Apparatus and method for 2-D discrete transform using distributed arithmetic module

An method for performing a discrete cosine transform (DCT) on a video signal, wherein the video signal includes a plurality of N×M image blocks, N and M being a positive integers, the method comprising the steps of:

• a) receiving the video signal in a block by block basis;
• b) receiving said each image data block as a serial data by selecting from a serial data of a new image data block from external or a serial data of the transformed image data block fed back from the output means;
• c) converting the received serial data to parallel data;
• d) storing the parallel data;
• e) examining the stored data and determining whether or not bits of the stored data are all “0”;
• f) if bits of the data are all “0”, bypassing a discrete cosine transform/inverse discrete cosine transform (DCT/IDCT) operation performing on the stored data;
• and
• g) if the bits of the data are not all “0”, performing the discrete cosine transform/inverse discrete cosine transform (DCT/IDCT) operation on the stored data;
• wherein N and M are both positive integers and at least one of N and M is greater than 1.

An apparatus for performing a discrete cosine transform (DCT) on a video signal, wherein the video signal includes a plurality of N×M image blocks, N and M being a positive integer, the apparatus comprising:

• input means for receiving the video signal in a block by block basis;
• discrete cosine transform (DCT) means for receiving each image data block from the input means and conducting a discrete cosine transform/inverse discrete cosine transform (DCT/IDCT) operation on the received image data block to generate a transformed image data block containing N×M pixel values;
• zero input detect means for determining whether pixel values of a current image data block are all “0” and generating a detection signal in order to bypass the discrete cosine transform/inverse discrete cosine transform (DCT/IDCT) performing on the current image block;
• and
• output means for outputting the transformed image data block as a transformed video signal;
• wherein the input means includes:
• multiplex means for receiving said each image data block as a serial data by selecting from a serial data of a new image data block from external or a serial data of the transformed image data block fed back from the output means;
• first conversion means for converting the serial data received from the multiplexing means to parallel data;
• and
• storage means for loading and temporarily storing the parallel data outputted from the first conversion means in parallel;
• and
• wherein the discrete cosine transform means includes:
• first temporary storage means for temporarily storing the parallel data outputted from the storage means for performing the discrete cosine transform (DCT) operation;
• reorder IDCT means for readjusting an order of the parallel data outputted from the first temporary storage means for performing the inverse discrete cosine transform (IDCT) operation;
• first serial addition means for adding the parallel data outputted from the first temporary storage means for the DCT operation;
• distributed arithmetic means for conducting distributed arithmetic operation on the parallel data outputted from the reorder IDCT means and the serial addition means;
• second temporary storage means for temporarily storing the processed data outputted from the distributed arithmetic means;
• reorder DCT means for readjusting an order of the data outputted from the second temporary storage means for the DCT operation;
• second serial addition means for adding the data outputted from the second temporary storage means for the IDCT;
• and
• rounding means for rounding off the data outputted from the reorder DCT means and the second serial addition means.