JPH07143104A - Method for video and voice information communication - Google Patents

Abstract

PURPOSE:To utilize a data transfer system adapted to various transmission purposes of video and voice information. CONSTITUTION:A sender side (receiver side) is provided with a low delay data transfer section 14(23) without an error re-transmission procedure and an error free data transfer means 15 (24) with a re-transmission procedure to attain an error free characteristic. Prior to the transmission of video and voice information, a transfer mode communication control section 18 of the sender side and a transfer mode communication control section 27 of the receiver side communicate the type of the available transfer mode and the object of the transfer mode desired to be used with each other to decide the transfer mode. When the transfer mode is decided, changeover switches 13, 16, 22, 25 are operated synchronously with each other by a transfer mode command signal from the transfer mode communication control sections 18, 27 to select the low delay data transfer sections 14, 23 or the free data transfer sections 15, 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audiovisual communication method for exchanging audiovisual information including video and audio between remote locations, and more specifically, live communication, accumulated viewing, accumulated transfer, etc.
The present invention relates to an audiovisual communication method for exchanging audiovisual information between remote places adaptively for various transmission purposes.

[0002]

2. Description of the Related Art H.221, which is an international standard for transmitting videophones and conference images, is a standard for fixed bit rate, live video communication. In the conventional video information transmission system based on H.221, since it was basically considered to transmit video information for direct viewing by a human, it is necessary to maintain continuity at the time of video reproduction, so that a transmission line error may occur. However, the error cannot be corrected by using the data resending means.

When a person directly watches, there is a transmission path error to some extent, and even if it cannot be corrected, the time rate in which an image is disturbed is not so high, and a video information transmission system based on H.221 is a substantial problem. It didn't happen. However, when using this system, for example, when the stored video information is transmitted via the communication path for re-editing on the other party's terminal, the mixing of errors causes trouble during re-editing. Become. That is, when re-editing, a portion disturbed by an error is repeatedly used, or when more video information is transmitted for re-editing, there is a problem that the time rate in which the image is disturbed increases more and more.

[0004]

As described above, the prior art does not take into consideration that the transmission characteristics required for each transmission purpose are different when image information is exchanged between remote locations. However, since only a single data transfer method can be used for the audiovisual information, there is a problem that the transmission characteristics required by the application cannot be satisfied when transmitting the audiovisual information.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a video / audio communication method capable of responding to various transmission requests of video / audio information.

[0006]

In order to achieve the above object, the present invention provides an error-free data transfer means with an error resending procedure and an error resending procedure on each of a transmitting side and a receiving side for achieving an error-free characteristic. And a low-delay data transfer means having no data transfer function are provided, and the transmitting side and the receiving side are adapted to switch the error-free data transfer means and the low-delay data transfer means according to the purpose of transmission so as to transmit / receive the audiovisual information. Is.

[0007]

In the transmitting side and the receiving side of the audiovisual information, the data transfer mode is determined before the communication of the audiovisual information is started. Normally, the audiovisual communication is started when one terminal calls another terminal or an audiovisual server device, and the called terminal or server device responds to the call. Therefore, when a call is made, some code indicating the transfer method is transmitted to the called side, and if the called side supports the transfer method indicated there, communication can be performed in that transfer mode. .

By defining the procedure for changing the transfer mode, the transfer mode can be changed even during communication. Usually, not all bitstreams that are communicated are audiovisual information in audiovisual communication, but channels for various controls are prepared. The transfer mode can be switched by exchanging a command for controlling the transfer mode using such a channel.

As described above, by switching and using the data transfer methods that meet the respective requirements, it is possible to perform audiovisual communication suitable for any transmission purpose. That is, a transmission characteristic suitable for the purpose of transmission can always be obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an audiovisual transmission system according to an embodiment of the present invention. In the figure, the transmitting side includes a video sound input terminal 11, a transfer mode control signal input / output terminal 12, a first changeover switch 13, a low delay data transfer section 14, an error-free data transfer section 15, and a second changeover switch 1.
6, multiplexing / demultiplexing unit 17, transfer mode communication control unit 1
8 and so on. Further, the receiving side has a multiplexing / demultiplexing unit 21, a first changeover switch 22, a low-delay data transfer unit 23, an error-free data transfer unit 24, a second changeover switch 25, a sound output terminal 26, a transfer mode. It is composed of a communication control unit 27, a transfer mode control signal input / output terminal 28, and the like.

FIG. 2 shows the relationship between the audiovisual transmission purpose and the data transfer mode adapted to it.

