JP2000269864A - System changeover system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain seamless switching that causes no failure on a coded signal in the case of switching a duplicate system and to enhance reliability. SOLUTION: An encoder 12 acting like an active system informs, in real time, an encoder 15 acting like a standby system about state parameter information denoting the state of the encoder 12 and processing MPEG coding format, and the encoder 15 matches the state of itself and the coding format with those of the encoder 12 on the basis of the informed state parameter information. Furthermore, synchronization sections 11, 14 synchronize a source signal between the systems before the encoders 12, 15 receive the source signal. An encoder output changeover device 13 selects respective outputs of the encoders 12, 15 and outputs the selected output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in, for example, a digital broadcasting system, and seamlessly switches between an active system and a standby system in a duplex system including an active system and a standby system each including an encoder and the like. The present invention relates to such a system switching system.

[0002]

2. Description of the Related Art In a digital broadcasting system which has been conventionally operated, an MPEG (Moving Picture) is used to transmit a material signal for broadcasting.
An encoder for MPEG that encodes with a coding method standardized by Coding Experts Group-2 and outputs it as a transport stream is used. In this type of system, a duplex system is constructed using a plurality of encoders, one of which functions as an active system performing a main operation, and the other functions as a standby system for the active system.

In this redundant system, system switching is performed in order to perform maintenance or the like for one of the working system and the standby system. However, in this duplex system, the synchronous operation is not performed between the encoders of each system. Therefore, when the system switching is required for maintenance of the encoder while the transport stream is being output, seamless switching should be performed. Can not. In addition, even when switching occurs when a failure occurs in one of the systems, the stream always fails.

In order to ensure the reliability of the above-mentioned redundant system, it is conceivable to perform switching by synchronizing the respective systems with a switching device for switching the systems. This will lead to complications.

[0005]

As described above, in the duplex system used in the conventional digital broadcasting system, the synchronous operation is not performed between the working system and the standby system encoders. Is switched, the stream output from each encoder is broken.

SUMMARY OF THE INVENTION An object of the present invention is to provide a system switching system capable of performing seamless switching without causing a breakdown of a coded signal and improving reliability in system switching in a duplex system. It is in.

[0007]

A system switching system according to the present invention comprises a first system comprising a first encoder for encoding a transmission signal in which a plurality of packets having a fixed number of bits are arranged. And a second system including a second encoder that performs the same function as the first encoder, and switches between the first system and the second system in the duplex system. In the system switching system for performing, between the first encoding device and the second encoding device, the state of its own device and the state parameter information indicating a predetermined encoding format for encoding the transmission signal, State parameter information transmitting / receiving means for performing transmission / reception, and operating states of the first and second encoding devices based on the state parameter information transmitted / received by the state parameter information transmitting / receiving means. Operation control means for matching, and first switching derivation means for selectively deriving an encoded signal encoded by the first encoding device and an encoded signal encoded by the second encoding device. It is provided with.

[0008] According to this configuration, the state of the first encoding device functioning as the first system and the state parameter information indicating the predetermined encoding format are stored in the second encoding device functioning as the second system.
Will be notified in real time to the encoding device of
The second encoding device determines the status and encoding format of the first encoding device based on the notified status parameter information.
Can be adapted to the encoding device of That is,
The coded signal coded by the first coding device and the coded signal coded by the second coding device can be synchronized with each other. An encoded signal is obtained.

For this reason, when it is desired to switch the system for maintenance of each system while outputting the coded signal from each of the first and second coding devices, the probability of causing a breakdown of the coded signal can be reduced and the seamlessness can be reduced. Switching can be performed.

Further, in the above configuration, before the transmission signal is input to each of the first and second encoding devices, a synchronization means for synchronizing the transmission signals of the respective systems with each other is provided. .

According to this configuration, for example, when various components such as video and audio are included in the transmission signal, the signals are synchronized between the first system and the second system before being input to the encoding device. If this is done, the transmission signals can be encoded with the same components between the first and second encoding devices, and encoded signals having the same components can be output. Further, it is possible to reduce a load in a process for achieving synchronization between the first and second encoding devices.

