JPS6129454A - Method for transmitting digital sound signal - Google Patents

Abstract

PURPOSE:To synchronize a video signal and a digital sound signal at each track by adding a bit to synchronize with a video signal at each sample data of a digital sound signal outputted from a VTR. CONSTITUTION:A video signal synchronizing bit is added to each sample data of a sound signal outputted from a reproducing device in addition to a synchronizing bit, a sample period display bit and a parity and the result is outputted to an edition device. In this case, a video signal synchronizing bit of sample data at the head of each track is taken as 1 and a synchronizing bit of other sample data is taken as 0 for output. The editing device detects the video signal synchronizing bit from a sample string of the digital sound signal and synchronizes it with the sample data having the bit of 1 in the unit of field of the video signal, and the sample data having the bit 1 is recorded as the sample data of the head of the sound signal recording area of each track. Thus, the video signal and the digital sound signal are synchronized.

Description

[Detailed description of the invention] Industrial applications The present invention relates to video and audio editing.

Configuration of a conventional example and its problems FIG. 1 shows a block diagram of a digital audio recording and reproducing circuit, and its operation will be explained.

In FIG. 1, 1 is an analog compression section, 2 is a low-frequency filter, s is an A/D converter, 4 is a framing section, 5 is a bi-phase modulation section, 6 is a recording section, 7 is a reproduction section, and 8 is a bi-phase demodulation section, 9 is an error correction section, 10
is a D/A converter, 11 is a low pass filter, 1
2 is an analog expansion section.

The input analog audio signal is compressed in the amplitude direction by the analog compression section 1. After passing the compressed analog audio signal through a low pass filter 2, it is passed through an A/D controller. converter 3
It is input into a digital audio signal and converted into a digital audio signal in which one sample consists of 10 bits.

The framer 4 compresses the digital audio signal in the time axis direction, adds a synchronization signal and an error correction code, and outputs the signal. The bi-phase modulation section performs bi-phase modulation on the framed digital audio signal, and then the recording section 6 records the signal.

During reproduction, the digital audio signal reproduced by the reproduction section 7 is subjected to biphase demodulation by the biphase demodulation section. The error correction unit 9 corrects errors in the biphase demodulated digital audio signal, expands it in the time axis direction, and outputs the signal. Next, the D/A converter 1o converts the digital audio signal into an analog audio signal, and the low pass filter 11 converts the digital audio signal into an analog audio signal.
After passing through the signal, the signal is expanded in the amplitude direction by the analog expansion section 12 and output.

The above operations record and reproduce digital audio, and the editing operations will be explained below.

Figure 2 shows a configuration diagram of the editing system. 13 is an editing machine,
14 is a regenerator, and 16 is a controller.

Let us consider a case where the editing system shown in FIG. 2 is used to record the $1 track and subsequent tracks of the tape on the player side of FIG. 3 in succession to the #1 track of the tape on the editor side of FIG. 4.

In the reproducing machine, the position of the reproducing head is determined as shown in FIG. That is, in FIG. 6, heads 1 and 2 are heads for reproducing video signals, and the leading head 3 of head 1 is
The preceding head 4 of the head 2 is a head for reproducing digital audio signals.

When recording both the tapes on the playback machine side and the editing machine side, an address code, for example, a time code, is recorded in a part of the gage digital audio section. As shown in FIG. 6, the track indicated by diagonal lines is set as the editing point on both the player side and the recorder side. The playback device stores the digital audio signal of the track being played back in the memory after the error correction shown in FIG. At the same time as determining the $1 track as an editing point, the digital audio signal of the $1 trunk is stored in the memory.

On the other hand, the editing machine determines the #1 track as the video editing point, and at the same time stores the digital audio signal of the #2 track in the memory after performing the error correction shown in Figure 1 in the same way as the playback machine. I'll keep it.

Next, by a signal such as pressing a button, the two digital audio signals stored in the memory are faded out on the recording side at an arbitrary time interval up to the playback time interval of a maximum of one track, and the digital audio signals on the recording side are faded out. A synchronization signal and an error correction code are added to the cross-faded digital audio signal by the frame generator 4 on the editing machine side, and the frame is stored in the memory. It is recorded and the user is informed that the cross-fade process has been completed by lighting a lamp or the like.

