International Business Machines Corporation

Barbara A Hall

Agnes Yee Ngai

Edward Francis Westermann

James David Greenfield

Charles E Boice

John Mark Kaczmarczyk

John M Sutton

Michael Patrick Vachon

Charles John Stein

John A Murdock

Charlene Ann Gebler

Everett G Vail, Iii

Stephen Philip Pokrinchak

John David Jabusch

Robert L Woodard

Kevin C Huang

John Michael Sutton

Robert Leslie Woodward

Plural encoders operating in parallel to achieve a desired data rate have their respective outputs combined by an autonomously operating arrangement for transfer of data to a direct memory access arrangement from respective encoders in order in response to a signal asserted upon completion of encoding and output of encoded data corresponding to a predetermined portion of input data. Buffering of encoder output can be either internal or external to the encoders. Zero bytes which may be inherently generated at the beginning and end of an encoder output stream may be suppressed to improve encoded signal quality and efficiency.

Cascaded output for an encoder system using multiple encoders

The present invention provides a system and method for processing a High Definition Television (HDTV) image. Specifically, the system and method of the present invention provides a plurality of programmable encoders connected in parallel and directly (i.e., gluelessly) attached to a HDTV video source. The system and method of the present invention allows a fall HDTV image to be received by each encoder at 74.25 MHz directly from the HDTV video source. Based on programming, each encoder will process only a portion of the full image.

System and method for processing a high definition television (HDTV) image

A technique is provided for adaptively encoding in hardware, software or a combination thereof a sequence of frames in real time, wherein one or more of the frames includes a random noise portion. The technique includes using statistics analysis to determine whether a current frame includes a random noise portion, and if so, to evaluate and dynamically encode each macroblock thereof based on activity level of the macroblock. Evaluating macroblock activity level includes determining whether its activity level exceeds a predefined threshold indicative of random noise. The macroblock is adaptively encoded by adjusting one or more coding parameters if the macroblock activity level is excessive and its target bitrate is low. For example, when the macroblock is within the random noise portion of the frame, the macroblock is biased towards being coded predictive and an adjusted quantization level is calculated to conserve bits used in encoding the macroblock, thereby moving encode bits from macroblocks within the random noise portion of the frame to macroblocks within the normal portion of the frame.

Adaptively encoding a picture of contrasted complexity having normal video and noisy video portions

A technique for encoding macroblocks of a frame is provided which includes switching a coding decision for a macroblock from a non-intra decision to a skip macroblock decision when the absolute prediction error for the macroblock is less than a prediction error threshold and the magnitude of the motion vector for the at least one macroblock is less than a motion vector threshold. In one embodiment, the prediction error threshold is multiple programmable prediction error thresholds, which are for comparison with the absolute luminance and chrominance summation components and the maximum luminance and chrominance difference values. The motion vector threshold may be a preset value when the macroblock is to be predictive coded, and may be the magnitude of the motion vector of the previous macroblock when the macroblock is to be bi-directionally encoded.

Macroblock coding technique with biasing towards skip macroblock coding

A technique is provided for programmably vertically filtering pixel values of frames of a sequence of video frames. The technique includes separating luminance components and chrominance components of the pixel values within a vertical filter buffer, then vertically filtering luminance components of the pixel values using programmable luminance filter coefficients, and vertically filtering chrominance components of the pixel values using programmable chrominance filter coefficients. The filtered luminance component data and filtered chrominance component data is subsequently merged onto a single luminance/chrominance bus for further filtering and/or encoding. The luminance and chrominance filter coefficients are programmable and may be changed dynamically and repeatedly at picture boundaries. In one embodiment, the programmable vertical filter includes a four tap luminance component filter and a five tap chrominance component filter.

Programmable vertical filter for video encoding

A method and system for encoding digital video picture data. In accordance with this method, the video picture data is partitioned into a group of blocks, at least some of those blocks are selected, one block at a time, and each of the selected blocks of data is encoded to form an encoded coefficient having an associated number of bits. The encoded coefficients are outputted, and an accumulated sum of the number of bits in the outputted encoded coefficients is kept. The outputting of the encoded coefficients is terminated at a defined time in order to prevent the accumulated sum from exceeding a given number.

Precise bit control apparatus with look-ahead for MPEG encoding

Method, system and computer program product are provided for adaptively encoding in hardware, software or a combination thereof a series of still or partially still pictures using motion video encoding. A pre-encode statistics measurement unit is employed to derive statistics on each frame of the sequence of video frames to be encoded. The statistics are determinative of whether the frame comprises a still frame. If so, at least one controllable parameter to be used to encode the still frame is modified, and an encoding engine employs the at least one controllable parameter to encode the still frame so that pulsation artifacts are prevented between still frames of the series of still frames. Partial still picture encoding to prevent pulsation artifacts on a macroblock level is also addressed.

