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公开(公告)号：CA2396305A1
公开(公告)日：2003-12-25
申请号：CA2396305
申请日：2002-07-29
Applicant: GEN INSTRUMENT CORP
Inventor： LIU VINCENT , WU SIU-WAI , HE YONG
Abstract: Methods and apparatus for rate control in a dual pass encoding scheme are provided. A first pass encoder encodes alternate slices of anchor frames as I-slices and P- slices respectively in order to generate statistics for both I and P frame encoding for the same anchor frame. An initial complexity estimate for encoding a current frame is determined by the first pass encoder based on statistics from first pass encoding of the current fra me and from first pass encoding of a prior encoded frame. A second pass encoder estimates an encoding complexity for the current frame based on the initial complexity and statistics from second pass encoding of the prior encoded frame. The second pass encoder then determines a bit budget for second pass encoding of the current frame based on the encoding complexity.
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公开(公告)号：AU8699001A
公开(公告)日：2002-04-02
申请号：AU8699001
申请日：2001-08-31
Applicant: GEN INSTRUMENT CORP
Inventor： NEMIROFF ROBERT S , LIU VINCENT , WU SIU-WAI
IPC: H04N7/26 , H04N21/2343 , H04N21/236 , H04N21/2365 , H04N7/24
Abstract: A system for providing an accurate time reference for multiple input and output digital video signals of a transcoder that is particularly suited for use with MPEG data. The multiple streams are synchronized with a single master system time clock at the transcoder. Timing data from the master clock is compared to timing data from packets that are input to the transcoder to determine an offset. In particular, timing data, such as a program clock reference (PCR) field, is recovered from packets of different channels that are input to the transcoder. For each channel, timing data is then provided for packets that are output from the transcoder based on the offset and timing data of the master clock at the respective output times. In particular, the adjusted timing data is determined as a sum of the offset and an associated hardware error, less a delay (PcrSysDly) associated with the transcoder, which includes a lookahead delay and a buffer delay. The associated hardware error represents an error of the master clock and/or a system time clock of an encoder that encoded the particular channel.
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公开(公告)号：ES2141780T3
公开(公告)日：2000-04-01
申请号：ES94104591
申请日：1994-03-23
Applicant: GEN INSTRUMENT CORP
Inventor： DEROVANESSIAN HENRY , LIU VINCENT
Abstract: A variable length codeword packer (Fig. 3) communicates codeword data in successive m-bit bytes. A binary sum is accumulated (86) indicative of a total number of codeword bits received over time. A byte pointer (90) is derived from at least one most significant bit of the binary sum. A bit pointer (92) is derived from a plurality of least significant bits of the binary sum. A first data storage array (20) has a plurality of m-bit first storage bytes and is responsive to the byte pointer for storing received codeword data in the first storage bytes. A second data storage array (22) has a plurality of m-bit second storage bytes and is responsive to the byte and bit pointers for filling the second storage bytes with codeword data from the first data storage array (20). m-bit bytes of codeword data (25) are output from each filled second storage byte to provide successive m-bit bytes of codeword data. The use of a multistage approach in packing variable length codewords substantially reduces the complexity as compared to single stage designs.
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公开(公告)号：AT189088T
公开(公告)日：2000-02-15
申请号：AT94104591
申请日：1994-03-23
Applicant: GEN INSTRUMENT CORP
Inventor： DEROVANESSIAN HENRY , LIU VINCENT
Abstract: A variable length codeword packer (Fig. 3) communicates codeword data in successive m-bit bytes. A binary sum is accumulated (86) indicative of a total number of codeword bits received over time. A byte pointer (90) is derived from at least one most significant bit of the binary sum. A bit pointer (92) is derived from a plurality of least significant bits of the binary sum. A first data storage array (20) has a plurality of m-bit first storage bytes and is responsive to the byte pointer for storing received codeword data in the first storage bytes. A second data storage array (22) has a plurality of m-bit second storage bytes and is responsive to the byte and bit pointers for filling the second storage bytes with codeword data from the first data storage array (20). m-bit bytes of codeword data (25) are output from each filled second storage byte to provide successive m-bit bytes of codeword data. The use of a multistage approach in packing variable length codewords substantially reduces the complexity as compared to single stage designs.
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公开(公告)号：HK1013759A1
公开(公告)日：1999-09-03
申请号：HK98115013
申请日：1998-12-23
Applicant: GEN INSTRUMENT CORP
Inventor： KRAUSE EDWARD A , PAIK WOO H , LIU VINCENT , ESSERMAN JIM
Abstract: A method and apparatus are provided for processing digital video signals for transmission in a compressed form. A set of pixel data is compressed without motion compensation to provide a first compressed video signal. The pixel data is compressed using motion compensation to provide a second compressed video signal. The data in the first and second compressed video signals is quantified. A comparison is made to determine which of the signals contains the least data. Successive sets of pixel data are sequentially compressed and quantified and the compressed video signal having the least data for each particular set is selected. The selected signals are encoded to identify them as motion compensated or non-motion compensated signals, and combined to provide a compressed video signal data stream for transmission. Apparatus for receiving and decoding the signals is also disclosed.
