C-cube Microsystems, Inc.

Alexandre Balkanski

Steve Purcell

James Kirkpatrick

Stephen C Purcell

Mauro Bonomi

James W Kirkpatrick, Jr

Wen-Chang Hsu

A digital video compression system and an apparatus implementing this system are disclosed. Specifically, matrices of pixels in the RGB signal format are converted into YUV representation, including a step of selectively sampling the chrominance components. The signals are then subjected to a discrete cosine transform (DCT). A circuitry implementing the DCT in a pipelined architecture is provided. A quantization step eliminates DCT coefficients having amplitude below a set of preset thresholds. The video signal is further compressed by coding the elements of the quantized matrices in a zig-zag manner. This representation is further compressed by Huffman codes. Decompression of the signal is substantially the reverse of compression steps. The inverse discrete cosine transform (IDCT) may be implemented by the DCT circuit. Circuits for implementing RGB to YUV conversion, DCT, quantization, coding and their decompression counterparts are disclosed. The circuits may be implemented in the form an integrated circuit chip.

System for compression and decompression of video data using discrete

A digital video compression system and an apparatus implementing this system are disclosed. Specifically, matrices of pixels in RGB, YUV or CMYK formats are accepted for data compression. The data are rearranged in 8x8 pixel blocks, each block being of one pixel component type. The pixel data are then subjected to a discrete cosine transform (DCT). A quantization step eliminates DCT coefficients having amplitude below a set of preset thresholds. The video signal is further compressed by coding the elements of the quantized matrices in a zig-zag manner. This representation is further compressed by Huffman codes. Decompression of the signal is substantially the reverse of compression steps. The inverse discrete cosine transform (IDCT) may be implemented by the DCT circuit. The circuits may be implemented in a single integrated circuit chip. Three levels of compression rate control are provided during processing of video data.

A digital video compression system and an apparatus implementing this system are disclosed. Specifically, matrices of pixels in the RGB signal format are converted into YUV representation, including a step of selectively sampling the chrominance components. The signals are then subjected to a discrete cosine transform (DCT). A circuitry implementing the DCT in a pipelined architecture is provided. A quantization step eliminates DCT coefficients having amplitude below a set of preset thresholds. The video signal is further compressed by coding the elements of the quantized matrices in a zig-zag manner. This representation is further compressed by Huffman codes. Decompression of the signal is substantially the reverse of compression steps. The inverse discrete cosine transform (IDCT) may be implemented by the DCT circuit. Circuits for implementing RGB to YUV conversion, DCT, quantization, coding and their decompression counterparts are disclosed. The circuits may be implemeneted in the form an integrated circuit chip.

A method and a structure provide discrete cosine transform (DCT) and its inverse (IDCT) using digital FIR filters in a filter bank. The filter bank of the present invention forms a structure of cascaded filters, in which data are communicated only between filters having 'parent-child' relationships. Each filter in the filter bank is required only to communicate with at most two other filters in the filter bank. Consequently, in any implementation, both the communication overhead between filters in the filter bank, and the circuit size are minimized. Therefore, the filter bank is particularly suited for integrated circuit implementation. In one embodiment, the filter bank is implemented in an image compression and decompression integrated circuit using a structure which includes pipeline registers, adders and multipliers. In that embodiment, the filter bank provides an 8-point DCT in each of the two passes of a 2-dimensional DCT used in a data compression operation. The same structure also provides an 8-point IDCT in each of the two passes of the 2-dimensional IDCT used in an data decompression operation.

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Palo Alto, CA, United States of America

Alexandre Balkanski