In the above configuration, each of the first and second encoding devices executes an encoding process on an input transmission signal, and performs a first encoding between packets encoded by an external instruction. Switching instruction data inserting means for inserting switching instruction data for instructing switching execution to the switching deriving means, and switchable position instruction data inserting means for inserting switchable position instruction data for instructing a switchable position. The first switching deriving means includes: switching instruction data detecting means for detecting switching instruction data included in the coded signal encoded by each of the first and second encoding devices; Means for detecting switchable position indicating data when the switch instruction data is detected by the indicating data detecting means, and executing seamless switching processing to another system, and a switching instruction input from outside Detecting a switchable position indication data when detected, characterized by comprising a means for performing the seamless switching process to other systems.

According to this configuration, the first and second encoding devices insert switchable position indicating data indicating a switchable position between packets in the encoded signal,
Since the switchable position indicating data is detected at the time of the system switching process, the system automatically and seamlessly assures continuity from the coded signal of one system to the coded signal of the other system based on the detection result. It is possible to perform the switching, and it is not necessary to perform a process of finding a point where data interruption does not occur by the user and switching.

In the above configuration, the first switching deriving means, when an abnormal packet is included in the coded signal coded by each of the first and second coding devices, converts the abnormal packet An abnormal packet detecting means for detecting, and a means for performing seamless switching processing to another system when an abnormal packet is detected by the abnormal packet detecting means by always detecting the switchable position instruction data in advance. It is characterized by having.

According to this configuration, when an abnormal packet occurs in the encoded signal output from each of the first and second encoding devices, the abnormal packet is detected, and at the time of this detection, the other packet is detected. Since the coded signal of the normal system is switched and derived, it is possible to reduce the breakdown of the coded signal that occurs when a failure occurs.

In the above configuration, there is further provided a second switching deriving means having the same configuration as the first switching deriving means and functioning as a complement or alternative to the first switching deriving means. Between the first switching derivation means,
One of the first switching deriving means and the second switching deriving means based on an operation information transmitting / receiving means for transmitting / receiving operation information indicating its own operation state, and a result of the operation information transmission / reception by the operation information transmitting / receiving means. When it is determined that an operation abnormality has occurred in one of them, the operation of the switching deriving means having the operation abnormality is stopped, and switching abnormality handling means for operating the other normal switching deriving means is provided. Features.

According to this configuration, for example, when a failure occurs during the operation of the switching deriving means of one of the systems, the non-response or abnormal operation information is notified from the failed switching deriving means to the normal switching deriving means. Thus, the normal switching derivation unit can automatically start the operation upon receiving this notification. Therefore, it is possible to reduce the possibility that the coded signal is broken due to the failure of the switching deriving unit during operation.

In the above configuration, the first and the second
, And a first system control device that controls the processing of each of the first and second switching deriving means. The first system control device includes first and second encoding devices.
Monitoring means for monitoring the operation state of each of the first and second switching deriving means; and one of the first and second encoding devices and the first and second switching deriving means by the monitoring means. When an operation abnormality is detected, the system includes a system abnormality countermeasure for disconnecting the apparatus in which the abnormality has occurred from the system.

In particular, regarding the system abnormality handling means,
When it is determined that an operation abnormality has occurred in one of the first and second encoding devices, first switching deriving means or When the switching process of the second switching derivation unit is controlled or the abnormal encoding device is reset, and it is determined that an operation abnormality has occurred in one of the first and second switching derivation units, an abnormality occurs. The reset deriving means is reset or stopped.

According to this configuration, since the processing of the constituent devices of each system is controlled by one system control device, the processing of each constituent device is performed rather than transmitting and receiving control information between the systems and executing the control processing. The above-mentioned burden can be reduced, and if an abnormal operation occurs in each component device, the system control device will deal with the abnormal operation, so it is necessary for each component device to recognize the abnormal operation and respond to the abnormal operation In this respect, the processing load on each component can be reduced.
The reliability of the duplex system can be improved with simple processing.

