Video-on-demand system capable of performing a high-speed playback at a correct speed

• US 5,732,217 A
• Filed: 09/19/1996
• Issued: 03/24/1998
• Est. Priority Date: 12/01/1995
• Status: Expired due to Term

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Emura, Koichi
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): Flynn, Nathan J.
• Application Number:
  US08/715,870
• Time in Patent Office: 551 Days
• Field of Search: 348/6, 348/7, 348/8, 348/9, 348/10, 348/12, 348/13, 455/3.1, 455/4.1, 455/4.2, 455/5.1, 455/6.1, 455/6.2, 455/6.3, 345/610, 345/326, 345/327, 345/328, 345/200.3, 345/200.36, 345/200.47, 345/200.48, 345/200.49
• US Class Current: 725/90
• CPC Class Codes: H04N 21/2387 Stream processing in response to a playback request from an end-user, e.g. for trick-play
• CPC Class Codes: H04N 21/4325 by playing back content from the storage medium reproduction of recorded television signals H04N5/76; reproduction of recorded television signals H04N9/79
• CPC Class Codes: H04N 21/47202 for requesting content on demand, e.g. video on demand
• CPC Class Codes: H04N 21/6373 for rate control , e.g. request to the server to modify its transmission rate flow control in packet networks H04L47/10
• CPC Class Codes: H04N 21/6587 Control parameters, e.g. trick play commands, viewpoint selection
• CPC Class Codes: H04N 21/8455 involving pointers to the content, e.g. pointers to the I-frames of the video stream
• CPC Class Codes: H04N 7/17336 Handling of requests in head-ends

Abstract

A video server apparatus is provided with a stream control section which determines a keyframe readout interval and a keyframe playback interval that satisfy a playback speed designated by a terminal apparatus. The video server apparatus transmits data of the thus-determined keyframe playback interval to the terminal apparatus. The video server apparatus reads out keyframes of a stored bit stream from at the thus-determined keyframe readout interval, and transmits a stream including the read-out keyframes to the terminal apparatus. The terminal apparatus decodes and displays the transmitted stream at the received keyframe playback interval. This system can correctly perform a playback at an arbitrary speed that is designated by the terminal apparatus.

Claims

1. A video server apparatus comprising:

stream storage means for storing compressed and coded streams;

stream reading means for reading out one of the streams which is designated by a terminal apparatus;

stream transmitting means for transmitting the read-out stream to the terminal apparatus;

access table managing means for managing addresses of keyframes of the stream;

keyframe data length calculating means for acquiring data lengths of the keyframes; and

stream readout position determining means for determining a first keyframe located in the vicinity of a playback start position that is designated by the terminal apparatus based on the addresses managed by the access table managing means, informing the stream reading means of a readout position of the first keyframe, selecting keyframes to be extracted from the stream so as to satisfy an arbitrary playback speed that is designated by the terminal apparatus based on a bit rate at which the stream reading means reads out the stream, a coding bit rate and a keyframe interval of the stream, and the keyframe data lengths acquired by the keyframe data length calculating means, and informing the stream reading means of the selected keyframes.