Bell Communications Research, Inc.

C-cube Microsystems, Inc.

Other

Didier J LeGall

Aaron Wells

K Metin Uz

Cheng-Tie Chen

Martin Vetterli

Fure-Ching Jeng

A rate control algorithm for an MPEG-2 compliant encoder has embodiments useful for constant bit rate and variable bit rate encoding. In particular, the present invention relates to variable bit rate encoding.

Variable bit rate encoding

A rate control algorithm for an MPEG-2 compliant encoder is described. The rate control algorithm has embodiments useful for constant bit rate and variable bit rate encoding. In particular, the invention relates to a field frame macroblock encoding decision.

Field frame macroblock encoding decision

A rate control algorithm for an MPEG-2 compliant encoder is described. The rate control algorithm has embodiments useful for constant bit rate and variable bit rate encoding. In particular, the invention relates to scene change detection.

Scene change detection using quantization scale factor rate control

A rate control algorithm for an MPEG-2 compliant encoder of the present invention has embodiments useful for constant bit rate and variable bit rate encoding. In particular, the invention relates to a three stage hierarchial motion vector determination.

Three stage hierarchal motion vector determination

A filter bank comprising first and second finite impulse response diamond-shaped filters with finite precision filter coefficients is used to convert a high definition progressive video sequence in a vertical-time representation into an interlaced sequence and a deinterlacing sequence. The interlaced sequence may be used by a low resolution television receiver to display a low resolution television image. The interlaced and deinterlacing sequences may be recombined to perfectly reconstruct the progressive high definition video sequence which then may be used by a high definition television receiver. Thus, the inventive system has the advantage that it enables a single high definition video sequence to be utilized by both high definition television equipment and lower resolution television equipment so that an existing base of consumer television equipment is not rendered obsolete by the introduction of a high definition television sequence.

Multi-channel HDTV system

In accordance with our adaptive transform coding algorithm for a still image, the image is divided into small blocks of pixels and each block of pixels is transformed using an orthogonal transform such as a discrete cosine transform. The resulting transform coefficients are compressed and coded to form a bit stream for transmission to a remote receiver. The compression parameters for each block of pixels are chosen based on a busyness measure for the block such as the magnitude of the (K+1).sup.th most significant transform coefficient. This enables busy blocks for which the human visual system is not sensitive to degradation to be transmitted at low bit rates while enabling other blocks for which the human visual system is sensitive to degradation to be transmitted at higher bit rates. Thus, the algorithm is able to achieve a tradeoff between image quality and bit rate.

Adaptive transform coding of still images

A preprocessing method and circuit is utilized to convert a video sequence between a high resolution interlaced format used when the video sequence is read out of a storage medium and a low resolution progressive format suitable for compression encoding at a low bit rate. In accordance with the inventive format conversion preprocessing algorithm, the video sequence in the high resolution interlaced format is first processed by a linear filter with a diamond-shaped passband in y-t space. The output of the linear filter is processed by a non-linear filter and the resulting signal is then decimated to produce the video signal in the low resolution progressive format. The inventive preprocessing algorithm serves to eliminate aliasing, noise, and jerkiness of motion from the sequence in the low resolution progressive format.

Format conversion preprocessing method and circuit

A class of filters for use in connection with the sub-band coding of a video signal is disclosed. The filters are of short length, symmetric and have coefficients in the form of an integer divided by a power of two. The filters may be implemented with a minimum of circuitry and permit exact reconstruction of a sub-band coded video signal.

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Los Altos, CA, United States of America

Didier J LeGall