JP4021587B2 - Transmission line switching system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a transmission path for seamlessly switching between two or more encoded signals using a single switching device connected to a preceding stage or a succeeding stage of a matrix switching device that selectively switches video signals of various transmission rates. It relates to a switching system.
[0002]
[Prior art]
Recently, with the advancement of digital technology, not only standard standard television signals but also high-definition television signals have been digitized. Also, video compression technology has been actively developed by digitizing such video signals. As this video compression technique, for example, there is a coding compression system standardized by MPEG (Moving Picture Coding Experts Group).
[0003]
From the above, for example, in the studio equipment of a broadcasting station, video signals of various transmission rates are handled in the station. In this case, a matrix switch device is used in which a plurality of serial transmission lines in which a plurality of transmission rates are mixed are concentrated at one place and selectively exchanged.
[0004]
This matrix switch device is disposed, for example, in an appropriate switching control room, and a serial transmission path is laid from there to each editing room or the like.
[0005]
However, in the matrix switch device as described above, the number of serial transmission lines laid in each editing room or the like is determined in advance, so the expandability is poor. For example, the addition of serial transmission lines due to an increase in studios and equipment There is a problem that it is not possible to respond flexibly.
[0006]
In addition, in each editing room, it is necessary to add a new serial transmission line in order to switch the system due to maintenance, troubles, etc. In the conventional matrix switch device, the number of serial transmission lines laid in advance is limited. Because they are determined, it is not possible to respond flexibly to such maintenance and troubles.
[0007]
[Problems to be solved by the invention]
As described above, in the conventional matrix switch device, since the number of serial transmission lines to be laid in advance is determined, the expandability is poor, and for example, the addition of serial transmission lines due to an increase in studios and equipment can be flexibly supported. In addition, there is a problem that it is not possible to flexibly cope with system switching due to maintenance or trouble.
[0008]
An object of the present invention is to provide a transmission line switching system that can flexibly cope with system switching due to, for example, addition or change of transmission lines and maintenance or troubles.
[0009]
[Means for Solving the Problems]
A transmission line switching system according to the present invention includes a matrix switch device that selectively switches between N input transmission lines and M output transmission lines (N and M are arbitrary natural numbers of 2 or more), and this matrix. A switch unit that is connected to a part of N input transmission lines of the switch device and performs line switching between two or more input lines and one output line, captures signals from two or more transmission lines, Two or more input buffers to be supplied to the corresponding input lines of the switch unit, and the format of the signal from each transmission line input to the receiving unit at the time when a switching instruction input from the outside is detected is identified. And a control unit for controlling the sending process of the receiving unit and the switching process of the switch unit based on the detection result by the detecting unit. It is obtained so as to include a switching device.
[0010]
A transmission line switching system according to the present invention includes a matrix switch device that selectively switches between N input transmission lines and M output transmission lines (N and M are any natural numbers of 2 or more), A switch unit connected to one of the M output transmission lines of the matrix switch device and switching between two or more input lines and one output line, and an output transmission line of the matrix switch device Of two or more input buffers that take in signals from and supply them to the corresponding input lines of the switch unit, and the format of signals from each transmission line that is input to each input buffer when a switching instruction input from the outside is detected And detecting a switchable position based on the identified format, and an input buffer sending process based on a detection result by the detection unit It is obtained so as to include a switching device having a control unit for controlling the switching process of the fine the switch unit.
[0011]
According to this configuration, the switching device for switching two or more transmission paths is connected to one input transmission path or one output transmission path of the matrix switch device. When the switching instruction from the outside is detected during the operation of the system to which the transmission line belongs, the format of the signal from one and the other transmission line is identified, and the switchable position is determined based on the identified format. Then, based on the detection result, the signal of one transmission path is seamlessly switched to the signal of the other transmission path. Note that the switching device detects the switchable position from the signal of the other transmission path from the detection of the switchable position of the signal of one transmission path even when the signals of two or more transmission paths are not synchronized with each other. Until this is done, the signal of the other transmission path is held in the input buffer.
[0012]
For this reason, if a switching device for switching two or more transmission paths is connected to the input transmission path of the matrix switch device, the necessary transmission can be performed without newly adding a transmission path to the matrix switch device. Transmission lines can be easily added and changed simply by connecting the paths to the switching device. In addition, if two transmission paths are connected to the switching device in advance for the maintenance of the transmission path or the occurrence of troubles in at least one of the transmission paths, it can be dealt with only by switching the transmission path with the switching device. It is possible to obtain a signal that is seamless and ensures continuity from the output.
