Memory transfer controller and method of transfer control of video line data and macroblock data

A memory transfer controller, comprising:

• a means for determining a macroblock period and a video line period longer than the macroblock period;
• a means for dividing each set of video line data, associated with a first subsystem with video line processing, to be transferred within the video line period into two or more portions according to a difference between the determined macroblock period and video line period;
• a means for temporally aligning a burst transfer, on a shared system bus, of each of the portions of the divided set of video line data and each set of macroblock data, associated with a second subsystem with macroblock processing, to the macroblock period;
• and
• a means for initiating the burst transfer, having the sets of video line data and macroblock data integrated therein, at a start of the macroblock period the burst transfer being performed between the first and second subsystems and a memory on the shared system bus.

A video compression system, comprising:

• a first video unit associated with macroblock data;
• a second video unit associated with video line data having raster data;
• a system bus shared by the first and second video units;
• a memory coupled to the first and second video units by the shared system bus;
• and
• a memory transfer controller coupled to the first and second video units, to control transfer of macroblock data between the first video unit and the shared system bus, and transfer of video line data between the second video unit and the shared system bus,
• wherein a size of a unit of the video line data is larger than a size of a unit of the macroblock data and transfer of the macroblock data is effected in a first time period,
• wherein the memory transfer controller can divide the video line data into two or more portions to transfer, on the shared system bus, each of the portions in respective ones of the first time period, and
• wherein the memory transfer controller can temporally align a transfer, on the shared system bus, of a portion of the divided video line data and at least some of the macroblock data to a start of the first time period, the transfer being temporally aligned to the first period in a manner that the transfer is performed during the first time period, the transfer being performed between the first and second video units and the memory on the shared system bus.