Decompression of MPEG compressed data in a computer system

• US 5,778,096 A
• Filed: 06/12/1995
• Issued: 07/07/1998
• Est. Priority Date: 06/12/1995
• Status: Expired due to Term

• Current Assignee: S3 Graphics Co., Ltd. (HTC Corporation)
• Original Assignee: S3 Inc. (SONICblue Incorporated)
• Inventors: Stearns, Charles C.
• Primary Examiner(s): Boudreau, Leo H.
• Assistant Examiner(s): Mariam, Daniel G.
• Application Number:
  US08/489,488
• Time in Patent Office: 1,121 Days
• Field of Search: 382/233, 382/246, 382/234, 358/432, 358/433, 395/162, 395/412, 395/439, 348/461
• US Class Current: 382/233
• 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 19/428 Recompression, e.g. by spatial or temporal decimation
• CPC Class Codes: H04N 19/436 using parallelised computational arrangements
• CPC Class Codes: H04N 19/439 using cascaded computational arrangements for performing a single operation, e.g. filtering
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/90 using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals
• CPC Class Codes: H04N 21/4143 embedded in a Personal Computer [PC]

Abstract

MPEG compressed data is decompressed in a computer system by sharing computational decompression tasks between the computer system host microprocessor, the graphics accelerator, and a dedicated MPEG processor in order to make best use of resources in the computer system. Thus the dedicated MPEG processor is of minimum capability and hence advantageously minimum cost. The host microprocessor is used to decompress the MPEG upper data layers. The more powerful the host microprocessor, the more upper data layers it decompresses. The remainder of the decompression (lower data layers) is performed by the MPEG dedicated processor and/or the graphics accelerator.

Claims

1. A method in a computer system of decompressing data that has been subject to compression and the compressed data being in a set of predetermined data layers, the computer system including a host processor on a first integrated circuit chip connected via a peripheral bus to a secondary processor on a second integrated circuit chip, the method comprising the steps of:

decompressing at least a system layer, which is a higher level layer than a video layer, of the compressed data in the host processor; and

decompressing other data layers of the set including the video layer in the secondary processor.

2. The method of claim 1, wherein the secondary processor is a graphics accelerator.

3. The method of claim 1, wherein the secondary processor is a dedicated MPEG decompression circuit for decompression of data subject to MPEG compression and the host processor is a general purpose microprocessor.

4. The method of claim 1, wherein the step of decompressing at least a system layer further comprises decompressing a book layer of the set.

5. The method of claim 1, wherein the data includes audio and video data.

6. The method of claim 1, wherein the step of decompressing other data layers includes the steps of:

variable length decoding the compressed data;

inverse zig-zagging the decoded data;

inverse quantizing the zig-zagged data, and inverse discrete cosine transforming the inverse quantized data.

7. The method of claim 1, wherein the step of decompressing other data layers includes motion vector compensation of the data.

8. A computer system adapted for decompression of compressed data which is in a set of predetermined data layers, comprising:

a host processor on a first integrated circuit chip;

a peripheral bus connected to the host processor;

a secondary processor on a second integrated circuit chip and connected to the peripheral bus; and

means for decompressing in the host processor at least a system layer, which is a higher level layer than a video layer, of the compressed data, wherein other data layers of the set including the video layer are decompressed in the secondary processor.

9. The system of claim 8, wherein the secondary processor is a graphics accelerator.

10. The system of claim 8, wherein the secondary processor is a dedicated decompression circuit for decompression of data which has been compressed using MPEG compression and the host processor is a general purpose microprocessor.

11. The system of claim 8, wherein the means for decompressing at least a system layer further comprises decompressing means for decompressing a book layer of the set.

12. The system of claim 8, wherein the data includes audio and video data.

13. The system of claim 8, wherein the means for decompressing at least the system layer includes:

means for variable length decoding the compressed data;

means for inverse zig-zagging the decoded data; and

means for inverse quantizing the data.

14. The system of claim 8, wherein decompression of the other layers of the set includes motion vector compensation of the data.

15. The computer system of claim 8, further comprising a frame buffer connected to the secondary processor.