JPS63221773A - Still picture broadcast program transmission equipment - Google Patents

Abstract

PURPOSE:To obtain a device with high economy by using a time base collector so as to process a video output signal from an information recording medium recorded with plural still picture broadcast programs thereby sending the still picture broadcast. CONSTITUTION:After a video output of each VTR1 is switched by a video switcher 3 and synthesized and inputted to a TBC (time base collector) 5. In this case, when the switching speed is quickened, since flicker takes place on a reproduced pattern, the video signal output of each VTR is inputted to the video switcher 3 after the DC level is matched by a clamp circuit 2 respectively. When the program on the VTR tape is subjected to electronic edition, the position of a queue signal representing the picture switching position is retarded by several frames and the still picture broadcast signal is sent at the position of stabilized picture. Thus, the still broadcast program sender where VTRs are operated in parallel is easily realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to still image broadcasting in which a large number of programs consisting of still images and audio are simultaneously transmitted on one channel of a television signal.

(Prior Art) Still image broadcasting is a method of simultaneously broadcasting several dozen programs consisting of color still images and audio within radio waves for one channel of a television signal. For the broadcast signal, the television video signal is divided into frames as shown in the second diagram, and for example, one frame is allocated to video 21 and two frames are allocated to audio 22, and these are alternately and repeatedly transmitted. The video frame 21 is sent with an identification code indicating to which program the screen belongs, and in the audio frame 22, digitally encoded audio signals are time-division multiplexed for all programs and transmitted. Here, the number of frames of video 21 and audio 22 differs depending on the audio encoding method and the number of programs, and there are cases where the ratio of video frames and audio frames is set to 1:1, but the method described below is different from the above method. It is also applicable to

In the example shown in the second diagram, the video frame 21 is sent every 1710 seconds, so if the average presentation time of still images for each still image broadcast program is 5 seconds, approximately 50 programs can be sent simultaneously. On the receiver side, when a desired program is selected, the video frame 21 having the identification code of that program is selected from the transmitted signals, and written into the image memory, until the next video of the same program is sent. This memory is played repeatedly and sent to the monitor. On the other hand, as for the audio signal, the time slot of the audio signal of the selected program is selected, and this signal is demodulated and sent to the monitor.

Conventional still image broadcast program transmitting apparatuses have been configured, for example, as shown in FIG. 3 in order to efficiently handle images and sounds of a large number of programs. That is, images of a plurality of still image broadcast programs are recorded in the large-capacity still image memory 11, and are sequentially read out and sent out when the program is sent out. As this large-capacity still image memory 11, for example, a randomly accessible magnetic disk memory, an optical disk memory, or a sequentially accessible VTR tape is used. For example, if the still image broadcast program has a configuration such as program A, program B, number & IIC shown in Figure 4, the broadcast signal will have the time and image AI of number IJIA as shown in the composite signal shown in Figure 4. However, image C1 of program C is sent out at time t2, image B of program B is sent out at time t3, image A2 of program A is sent out at time t, and so on. In the case of a disk memory, the relationship between the time and the transmitted image is stored in advance in the program transmission control device 12, and the image is read out from the disk and transmitted based on this data. On the other hand, in the case of VTR tapes, etc., the fourth
Images are edited and recorded in advance in a time relationship such as the composite signal shown in the figure, and the images are reproduced to transmit a program.

On the other hand, regarding audio, the audio for each program, for example, audio a
, audio S, and audio C are respectively recorded in a multichannel audio memory 13, and are transmitted by starting them in synchronization with the image memory when transmitting a program.

Furthermore, as shown in the third diagram, a camera 14 and a microphone 15 are provided.
Alternatively, it is also possible to send it from the VTR16 (with TBG).

