JP2795256B2 - Error handling system in multimedia communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality processing system in a multimedia communication system, and more particularly, to a system for decoding and reproducing compressed moving image data transmitted from a server in response to a request from a terminal device. The present invention relates to an abnormality processing system in a media communication system.

[0002]

2. Description of the Related Art Conventionally, as a line abnormality detection system of a data communication system, for example, as disclosed in JP-A-3-29349 and JP-A-3-241942, a local station requests a transmission to a partner station. There is a technique of a system in which if a response from the partner station is not received even after a predetermined time elapses after a predetermined time, it is regarded as a communication abnormality. Here, the predetermined time is a time calculated by calculating the average of the past response times and estimating the average time with a certain margin time.

Another technique is disclosed in Japanese Patent Application Laid-Open No. 62-209.
As disclosed in Japanese Unexamined Patent Publication No. 945, there is also a technique in which, when an abnormal DC current does not flow for a preset time in a communication line between terminal devices, it is regarded as abnormal.

[0004] On the other hand, as means for recovery when a line abnormality is detected, there is generally a method of performing retransmission when there is no response from the partner station. At this time, retransmission is performed by controlling the number of times. A technique for reducing the number of times as much as possible and changing the number of times depending on the state is disclosed in Japanese Patent Laid-Open No. 2-1238.
No. 41 discloses this.

Further, the received data immediately before the abnormality is confirmed is held until the abnormality is recovered, and the data is processed until the recovery is performed. Japanese Patent Application Laid-Open No. 5-122292 discloses a technique in which a difference is obtained, and when the difference is equal to or more than a predetermined value, new data is changed at a predetermined change rate to gradually approach the original received data. .

Japanese Patent Laid-Open Publication No. Heisei 1 (1994) discloses a method in which two main and sub control units are provided, and are usually controlled by the main control unit, and when an abnormality occurs, the control unit is switched to the sub unit to recover the main control unit. −
No. 252047.

[0007]

The conventional line abnormality detection method and line abnormality recovery method have the following problems. First, JP-A-3-296349 and JP-A-3-24
This is a line abnormality detection method described in each of the publications of 1942. However, if a local station makes a transmission request to a partner station and does not receive a response after a certain period of time, it is determined that the transmission is abnormal. Since it is determined whether or not there is an abnormality based on whether or not there is a response to the request, it is not possible to cope with an abnormality occurring during data transmission.

In a data transfer for several tens of minutes to several hours, such as a multimedia communication system to which the present invention is applied, a certain amount of data is transmitted after a transmission request, and then a line disconnection or a line abnormality occurs. Because of the possibilities, the above method is problematic.

As described in Japanese Patent Application Laid-Open No. 62-209945, a method in which a DC current is not detected for a certain period of time is regarded as abnormal if the DC current is not detected. There is also a problem that it cannot be dealt with, and is not suitable for abnormal situations such as when actual video data is not transmitted even though the DC current is flowing normally.

On the other hand, Japanese Unexamined Patent Publication No.
In the general retransmission method described in Japanese Patent Publication No. 41, it is sufficient if the cause of the abnormality is due to some bad timing, but if the line cable of the terminal is disconnected, etc. Without recovery, the user must wait without knowing what is happening during the retransmission process, which is unpleasant.

The same can be said for the means for holding the immediately preceding data, as described in Japanese Patent Application Laid-Open No. Hei 5-12292. Also, it is impossible for compressed video data to gradually approach new data after recovery.

Further, in Japanese Patent Application Laid-Open No. 1-252047, in which two main and sub control units are provided and control is switched to a sub control unit when an abnormality occurs, the line scale becomes large. In addition, there is a problem that it is not necessary to cope with a case where an abnormality occurs on the line and data is no longer transmitted, as long as the control unit is abnormal.

[0013] It is an object of the present invention to provide an abnormality processing system capable of quickly and accurately detecting when an abnormality has occurred on a line in a multimedia communication system.

Another object of the present invention is to provide an abnormality processing system capable of easily restarting reproduction of a moving image from the time of occurrence of an abnormality.

[0015]

According to the present invention, an abnormal processing in a multimedia communication system for decoding and reproducing compressed moving image data transmitted from a server in response to a request from a terminal device. A decoding unit that decodes the compressed moving image data; a counter unit that is updated each time the decoding unit decodes one frame of the compressed moving image data; An abnormality processing system characterized by including abnormality detection means for performing abnormality detection according to the count content is obtained.

