Texas Instruments Corporation

Kapil Ahuja

Mihir Narendra Mody

Vipul Paladiya

Pavan Venkata Shastry

Ratna M V Reddy

A progressive JPEG (joint photographic experts group) decoder is disclosed. The progressive JPEG decoder includes a processing unit that receives a plurality of progressive scans and generates a plurality of modified progressive scans (MPSs). A baseline JPEG decoder, coupled to the processing unit, includes a Huffman decoder, an inverse quantization unit and an inverse transform unit. The Huffman decoder receives a current MPS and generates a set of transform coefficients corresponding to the current MPS. The processing unit adds a set of transform coefficients corresponding to a previous MPS to the set of transform coefficients corresponding to the current MPS, and the processing unit generates quantization indices. The inverse quantization unit estimates inverse quantization values based on the quantization indices. The inverse transform unit estimates inverse transform decoded values based on the estimated inverse quantization values and generates a set of pixels corresponding to the current MPS.

Method and apparatus for decoding a progressive JPEG image

A computer implemented method of video data encoding generates a mask having one bit corresponding each spatial frequency coefficient of a block during quantization. The bit state of the mask depends upon whether the corresponding quantized spatial frequency coefficient is zero or non-zero. The runs of zero quantized spatial frequency coefficients determined by a left most bit detect instruction are determined from the mask and run length encoded. The mask is generated using a look up table to map the scan order of quantization to the zig-zag order of run length encoding. Variable length coding and inverse quantization optionally take place within the run length encoding loop.

Growing community of inventors

Bengaluru, India

Kapil Ahuja