Abstract: Previously-unused slots in a Huffman code table associated with a Joint Photographic Experts Group (JPEG) image file are associated with various quantization matrices (Q matrices) that are used to quantize data blocks of the JPEG image file. Huffman codes associated with the various Q matrices permit the particular Q matrix used to quantize a given data block to be signaled by a decoder as an end-of-block (EOB) code. The EOB codes and the Huffman code table are sent with the JPEG image file. Upon decoding of the image file, a standard JPEG decoder reads each of the EOB codes as a standard JPEG EOB code and does not vary the Q matrix. A modified decoder reads from each of the EOB codes which Q matrix was used to encode each particular data block of the image and uses that Q matrix to dequantize the data block.

Abstract: Previously-unused slots in a Huffman code table associated with a Joint Photographic Experts Group (JPEG) image file are associated with various quantization matrices (Q matrices) that are used to quantize data blocks of the JPEG image file. Huffman codes associated with the various Q matrices permit the particular Q matrix used to quantize a given data block to be signaled by a decoder as an end-of-block (EOB) code. The EOB codes and the Huffman code table are sent with the JPEG image file. Upon decoding of the image file, a standard JPEG decoder reads each of the EOB codes as a standard JPEG EOB code and does not vary the Q matrix. A modified decoder reads from each of the EOB codes which Q matrix was used to encode each particular data block of the image and uses that Q matrix to dequantize the data block.

Abstract: An apparatus computes an inner product vector of a matrix and a vector. The matrix has a first set of coefficients and the vector has a second set of coefficients. At least one input register is used to store the second set of coefficients. A plurality of storage elements are used to store partial sums that are pre-calculated from the first set of coefficients of the matrix. The outputs of the at least one input register are used as the address inputs to the plurality of storage elements to select a subset of the partial sums. In addition, a select circuit is coupled to the storage elements' address lines to determine which row in the matrix the vector forms one element of the resultant inner product for that row. The subset of partial sums from the outputs of the storage elements are added in an adder circuit to create a summation output that presents the element of the inner product vector of the matrix multiplied by the vector.