[0013]
Further, in the above configuration, each input buffer of the switching device is supplied with an encoded signal encoded with a group of picture structure directly or via a matrix switch device. Group of picture header information is extracted from the encoded signal, and a switchable position is detected based on the extracted group of picture header information. In this way, the detection unit extracts the group of picture header information from the encoded signal, thereby grasping the group of picture structure of the encoded signal and switching the group of picture structure. Since possible positions, that is, breaks between frames, are detected, it is possible to obtain a continuous signal without a sense of incongruity even when the transmission path is switched.
[0014]
Further, since the switching device in the above configuration is connected to the network, it is possible to select a signal from a device connected to the network by switching the switching device.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a circuit block diagram showing an embodiment of a transmission line switching system according to the present invention.
This system includes a matrix switch device (N and M are arbitrary natural numbers of 2 or more) 11 that selectively switches N input transmission lines and M output transmission lines, and N of the matrix switch apparatus 11. A seamless splicer 12 connected to a part of each of the input transmission paths, and encoders 13 and 14 respectively connected to the two input transmission paths of the seamless splicer 12 and encoding input signals. Yes.
[0016]
Here, the encoders 13 and 14 encode the input video signal with a GOP (Group Of Picture) structure and send it to the splicer 12. This GOP structure has an I frame encoded by the intraframe encoding method, a P frame and a B frame encoded by the interframe encoding method, and is a repeating structure of 15 frames of IBBPBBPBBPBBPBB. The video signals input to the encoders 13 and 14 may be two different programs or the same program.
[0017]
When a switching trigger is input, the seamless splicer 12 switches from one transmission path to the other transmission path, and outputs a signal on the other transmission path to the Nth input terminal of the matrix switch device 11. In the seamless splicer 12, in general, it is difficult to switch seamlessly. However, when switching is performed at a predetermined seamless splicer point or when two encoded signals are synchronized, seamless switching is not possible. Can be done.
[0018]
The matrix switch device 11 outputs the output of the seamless splicer 12 from, for example, the Mth output terminal.
[0019]
FIG. 2 is a circuit block diagram showing a specific configuration of the seamless splicer 12.
[0020]
Here, as shown in FIG. 2, the seamless splicer 12 takes in the encoded signals from the encoders 13 and 14 and a switch unit that switches between two or more input lines and one output line, A receiving unit 122 including input buffers 1221 and 1222 to be supplied to corresponding input lines of the switch unit 121; and an output buffer 123 that takes in an output line signal of the switch unit 121 and supplies the signal to an input transmission line of the matrix switch device It has. Furthermore, GOP header information of the encoded signal input to the input buffers 1221 and 1222 is extracted when an external switching trigger is detected, and a GOP that detects a switchable position based on the extracted GOP header information. Detection units 124 and 125, and a switching control unit 126 that controls transmission processing of the input buffers 1221 and 1222 and switching processing of the switch unit 121 based on detection results by the GOP detection units 124 and 125.
[0021]
For example, the seamless splicer 12 receives the GOP header information of the encoded signal from the encoders 13 and 14 when the external switching trigger is input during the operation of the system to which the encoder 13 belongs. To extract each. The GOP detection units 124 and 125 grasp the GOP structure of the encoded signal based on the extracted GOP header information, detect the switchable position of the GOP structure, that is, the beginning of the I frame or the break of the IPB frame, This detection result is supplied to the switching control unit 126. The switching control unit 126 controls the receiving unit 122, the switch unit 121, and the output buffer 123 so as to seamlessly switch from the signal on one transmission path to the signal on the other transmission path in response to the detection result.
[0022]
Next, an example in which the configuration of the transmission path switching system is applied to an intra-station transmission system in the following broadcasting station will be described.
[0023]
First, the matrix switch device 11 is arranged in an appropriate switching control room, a transmission path is laid from there to each editing room, and a seamless splicer 12 is attached in each room as required.
[0024]
In each editing room, two encoders 13 and 14 are respectively connected to the seamless splicer 12, and the seamless splicer 12 is switched when it becomes necessary to perform switching due to maintenance or trouble. Further, when it is desired to add a transmission line as necessary, it can be easily added by using the seamless splicer 12.
