Inter sub-mode decision process in a transcoding operation

• US 8,929,448 B2
• Filed: 12/22/2006
• Issued: 01/06/2015
• Est. Priority Date: 12/22/2006
• Status: Expired due to Fees

• 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
• Primary Examiner(s): Vaughn, Jr., William C
• Assistant Examiner(s): PEREZ FUENTES, LUIS M
• Application Number:
  US11/644,296
• Publication Number:
  US 20080152010A1
• Time in Patent Office: 2,937 Days
• Field of Search: 375/240.16
• 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 one or more sub-block sizes 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, each segmented block being characterized by a first size including a plurality of pixels;

determining for each of the plurality of segmented blocks, a statistical measure comprising a sum of absolute difference (SAD), computed for each of the plurality of segmented blocks using a motion vector for the macroblock;

comparing the statistical measures for a first one and a second one of the plurality of segmented blocks within the macroblock; and

if the difference between the statistical measures for the first one and the second one of the plurality of segmented blocks is lower than a predetermined threshold, combining the first and second segmented blocks, and selecting the size of the combination as a sub-block size for the transcoding process for the first and second segmented blocks;

but if the difference between the statistical measures for the first one and the second one of the plurality is not lower than the predetermined threshold, comparing the statistical measures for the first one and a third one of the plurality of segmented blocks within the macroblock; and

if the difference between the statistical measures for the first one and the third one of the plurality of segmented blocks is lower than the predetermined threshold, combining the first and third segmented blocks, and selecting the size of the combination as a sub-block size for the transcoding process for the first and third segmented blocks;

but if the difference between the statistical measures for the first one and the third one of the plurality is not lower than the predetermined threshold, selecting the first size as a sub-block size for the transcoding process for the first segmented block.

2. The method of claim 1, further comprising generating a motion vector for each of the sub-blocks determined after sub-block sizes have been selected for all of the plurality of segmented blocks within the macroblock.

3. An apparatus configured to determining one or more sub-block sizes 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, each segmented block being characterized by a first size including a plurality of pixels

determine for each of the plurality of segmented blocks, a statistical measure comprising a sum of absolute difference (SAD), computed for each of the plurality of segmented blocks using a motion vector for the macroblock;

compare the statistical measures for a first one and a second one of the plurality of segmented blocks within the macroblock; and

if the difference between the statistical measures for the first one and the second one of the plurality of segmented blocks is lower than a predetermined threshold, combine the first and second segmented blocks, and select the size of the combination as a sub-block size for the transcoding process for the first and second segmented blocks;

but if the difference between the statistical measures for the first one and the second one of the plurality is not lower than the predetermined threshold, compare the statistical measures for the first one and a third one of the plurality of segmented blocks within the macroblock; and

if the difference between the statistical measures for the first one and the third one of the plurality of segmented blocks is lower than the predetermined threshold, combine the first and third segmented blocks, and select the size of the combination as a sub-block size for the transcoding process for the first and third segmented blocks;

but if the difference between the statistical measures for the first one and the third one of the plurality is not lower than the predetermined threshold, select the first size as a sub-block size for the transcoding process for the first segmented block.

4. The apparatus of claim 3, wherein the logic when executed is further operable to generate a motion vector for each of the sub-blocks determined after sub-block sizes have been selected for all of the plurality of segmented blocks within the macroblock.