Nippon Telegraph and Telephone Corporation

Nippon Telegraph & Telephone Co.

Tatsuo Mori

Kazutoshi Nishimura

Hideki Sakamoto

Hideharu Suzuki

Tomoaki Kawaguchi

Mitsuru Maruyama

Hiroyuki Kimiyama

Yutaka Ishibashi

Kazuo Okada

Akira Uemori

Hiroshi Sugiyama

Kouichi Itoh

Osamu Nakano

A video data playback system for reproducing requested video data by switching coded video data to be reproduced between normal playback coded video data and fast playback coded video data according to a requested playback mode, where the normal playback coded video data are encoded by a first video coding scheme using both intra-frame coding and inter-frame coding, while the fast playback coded video data are encoded by a second video coding scheme using only intra-frame coding and having a playback bit rate and a frame rate identical to those of the normal playback coded video data. The normal playback coded video data can be obtained by encoding the original video data first, then the fast playback coded video data can be obtained by encoding selectively decoded normal playback coded video data. Alternatively, the normal and fast playback coded video data can be obtained by synchronizing start and end of encoding by the first video coding scheme and encoding by the second video coding scheme.

Video data playback system using effective scheme for producing coded

A multiple readout of digital video data, capable of realizing the fast forward and fast reverse modes even under the logically multiplexed circumstances, and reducing a time required for the playback mode switching. A cycle for a readout operation is formed by a plurality of slots, each slot representing a unit time for reading a unit amount of the digital video data for each channel assigned to each user terminal; at least one of the plurality of slots forming each cycle is allocated to each channel and at least one of the plurality of slots not yet used for any channel in each cycle is additionally allocated to a user terminal which is requesting a playback mode switching; and the readout operation to read the digital video data for each channel from the storage device is carried out at every slot allocated to each channel in each cycle, by cyclically repeating the cycle for the readout operation. The requested playback mode switching can be a switching to a fast forward/reverse mode.

Method and apparatus for multiple readout of digital video data with

A method of multiplexed data reading and visual search, in which each video program is divided into a plurality of video data groups which are stored in a prescribed order among the memory devices, and m memory control units are connected with mxn input/output channels selectively and sequentially in units of time-slots such that each memory control unit is connected with each of input/output channel at least once within a prescribed period. Then, the reading operations of the video data groups stored in the memory devices are carried out by making accesses from m memory control units in parallel at each time-slot. Also, the visual search operations are carried out by abandoning a time-slot allocated to one input/output channel in a next small period when a request for changing a current playback mode to a new playback mode is received from a terminal in a current small period, allocating a new time-slot at which a next video data group to be accessed in the next small period according to the new playback mode is accessible to that input/output channel in the next small period, and reading and buffering the next video data group by using the new time-slot in the next small period.

Method of multiplexed data reading and visual search suitable for

A video library system capable of shortening the worst response time with respect to each video data reading request, without lowering the possible level of multiplexing. The multiplexed video data reading is achieved by distributedly storing video data divided into segments among a plurality of data storage devices, where each segment is capable of being read out in one time-slot; selectively connecting each data storage devices with one of data transfer targets by a plurality of switches provided in correspondence to the data storage devices; generating a plurality of control time-slot sequences formed by periodic time-slots in correspondence to the data storage devices with mutually displaced phases in each period of the control time-slot sequences; and controlling the data storage devices and switches such that, in response to a request for reading video data from a data transfer target, an earliest available idle time-slot is selected from the control time-slot sequences, and the segments of the requested video data are sequentially read out from the data storage devices at time-slots corresponding to the selected earliest idle time-slot in the control time-slot sequences and transmitted to the requesting data transfer target as the data storage devices are sequentially switched to the requesting data transfer target by the switches.

Method and apparatus for multiplexed video data reading in video library

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Chiba-ken, Japan

Tatsuo Mori