In the above configuration, a second system control device having the same configuration as the first system control device and functioning as a complement or alternative to the first system control device is further provided. A system control side operation information transmitting / receiving means for transmitting and receiving an operation state indicating an operation state of the own apparatus between the first system control apparatus and the first system control apparatus;
When it is determined that one of the first and second system control devices has an operation abnormality based on the result of the operation information exchange by the system control-side operation information exchange means, the occurrence of the operation abnormality Means for stopping the operation of the other system control device and operating the other normal system control device.

According to this configuration, for example, when a failure occurs during operation of the first system controller, the first system controller transmits no response or abnormal operation information to the second system controller. Is notified, the second system control device receives this notification, recognizes that the first system control device has failed, and can automatically start the operation. The first system controller can be stopped or reset. For this reason, it is possible to further enhance the reliability of the duplex system.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment) FIG. 1 is a circuit block diagram showing an embodiment of a system switching system according to the present invention. FIG.
The system shown in FIG. 1 includes an active system including a synchronization unit 11, an encoder 12, an encoder output switching device 13, and the like, and a synchronization unit 1
4, a standby system including an encoder 15, an encoder output switching device 16, and the like.

First, in each of the active system and the standby system, a plurality of material signals such as video, audio and data are synchronized by the synchronizing units 11 and 14, and then the encoders 12 and 1 are synchronized.
5, the data is encoded by the MPEG-2 encoding method, and is output as a TS (transport stream) signal of the MPEG standard composed of fixed-length packets. And encoder 1
TS1 signal and TS2 output from each of the second and the second 15
The signal is selectively derived by the encoder output switching device 13 functioning as a working system.

In this embodiment, in order to reduce the influence of the switching process of the encoder output switching devices 13 and 16, the outputs of the encoders 12 and 15 are set to the same MPE.
It is effective to use a G TS signal. Therefore, the encoders 12 and 15 have a state parameter information exchange communication function for exchanging state parameter information indicating a predetermined encoding format for encoding the state of the own apparatus and the transmission signal between the systems, An operation control function is provided for making the operation states of the encoders 12 and 15 coincide with each other based on the state parameter information transmitted and received by the state parameter information communication function. The state parameter information includes, for example, the buffer occupancy, the target code amount at the time of video encoding, the order of the video / audio / data packets on the MPEG transport stream, and the PES (Packetized Elementary Stream) for the audio packets.
Flag indicating the presence of header, GOP in video packet
(Group Of Picture) header,
And an operation clock.

By providing such a function, for example, the status parameter information is notified in real time from the encoder 12 functioning as the working system to the encoder 15 functioning as the standby system. Based on the parameter information, the state of the apparatus itself and the encoding format of the MPEG standard can be adjusted to the encoder 12. That is, the TS1 signal encoded by the encoder 12 and the TS2 signal encoded by the encoder 15 can be synchronized, and even if the system is switched by the encoder output switching device 13, a continuous TS without data interruption is obtained. A signal is obtained.

Further, by synchronizing the material signals with the synchronizing units 11 and 14, the load in the processing for synchronizing the encoders 12 and 15 can be reduced.

Next, an example of the operation of the encoder output switching device 13 will be described with reference to FIGS. First, FIG. 2 shows a switching process based on switchable points. The switchable point is a point that exists for each encoded data of each material (indicated by DS1, DS2, AS1, AS2, and the like in FIGS. 2A and 2B). Decoding is possible without data. That is, the encoder 12,
15 executes an encoding process on the input material signal as shown in FIGS.
In accordance with G, encoding is performed so that a switchable point is inserted between packets. The indication of the switchable point on the encoded data is determined in advance with the encoder output switching device 13. For example, a switchable point is placed at the head of a packet having a GOP header in video, at the head of a packet having a PES header in audio,
A flag on the header of the signal can be considered.

Then, the encoder output switching device 13
As shown in FIG. 2C, at the stage of executing the switching process by the switching process execution trigger or the like, a switchable point is detected for each material of the TS1 signal and the TS2 signal. Is sequentially executed. This makes it possible to automatically switch from the TS1 signal to the TS2 signal seamlessly and while maintaining continuity.

Next, FIG. 3 shows a case where the failure of the TS signal can be saved at the time of switching by detecting a stream abnormality. That is, when an abnormal packet (VX1 in FIG. 3) is included in the TS1 signal encoded by the encoder 12 as shown in FIG. Detected, and at the time of this detection, FIG.
TS2 encoded by the encoder 15 as shown in FIG.
The signal is switched and derived. By doing so, as shown in FIG. 3 (c), T
It is possible to reduce the breakdown of the S signal.

