Lsi Logic Corporation

C-Cube Semiconductor Ii Inc.

K Metin Uz

Vijay Maheshwari

A method and apparatus are provided for restricting access to a digital video signal. According to the method, the digital video signal is encoded to produce an encoded video signal. In encoding the digital video signal, motion compensated encoding is performed on one or more first video picture portions of the digital video signal using a second video picture portion of the video signal as a reference for forming predictions. Only the second video picture portion of the encoded video signal is scrambled thereby producing a restricted access signal that is subsequently stored on a storage medium. Also provided is a method and apparatus for enabling access to a video signal. According to the method, the encoded video signal is received and only a first video picture portion of the video signal is descrambled. The encoded video signal is then decoded. In decoding the encoded video signal, motion compensated decoding is performed on one or more second video picture portions of the video signal using predictions formed from the descrambled first video picture portion thereby providing a decoded accessed signal.

Conditional access and copy protection scheme for MPEG encoded video data

A method and apparatus for memory-efficient decoding of frame chroma of progressive frames. During the display of a first field of the frame, lines of interpolated chroma values are calculated for both even and odd field lines. The lines of interpolated values for the first field are generated by applying a two-tap filter with coefficients (1/4, 3/4) to corresponding lines of chroma samples, and the lines of interpolated values for the second field are generated by applying a two-tap filter with coefficients (3/4, 1/4) to the corresponding lines of chroma samples. The lines of first field interpolated values are displayed with the first field, while a given even line of second field interpolated values is written to memory locations occupied by a line of chroma samples used to generate the given line. The other line of chroma samples used to generate the given line of second field interpolated values is allowed to be overwritten with additional progressive frame data, such that one line of decoder memory is freed up for each pair of displayed lines. This permits the frame chroma decoding process to be performed utilizing a total memory capacity of only 2.5 framestores. The odd lines of second field interpolated values are generated by averaging two of the previously-stored adjacent even lines of second field interpolated values, such that decoded video quality degradation is minimized.

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Los Altos, CA, United States of America

K Metin Uz