Adaptive encoding of a sequence of still frames or partially still frames within motion video

A technique is provided for encoding macroblocks of a frame of a sequence of video frames initially employing luminance data only to analyze temporal redundancy of the macroblocks within the frame. Upon deciding to code at least one macroblock as a non-intra macroblock, the technique includes considering whether to switch the coding decision for the at least one macroblock from non-intra to intra by evaluating chrominance data of the at least one macroblock. The evaluating of the chrominance data can include determining whether chrominance difference data, obtained by comparing chrominance values of a current macroblock with a reference macroblock, is greater than a user set chrominance difference threshold, and if so then the technique includes switching the macroblock coding decision. As a further qualification, the switching might occur only if the chrominance difference data is also greater than the corresponding luminance difference data.

Macroblock coding using luminance date in analyzing temporal redundancy of picture, biased by chrominance data

Two encoders are used in cascade wherein one encoder functions as a preprocessor for the other by collecting statistics concerning partially processed input data. The statistics thus derived are autonomously transferred to a second decoder in a self-synchronized manner, avoiding any need for external glue logic, and utilized to select encoding options for encoding and/or compressing the data so that the quality of encoded data is optimized based on the content of current input data.

Apparatus for integrated cascade encoding

A technique is provided for programmably controlling output of compressed data from, for example, a video encoder. The technique can be implemented within the video encoder and includes buffering the compressed data in a write buffer, followed by transferring the compressed data from the write buffer to a read buffer. At least one programmable output mode is provided for selectively controlling output of the compressed data from the read buffer. When the read buffer is full, the compressed data is stored to the encoder's external memory to await transfer to the read buffer. The at least one programmable mode can include a slave mode, a gated master mode, a multi-cycle speed mode, and a paced master mode, which may be employed individually or in combination. A mechanism for inserting pad bytes of data into the compressed data is also provided.

Programmable output control of compressed data from encoder

A digital video encode system, method and computer program product are described wherein a picture is divided into multiple active areas that are parallel encoded using multiple encoders. The encoders associated with adjoining active areas of the picture are configured to exchange reference data to facilitate avoiding appearance of a seam between the adjoining active areas of a subsequent picture in a sequence of pictures due to separate encoding thereof by the multiple encoders. The reference data transferred from one encoder to an adjoining encoder is an encoded and decoded section of the picture and is used by the adjoining encoder as an expanded reference area for motion estimation when encoding the subsequent picture.

Sharing reference data between multiple encoders parallel encoding a sequence of video frames

A method to insert or splice new pictures into an existing video stream is provided where the video stream is compressed according to the MPEG-2 video compression standard. The method assures that the new pictures will fit into the encoded stream in the space allotted without running over or under their given bit allocation. The method comprises of steps by which a number of new pictures may be encoded to a precise bit target given the number of free bits in the buffer at the start and end of the splicing, while preventing buffer overruns and under runs.

Method of precise buffer management for MPEG video splicing

A method for compensating for reduced picture quality when combining a multi-chip encoding chipset into a single integrated semiconductor IC. The method includes additional functions provided on the single IC to compensate for the negative effects on picture quality produced as a result of rounding 8 bit luminance pixel data to 5 bits, where the luminance data values are supplied as input to the search function. The additional functions are collectively referred to as motion biasing and are applied to influence the choice of a 'best match' motion type, which is well known in the art. The biasing is performed by the addition of a weight factor to a total difference result that is calculated by the search function. The biasing is applied only for the purpose of influencing the choice of a reference frame that is not necessarily the frame which produces an optimal motion vector, but rather will result in using fewer bits to encode macroblocks.

Motion estimation architecture for area and power reduction

Method, system and computer program product are provided for adaptively encoding in hardware, software or a combination thereof a sequence of video frames in real-time. A first encoding subsystem analyzes the sequence of video frames to derive information on at least one characteristic thereof, such as motion statistics, non-motion statistics, scene change statistics, or scene fade statistics. The gathered information may be either an intraframe characteristic or an interframe characteristic. A control processor is coupled to the first encoding subsystem to automatically analyze the gathered information in real time and dynamically produce a set of control parameters. A second encoding subsystem, coupled to the control processor, then encodes each frame of the sequence of video frames employing the corresponding set of control parameters.

Real-time encoding of video sequence employing two encoders and

A method of encoding a picture in an MPEG2 compliant digital video encoder. The method calculates a contrast function,

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Endwell, NY, United States of America

Barbara A Hall