Inter sub-mode decision process in a transcoding operation

• US 20080152010A1
• Filed: 12/22/2006
• Published: 06/26/2008
• Est. Priority Date: 12/22/2006
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Youn, Jeongnam
• Granted Patent: US 8,929,448 B2
• Time in Patent Office: Days
• US Class Current: 375/240.16
• CPC Class Codes: H04N 19/103 Selection of coding mode or of prediction mode
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/139 Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
• 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 7/52 Systems for transmission of a pulse code modulated video signal with one or more other pulse code modulated signals, e.g. an audio signal or a synchronizing signal assembling of a multiplex stream by combining a video stream with other content or additional data, remultiplexing of multiplex streams, insertion of stuffing bits into the multiplex stream, assembling of a packetised elementary stream at server side H04N21/236; disassembling of a multiplex stream, remultiplexing of multiplex streams, extraction or processing of Service Information, disassembling of packetised elementary stream at client side H04N21/434

Abstract

In one embodiment, a macroblock is determined in an incoming bitstream. In one example, the macroblock may be a 16×16 macroblock for a first coding standard, such as MPEG-2. The macroblock is then divided into a plurality of segmented blocks. For example, an arbitrary sized segment of blocks may be used to divide the macroblock into segmented blocks. In one example, the macroblock is divided into four 8×8 segmented blocks. A plurality of statistical measures are then determined for the plurality of segmented blocks. For example, for each segmented block, a sum of absolute differences (SAD) is determined. Then, one or more sizes for the sub-blocks are determined based on the comparison. For example, a variable sub-block size for an AVC bitstream is determined.

Claims

1. A method for determining a sub-block size for a macroblock in a transcoding process for an incoming bitstream, the method comprising:

determining a macroblock in the incoming bitstream;

dividing the macroblock into a plurality of segmented blocks;

determining a plurality of statistical measures for the plurality of segmented blocks;

determining one or more sizes for sub-blocks to be used in the transcoding process for the macroblock based on a comparison of the plurality of statistical measures for the plurality of segmented blocks.

2. The method of claim 1, wherein determining the plurality of statistical measures comprises determining the plurality of statistical measures using information in the incoming bitstream.

3. The method of claim 2, wherein the information comprises a motion vector for the macroblock.

4. The method of claim 1, wherein the plurality of statistical measures comprise a sum of absolute difference (SAD).

5. The method of claim 4, wherein the SAD is computed for each of the plurality of segmented blocks using a motion vector for the macroblock.

6. The method of claim 1, further comprising encoding the sub-blocks into an outgoing bitstream.

7. The method of claim 6, wherein the incoming bitstream is an MPEG-2 bitstream and the outgoing bitstream is an AVC bitstream.

8. The method of claim 1, further comprising generating a motion vector for each of the one or more sub-blocks determined.

9. The method of claim 1, further comprising:

determining if the macroblock is encoded using an inter mode or intra mode encoding;

performing the method in claim 1 only if the macroblock is encoded using the inter mode.

10. The method of claim 1, further comprising:

determining a number of sub-blocks to form from the macroblock based on the comparisons of statistical measures between the first and second segmented block, the third and fourth segmented block, the first and third segmented block, and the second and the fourth segmented block.

19. The apparatus of claim 11, wherein the logic when executed is further operable to:

determine if the macroblock is encoded using an inter mode or intra mode encoding;

perform the method in claim 1 only if the macroblock is encoded using the inter mode.

11. An apparatus configured to determining a sub-block size for a macroblock in a transcoding process for an incoming bitstream, the apparatus comprising:

one or more processors; and

logic encoded in one or more tangible media for execution by the one or more processors and when executed operable to;

determine a macroblock in the incoming bitstream;

divide the macroblock into a plurality of segmented blocks;

determine a plurality of statistical measures for the plurality of segmented blocks;

determine one or more sizes for sub-blocks to be used in the transcoding process for the macroblock based on a comparison of the plurality of statistical measures for the plurality of segmented blocks.

12. The apparatus of claim 11, wherein the logic when executed is further operable to determine the plurality of statistical measures comprises determining the plurality of statistical measures using information in the incoming bitstream.

13. The apparatus of claim 12, wherein the information comprises a motion vector for the macroblock.

14. The apparatus of claim 11, wherein the plurality of statistical measures comprise a sum of absolute difference (SAD).

15. The apparatus of claim 14, wherein the SAD is computed for each of the plurality of segmented blocks using a motion vector for the macroblock.

16. The apparatus of claim 11, wherein the logic when executed is further operable to encode the sub-blocks into an outgoing bitstream.

17. The apparatus of claim 16, wherein the incoming bitstream is an MPEG-2 bitstream and the outgoing bitstream is an AVC bitstream.

18. The apparatus of claim 11, wherein the logic when executed is further operable to generate a motion vector for each of the one or more sub-blocks determined.

20. The apparatus of claim 11, wherein the logic when executed is further operable to determine a number of sub-blocks to form from the macroblock based on the comparisons of statistical measures between the first and second segmented block, the third and fourth segmented block, the first and third segmented block, and the second and the fourth segmented block.