In the above description, one encoder output switching device 13 has been described. In this embodiment, however, the encoder output switching device 1 corresponding to the standby system is further provided.
6 are provided. This encoder output switching device 16
Are the TS1 signal and TS2 output from the encoders 12 and 15, respectively, as in the encoder output switching device 13.
It selectively switches and derives a signal, and functions as a complement or alternative to the encoder output switching device 13.

Then, the encoder output switching devices 13, 1
6 has an operation information transmission / reception control function for mutually transmitting / receiving operation information indicating their own operation states, and based on the result of operation information transmission / reception by the operation information transmission / reception function, that any one of the abnormality has occurred. A switching abnormality handling control function is provided for switching to a normal system to operate when it is determined. In addition, the switching abnormality handling control function
The operation of the abnormal encoder output switching device is stopped.

According to this configuration, for example, when a failure occurs during operation of the encoder output switching device 13, the encoder output switching device 13 notifies the encoder output switching device 16 of non-response or abnormal operation information. That is, the encoder output switching device 16 can automatically start the operation upon receiving this notification. Therefore, it is possible to reduce the possibility that the TS signal is broken due to the failure of the encoder output switching device 13 during operation.

As described above, according to the above embodiment, the encoder 12 functioning as the active system notifies the encoder 15 functioning as the standby system of its own state and state parameter information indicating a predetermined MPEG encoding format. Thus, the encoder 15 can adjust the state and coding format of the own apparatus to the encoder 12 based on the notified state parameter information.
That is, the TS1 signal encoded by the encoder 12 and the TS2 signal encoded by the encoder 15 can be synchronized, and even if the system is switched by the encoder output switching device 13, a continuous TS without data interruption is obtained. A signal is obtained.

For this reason, when it is desired to switch the system during maintenance of each system while the encoders 12 and 15 are outputting, the probability of the TS signal being broken can be reduced and seamless switching can be performed.

Also, before the material signals are input to the encoders 12 and 15, the synchronizing units 11 and 14 synchronize the material signals between the systems.
At 15, the material signal can be encoded by the MPEG-2 encoding method by aligning the same component with each other, and the TS1 of the same component can be encoded.
This makes it possible to output the signal and the TS2 signal, and further simplifies the processing for synchronizing between the encoders 12 and 15, thereby reducing the processing load.

The encoders 12 and 15 encode so that a switchable point can be formed between packets in the TS signal, and the encoder output switching devices 13 and 16 detect the switchable point during the system switching process. Therefore, based on this detection result, it is possible to automatically switch from the TS signal of one system to the TS signal of the other system while ensuring the continuity seamlessly and without data interruption by the user. It is not necessary to perform a process of finding and switching between them.

Further, the encoder output switching devices 13, 1
6 detects an abnormal packet in the TS signals output from the encoders 12 and 15, detects the abnormal packet, and switches and derives the other normal system TS signal at the time of detection. Therefore, T
The breakdown of the S signal can be reduced.

Further, for example, when a failure occurs during the operation of the working encoder output switching device 13, no response or abnormal operation information is transmitted from the failed encoder output switching device 13 to the normal encoder output switching device 16. Is received, the encoder output switching device 16 receives this notification, recognizes that an abnormality has occurred in the encoder output switching device 13, and can automatically start the operation.
Therefore, it is possible to reduce the possibility that the TS signal is broken due to the failure of the encoder output switching device 13 during operation.

(Second Embodiment) In a second embodiment of the present invention, the processing of each of the encoder and the encoder output switching device can be externally controlled.

FIG. 4 is a circuit block diagram showing a configuration of a system switching system according to the second embodiment. In this figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description is omitted.

That is, the respective processes of the encoders 12 and 14 and the encoder output switching devices 13 and 16 are controlled by the external system control device 21. The external system control device 21 provides an interface for setting various parameters in the encoders 12 and 14 and the encoder output switching devices 13 and 16. These various parameters include switching process execution trigger, current / preliminary designation, reset process, on / off of automatic switching process, MPE
Examples include a parameter for specifying a format and a parameter for specifying a bit rate relating to G transport stream generation.

