Video compression method and apparatus

• US 7,519,115 B2
• Filed: 03/31/2003
• Issued: 04/14/2009
• Est. Priority Date: 03/31/2003
• Status: Expired due to Fees

• Current Assignee: Broadcast Microwave Services, Inc. (COHU Incorporated)
• Original Assignee: Duma Video, Inc.
• Inventors: Weatherspoon, Sultan
• Primary Examiner(s): DIEP, NHON THANH
• Application Number:
  US10/404,952
• Publication Number:
  US 20050008077A1
• Time in Patent Office: 2,206 Days
• Field of Search: None
• US Class Current: 375/240.12
• 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 19/423 characterised by memory arrangements H04N19/433 takes precedence
• CPC Class Codes: H04N 19/43 Hardware specially adapted for motion estimation or compensation
• CPC Class Codes: H04N 19/436 using parallelised computational arrangements
• CPC Class Codes: H04N 19/53 Multi-resolution motion estimation; Hierarchical motion estimation
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

A video compression system includes first and second dual-port memory devices, a third memory device, and first and second processors that may provide enhanced processing, including motion estimation. The first processor may be configured to store in the second memory device first and second video frames and to transfer sequential sets of data from the first video frame corresponding to fields of search. A second set of a plurality of adjacent macroblocks of the second video frame may be compared to macroblocks selected from the field of search. Dual-port memory devices may allow for the concurrent use of shared memory by the two processors as well as data transfer during processing.

Claims

1. A video compression system comprising:

a first memory device;

a dual-port second memory device;

a third memory device;

a first processor configured to read video data from the first memory device, to process the read video data in a manner altering the read video data according to a first video compression process, and to write data processed by the first processor to the dual-port second memory device; and

a second processor configured to read video data processed by the first video compression process from the dual-port second memory device while the first processor is writing processed data to the dual-port second memory device, to process the data read by the second processor in a manner altering the read video data according to a second video compression process, and to write the data processed by the second processor to the third memory device.

2. The system of claim 1, where the first and second processes include at least one of motion estimation, motion compensation, discrete-cosine transformation, quantization, and entropy encoding.

3. The system of claim 2, where at least one of the first and second processes includes motion estimation, and further includes a stage of a hierarchical search.

4. The system of claim 2, where the first and second processes include motion estimation having overlapping fields of search, the system further comprising a fourth memory device configured to store video data representative of the combined fields of search of the first and second processes, the first and second processors further configured to read data stored in the fourth memory device.

5. The system of claim 4, where the first and second processors are configured to read concurrently data from the fourth memory device.

6. The system of claim 4, further comprising a fifth memory device coupled to the fourth memory device for storing a plurality of frames of the video data, and a third processor configured to write data into the fifth memory device and transfer data from the fifth memory device to the fourth memory device.

7. The system of claim 6, where the first processor processes a first set of data for a first frame while the field of search for a subsequent set of data for the first frame is being written into the fourth memory device.

8. A video compression system comprising:

first and second dual-port memory devices;

a third memory device;

a first processor configured to store in the second dual-port memory device data representative of first and second video frames, to transfer sequential sets of data representative of corresponding portions of the first frame from the second dual-port memory device to the third memory device, each set of data representative of a first field of search including a first set of a plurality of macroblocks of a first video frame, and to process each set of data stored in the third memory device according to a first motion estimation process, the first motion estimation process including searching the first set of macroblocks relative to a second set of a plurality of adjacent macroblocks of a second video frame, the first motion estimation process being performed while transferring, from the second dual-port memory device to the third memory device, a portion of a sequentially next set of data not included in the set of data currently stored in the third memory device, the first processor further being configured to write processed data processed according to the first motion estimation process to the first dual-port memory device; and

a second processor configured to read video data processed by the first processor from the first dual-port memory device while the first processor is writing processed data to the first dual-port memory device, and process the read data by a second motion estimation process including searching an associated plurality of macroblocks selected from the first set of macroblocks, relative to each macroblock of the second set of macroblocks, and comparing sequentially each macroblock in the second set with overlapping macroblocks included in the data corresponding to an associated plurality of macroblocks selected from the first set, and comparing each macroblock of the second set concurrently with a plurality of macroblocks from the first set.

9. A method of compressing video data comprising:

reading video data from a first memory device;

processing the video data read from the first memory device in a manner altering the read video data according to a first video compression process;

writing to a dual-port second memory device the video data processed according to the first video compression process;

while writing the processed video data to the dual-port second memory device, reading the processed video data from the dual-port second memory device;

processing the video data read from the dual-port second memory device in a manner altering the read video data according to a second video compression process; and

writing the video data processed according to the second video compression process to a third memory device.

10. The method of claim 9, where processing the video data according to a first video compression process and processing the video data according to a second video compression process, each includes at least one of motion estimating, motion compensating, discrete-cosine transforming, quantizing, and entropy encoding.

11. The method of claim 9, where at least one of processing the video data according to a first video compression process and processing the video data according to a second video compression process includes motion estimating, and further includes performing a stage of a hierarchical search.

12. The method of claim 9, where processing the video data according to a first video compression process and processing the video data according to a second video compression process each includes motion estimating, and further includes searching with overlapping fields of search, the method further comprising storing video data representative of the combined fields of search in a fourth memory device, and reading data stored in the fourth memory device.

13. The method of claim 12, where processing the video data according to a first video compression process and processing the video data according to a second video compression process includes reading concurrently data from the fourth memory device.

14. The method of claim 12, further comprising storing a plurality of frames of the video data in a fifth memory device, and writing data into the fifth memory device and transferring data from the fifth memory device to the fourth memory device.

15. The method of claim 14, where processing the video data according to a first video compression process includes processing a first set of data for a first frame while writing into the fourth memory device a field of search for a subsequent set of data for the first frame.

16. The method of claim 9, where processing the video data according to a first video compression process includes writing a third set of processed data over a first set of processed data, and processing the video data according to a second video compression process includes reading a second set of processed data during writing of the third set of data.

17. A computer-readable medium readable by one or more processors and having embodied therein a program of computer-readable instructions that, when executed by the one or more processors, provide for:

reading video data from a first memory device;

processing the video data read from the first memory device in a manner altering the data according to a first video compression process;

writing to a dual-port second memory device the video data processed according to the first video compression process;

while writing the processed video data to the dual-port second memory device, reading the processed video data from the dual-port second memory device;

processing the video data read from the dual-port second memory device in a manner altering the data according to a second video compression process; and

writing the video data processed according to the second video compression process to a third memory device.

18. The computer-readable medium of claim 17, where processing the video data according to a first video compression process and processing the video data according to a second video compression process each includes at least one of motion estimating, motion compensating, discrete-cosine transforming, quantizing, and entropy encoding.

19. The computer-readable medium of claim 17, where at least one of processing the video data according to a first video compression process and processing the video data according to a second video compression process includes motion estimating, and further includes performing a stage of a hierarchical search.

20. The computer-readable medium of claim 17, where processing the video data according to a first video compression process and processing the video data according to a second video compression process each includes motion estimating, and further includes searching with overlapping fields of search, the instructions further provide for storing video data representative of the combined fields of search in a fourth memory device, and reading data stored in the fourth memory device.

21. The computer-readable medium of claim 20, where processing the video data according to a first video compression process and processing the video data according to a second video compression process includes reading concurrently data from the fourth memory device.

22. The computer-readable medium of claim 17, where processing the video data according to a first video compression process includes writing a third set of processed data over a first set of processed data, and processing the video data according to a second video compression process includes reading a second set of processed data during writing of the third set of data.