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Patent Agency Ranking
公开(公告)号：AT182243T
公开(公告)日：1999-07-15
申请号：AT91108087
申请日：1991-05-18
Applicant: GEN INSTRUMENT CORP
Inventor： KRAUSE EDWARD A , PAIK WOO H , LIU VINCENT , ESSERMAN JIM
Abstract: A method and apparatus are provided for processing digital video signals for transmission in a compressed form. A set of pixel data is compressed without motion compensation to provide a first compressed video signal. The pixel data is compressed using motion compensation to provide a second compressed video signal. The data in the first and second compressed video signals is quantified. A comparison is made to determine which of the signals contains the least data. Successive sets of pixel data are sequentially compressed and quantified and the compressed video signal having the least data for each particular set is selected. The selected signals are encoded to identify them as motion compensated or non-motion compensated signals, and combined to provide a compressed video signal data stream for transmission. Apparatus for receiving and decoding the signals is also disclosed.
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公开(公告)号：HK1010299A1
公开(公告)日：1999-06-17
申请号：HK98111357
申请日：1998-10-20
Applicant: GEN INSTRUMENT CORP
Inventor： CHEN XUEMIN , LIU VINCENT
Abstract: In a method for detecting a scene change between a prior video picture and a current video picture of a sequence of pictures, an average luminance value is determined for a block pair of the prior and current video pictures. Preferably, the blocks of the block pair are located, respectively, in the same relative position in the prior and current pictures. An incremental visual sensation value is determined using a difference between the average luminance values. If the incremental visual sensation value exceeds a block contrast threshold level, a scene change is indicated. In particular, if the minimum of the average luminance values of the current and prior picture blocks exceeds a dark scene threshold, the incremental visual sensation value is determined using the ratio of (a) the absolute value of the difference between the average luminance values, and (b) the minimum of the average luminance values of the current and prior picture blocks. Otherwise, the incremental visual sensation value is determined using the ratio of (a) the absolute value of the difference, and (b) the dark scene threshold. The method may be optimized by adjusting the block size based on the relative amount of motion and the current picture type.
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公开(公告)号：CA2212069A1
公开(公告)日：1998-02-06
申请号：CA2212069
申请日：1997-07-31
Applicant: GEN INSTRUMENT CORP
Inventor： LIU VINCENT , CHEN XUEMIN
Abstract: Disparity estimation between the right and left view pixel luminance values in a stereoscopic video signal is optimized by determining the minimum least-square-error between macroblocks of the right and left view pictures. Affine transform coefficients and disparity vectors which correspond to the minimum error are also determined and transmitted in the data stream for use by a decoder in reconstructing the right view picture. The scheme can be implemented either locally, at the macroblock level, or globally, at the picture level. At the macroblock level, least-square-error optimization may occur for each individual macroblock in the right view picture. In this case, affine transform coefficients are provided for each macroblock. At the picture level, the sum of the least-square-errors is minimized after the blocks of the right view picture are matched to the left view picture. In this case, only one set of affine transform coefficients are required for the entire right view picture. Or, block matching between an affinely transformed left view picture and the right view picture may be performed after minimizing the sum of the least-square-errors. The scheme is particularly useful in minimizing the effects of cross-channel luminance imbalances due to camera variations and scenes with significant changes in brightness or contrast, and is compatible with stereoscopic video systems such as the MPEG Multi-view Profile (MVP) system.
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公开(公告)号：AU650219B2
公开(公告)日：1994-06-09
申请号：AU2995592
申请日：1992-12-07
Applicant: GEN INSTRUMENT CORP
Inventor： PAIK WOO H , KRAUSE EDWARD A , LIU VINCENT , SHEN PAUL , DEROVANESSIAN HENRY
IPC: H04N1/41 , G06T9/00 , H04N7/08 , H04N7/081 , H04N7/58 , H04N19/00 , H04N21/2365 , H04N21/434 , H04N7/12
Abstract: A multichannel image compression system uses a plurality of encoders (10, 12 ... 14) to compress image data. A coding level command is provided to each of the encoders to specify a level of quality to be provided by each encoder. Encoded image data, provided by the encoders in response to the coding level command, is multiplexed (26) into a combined signal for transmission. The coding level command is adjusted in response to an accumulated amount of data from the combined signal, to maintain the accumulated data within a throughput capability of a communication channel (48). Although the coding level command may specify a global coding level that is the same for all of the encoders, the encoders can derive local coding levels from the global coding level to provide different encoding qualities. Decoder apparatus (30-46) is provided to recover an image from the compressed image data.
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公开(公告)号：NO924822D0
公开(公告)日：1992-12-14
申请号：NO924822
申请日：1992-12-14
Applicant: GEN INSTRUMENT CORP
Inventor： PAIK WOO H , KRAUSE EDWARD A , LIU VINCENT , SHEN PAUL , DEROVANESSIAN HENRY
IPC: H04N1/41 , G06T9/00 , H04N7/08 , H04N7/081 , H04N7/58 , H04N19/00 , H04N21/2365 , H04N21/434 , H04J
Abstract: A multichannel image compression system uses a plurality of encoders (10, 12 ... 14) to compress image data. A coding level command is provided to each of the encoders to specify a level of quality to be provided by each encoder. Encoded image data, provided by the encoders in response to the coding level command, is multiplexed (26) into a combined signal for transmission. The coding level command is adjusted in response to an accumulated amount of data from the combined signal, to maintain the accumulated data within a throughput capability of a communication channel (48). Although the coding level command may specify a global coding level that is the same for all of the encoders, the encoders can derive local coding levels from the global coding level to provide different encoding qualities. Decoder apparatus (30-46) is provided to recover an image from the compressed image data.
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