When the cross-fade process is completed, the editing machine 13 in FIG.
After rewinding the tape for a certain length, both playback machines 14 run in the playback mode, and the controller 15 records the reproduced time code and the time code of the editing point on the playback machine side and the recorder side, which are stored in the memory. Enter. The controller 15 uses the control signal obtained from the time code to
When the head of the editing machine 13 finishes playing track #1, #
At the same time as tracing 2 tracks, on the playback side, $1
The video signal playback head starts tracing the track,
Synchronous running is performed so that the head traces the video signal area of the #2 track and the video signal area of the $1 track at the same time. At the editing point, after playing the #1 track on the editing machine side, the mode changes from the playback mode to the recording mode, and instead of the digital audio signal of the $1 track from the playback machine side, cross-fade processing is performed and stored in the memory. Record the digital audio that was being played in #2 trunk, and $ from the playback device side.
One track of the video signal is recorded on track #2 following the digital audio signal.

After the connection processing at the editing point, the video signal of the trunk after the $2 track on the playback side and the digital audio signal on which error correction has been performed are sent to the editing side.

On the editing machine side, video signals and digital audio signals are sequentially recorded.

At this time, as shown in FIG. 7, the digital audio signal from the playback device is outputted with bit synchronization bits, sample period display bits, and parity added to each sample data. However, since it is not possible to synchronize the video signal and the digital audio signal by identifying the sample data at the beginning of each track, there is a problem that the video and audio are out of sync during playback.

OBJECTS OF THE INVENTION An object of the present invention is to solve the problems of the conventional example described above, and to synchronize the video signal and digital audio signal for each track.

Structure of the Invention The present invention adds and outputs a bit for synchronizing with a video signal to each sample data of a digital audio signal that is output multiple times from a video tape recorder.
This is to synchronize the video signal and digital audio signal.

DESCRIPTION OF THE EMBODIMENTS In the embodiment of the present invention, as in the conventional example, the editing machine 15, the playback machine 16, and the control machine 17 are connected as shown in FIG. Let us consider a case in which, following the track, the $1 track and subsequent tracks on the tape on the player side in FIG. 4 are recorded and turned over.

The editing procedure is the same as in the embodiment. In this example, the eighth
As shown in the figure, in addition to synchronization bits, sample period display bits, and parity, video signal synchronization bits are added to the lip sample data of the digital audio signal that is outputted from the playback device 16, and the editing device 16 adds the bits for video signal synchronization. Output to.

At this time, the video signal synchronization bit of the sample data at the beginning of each track is set to 1'', and the video signal synchronization bits of the other sample data are outputted as O''.

The editing machine 16 detects the video signal synchronization bit in the sample data string of the digital audio signal, and synchronizes the video signal field by field with the sample data in which the video signal synchronization bit is '1''. The sample data in which the video signal synchronization bit is 1'' is recorded as the first sample data in the digital audio signal recording area of each track.

As described above, by adding a video signal synchronization bit to each data sample, it is possible to synchronize the video signal and the digital audio signal.

In this embodiment, bit synchronization bits, sample period display bits, and parity are added to each sample data.
It is also possible to add other bits or not to add each of the above bits.

Effects of the Invention The present invention is capable of synchronizing the video signal and the digital audio signal during editing by adding a bit for synchronization with the video signal to each data sample of the digital audio.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional digital audio signal recording and reproducing circuit, Fig. 2 is a block diagram showing the configuration of a conventional system, Fig. 3 is a recording pattern diagram of a tape on the conventional player side, and Fig. 4 is a recording pattern diagram of the conventional editing machine side tape,
FIG. 5 is a head rotation diagram of a conventional playback device, FIG. 6 is a conventional editing state diagram, FIG. 7 is a diagram of a conventional digital audio signal transmission format, and FIG. 8 is a digital audio signal diagram according to an embodiment of the present invention. Audio signal transmission format diagram 0 Name of agent Patent attorney Toshio Nakao and 1 other person Figure 2 Figure 3 Figure 4 Figure 5 Orijo 1

Claims (1)

[Claims] When outputting the video signal and digital audio signal separately from a helical scan video tape recorder that records the video signal and digital audio signal on the same track,
A digital audio signal transmission method characterized by adding a bit for synchronization with a video signal to each sample data in the digital audio signal.