Among the configurations shown in Figure 3, the system using one large-capacity still image memory and the multi-channel audio memory 13 is superior in terms of efficient use of the memory of the program transmission device, but it There are many problems from this perspective. That is, if the memory 11 is a disk memory, after the program is produced,
It is necessary to move the required still images to this disk memory, and if the memory is a VTR tape, editing must be performed together with other programs. Although it is conceivable to create a program directly on a disk memory, producing the program while transmitting the program is difficult to control and requires equipment with advanced functions. Therefore, the places where programs can be produced are limited and are not practical. VTR
When using tape, it is suitable for recording several related programs as a package, but there are many problems such as the difficulty of replacing programs on a recorded tape.

In addition, in any of the above cases, since images and audio are recorded in separate memory media, they must be operated in complete synchronization when transmitting a program, which requires some ingenuity in operation.

Considering the above points, it is advantageous in terms of program production and operation to use a still image broadcasting program transmitting apparatus in which VTRs are operated in parallel, as shown in FIG.

In this case, each VTR tape 1 (VTR(1), VTR
TR (2), VTR (31----) 2) As shown in Fig. 6, the video signal records still images of each still image broadcast program in sequence, and the audio track indicates the program audio and image switching position. A cue signal is recorded. The video output of each VTR 1 is connected to the video switcher 3 via the TBG 5,
The audio output is input to the audio encoding device 6 for each VTR,
After being digitally encoded, it is time-division multiplexed (8). The cue signal output is input to the cue signal detection circuit 4 for each VTR. When a cue signal is detected at the cue signal output of the first VTR, the information is applied to the video switcher 3 and the video output of the first VTR appears at the output of the video switcher 3. This video signal together with the audio signal constitutes a broadcast signal for multiplexed still image broadcasting in frame units as shown in FIG. At this time, each video frame is attached with an identification code indicating which program the screen belongs to, and this code is determined by the control signal generation circuit based on the cue signal information detected by the cue signal detection circuit 4. 7
occurs in The control signal generation circuit 7 creates a table showing the relationship between program numbers, video frame identification codes, and audio transmission channel numbers, and sends out the table as well. This control signal is inserted, for example, into the vertical retrace period of the broadcast signal.

By the way, this program transmission device is an independent VTR for each program.
1, it is extremely practical in terms of program production and operation, but in order to multiplex the video outputs of independent VTRs, each output signal must be perfectly synchronized in video frame units. A time base collector (TBC) 5 is required for each VTR output. However, TBC5
Providing one for each VTR would be extremely uneconomical in terms of price and device configuration, and would be impractical.

It should be noted that the queue signal detection circuit 4 has a function of assigning some kind of priority and controlling traffic when queue signals detected by a plurality of VTRs conflict with each other. At this time,
There is a delay in switching the video signal of the VTR on the delayed side, but this delay is generally slight and there is no problem since the same still image is recorded on the VTR tape for the entire length of time.

An object of the present invention is to eliminate the above-mentioned drawbacks and to transfer video output signals from an information recording carrier (such as a VTR) on which a plurality of still image broadcast programs are recorded to a single time base collector (T).
It is an object of the present invention to provide a highly economical still image broadcast program transmitting device that can process still image broadcasts using BC) and transmit still image broadcasts.

(Means for Solving the Problems) In order to achieve this object, the still image broadcasting program transmitting device of the present invention provides a still image broadcasting program transmitting device that simultaneously transmits a large number of programs composed of still images and audio on one channel of a television signal. In broadcasting, means for recording still images and audio of each program and information indicating switching times of the still images on an information recording carrier for each program, and reproducing the still images of each program recorded on these information recording carriers. means for applying each of the reproduced output signals to a video switcher; and a means for applying the reproduced output signals to a video switcher, and the video switcher such that reproduced output signals of the still images in which information indicating the switching time of each of the still images is detected are sequentially outputted from the video switcher. and means for time-division multiplexing the output signal of the video switcher via a time base collector with an audio signal and a control signal for still image broadcasting to obtain a transmission signal for still image broadcasting. That is.

Further, a preferred embodiment of the present invention is characterized in that each of the reproduced output signals is applied to the video switcher after passing through a clamp circuit.

(Examples) The present invention will be described in detail below by way of examples with reference to the accompanying drawings.

The embodiment of the still image broadcasting program transmitting apparatus of the present invention has a configuration as shown in FIG. The device configuration other than this part is the same as that shown in FIG.