[0016] The abnormality detection means is characterized in that when the count content of the counter means is not updated within a predetermined period, it is determined that a communication error has occurred.

Further, the abnormality detecting means is characterized in that the communication abnormality is notified to the server, and the abnormality detecting means responds to the determination of the communication abnormality by initializing the decoding means. It is characterized by the fact that the conversion is performed.

The terminal device may further include an instruction unit for instructing the decoding unit to start decoding reproduction in response to a key input instruction by the user after the abnormality detection unit determines that a communication error has occurred. I have.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The operation of the present invention will be described. A counter is provided in a portion for decoding encoded data sent from the server side, that is, a decoding unit on the terminal side, and by monitoring this counter, it is determined whether there is any abnormality. The counter is incremented each time the decoding unit successfully decodes the code data. If an error occurs in the decoding unit and decoding cannot be performed normally, the counter is not incremented and continues to transmit the same value.

Similarly, when an error occurs on the line and data is no longer sent, or when data does not reach the terminal due to a cable being disconnected, the counter stops and returns the same value. When it is confirmed that the increment is not performed for a predetermined time, it is regarded as abnormal. In this way, abnormality is detected.

When a line abnormality is detected, the multimedia communication server unit is first notified of the line abnormality by using another line to stop data transmission. The terminal switches the display unit to the graphics display (overlay-off) mode, displays a message prompting the user to confirm the line cable, initializes the decoder unit, and waits for a key input from the user. Thereafter, at the timing of a key input or the like from the user, a data transmission request, a decoding restart instruction to the decoder unit, switching to a moving image display (overlay ion) mode of the display unit is performed, and reproduction from a portion where a line abnormality occurs is performed. Resume.

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. The multimedia communication system has a server unit 1
0 and the terminal unit 11 can be roughly classified. In the server part,
There are several types of servers that store compressed video data and communicate it, or add various information to the header of the data at the request of the terminal and send it to the terminal side. These are collectively referred to as a multimedia communication server unit (hereinafter, server unit) 11.

The terminal unit 10 reproduces and displays video data when operated by a user. MPEG
(Moving Picture Experts G
(loop) The data separation unit 12 separates the MPEG data sent from the server unit into audio data and video data.

The audio data decoding unit 13 and the video data decoding unit 15
The data from the EG data separation unit 12 is decoded and output. The audio data is output to the audio output unit 14 as it is, and the image data is overlaid on the graphics generated by the graphic unit 19 by the overlay control unit 16 and output to the video output unit 17.

The control of each module is performed by software such as an application or H / W (hardware) control software.

The decode counter 27 is a counter that is incremented each time the video data decoding section 15 decodes video data. The CPU 18 constantly monitors the contents of the counter 27 to monitor an abnormality.

FIG. 2 is a diagram showing extracted blocks of the decode counter 27 and its peripheral parts. The video data decoder 15 decodes one frame of the MPEG stream data shown in FIG. , One count pulse is generated. In this case, as shown in FIG. 3, a header is added to the head of one frame of data in the picture layer of the MPEG stream, and a PSC (Picture Start) is provided at a predetermined position of the header.
Code) is inserted.

Each time the decoding section 15 detects and decodes this PSC, a count pulse is generated. Therefore, the decode counter 27 counts this pulse and increments its content.

Therefore, the abnormality monitoring function unit 18 of the CPU 18
In step 1, the counter 27 is incremented by a certain period. If the counter 27 is incremented, it is determined that the counter 27 is normal. If the counter 27 is not incremented, it is determined that the counter 27 is abnormal.

FIG. 4 is a functional block diagram systematically showing the terminal unit 10 shown in FIG. 1, and functional parts equivalent to those in FIG. 1 are denoted by the same reference numerals.

The application unit 21 is a user GU
Software that provides I (graphics user interface). Application unit 21
Is operated by the operation system 2
2 lower terminal control software 23 and GDI
(Graphics display interface)
24. The GDI 24 receiving the command generates graphics, the terminal control software 23 issues a command to the communication software for transmission to the server unit 11, and issues a command to the H / W control software 26 for control of the terminal unit.

The communication software 25 and the H / W control software 26 control the H / W unit 100 of the terminal unit, respectively.

