Method and apparatus for decoding mpeg video signals

• US 6,850,568 B1
• Filed: 01/12/2000
• Issued: 02/01/2005
• Est. Priority Date: 01/12/2000
• Status: Expired due to Term

• 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: Luna, Amelia Carino, Williams, Richard L., Wang, Jason N.
• Primary Examiner(s): Kelley, Chris
• Assistant Examiner(s): PARSONS, CHARLES E
• Application Number:
  US09/481,337
• Time in Patent Office: 1,847 Days
• Field of Search: 375/240.1, 375/240.27, 375/240.16, 375/240.12
• US Class Current: 375/240.16
• 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 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding

Abstract

A method and apparatus for decoding an input MPEG video stream are provided that includes a core processor with a very long instruction word (VLIW) processor and a co-processor that includes a variable length decoder (VLD) for decoding the MPEG video stream. The input MPEG video stream is organized into macroblocks, wherein each macroblock includes a header for a macroblock that is not decoded, and encoded data for a macroblock whose header is previously decoded by VLD. Thereafter, VLD decodes the encoded video data of a first macroblock whose header has been decoded, and decodes the header of a second (current) macroblock. VLIW then performs motion compensation on a current macroblock based upon reference data of a previously decoded macroblock. VLIW also adds a fake slice start code and fake macroblock data at the end of each picture into the input MPEG video data stream; and utilizes the fake slice start code and fake macroblock data to skip to a next slice. The fake macroblock data indicates an error to the VLD stopping the decoding process until the core processor clears the interrupt and reinitiates decoding of a selected macroblock.

Claims

1. A method for decoding and reconstructing an input MPEG video data stream, comprising:

decoding the encoded video data of a first macroblock whose header has been decoded, and simultaneously decoding the header of a second macroblock;

wherein each macroblock includes a header for a current macroblock and encoded MPEG video data of a previous macroblock block whose header has been decoded;

performing motion vector reconstruction on the decoded first macroblock video data, based upon the decoded macroblock header data;

adding a fake slice start code and fake macroblock data at the end of each picture in the input MPEG video data stream; and

utilizing the fake slice start code and fake macroblock data to skip to the next picture.

2. The method of claim 1, wherein the fake macroblock data indicates an error to the VLD stopping the decoding process until the core processor reinitiates decoding of a selected slice.

3. The method of claim 1, wherein the decoded macroblock data includes discrete cosine transform coefficients.

4. The method of claim 1, wherein the decoded macroblock data includes motion vectors.

5. The method of claim 3, wherein the modifying step includes performing inverse discrete cosine transformations on decoded discrete cosine transform coefficients for the decoded first macroblock.

6. The method of claim 5, further comprising:

selecting a matching macroblock from another frame based upon the reference data for motion compensation; and

adjusting the decoded first macroblock data according to the reference data for motion compensation.

7. A video decoder adapted to reconstruct raw video signal data from an input MPEG coded video data stream, comprising:

a core processor for parsing the input coded video data stream to identify start code and end location for slices and pictures, and the core processor is adapted to perform motion compensation on the encoded MPEG video data; and

a differential decoder in a co-processor adapted to decode a macroblock header for the input MPEG video data for a second macroblock and simultaneously decode the input MPEG video data for a first macroblock whose header is already decoded, wherein each macroblock includes a macroblock header for a current macroblock and encoded video data of a previous macroblock whose header has already been decoded, the core processor includes a very long instruction word (VLIW) processor and the VLIW adds a fake slice start code and fake macroblock data at the end of each picture in the input MPEG video stream, and the VLD utilizes the fake slice start code and fake macroblock data to skip to the next picture.

8. The apparatus of claim 7, wherein the fake macroblock data indicates an error to the VLD stopping the decoding process until the core processor reinitiates decoding of a selected slice.

9. The apparatus of claim 7, wherein the decoded macroblock data includes discrete cosine transform coefficients.

10. The apparatus of claim 7, wherein the VLIW performs inverse discrete cosine transforms on decoded discrete cosine transform coefficients of the first macroblock.

11. The apparatus of claim 7, wherein the co-processor includes a memory buffer for storing decoded header and decoded macroblock data.