The external system control device 21 includes encoders 12 and 15 and encoder output switching devices 13 and 1.
(6) A monitoring function for monitoring each operation state, and when any one of the encoders 12 and 15 and the encoder output switching devices 13 and 16 is detected to be abnormal by this monitoring function, the apparatus in which the abnormality has occurred is detected. The system has a function to deal with system errors that can be disconnected from the system. In particular, the system abnormality handling function is to provide the encoder output switching device 13 or the encoder output switching device 13 so as to derive a TS signal output from a normal encoder when it is determined that an operation abnormality has occurred in one of the encoders 12 and 15. If the switching process of the encoder output switching device 16 is controlled or an abnormal encoder is reset, and it is determined that one of the encoder output switching devices 13 and 16 has malfunctioned,
The encoder switching device in which the abnormality has occurred is reset or stopped.

Therefore, according to the second embodiment, the processing of each of the encoders 12 and 15 and the encoder output switching devices 13 and 16 is performed by one external system control device 2.
1 to control the encoders 12 and 15 and the encoder output switching devices 13 and 16, rather than performing control processing by exchanging control information between the active system and the standby system as in the previous embodiment. The processing load can be reduced, and when an abnormal operation occurs in the encoders 12 and 15 and the encoder output switching devices 13 and 16, the external system control device 21 handles the abnormal operation. Encoder output switching device 13, 1
6 does not need to recognize the abnormal operation and respond to the abnormal operation. In this respect, the processing load on each component device can be reduced, and the reliability of the redundant system can be improved by simple processing. Become.

In the second embodiment, an external system control device 22 having the same configuration as the external system control device 21 and functioning as a complement or alternative may be provided. In this case, the external system controllers 21 and
2 includes a function for mutually transmitting and receiving operation information indicating their own operation states, and a function for transmitting and receiving the operation information.
And a function for operating a normal external system control device when it is determined that an abnormality has occurred in one of them. By doing so, for example, when a failure occurs while the external system control device 21 is operating,
The external system control device 21 notifies the external system control device 22 of a non-response or abnormal operation information. The external system control device 22 receives the notification and indicates that the external system control device 21 has failed. , The operation can be automatically started, and the abnormal external system control device 21 can be stopped or reset. For this reason, it is possible to further enhance the reliability of the duplex system.

(Other Embodiments) The present invention is not limited to the above embodiments. For example, encoder 1
Encoded signals that do not conform to MPEG may be output for the encoders 2 and 15, and the encoder output switching devices 13 and 16 may also handle encoded signals that do not conform to MPEG. Also, the encoder output switching device 13,
Regarding 16, the switching of the system may be executed by a user operation.

In addition, the configuration of the encoder, the configuration of the encoder output switching device, the configuration of the external system control device, and the like can be variously modified without departing from the gist of the present invention.

[0048]

As described in detail above, according to the present invention,
In a duplex system, when switching a system, a system switching system capable of performing seamless switching without causing a breakdown of an encoded signal and improving reliability can be provided.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing an embodiment of a system switching system according to the present invention.

FIG. 2 is a signal timing chart for explaining an example of the operation of the encoder output switching device shown in FIG. 1;

FIG. 3 is a signal timing chart for explaining another example of the operation of the encoder output switching device shown in FIG. 1;

FIG. 4 is a circuit block diagram showing a second embodiment of the system switching system according to the present invention.

[Explanation of symbols]

 11, 14: Synchronizing unit, 12, 15: Encoder, 13, 16: Encoder output switching device, 21, 22: External system control device.

