Method and apparatus of temporary image frame compression

1. A method of compressing a sequence of image frames and saving the compressed data into a storage device for future operations, comprising:

calculating the bit rate of each image frame;

accumulating the bit rate of a predetermined amount of image frames;

saving the accumulative bit rate into a bit rate register;

comparing the accumulative bit rate to predetermined threshold values and decide the compression ratio for the targeted current image frame;

compressing each targeted image frame of pixels by referring to the calculated compression ratio; and

saving the compressed image data and the corresponding starting address of each image frame into the targeted storage device.

2. The method of claim 1 , wherein at least to registers are used to save the starting location of the targeted storage device which saves at least two compressed image frames and the register will be overwritten when the content have been sent and saved into targeted storage device.

3. The method of claim 1 , wherein the threshold values determine the compression ratio of each image frame are determined by calculating the bandwidth availability of the targeted storage device and the resolution of the image frames to be stored.

4. The method of claim 1 , wherein in compressing an image frame, each group of pixels with predetermined amount of pixels can be compressed according to calculated compression ratio.

5. The method of claim 1 , wherein at least one image frame of a group of frames has different compression ratio to other frames which might be higher or lower compression ratio compared to the mean compression ratio of a group of frames.

6. The method of claim 1 , wherein during accessing a frame of compressed pixels, the starting location saved in the predetermined location is accessed firstly, then followed by accessing the data representing the compressed pixels.

7. The method of claim 1 , wherein the compressed image frame data are saved into the storage device in a predetermined location while the starting addresses of the compressed frame are saved in another predetermined location of the storage device.

8. An apparatus for compressing a sequence of image frames and saving the compressed data into a storage device for future operations, comprising:

a calculator including a temporary register counting the bit rate of each image frame and the accumulative bit rate of a predetermined amount of image frames;

a comparator comparing the accumulative bit rate to predetermined threshold values and deciding the compression ratio for the targeted current image frame;

a compression engine compressing each targeted image frame of pixels by referring to the calculated compression ratio; and

a storage interface controller unit saving the compressed image data and the corresponding starting address of each image frame into the targeted storage device.

9. The apparatus of claim 8 , wherein the temporary register saving the calculated bit rate and the accumulative bit rate can be overwritten when an image frame compression task is completed.

10. The apparatus of claim 8 , wherein the compression engine receives the compression ratio and switches to the corresponding compression algorithm for compressing each image frame.

11. The apparatus of claim 8 , wherein the comparator is comprised of comparing circuitry and several registers for partitioning the levels of bandwidth and density availability of the storage device.

12. The apparatus of claim 8 , wherein the storage interface controller sends the compressed pixel data into a predetermined location with burst mode of data transferring mechanism and saves the starting address of groups of pixels into another location with the control signals indicating which cycle time has compressed pixel data or starting address on the data bus.

13. The apparatus of claim 8 , wherein the storage interface controller output at least two signals, one indicating “Data ready” another for “Starting address ready” coupled with a output data selection signal.