[0025]
As described above, in the above embodiment, the seamless splicer 12 is connected to the input transmission path laid in the editing room determined in the matrix switch device 11. When an external switching trigger is input during operation of the system to which the system belongs, GOP header information is extracted from the encoded signals from the encoders 13 and 14 by the GOP detectors 124 and 125, respectively. Based on the header information, the switchable position, that is, the start of the I frame or the break of the IPB frame is detected, and the switching control unit 126 receives the detection result from the encoded signal from the encoder 13 to the encoded signal from the encoder 14. The transmission processing of the receiving unit 122, the switching processing of the switch unit 121, and the output bar so as to switch seamlessly So as to control the process of sending the file 123. The seamless splicer 12 switches from the encoded signal from the encoder 14 from the time of detection of the switchable position of the encoded signal of the encoder 13 even when the encoded signals from the encoders 13 and 14 are not synchronized with each other. The encoded signal from the encoder 14 is held in the input buffer 1222 until a possible position is detected.
[0026]
For this reason, if the seamless splicer 12 is connected to the input transmission path of the matrix switch device 11, the required transmission path can be connected to the seamless splicer without adding a new transmission path to the matrix switch device 11. The transmission line can be easily added and changed by simply connecting to the terminal 12. In addition, when two transmission paths are connected to the seamless splicer 12 in advance for the maintenance of the transmission path or the occurrence of at least one transmission path trouble, the seamless splicer 12 can cope with it only by switching the transmission path, and From the output of the seamless splicer 12, it becomes possible to obtain a signal that is seamless and ensures continuity.
[0027]
Another example of the above embodiment is a system as shown in FIG.
In this system, a network 15 is connected to the input terminal of the seamless splicer 12 instead of the encoder 13. The network 15 is, for example, a LAN (local area network) or the like, and connects encoders between the editing rooms. The seamless splicer 12 replaces the input buffer 1221 in the receiving unit 122 with a network input buffer.
[0028]
That is, according to this system, if the network 15 connecting the editing rooms is connected to the seamless splicer 12, encoded signals from other editing rooms are selected and set by switching the seamless splicer 12. be able to.
[0029]
Further, in the above embodiment, compared to the case where the matrix switch device 11 and the seamless splicer 12 are arranged independently, the fluctuation range of the delay time of the circuit can be limited to a specific range by fixing the connection relationship in advance. The generation of the switching timing is facilitated.
[0030]
(Second Embodiment)
FIG. 4 is a circuit block diagram showing a second embodiment of the transmission line switching system according to the present invention. In FIG. 4, the same parts as those in FIG.
That is, the seamless splicer 12 has one input terminal connected to the output transmission line of the matrix switch device 11. The seamless splicer 12 has the other input terminal connected to the encoder 21. The matrix switch device 11 connects the encoder 22 to one of the N input transmission lines, and sends the encoded signal from the encoder 22 to one input terminal of the seamless splicer 12.
[0031]
The seamless splicer 12 then converts the encoded signal from the encoder 21 to the encoded signal from the encoder 22 via the matrix switch device 11 or the matrix switch device 11 when an external switching trigger is input. The encoded signal from the encoder 22 that has passed through is seamlessly switched to the encoded signal from the encoder 21.
[0032]
Therefore, according to the second embodiment, the same effect as that of the first embodiment can be obtained in the subsequent stage of the matrix switch device 11, for example, when maintenance of the matrix switch device 11 is desired or the matrix switch If a trouble occurs in the device 11, if the seamless splicer 12 switches to the encoded signal from the encoder 21 and sends it out, the seamless splicer 12 can provide a continuous signal without data interruption. It becomes possible.
[0033]
In the second embodiment, the seamless splicer 11 may handle an encoded signal from an encoder other than the encoder 22.
[0034]
In the second embodiment, there is another system as shown in FIG.
This system is a duplex system in which another matrix switch device 23 is connected to the other input terminal of the seamless splicer 12. In this case, the matrix switch device 11 functions as an active system, and the matrix switch 23 functions as a standby system for the active system. Further, the matrix switch device 23 connects an encoder 24 to one of the N input transmission lines, and sends the encoded signal from the encoder 24 to the other input terminal of the seamless splicer 12.
[0035]
According to this configuration, for example, when the matrix switch device 11 is to be maintained or when trouble occurs in the matrix switch device 11, the seamless splicer 12 selects the encoded signal from the matrix switch device 23. For example, it is possible to provide a continuous signal from the seamless splicer 12 without data interruption. Note that the seamless splicer 12 may handle an encoded signal from an encoder other than the encoder 24.