Continued on the front page F term (reference) 5C023 AA21 BA09 BA16 CA02 CA04 5C059 MA00 RB09 RB16 RC02 RE02 RF00 SS02 UA01 5K021 AA01 AA02 AA08 BB04 CC04 DD02 FF03

Claims (9)

[Claims] 1. A first system comprising a first encoder for encoding a transmission signal formed by arranging a plurality of packets each having a fixed number of bits, and having the same function as that of the first encoder. A system switching system for switching between the first system and the second system in the duplex system, the system switching system being applied to a duplex system including a second system including a second encoding device to be executed; State parameter information exchange means for exchanging state parameter information indicating a predetermined encoding format for encoding the state of the own apparatus and a transmission signal between the encoding apparatus and the second encoding apparatus; An operation control unit that matches operation states of the first and second encoding devices with each other based on the state parameter information exchanged by the state parameter information exchange unit; A first switching deriving unit for selectively deriving an encoded signal encoded by the first encoding device and an encoded signal encoded by the second encoding device. Characteristic system switching system. 2. The apparatus according to claim 1, further comprising a synchronizing means for synchronizing the transmission signals of each system before the transmission signals are input to each of said first and second encoding devices. Item 1. The system switching system according to Item 1. 3. The first and second encoding devices each execute an encoding process on an input transmission signal, and execute the first encoding between packets encoded according to an external instruction. Switching instruction data inserting means for inserting switching instruction data for instructing switching execution to the switching deriving means, and switchable position instruction data inserting means for inserting switchable position instruction data for instructing a switchable position. Wherein the first switching deriving means comprises: switching instruction data detecting means for detecting the switching instruction data included in the encoded signal encoded by each of the first and second encoding devices; and ,
When the switching instruction data is detected by the switching instruction data detecting means, the switchable position instruction data is detected, and a means for executing a seamless switching process to another system and a switching instruction input from the outside are detected. 2. The system switching system according to claim 1, further comprising means for detecting switchable position instruction data at a point in time and performing a seamless switching process to another system. 4. The first switching and deriving means, when an abnormal packet is included in the encoded signal encoded by each of the first and second encoding devices, identifies the abnormal packet. Means for detecting an abnormal packet, and means for constantly detecting the switchable position instruction data in advance, and performing a seamless switching process to another system when the abnormal packet is detected by the abnormal packet detecting means. The system switching system according to claim 1, comprising: And a second switching deriving means having the same configuration as the first switching deriving means and functioning as a complement or alternative to the first switching deriving means. Operation information exchange means for exchanging operation information indicating its own operation state with the first switching derivation means; and the first switching based on the result of the operation information exchange by the operation information exchange means. When it is determined that one of the deriving means and the second switching deriving means has an operation abnormality, the operation of the switching deriving means in which the operation abnormality has occurred is stopped, and the other normal switching deriving means is operated. 2. The system switching system according to claim 1, further comprising: a switching abnormality handling unit for operating the system. 6. A first system control device for controlling the processing of each of the first and second encoding devices and the first and second switching deriving means, wherein the first system control The apparatus includes: a monitoring unit that monitors an operation state of each of the first and second encoding devices, the first and second switching derivation units; and the first and second encoding devices by the monitoring unit. The system according to claim 1, further comprising: a system abnormality handling unit that disconnects a device in which an abnormality has occurred from a system when an operation abnormality of one of the first and second switching derivation units is detected. Item 1. The system switching system according to Item 1. 7. The system abnormality handling unit according to claim 1, wherein:
And when it is determined that an operation abnormality has occurred in one of the second encoding device, the first switching deriving means or the first switching deriving means or the above so as to derive an encoded signal output from a normal encoding device. Controlling the switching process of the second switching deriving means,
7. The system switching system according to claim 6, wherein an abnormal encoding device is reset. 8. The system abnormality handling means according to claim 1, wherein:
7. The system switching system according to claim 6, wherein when it is determined that an operation abnormality has occurred in one of the switching derivation unit and the second switching derivation unit, the switching derivation unit in which the operation abnormality has occurred is reset or stopped. . And a second system control device having the same configuration as the first system control device and functioning as a complement or alternative to the first system control device. A system control-side operation information transmitting / receiving means for transmitting / receiving operation information indicating an operation state of the own apparatus to / from the first system control device, and based on a result of the operation information transmission / reception by the system control-side operation information transmitting / receiving means When it is determined that an operation abnormality has occurred in one of the first and second system control devices, the operation of the system control device in which the operation abnormality has occurred is stopped, and the other normal system control device is stopped. 7. The system switching system according to claim 6, further comprising means for operating a system control device.