Rca Thomson Licensing Corp.

Sarnoff Corporation

C-cube Microsystems, Inc.

Sharp Corporation

Thomson Multimedia S.a.

Wilson Kwok

Huifang Sun

Max Chien

Joel Walter Zdepski

Tihao Chiang

Ya-Qin Zhang

Billy W Beyers, Jr

Babak Ayazifar

An apparatus and concomitant method for selecting a macroblock coding mode based upon the quantization scale selected for the macroblock. The total number of bits needed to code each macroblock consists of two parts, bits needed for coding motion vectors and bits for coding the predictive residual. The number of bits for coding the motion vectors is generally obtained from a look-up table. The number of bits for coding the predictive residual is obtained by an estimation which assumes that the number of bits for encoding the predictive residuals is directly proportional to the value of its variance and inversely proportional to the value of quantizer steps (quantizer scale). Using this estimation, the total number of bits necessary to code a macroblock is calculated and compared for each coding mode. By selecting the coding mode with the least number of bits, a near-optimal solution of low complexity for practical implementation is acquired.

Apparatus and method for selecting a coding mode in a block-based coding system

A method and apparatus for selecting a quantizer scale for each macroblock to maintain the overall quality of the video image while optimizing the coding rate. A quantizer scale is selected for each macroblock such that target bit rate for the picture is achieved while an optimal quantization scale ratio is maintained for successive macroblocks to produce a uniform visual quality over the entire picture. One embodiment applies the method to the frame level while another embodiment applies the method in conjunction with a wavelet transform.

Apparatus and method for optimizing the rate control in a coding system

The invention provides methods and apparatus for performing inverse telecine processing on an input video frame sequence to be encoded. A method well-suited for detelecine of film-only telecine in MPEG-1 or MPEG-2 applications includes the steps of attempting to fit known 3:2 pulldown pattern phases to the entire sequence, determining a likely edit point in the sequence if a known phase cannot be fit to the sequence, and recursively repeating the fitting and edit point determination steps on subsequences until the entire sequence is partitioned into subsequences which can be fit with one of the known phases. The phases fit to the sequence or subsequences are then used to generate field-match indicators which are further processed to generate MPEG-1 or MPEG-2 compliant repeat field codes.

Method and apparatus for inverse telecine processing by fitting 3:2

A method and apparatus for scaling the bitstream of a compressed video signal includes partial decoding hardware (38, 41) to permit excising of higher frequency AC DCT coefficients or re-quantizing quantized data with a coarser quantization factor. The scaling is performed on a block (macroblock) basis in a manner which linearly scales the amount of compressed data per block. An analyzer (40) generates a profile of cumulative partially decompressed data over a video frame, and bitstream scaling (42) is performed in a manner which insures that a profile of the scaled signal substantially comports with the profile of the original data.

Method and apparatus for scaling a compressed video bitstream

The invention provides methods and apparatus for performing inverse telecine processing on an input video frame sequence to be encoded. A method well-suited for use with mixed video/telecine material in MPEG-2 applications includes the steps of generating a vector of pixel difference scores for a given field in the sequence, dividing each difference score by its smallest adjacent score, filtering the result in a median-like filter, and correlating the divided and filtered scores with a reference vector characteristic of the sequence to generate a correlation metric which is thresholded to provide a field-match indicator for the given field. These steps are repeated for the other fields in the frame sequence, and the resulting repeat field indicators are processed to provide MPEG-2 compliant repeat field codes.

Method and apparatus for inverse telecine process by correlating vectors

A video decompression system includes block error concealment means for generating substitute data for lost blocks of pixel data. An interpolator generates both spatially and temporally interpolated or predicted blocks of data for concealing a lost block. Pixel data in the respective blocks of spatially and interpolated data are transformed to coefficients representing frequency spectra. A substitute block of coefficients is assembled from coefficients from both the transformed blocks, according to a predetermined criteria. The substitute block is transformed back to the spatial domain for substitution of lost pixel values.

Temporal-spatial error concealment apparatus and method for video signal

A compression/decompression system includes a source of non-interlaced scanned video signal. A preprocessor constructs interlaced scanned video signal from the non-interlaced scanned video signal by selection of alternate lines of successive non-interlaced image signals. The interlaced scanned video signal is compressed according to known methods to generate primary compressed video data. The primary data is decompressed by known processes, inverse to the compression processes, to regenerate the interlaced scanned frames. Interlaced scanned video signal, corresponding to the intervening lines of the non-interlaced scanned video signal, which were not included in the primary interlaced scanned video signal, is predicted from the decompressed frames of video signal. In addition the intervening lines of the original non-interlaced scanned video signal, which were not included in the primary interlaced scanned video signal, are formed into secondary interlaced scanned video signal. The secondary video signal is subtracted from the predicted video signal to generate secondary field residues. These residues are compressed by known methods to form compressed secondary video data. The primary and secondary compressed data are thereafter transmitted for reception by either interlaced scanned receivers or non-interlaced scanned receivers.

Method and apparatus for providing scaleable compressed video signal

Error concealment apparatus for correcting errors in signals representing video images includes means for detecting image gradients in an area surrounding a lost block of image data. Circuitry responsive to these image gradients generates a plurality of blocks of directionally interpolated pixel values. The pixel values in the respective blocks of directionally interpolated pixel values are sorted according to amplitude, and then pixel values from mutually exclusive positions in the respective blocks are selected to form a block of pixel values for error concealment.

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Wilson Kwok