FIG. 5 is a diagram showing the operation of the embodiment of the present invention, and is a diagram sequentially showing a method of detecting a line abnormality at the time of reproducing image data in a multimedia communication system and a method of recovering the line abnormality.

When the user selects the reproduction of a moving image, the application section of the terminal section issues a reproduction start instruction to the terminal section control software (S31). The terminal unit control software 23 requests data to the server unit 11 via the communication software (S32), issues an instruction to start decoding of the H / W unit (S33, S34), and simultaneously updates the counter value of the decode counter 27. Checking is started (S35).

The check of the decode counter 27 is performed at an arbitrary time interval from the start of reproduction to the end thereof. For example, a counter value is read every second, and when the counter value is the same value five consecutive times, that is, when decoding is not performed for five seconds, it is regarded as a line abnormality.

On the other hand, the server unit 11 receiving the data request
Starts transmission of the compressed video / audio data (S36, S37, S38). When a line abnormality occurs (S39) and the H / W control software 26 detects the abnormality (S40), the screen is switched from the moving image display mode to the graphics display mode, and the terminal unit control software 23 is notified of the occurrence of the abnormality. (S41), the H / W section is reset (S42).

Upon receiving the notification of the occurrence of the abnormality, the terminal unit control software 23 issues a data stop request to the server unit to stop the transmission data (S43), and the application unit 2
1 is notified (S44). Thereafter, the application unit displays a message indicating that an abnormality has occurred, and prompts the user to check the cable and the like.

When the user confirms and performs a key input,
The application unit 21 is a terminal unit control software 2
3 is instructed to start resuscitation (S45). The terminal unit control software 23 receiving the request requests the server unit 11 for data (S46), and the H / W control software 26
Is issued to the user (S47). Server unit 1
1 transmits data from data (3) before abnormal stop (S49), and the H / W control software 26
The screen display mode is switched to the moving image display mode when the decoding of the W section is started.

According to the present invention, a decoding counter is provided with a decoding counter that is incremented for each decoding, and an abnormality is detected by constantly monitoring the decoding counter, and data is reproduced from the time of occurrence of the abnormality in the above-described procedure.

The embodiment described here is a method of notifying the user of the occurrence of an abnormality.
Automatic return for performing the processing of No. 9 is also possible. There is also a method of combining them, performing an automatic return process several times, and then notifying the user when the process has not been restored even after repeating a certain number of times.

[0042]

As described above, a counter which is incremented for each decoding is provided in the portion for decoding the video data sent from the server of the terminal unit, and by monitoring the counter, the line abnormality or the decoding unit is monitored. Can be easily detected.

Further, after the abnormality is detected, the procedure described in the embodiment can be used to quickly recover without troublesome operation of the user.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing a peripheral portion of a decode counter in the block of FIG. 1;

FIG. 3 is a diagram showing a format of an MPEG data stream.

FIG. 4 is a functional system configuration diagram of a terminal unit of the block in FIG. 1;

FIG. 5 is a sequence diagram showing an operation of the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 terminal unit 11 multimedia communication server unit 12 MPEG data separation unit 13 audio data decoding unit 14 audio output unit 15 video data decoding unit 16 overlay control unit 17 video output unit 18 CPU 19 graphics unit 20 communication hardware unit 27 decoding Counter 181 error monitoring function

Claims (5)

(57) [Claims] 1. An abnormality processing system in a multimedia communication system configured to decode and reproduce compressed moving image data transmitted from a server in response to a request from a terminal device, wherein: Decoding means for decoding the compressed moving image data, counter means updated each time the decoding means decodes one frame of the compressed moving image data, and abnormality detecting an abnormality in accordance with the count content of the counter means An abnormality processing system comprising: a detection unit. 2. The abnormality processing system according to claim 1, wherein said abnormality detecting means determines that the communication is abnormal when the count content of said counter means is not updated within a predetermined period. 3. The abnormality processing system according to claim 2, wherein said abnormality detection means sends said communication abnormality to said server. 4. The abnormality processing system according to claim 2, wherein said abnormality detecting means initializes said decoding means in response to said communication abnormality determination. 5. The terminal device further comprises instruction means for instructing the decoding means to start decoding reproduction in response to a key input instruction by a user after the abnormality detection means has determined a communication abnormality. Claims 2 to 4
An error handling system according to any of the above.