The purpose of exchanging audiovisual information between the transmitting side and the receiving side can be divided into three types: live communication, storage viewing, and storage transfer. (1) Live communication: A communication such as a videophone call or a videoconference that requires transmission of an image just shot in real time with as low a delay as possible. (2) Storage and viewing: Video information is digitally stored and viewed by pulling out the information via a communication path. Communication needs to be performed at a speed higher than the information speed required for continuous playback of video. Since the viewed data information is not further processed, the error resending procedure is not particularly necessary. (3) Accumulation and transfer: Communication for receiving video information transmitted from a video server or the like, accumulating it on the receiving side, and performing re-sending or re-editing. No or very few transmission line errors are required.

Two types of data transfer modes (data transfer means), a low-delay data transfer mode and an error-free data transfer mode, are prepared for the purposes of transmission classified as described above. (A) Low-delay data transfer mode: A mode in which information generated at the transmitting side is transferred to the receiving side at any speed. The error occurring on the transmission path is not corrected in the data transfer means. It is necessary to consider on the application side to allow the error occurrence in the transfer method. (B) Error-free data transfer mode: When an error occurs during data transfer, the part is retransmitted to correct the error. The application side can be designed on the assumption that an error-free transmission line can be basically used.

In FIG. 1, the data transfer mode is determined by negotiation between the transmitting side and the receiving side before the transmission of the audiovisual information is started or before the transmission purpose of the audiovisual information is changed. In determining the transfer mode, first, the types of transfer modes available on the device side and the transfer mode candidates desired to be used are input from the transfer mode control signal input / output terminals 12 and 28 on the transmitting side and the receiving side, respectively. The transfer mode communication control units 18 and 27 on the transmitting side and the receiving side respectively input the type of the available transfer mode and the input transfer mode candidate (request transfer mode) which are input, to the multiplexing / demultiplexing unit 1.
7, 21, and communicates to the other party via communication path 1. Next, the transfer mode control signal communication units 18, 27 on the receiving side and the transmitting side
Determines the transfer mode to be actually used based on such information. Information on the determined transfer mode is output to the transfer mode control signal input / output terminals 12 and 28, respectively, in order to indicate the current transfer mode to the application side. FIG. 3 shows a transfer mode determination method in the transfer mode communication control units 18 and 27.

On the transmitting side and the receiving side, when the transfer mode is determined, the transfer mode communication control units 18 and 27, respectively.
Changeover switch 1 by the transfer mode instruction signal from
3, 16, 22, and 25 operate in synchronization, and the low-delay data transfer units 14 and 23 or the error-free data transfer unit 1
5, 24 are selected. In this way, when the low-delay transfer mode is selected, the low-delay data transfer units 14 and 23 are used as the audio information transfer units, and when the error-free data transfer mode is selected, the The free data transfer units 15 and 24 are used as the audiovisual information transfer unit, and the audiovisual information is exchanged between the transmitting side and the receiving side. If there is no transfer mode to be actually used, "communication disabled" is output to the transfer mode control signal input / output terminals 12 and 28 from the transfer mode communication control units 18 and 27 on the transmitting side and the receiving side, respectively.

[0017]

As described above, according to the present invention,
Since it is possible to switch and use the data transfer means suitable for the purpose of transmitting the audiovisual information, it is possible to answer various transmission requests for the audiovisual information.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an audiovisual transmission system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between an audiovisual transmission purpose and a data transfer mode.

FIG. 3 is a diagram showing an example of a transfer mode determination method.

[Explanation of symbols]

 11 video sound input terminal 12 transfer mode control signal input / output terminal 13, 16 changeover switch 14 low-delay data transfer section 15 error-free data transfer section 17 multiplexing / demultiplexing section 18 transfer mode communication control section 21 multiplexing / demultiplexing section 22, 25 Changeover switch 23 Low-delay data transfer section 24 Error-free data transfer section 26 Video output terminal 27 Transfer mode communication control section 28 Transfer mode control signal input / output terminal

Claims (1)

[Claims] 1. A method of transmitting and receiving audiovisual information including video and audio via a communication path between remote locations, wherein an error-free procedure with a retransmission procedure for achieving error-free characteristics is provided to each of a transmitting side and a receiving side. Data transfer means and low-delay data transfer means having no error resending procedure are prepared, and the transmitting side and the receiving side switch between the error-free data transfer means and the low-delay data transfer means in accordance with the transmission purpose, and the audio information is transmitted. An audiovisual communication method characterized by transmitting and receiving.