Video compression method and apparatus

Abstract

A video compression system may have 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.

1 . A video compression system comprising:
 a first memory device;   a first processor configured to process sequential sets of video data according to a first video compression process, and to write processed data to the memory device; and   a second processor configured to read video data processed by the first video compression process from the memory device while the first processor is writing processed data to the memory device, and process sequential sets of the read data by a second video compression process;   the first processor being further configured to write a third set of processed data over a first set of processed data while the second processor reads a second set of processed data.   
   
   
       2 . The system of  claim 1 , where the first processor is configured to process sets of data with each set including a plurality of adjacent blocks of data, and to perform at least one process step on each block of data. 
   
   
       3 . The system of  claim 2 , where the first processor is further configured to write into the memory device a set of processed data prior to processing a subsequent set of data. 
   
   
       4 . A video compression system comprising:
 a first memory device;   a second memory device; and   at least a first processor configured to store in the first memory device data representative of at least a portion of a first video frame, to transfer sequential sets of data representative of corresponding portions of the frame from the first memory device to the second memory device, to process each current set of data stored in the second memory device according to a first video compression process while transferring a sequentially next set of data from the first memory device to the second memory device.   
   
   
       5 . The system of  claim 4 , where the processor is configured to process sequential sets of overlapping data in which the sequentially next set of data overlaps with the current set of data, the processor being further configured to read from the first memory that portion of the next sequential set of data not included in the current set of data during processing of the current set of data. 
   
   
       6 . The system of  claim 5 , where the video compression process is motion estimation, the processor is configured to store in the first memory device at least portions of each of a plurality of video frames, and the sets of data are fields of search. 
   
   
       7 . The system of  claim 5 , further comprising a second processor configured to read data stored in the second memory device and to process a portion of each current set of data stored in the second memory device according to a second video compression process. 
   
   
       8 . The system of  claim 7 , where the first and second processors are configured to read concurrently data from the second memory device. 
   
   
       9 . A method of compressing video data comprising:
 processing according to a first video compression process sequential sets of video data with each set including a plurality of adjacent blocks of data, including processing each block in each set of data;   writing a first set of video data processed by the first video compression process to a memory device;   writing a second set of video data processed by the first video compression process to the memory device;   while writing the second set of data processed by the first video compression process, reading the first set of video data from the memory device;   processing the read data by a second video compression process;   writing a third set of data processed by the first video compression process over the first set of data processed by the first video compression process; and   reading a second set of data processed by the first video compression process during writing of the third set of data.   
   
   
       10 . The method of  claim 9 , where processing the video data includes processing sequential sets of data with each set including a plurality of adjacent blocks of data, including processing each block in each set of data. 
   
   
       11 . The method of  claim 10 , where writing into the memory device the first set of processed data is prior to processing the subsequent second set of video data by the first video compression process. 
   
   
       12 . A method of compressing video data comprising:
 storing in a first memory device data representative of at least a portion of a first video frame;   transferring sequential sets of data representative of corresponding portions of the frame from the first memory device to a second memory device;   processing each set of data stored in the second memory device according to a first video compression process; and   during processing of each set of data stored in the second memory device, transferring a sequentially next set of data from the first memory device to the second memory device.   
   
   
       13 . The method of  claim 12 , where processing data stored in the second memory device includes processing sequential sets of overlapping data in which a sequentially next set of data overlaps with a current set of data, and reading from the first memory that portion of the next sequential set of data not included in the current set of data during processing of the current set of data. 
   
   
       14 . The method of  claim 13 , where processing each set of data includes estimating motion by searching in a field of search, and storing data in the first memory device includes storing at least portions of each of a plurality of video frames, and transferring sets of data includes transferring sets of data corresponding to fields of search. 
   
   
       15 . The method of  claim 13 , further comprising processing a portion of each current set of data stored in the second memory device according to a second video compression process. 
   
   
       16 . The method of  claim 15 , where processing each set of data stored in the second memory device includes reading a first portion of data from the second memory device, and processing a portion of each current set of data stored in the second memory device includes reading a second portion of data from the second memory device concurrently with reading the first portion of data from the second memory device. 
   
   
       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:
 processing according to a first video compression process sequential sets of video data with each set including a plurality of adjacent blocks of data, including processing each block in each set of data;   writing a first set of video data processed by the first video compression process to a memory device;   writing a second set of video data processed by the first video compression process to the memory device;   while writing the second set of data processed by the first video compression process, reading the first set of video data processed by the first video compression process from the memory device;   processing the read data by a second video compression process;   writing a third set of data processed by the first video compression process over the first set of data processed by the first video compression process; and   reading the second set of data processed by the first video compression process during writing of the third set of data.   
   
   
       18 . 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:
 storing in a first memory device data representative of at least a portion of a first video frame;   transferring sequential sets of data representative of corresponding portions of the frame from the first memory device to a second memory device;   processing each set of data stored in the second memory device according to a first video compression process; and   during processing of each set of data stored in the second memory device, transferring a sequentially next set of data from the first memory device to the second memory device.   
   
   
       19 . The computer-readable medium of  claim 18 , where processing data stored in the second memory device includes processing sequential sets of overlapping data in which a sequentially next set of data overlaps with a current set of data, and reading from the first memory that portion of the next sequential set of data not included in the current set of data during processing of the current set of data. 
   
   
       20 . The computer-readable medium of  claim 19 , where processing each set of data includes estimating motion by searching in a field of search, and storing data in the first memory device includes storing at least portions of each of a plurality of video frames, and transferring sets of data includes transferring sets of data corresponding to fields of search. 
   
   
       21 . The computer-readable medium of  claim 19 , where the instructions further provide for processing a portion of each current set of data stored in the second memory device according to a second video compression process. 
   
   
       22 . The computer-readable medium of  claim 21 , where processing each set of data stored in the second memory device includes reading a first portion of data from the second memory device, and processing a portion of each current set of data stored in the second memory device includes reading a second portion of data from the second memory device concurrently with reading the first portion of data from the second memory device.