[0036]
Furthermore, in the second embodiment, a network may be connected to the input terminal of the seamless splicer 12 as in the example shown in FIG.
[0037]
(Other embodiments)
The present invention is not limited to the above embodiments. The seamless splicer in each of the above embodiments handles an encoded signal encoded with the GOP structure, but may handle an encoded signal encoded with a structure other than the GOP structure. In this case, in the seamless splicer, the GOP detection unit is replaced with a detection unit that identifies the format of the encoded signal and detects the switchable position based on the identified format.
[0038]
The seamless splicer can also handle signals other than the encoded signal. In this case, the input buffer and the output buffer corresponding to the transmission rate of the signal to be handled are exchanged. Furthermore, the seamless splicer is provided with an output buffer. However, if a black signal is output when switching from one transmission path to the other transmission path, the output buffer may not be provided.
[0039]
In addition, as the seamless splicer input buffer and output buffer, it is versatile and convenient to preliminarily correspond to a plurality of transmission rates so that they can be selected and set according to the connected device.
[0040]
In addition, the configuration of the seamless splicer, the type of transmission line, and the like can be variously modified and implemented without departing from the gist of the present invention.
[0041]
【The invention's effect】
As described above in detail, according to the present invention, for example, it is possible to flexibly cope with system switching due to addition, change, maintenance, trouble, etc. of a transmission line, and even if there is switching, a continuous signal without data interruption is obtained. An obtainable transmission path switching system can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of a transmission line switching system according to the present invention.
FIG. 2 is a circuit block diagram showing a specific configuration of the seamless splicer shown in FIG.
FIG. 3 is a block diagram showing a configuration of another example of the first embodiment.
FIG. 4 is a block diagram showing a configuration of a second embodiment of a transmission line switching system according to the present invention.
FIG. 5 is a block diagram showing the configuration of another example of the second embodiment.
[Explanation of symbols]
11, 23 ... Matrix switch device,
12. Seamless splicer,
13, 14, 21, 22 ... encoder,
15 ... Network,
121 ... switch part,
122... Receiver
1221, 1222 ... Input buffer,
123 ... Output buffer,
124, 125 ... GOP detector,
126... Switching control unit.

Claims (5)

A matrix switch device that selectively switches between N input transmission lines and M output transmission lines (N and M are arbitrary natural numbers of 2 or more);
A switch unit connected to a part of the N input transmission lines of the matrix switch device for switching the line between two or more input lines and one output line, and signals from the two or more transmission lines Two or more input buffers to be captured and supplied to the corresponding input lines of the switch unit, identifying the format of the signal from each transmission line input to the input buffer when a switching instruction input from the outside is detected; A switching device comprising: a detection unit that detects each switchable position based on the identified format; and a control unit that controls the output process of the input buffer and the switching process of the switch unit based on a detection result by the detection unit And
Each input buffer of the switching device is supplied with an encoded signal encoded with a group of picture structure,
The detection unit of the switching device extracts group-of-picture header information from each encoded signal, and detects a switchable position based on the extracted group-of-picture header information. Road switching system. A matrix switch device that selectively switches between the N input transmission lines and the M output transmission lines (N and M are arbitrary natural numbers of 2 or more);
A switch unit connected to one of the M transmission lines of the matrix switch device and switching between two or more input lines and one output line, transmission for output of the matrix switch device Two or more input buffers that take in signals from the path and supply them to the corresponding input lines of the switch unit, and signals from each transmission path that are input to the input buffers when a switching instruction input from the outside is detected And detecting a switchable position based on the identified format, and controlling the sending process of the input buffer and the switching process of the switch unit based on the detection result by the detection unit. A switching device including a control unit,
Each input buffer of the switching device is supplied with an encoded signal encoded in a group-of-picture structure directly or via the matrix switch device,
The detection unit of the switching device extracts group-of-picture header information from each encoded signal, and detects a switchable position based on the extracted group-of-picture header information. Road switching system. The detection unit of the switching device includes an I frame encoded by an intra-frame encoding scheme, a P frame and a B frame encoded by an inter-frame encoding scheme based on the group of picture header information. 3. The transmission line switching system according to claim 1, wherein a start of an I frame or a break of an IPB frame of an encoded signal having a group of picture structure is detected.   3. The transmission line switching system according to claim 1, wherein a part of each transmission line connected to each input buffer of the switching device is a network.   3. The transmission line switching system according to claim 2, wherein the switching apparatus is connected to output transmission lines of each of the two or more matrix switch devices.

Images