Patents by Inventor Agnes Y. Ngai

Agnes Y. Ngai has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7936814
    Abstract: 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.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: May 3, 2011
    Assignee: International Business Machines Corporation
    Inventors: James D. Greenfield, Barbara A. Hall, Agnes Y. Ngai, Edward F. Westermann
  • Patent number: 7738551
    Abstract: 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.
    Type: Grant
    Filed: March 18, 2002
    Date of Patent: June 15, 2010
    Assignee: International Business Machines Corporation
    Inventors: Barbara A. Hall, Agnes Y. Ngai, Robert L. Woodard
  • Patent number: 7085322
    Abstract: A distributed control strategy is provided for dynamically encoding multiple streams of video data in parallel for multiplexing onto a constant bit rate channel. The control strategy is a single pass strategy which allows individual encode bit rates to be dynamically adjusted for each video data stream based in part on relative complexity of the multiple streams of video data, as well as fullness of compressed video data buffers coupled between the encoders and the constant bit rate channel. The control strategy includes encoding the multiple streams of video frames in parallel using multiple encoders, exchanging one or more statistics between the encode processes using an exchange interface, and dynamically adapting encoding of at least one stream of the video frames using the exchanged statistics based on relative complexity of the video frames.
    Type: Grant
    Filed: January 18, 2002
    Date of Patent: August 1, 2006
    Assignee: International Business Machines Corporation
    Inventors: Agnes Y Ngai, Edward F Westermann
  • Patent number: 7016413
    Abstract: 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.
    Type: Grant
    Filed: March 20, 1998
    Date of Patent: March 21, 2006
    Assignee: International Business Machines Corporation
    Inventors: Barbara A. Hall, Agnes Y. Ngai, Charles J. Stein, Everett G. Vail, III, Edward F. Westermann
  • Patent number: 6996186
    Abstract: A technique is provided for programmably horizontally filtering pixel values of frames of a plurality of video frames. The technique includes, in one embodiment, passing pixel values through a real-time horizontal filter disposed as preprocessing logic of a video encode system. The horizontal filter is programmable and includes a filter coefficients buffer for holding multiple sets of filter coefficients. The horizontal filter programmably employs the multiple sets of filter coefficients to selectively perform spatial noise filtering, or spatial noise filtering and image scaling on the pixels. The filter coefficients are also programmable and may be changed dynamically and repeatedly, with changes being applied at frame boundaries. When performing image scaling, multiple sets of filter coefficients are employed.
    Type: Grant
    Filed: February 22, 2002
    Date of Patent: February 7, 2006
    Assignee: International Business Machines Corporation
    Inventors: Agnes Y. Ngai, Roger S. Rutter, Robert L. Woodard
  • Patent number: 6993078
    Abstract: 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.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: January 31, 2006
    Assignee: International Business Machines Corporation
    Inventors: Barbara A. Hall, Agnes Y. Ngai, John M. Sutton, Edward F. Westermann
  • Patent number: 6980598
    Abstract: 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.
    Type: Grant
    Filed: February 22, 2002
    Date of Patent: December 27, 2005
    Assignee: International Business Machines Corporation
    Inventors: James D. Greenfield, Barbara A. Hall, Agnes Y. Ngai, John M. Sutton
  • Patent number: 6961378
    Abstract: Method and encoder for encoding a digital video image stream. The encoding includes spatial compression of still images in the video stream and temporal compression between the still images. The spatial compression is carried out by converting a time domain image of a macroblock to a frequency domain image of the macroblock, taking the discrete cosine transform of the frequency domain image, transforming the discrete cosine transformed macroblock image by a quantization factor, and run length encoding the quantized discrete cosine transformed macroblock image. The temporal compression is carried out by reconstructing the run length encoded, quantized, discrete cosine transformed image of the macroblock, searching for a best match macroblock, and constructing a motion vector between them. This forms a bitstream of run length encoded, quantized, discrete cosine transform macroblocks and of motion vectors. This bitstream is passed to and through an external buffer to a transmission medium.
    Type: Grant
    Filed: November 5, 1998
    Date of Patent: November 1, 2005
    Assignee: International Business Machines Corporation
    Inventors: James D. Greenfield, John M. Kaczmarczyk, Agnes Y. Ngai
  • Patent number: 6956901
    Abstract: A control strategy is provided for dynamically encoding multiple streams of video data in parallel for multiplexing onto a constant bit rate channel. The control strategy is a single pass strategy which allows individual encode bit rates to be dynamically adjusted for each video data stream based on part in relative complexity of the multiple streams of video data, as well as fullness of compressed video data buffers and a channel buffer coupled between the encoders and the constant bit rate channel. The control strategy includes encoding the multiple streams of video frames in parallel, and dynamically adapting encoding of at least one stream of the video frames based on relative complexity of the video frames. The bit rate for each stream of video frames is only changed at GOP boundaries, or if a scene change occurs. The calculated bit rate is preferably further modified based upon buffer fullness.
    Type: Grant
    Filed: April 29, 2004
    Date of Patent: October 18, 2005
    Assignee: International Business Machines Corporation
    Inventors: Lilla Boroczky, Agnes Y. Ngai, Edward F. Westermann
  • Patent number: 6956899
    Abstract: 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.
