公开(公告)号：CA2421788A1

公开(公告)日：2002-03-28

申请号：CA2421788

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 ,  H04N7/58

Abstract: A system for providing an accurate time reference for multiple input and output digital video signals of a transcoder (100) that is particularly suit ed for use with MPEG data. The multiple streams are synchronized with a single master system time clock (155) at the transcoder (100). Timing data from the master clock is compared to timing data from packets that are input to the transcoder to determine an offset (120, 130). In particular, timing data, su ch as a program clock reference (PCR) field, is recovered from packets (104) of different channels that are input to the transcoder (122, 132). For each channel, timing data is then provided for packets (106) that are output from the transcoder based on the offset and timing data of the master clock (155) 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 (PcrSysDla) 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.

公开(公告)号：CA2321015A1

公开(公告)日：2002-03-27

申请号：CA2321015

申请日：2000-09-27

Applicant: GEN INSTRUMENT CORP

Inventor： CHEN JING YANG ,  WU SIU-WAI ,  NEMIROFF ROBERT S ,  CASTELOES MICHAEL ,  LIU VINCENT ,  LAM REBECCA ,  ON HANSON

IPC: H04J3/16 ,  H04N7/58 ,  H04N19/61 ,  H04N21/2365 ,  H04N21/434 ,  H04N7/08 ,  H04N7/015

Abstract: A statistical multiplexer for coding and multiplexing multiple channels of digital television data, or multiple panels of HDTV digital television data. A bit rate need parameter is determined for each encoder in a stat mux group by scaling the complexities of previous pictures of the same and different picture types. Scaling factors based on an activity level, motion estimation score, and number of pictures of a certain type in a GOP, may be used. Moreover, the scaling factors may be bounded based on a linear or non-linear operator to prevent large variations in the factors. An encoding bit rate is allocated to each channel based on its need parameter.

公开(公告)号：DE69229773T2

公开(公告)日：2000-03-02

申请号：DE69229773

申请日：1992-12-10

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 ,  H04N7/32 ,  H04N7/24

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.

公开(公告)号：GR3031164T3

公开(公告)日：1999-12-31

申请号：GR990402257

申请日：1999-09-08

Applicant: GEN INSTRUMENT CORP

Inventor： KRAUSE EDWARD A ,  PAIK WOO H ,  LIU VINCENT ,  ESSERMAN JIM

IPC: H03M7/30 ,  G06T9/00 ,  H04N7/26 ,  H04N7/32 ,  H04N7/36 ,  H04N7/50

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.

公开(公告)号：ES2134786T3

公开(公告)日：1999-10-16

申请号：ES92121030

申请日：1992-12-10

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 ,  H04N7/32 ,  H04N7/24

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.

公开(公告)号：CA2216077A1

公开(公告)日：1998-03-27

申请号：CA2216077

申请日：1997-09-19

Applicant: NEXTLEVEL SYSTEMS INC ,  GEN INSTRUMENT CORP

Inventor： LIU VINCENT ,  CHEN XUEMIN

IPC: H04N5/76 ,  H04N5/14 ,  H04N5/91 ,  H04N7/26 ,  H04N7/32 ,  H04N7/24 ,  H04N5/262 ,  H04N7/50 ,  H04N9/64

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.

公开(公告)号：CA2113045A1

公开(公告)日：1994-07-28

申请号：CA2113045

申请日：1994-01-07

Applicant: GEN INSTRUMENT CORP

Inventor： LIU VINCENT ,  FOX JOHN

IPC: H04N7/32 ,  G06T1/60 ,  H04N5/14 ,  H04N7/26 ,  H04N7/12

公开(公告)号：CA2091816A1

公开(公告)日：1993-10-26

申请号：CA2091816

申请日：1993-03-17

Applicant: GEN INSTRUMENT CORP

Inventor： PAIK WOO H ,  LIU VINCENT ,  SHEN PAUL ,  KRAUSE EDWARD A

IPC: H04N5/44 ,  H04N7/50 ,  H04N7/54 ,  H04N11/04 ,  H04N11/24 ,  H04N19/89 ,  H04N21/236 ,  H04N21/2368 ,  H04N21/2383 ,  H04N21/40 ,  H04N21/434 ,  H04N21/438 ,  H04N11/02

Abstract: A macroblock packet format is provided for use in a digital HDTV system wherein successive video frames are divided into a plurality of macroblocks. The macroblocks comprise a plurality of superblocks, each containing a plurality of luminance and chrominance video data blocks. A DLEN field is provided in the macroblock packet format to identify the length of the macroblock packet. The packets also include variable length encoded portions of video data. The macroblock packets are transmitted in a data multiplex that also includes a next macroblock position (NMP) word. A receiver compares the DLEN information with the NMP word to verify synchronization, and reacquires the signal if synchronization has been lost.

公开(公告)号：AU627421B2

公开(公告)日：1992-08-20

申请号：AU7808191

申请日：1991-05-30

Applicant: GEN INSTRUMENT CORP

Inventor： KRAUSE EDWARD A ,  PAIK WOO H ,  LIU VINCENT ,  ESSERMAN JIM

IPC: H03M7/30 ,  G06T9/00 ,  H04N7/26 ,  H04N7/32 ,  H04N7/36 ,  H04N7/50 ,  H04N7/13 ,  H04N7/137 ,  H04N7/133

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.

公开(公告)号：AT423432T

公开(公告)日：2009-03-15

申请号：AT02736895

申请日：2002-05-14

Applicant: GEN INSTRUMENT CORP

Inventor： LIU VINCENT ,  NEMIROFF ROBERT ,  WU SIU-WAI

IPC: H04N21/234 ,  H04N21/236 ,  H04N21/81

Abstract: A mechanism for splicing advertisements, local programming and the like into a digital video transport stream is provided. In order to achieve proper splicing, an appropriate number of frames is inserted between bitstreams to properly close a GOP of the first bitstream into which a second bitstream carrying the spliced content is inserted. Program clock references (PCRs) of the bitstreams are adjusted as necessary in order to force continuity between the bitstreams. For inserting advertisements, the PCR of the program stream and ad stream can be tracked, and the PCR of the program stream can be used both before and after splicing. For local program insertion (which are typically substantially longer than advertisements), the PCR of the local program can be used, after adjustment thereof with an offset to maintain continuity at the splice point. The PTS and/or DTS of the inserted bitstream can be modified to keep them continuous at the splice point for both video and audio streams. The spliced bitstream is transcoded to maintain a desired output bit rate, and to provide overflow/underflow protection of the video buffers.