When the video outputs of a plurality of VTRs 1 are switched by the video switcher 3 and inputted to the TBC 5, there is no particular problem if the switching speed is slow. However, in the case of still image broadcasting, it is necessary to switch at least every frame, and VTRI
If the video switcher 3 and TBC 5 are connected as they are, good operation will not be achieved. The reason is usually
This is because TBC performs AD conversion of an analog video signal and processes the digital signal, but if the clamp circuit does not function properly during AD conversion, normal operation will not occur. When the video output signals of each VTR are externally synchronized, they are vertically synchronized but not horizontally synchronized, so correct clamping can be established from signals that are randomly switched using a switch. It takes time to do that.

However, this situation settles down in a short time after the switch is changed, so it is not a problem in normal usage.

However, in still image broadcasting, one frame immediately after this switching is stored in the receiver's memory and played repeatedly for the presentation time of each still image (generally several seconds to several tens of seconds), so the first and second fields are Even a slight difference in level between fields causes flicker on the playback screen, which has a major visual impact. Therefore, in the apparatus of the present invention, the video output signals of each VTRI are input to the video switcher 3 via the clamp circuit 2, after matching the DC levels. In this case, the input signal of the clamp circuit 2 is the output signal of the VTR 1, and since the synchronization signal is continuous, reliable ramping is possible. However, if a program on a VTR tape is edited electronically, the horizontal synchronization signal may not be continuous at the editing point, so the position of the cue signal indicating the image switching position is delayed by several frames, and the image changes. It is necessary to send a still image broadcast signal at a stable position.

(Effect of the invention) By inputting the video output signal of each VTR to the video switcher after matching the DC level through a clamp circuit, and switching in units of at least one frame, this output signal is input to the TBC. It has become possible to easily realize a still image broadcast program transmitting device that operates VTRs in parallel. Program recording media using this method can be easily produced and viewed;
Still image broadcasting becomes extremely practical. That is, this medium contains complete video and audio and can be used alone as a program package. In addition, the operation of the program,
Since replacement etc. can be performed extremely easily, the problem of having to efficiently handle a large number of programs in still image broadcasting is solved.

[Brief explanation of drawings]

FIG. 1 shows a configuration block diagram of a transmitting device according to an embodiment of the present invention, FIG. 2 shows an example of a frame structure of a broadcast signal for still image broadcasting, and FIG. 3 shows one configuration of a conventional example of a transmitting device. 4 shows a diagram for explaining the time relationship of still image broadcast programs; FIG. 5 shows another configuration block diagram of a conventional example of the sending device; FIG. FIG. 6 is a diagram showing an example of a signal on a VTR tape used in the still image broadcast transmitting apparatus shown in FIGS. 1 and 5. FIG. 1... VTR 2... Clamp circuit 3... Video switcher 4... Cue signal detection circuit 5... TBC 6... Audio encoder 7... Control signal generation circuit 8... Multiplexing Circuit 11...Large capacity still image memory 12...Program transmission control device 13...Multi-channel audio memory 14...Camera 15...Microphone 16...
...VTR (with TBC) 21...Video 22...Audio Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] 1. In still image broadcasting in which a large number of programs consisting of still images and audio are simultaneously transmitted on one channel of a television signal, the switching time of the still images and audio of each program and the still images is means for recording information indicating each program on an information recording carrier; means for reproducing still images of each program recorded on these information recording carriers and applying each reproduced output signal to a video switcher; The playback output signal of the still image in which information indicating the switching time of the still image has been detected is
means for controlling the video switcher so that the video switcher sequentially outputs the video switcher; and a means for time-division multiplexing the output signal of the video switcher with an audio signal and a control signal for still image broadcasting after passing through a time base collector. 1. A still image broadcast program transmitting device, comprising means for obtaining a transmitting signal. 2. In the delivery device according to claim 1,
A still image broadcasting program transmitting device characterized in that each of the reproduced output signals is applied to the video switcher after passing through a clamp circuit.