A moving picture coding apparatus for performing inter-picture predictive coding for pictures constituting a moving picture is provided with a coding unit for performing predictive error coding for image data; a decoding unit for performing predictive error decoding for an output from the coding unit; a reference picture memory for holding output data from the decoding unit; and a motion vector detection unit for detecting motion vectors on the basis of the decoded image data stored in the memory. When coding a B picture as a target picture, information indicating whether or not the target picture should be used as a reference picture when coding another picture is added as header information. Therefore, in a decoding apparatus for decoding a bit stream Bs outputted from the moving picture coding apparatus, management of a memory for holding the reference picture can be facilitated on the basis of the header information.

Moving picture coding method and moving picture decoding method

A broadcast transmission system transmits data packets from a server to a client over a unidirectional broadcast network. The system transmits both full-length data packets, which have uncompressed headers, and reduced-length data packets, which have compressed headers derived from associated uncompressed headers. The server compresses the data packets by compressing the packet header. Compressed packet headers contain fewer header fields than their associated uncompressed headers. The server transmits a series of intermixed full-length and reduced-length packets to the client. As the packets are received, the client determines whether the packets are full-length or reduced-length. If the packet is full-length, the client stores the uncompressed header in a header table. If the packet is reduced-length, the client rebuilds the compressed header from its corresponding uncompressed headers in the header table.

Data packet header compression for unidirectional transmission

A method for increasing channel utilization for a data channel transmitting a multiplex of a set of one or more encoded program streams, each program stream being decodeable by a corresponding decoder, each corresponding decoder including a corresponding decoder buffer, the decoder buffers having a maximum allowable size, the method comprising selecting encoded pictures to be modified, said selecting according to a criterion which includes preventing any underflow of any decoder buffer, modifying each said selected encoded picture to form a corresponding modified encoded picture, said modified encoded picture having less data than said selected encoded picture, and transmitting the corresponding modified encoded pictures through the channel in place of the selected encoded pictures.

Method and apparatus for modifying encoded digital video for improved channel utilization

An optical disk recording thereon compressed moving picture data and an optical disk reproduction apparatus each capable of easily effecting trick play such as high speed reproduction and a retrieval operation at a high speed. Additional information necessary for trick play is recorded in an arbitrary area of an optical disk such as a TOC (Table of Contents) or a leading sector (sector 0) of the disk, and a sector address is added to each sector. To conduct trick play, an I picture, a P picture and a B picture contained in a GOP layer inside a bit stream of compressed image data are extracted and reproduced in accordance with a reproduction speed by looking up a trick play table.

Optical disk and optical disk reproduction apparatus

Necessary coded data only can be read out at random accessing even with recording medium having coded data recorded thereon but whose code quantity is out of proportion to time. Once a recording medium was loaded into a recorder-player connected with a coded-data control device, the device reads control data from the recording medium and stores the data in a coded data control portion. At random accessing, the control data is read-out from the coded-data control portion and entered into a recording medium controller which in turn controls the recording medium to read-out only desired data according to the information inputted from the coded data control portion. In random access playback, fast playback from the midway of a video-sequence can be realized by accessing coded data of a video frame by using control data.

Coded data control device

An apparatus and method for preparing a variable-rate coded signal, generated by compressing a digital input signal using a variable compression ratio and including a signal portion of a predetermined type, for recording on a recording medium. In the apparatus, a circuit generates a flag signal indicating the signal portion of the a predetermined type in the variable-rate coded signal. A signal-type marker generating circuit generates a signal-type marker in response to the flag signal. Finally, a circuit multiplexes the signal-type marker with the variable-rate coded signal to produce a multiplexed signal for recording on the recording medium. The signal-type marker is located adjacent to the signal portion of the predetermined type to indicate the signal portion of the predetermined type in the multiplexed signal. Where the multiplexed signal is divided into packs of plural packets, the signal marker is included in an entry pack located immediately preceding a packet that includes the signal portion of the predetermined type. Where the multiplexed signal is divided into sectors and each sector includes a sector header, the signal marker is included as subcode in the sector header of a sector that includes the signal portion of a predetermined type.

Apparatus and method for processing a variable-rate coded signal for recording to provide a high-speed search capability, apparatus and method for reproducing such processed signal, and recording including such processed signal

Method for processing a variable-rate coded signal for recording to provide a high-speed search capability, method for reproducing such processed signal, and recording including such processed signal

PURPOSE:To make quick search of predetermined data possible corresponding to an entry packet by multiplexing the entry packet, generated in response to an entry point signal, and a data generated at a variable rate. CONSTITUTION:A controller 8 receives an entry point generation data from a video encoder 1 or a video entry point detection circuit and inserts an entry packet immediately before the video entry point. Upon receiving an entry point generation signal, an entry packet generation circuit 32 generates an entry packet and turns a switching circuit 6 to the input terminal E3 side thus feeding the entry packet to a header adding circuit 7 for multiplexing the entry packet and audio/video data received from code buffers 4, 5. This constitution makes quick search of predetermined data possible corresponding to the entry packet.

Fujinami Yasushi

Papers

Apparatus and method for processing a variable-rate coded signal for recording to provide a high-speed search capability, apparatus and method for reproducing such processed signal, and recording including such processed signal

Method for processing a variable-rate coded signal for recording to provide a high-speed search capability, method for reproducing such processed signal, and recording including such processed signal

Data encoder and encoding method, data decoder and decoding method, and recording medium