1 16×

8 partition and (ii) a plurality of VC-1 8×

8 partitions.

7. The method according to claim 1, wherein said mode indicator comprises a picture adaptive field/frame mode indicator.

8. A method for transcoding from an MPEG-2 format to a VC-1 format, comprising the steps of:

(A) decoding an input video stream in said MPEG-2 format to generate a picture;

(B) determining an MPEG-2 quantization parameter for said picture; and

(C) controlling an encoder rate for an output video stream in said VC-1 format using said MPEG-2 quantization parameter as a VC-1 macroblock complexity indicator.

9. The method according to claim 8, further comprising the step of:

determining a number of bits used per macroblock of said picture, wherein said controlling said encoder rate further uses said number of bits.

10. The method according to claim 8, further comprising the step of:

determining a mode indicator for said picture.

11. The method according to claim 10, further comprising the step of:

coding said picture into said output video stream in said VC-1 format using one of (i) a VC-1 field mode coding and (ii) a VC-1 frame mode coding as determined from said mode indicator.

12. The method according to claim 8, further comprising the step of:

determining a plurality of MPEG-2 motion vectors for said picture.

13. The method according to claim 12, further comprising the step of:

coding said picture into said output video stream in said VC-1 format using said MPEG-2 motion vectors to refine a plurality of VC-1 motion vectors for said picture.

14. The method according to claim 13, further comprising the step of:

generating a plurality of intensity compensated reference frames for said coding of said output video stream.

15. A method for transcoding from an MPEG-2 format to a VC-1 format, comprising the steps of:

(A) decoding an input video stream in said MPEG-2 format to generate a picture having a plurality of macroblocks;

(B) determining at least one item from each of said macroblocks; and

(C) coding said macroblocks into an output video stream in said VC-1 format using said items to refine a plurality of VC-1 motion vectors for said macroblocks.

16. The method according to claim 15, wherein said items comprise a plurality of MPEG-2 motion vectors for said macroblocks, the method further comprising the step of:

generating a plurality of VC-1 motion vectors by using said MPEG-2 motion vectors as a plurality of centers for a plurality of motion compensation search.

17. The method according to claim 16, further comprising the step of:

generating said VC-1 motion vectors to a finer sub-pel accuracy than said MPEG-2 motion vectors.

18. The method according to claim 15, wherein said items comprise a plurality of MPEG-2 fcodes, the method further comprising he step of:

determining a plurality of sizes of said refine for said VC-1 motion vectors based on said MPEG-2 fcodes.

19. The method according to claim 15, wherein said items comprise a plurality of MPEG-2 motion vectors for said macroblocks, the method further comprising the step of:

generating a plurality of VC-1 motion vectors by using a plurality of MPEG-2 intra-frame concealment motion vectors as a plurality of-motion compensation search centers.

20. The method according to claim 19, wherein said MPEG-2 intra-frame concealment motion vectors are used as said motion compensation search centers where an MPEG-2 I-frame having said MPEG-2 intra-frame concealment motion vectors is changed to a VC-1 predicted frame.