    Type: Grant
    Filed: March 23, 1998
    Date of Patent: October 18, 2005
    Assignee: International Business Machines Corporation
    Inventors: Barbara A. Hall, John A. Murdock, Agnes Y. Ngai, Edward F. Westermann
  • Patent number: 6941025
    Abstract: Simultaneous vertical spatial filtering and chrominance conversion is achieved with reduced data buffering and simplified filtering circuits by using a single filter stage and hybrid filter coefficients. Data latency is reduced and performance requirements are reduced while avoiding critical signal propagation paths. The filter and buffers are fully compatible with any scan format having consecutively presented lines of image data, including both progressive and interlaced scan formats.
    Type: Grant
    Filed: April 19, 2001
    Date of Patent: September 6, 2005
    Assignee: International Business Machines Corporation
    Inventors: James D. Greenfield, Agnes Y. Ngai, John M. Sutton, Edward F. Westermann
  • Patent number: 6895048
    Abstract: 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.
    Type: Grant
    Filed: March 20, 1998
    Date of Patent: May 17, 2005
    Assignee: International Business Machines Corporation
    Inventors: Charles E. Boice, Barbara A. Hall, Agnes Y. Ngai, Charles J. Stein, Everett G. Vail, III, Edward F. Westermann
  • Patent number: 6859496
    Abstract: A control strategy is provided for dynamically encoding multiple streams of video data in parallel for multiplexing onto a constant bit rate channel. The control strategy allows individual encode bit rates to be dynamically adjusted for each video data stream based in part on relative complexity of the multiple streams of video data, as well as fullness of compressed video data buffers and a channel buffer coupled between the encoders and the constant bit rate channel. The control strategy includes analyzing the multiple streams of video to determine relative complexity thereof, encoding the multiple streams of video frames in parallel, and dynamically adapting encoding of at least one stream of the video frames based on the relative complexity of the video frames. The bit rate for each stream of video frames is only changed at GOP boundaries, or if a scene change occurs. The calculated bit rate is preferably further modified based upon buffer fullness.
    Type: Grant
    Filed: January 5, 1999
    Date of Patent: February 22, 2005
    Assignee: International Business Machines Corporation
    Inventors: Lilla Boroczky, Agnes Y. Ngai, Edward F. Westermann
  • Patent number: 6823015
    Abstract: 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.
    Type: Grant
    Filed: January 23, 2002
    Date of Patent: November 23, 2004
    Assignee: International Business Machines Corporation
    Inventors: Barbara A. Hall, Agnes Y. Ngai, John M. Sutton, Edward F. Westermann
  • Patent number: 6823013
    Abstract: An apparatus used for video encoding MPEG compliant digital visual images, having multiple MPEG encoders used in the motion estimation function. The search capabilities used in the motion estimation function of a single MPEG encoder are extended beyond its design limitations as a result of utilizing more than one MPEG encoder. The utilization of multiple encoders effectively creates the capability for a user to specify a wider search window than what is available in a single encoder configuration. The computational search efficency associated with searching the wider window is not adversely affected as a consequence of the multiple processors subdividing the extended window and analyzing each subdivision in parallel.
    Type: Grant
    Filed: March 23, 1998
    Date of Patent: November 23, 2004
    Assignee: International Business Machines Corporation
    Inventors: Charles E. Boice, John A. Murdock, Agnes Y. Ngai
  • Publication number: 20040202248
    Abstract: A control strategy is provided for dynamically encoding multiple streams of video data in parallel for multiplexing onto a constant bit rate channel. The control strategy is a single pass strategy which allows individual encode bit rates to be dynamically adjusted for each video data stream based on part in relative complexity of the multiple streams of video data, as well as fullness of compressed video data buffers and a channel buffer coupled between the encoders and the constant bit rate channel. The control strategy includes encoding the multiple streams of video frames in parallel, and dynamically adapting encoding of at least one stream of the video frames based on relative complexity of the video frames. The bit rate for each stream of video frames is only changed at GOP boundaries, or if a scene change occurs. The calculated bit rate is preferably further modified based upon buffer fullness.
    Type: Application
    Filed: April 29, 2004
    Publication date: October 14, 2004
    Applicant: International Business Machines Corporation
    Inventors: Lilla Boroczky, Agnes Y. Ngai, Edward F. Westermann
  • Patent number: 6788227
    Abstract: 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.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: September 7, 2004
    Assignee: International Business Machines Corporation
    Inventors: Barbara A. Hall, Agnes Y. Ngai, Michael P. Vachon
  • Patent number: 6720893
    Abstract: 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.
    Type: Grant
    Filed: February 22, 2002
    Date of Patent: April 13, 2004
    Assignee: International Business Machines Corporation
    Inventors: James D. Greenfield, Barbara A. Hall, Agnes Y. Ngai, Edward F. Westermann
  • Publication number: 20030184453
    Abstract: 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.
    Type: Application
    Filed: March 28, 2002
    Publication date: October 2, 2003
    Applicant: International Business Machines Corporation
    Inventors: Barbara A. Hall, Agnes Y. Ngai, Michael P. Vachon
  • Publication number: 20030185303
    Abstract: 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.
    Type: Application
    Filed: March 28, 2002
    Publication date: October 2, 2003
    Applicant: International Business Machines Corporation
    Inventors: Barbara A. Hall, Agnes Y. Ngai, John M. Sutton, Edward F. Westermann