Video server for video distribution system

• US 20010018772A1
• Filed: 12/20/2000
• Published: 08/30/2001
• Est. Priority Date: 02/24/2000
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Igawa, Masaru, Shibata, Koichi, Morita, Koichi, Sakamoto, Shuichi
• Granted Patent: US 7,069,332 B2
• Time in Patent Office: Days
• US Class Current: 725/93
• CPC Class Codes: H04N 21/21 Server components or server architectures
• CPC Class Codes: H04N 21/23 Processing of content or additional data; Elementary server operations; Server middleware

Abstract

A video server for distributing a digitized video content includes a unit for determining whether or not a video content requested from a terminal is stored in the video server, a unit for issuing a transmission request to another server for transmitting the video thereto in accordance with the HTTP protocol when the video content requested from the terminal is not stored in the video server, and a unit for receiving the video content transmitted from the other video server in accordance with the HTTP protocol, and transmitting the video content to the terminal in accordance with IP multicast or HTTP protocol.

Claims

1. A video server for distributing a digitized video content, comprising:

means for determining whether or not a video content requested from a terminal is stored in said video server;

means for transmitting a transmission request to another video server for transmitting said video content in accordance with the HTTP protocol when the video content requested by the terminal is not stored in said video server; and

means for receiving the video content transmitted from the other video server in accordance with the HTTP protocol, and transmitting the video content to said terminal in accordance with IP multicast.

2. A video server according to

claim 1

, wherein:

said transmitting means further includes means for transmitting the video content received from the other video server to said terminal in accordance with the HTTP protocol.

3. A video server according to

claim 1

, further comprising:

means for storing and managing the video content received from the other video server.

4. A video server according to

claim 1

, wherein:

said transmitting means includes a plurality of buffers, buffer selecting means, and a reference time generator;

said transmitting means detects a random access point in image information, and stores the image information up to the next random access point in one of said plurality of buffers; and

said buffer selecting means selects, from among said plurality of buffers, image information which has not been transmitted and has a time stamp equal to or smaller than a reference time generated by said reference time generator, and indicates the selected image information to said transmitting means.

5. A video server according to

claim 2

, wherein:

said means for transmitting a video content to the terminal in accordance with the HTTP protocol establishes a plurality of logical transmission paths between said terminal and said video server, and utilizes said plurality of logical transmission paths for transmitting image information.

6. A method of distributing a video content in a video server, comprising the steps of:

receiving an audience request from a terminal;

determining whether or not a requested video program is stored in said video server;

transmitting said video program to the terminal when the requested video program is stored in said video server; and

accessing to another video server when the requested video program is not stored in said video server to request said other video server to transmit the video program, and transmitting the received video program to the terminal.

7. A video distribution method according to

claim 6

, wherein:

the video program from the other video server is received in accordance with the HTTP protocol, and the video program is transmitted to the terminal in accordance with IP multicast or the HTTP protocol.

8. A program for distributing a video in a video server, said program including codes for executing the steps of:

receiving an audience request from a terminal;

determining whether or not a requested video program is stored in said video server;

transmitting said video program to the terminal when the requested video program is stored in said video server; and

accessing to another video server when the requested video program is not stored in said video server to request the other video server to transmit the video program in accordance with the HTTP protocol, and transmitting the received video program to the terminal.

9. A method of transferring image information in an asynchronous communication network, comprising the steps of:

detecting a random access point in received image information and storing the image information up to the next random access point in one of a plurality of buffers;

selecting image information which has not been transmitted and has a time stamp equal to or smaller than a reference time from among said plurality of buffers, transmitting the selected image information, and deleting the image information from the buffer after transmission; and

deleting image information which has not been transmitted and has a time stamp larger than the reference time from among said plurality of buffers.

10. A method of transmitting image information, comprising the steps of:

providing a reception side with a time stamp memory for storing a time stamp of reproduced image information;

establishing a plurality of logical transmission paths in accordance with the HTTP protocol between a transmission side and the reception side;

transmitting an image transmission request from the reception side to the transmission side through said plurality of logical transmission paths;

transmitting image information to the reception side in response to said video transmission request on the transmission side; and

comparing, on the reception side, a time stamp of the received image information with a time stamp stored in said time stamp memory to reproduce only image information having a time stamp more recent than the stored time stamp.