Lucent Technologies Inc.

At&t Bell Laboratories

Rajesh Hingorani

Kim N Matthews

Yi-Jen Chiu

Obed Duardo

Nelson Botsford, Iii

David Thomas

Paul Albin Wilford

Alireza Farid Faryar

Siu-Wai Wu

A method is disclosed for decoding multiple-coded symbols from a coded input symbol stream in a single clock cycle. The method constructs an original Huffman look-up table by extending the associated Huffman tree to decode multiple symbols in one clock cycle in a first embodiment and decodes multiple DCT coefficient symbols in an alternate embodiment. An advantage of the method is that the depth of the new Huffman tree is adjustable thereby making the method easily adaptable to various hardware architectures. A further advantage of the present invention is that the decoding process speed is significantly increased while the size of the lookup table is nominally increased.

Adaptive variable length decoding method

A method is disclosed for decoding multiple-coded symbols from a coded input symbol stream in a single clock cycle. The method constructs an original Huffman look-up table by extending the associated Huffman tree to decode multiple symbols in one clock cycle in a first embodiment and decodes multiple DCT coefficient symbols in an alternate embodiment. An advantage of the method is that the depth of the new Huffman tree is adjustable thereby making the method easily adaptable to various hardware architectures. A further advantage of the present invention is that the decoding process speed is significantly increased while the size of the look-up table is nominally increased.

A system and method controls an encoder data buffer. The system includes an encoder for encoding input data as a first bit sequence in a bitstream; a processor having a predetermined size for converting the first bit sequence to a sequence having the predetermined size; and a decoder for decoding the modified bit sequence. The processor generates a set of modified bit sequences for facilitating editing thereof, in which the set of modified bit sequences, assembled in an arbitrary order, are decodeable by the decoder to generate a decoded output signal free of editing artifacts. The modified bit sequences are generated by inserting bits to the first bit sequence. The encoder encodes the input data at a rate such that a final capacity of the data buffer is less than a function of the predetermined size, a desired decoding rate, and an initial capacity of the encoder buffer. The data buffer has a total buffer capacity which is less than a function of the actual rate and the desired decoding rate. The capacity of the data buffer is less than one half the capacity of the decoder buffer. A method controls a data buffer by receiving input data; encoding the input data to generate a first bit sequence; detecting a condition of the first bit sequence having a size of less than a predetermined size; converting the first bit sequence to sets of modified bit sequences having the predetermined size; receiving the bitstream; and decoding the modified bit sequences.

Method for controlling a compressed data buffer

A video encoder control system and method are disclosed for controlling a video encoder using a processor having a multiple field delay circuit for delaying input video data by a predetermined number of frames, and a statistics generator for generating statistics from the video data to control the encoder. The statistics generator calculates a sum of absolute values of field differences between pixels, with the sum used for detecting a redundant field, for generating a film flag, and for controlling the encoder using the film flag. The statistics generator calculates averages of blocks of pixels, and a fade detector uses the averages for detecting fades between successive frames to generate a fade flag to control the encoding. The rate controller responds to the statistics to change the resolution of the encoding of successive frames. The processor outputs the film flags, scene change flags, and fade flags to the rate controller to control the encoding of the delayed video data. A method is disclosed for controlling the video encoder including the steps of delaying the input video data, generating frame statistics, and controlling the encoder using the statistics.

Method of encoder control

A decoder for a modified and improved MPEG signal syntax includes a subtractor responsive to an input signal, a frame buffer responsive to the subtractor, a motion compensator responsive to the buffer and to applied motion vector signals, and a multiplier responsive to frame leak signals and to a modified prediction signal for developing an output signal applied to the subtractor. Furthermore, the decoder includes a processor responsive to the motion compensator and to applied adaptive macroblock leak signals for developing the modified prediction signal. The processor comprises a transform circuit responsive to the motion compensator, a gating template responsive to the transform circuit and the adaptive macroblock leak signals, and an inverse transform circuit responsive to the gating template. The transform circuit operates on 2.times.2 blocks of pixels to form 2.times.2 blocks of transform elements. The gating template is responsive to signals that specify a treatment for 2.times.2 blocks of transform elements.

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Princeton Junction, NJ, United States of America

Rajesh Hingorani