JPH01173983A - Method for simulating image and voice - Google Patents

Abstract

PURPOSE:To synchronize a video signal and a sound signal by writing the vertical synchronizing signal of the video signal to the redundant bit of an audio memory, detecting the vertical synchronizing signal, and controlling the time bases of the video signal and the sound signal. CONSTITUTION:A marker signal is written to the redundant bit of an audio memory 23 by the signal of a sampling signal generator 31. As the marker signal, a method to write eight continuous 0 pulses 42 correspondingly to a vertical synchronizing signal 41, etc., can be adopted. At the time of a reproducing, this marker signal (pulse) is detected, the time base is prepared by a counter 32 and transmitted to a processing computer 33 by either an interrupting signal or a status signal, and the time difference between the video signal and the sound signal is controlled by this processing computer 33. Thus, the time difference between the video signal and the sound signal can be corrected at the time of the reproducing, and the complete synchronization can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method of digitizing audio simultaneously with video and simulating this, and particularly relates to a method of correcting the time difference between the output of video and audio. It is.

(Prior Art and its Problems) A simulation device W is used that AD converts a television video signal into a digital signal, records this in a memory, reads out this digital signal, and performs various processing.

Until now, there has not been a device that processes video signals and audio signals simultaneously, and the video signals and audio signals are processed by separate simulation devices. However, there is also an increasing demand for a device that simultaneously simulates a video signal and an audio signal.

When a video signal and an audio signal are each digitized and recorded, data compression is performed, but the compression ratio is different for the video signal and the audio signal. Therefore, it is not possible to synchronize video No. 13 and the audio signal by simply reading it out as is during playback.

Since a synchronization signal is added to the video signal, it is easy to understand the time relationship, but the audio signal is a continuous signal, and the time axis cannot be understood.

For these reasons, when simulating a video signal and an audio signal simultaneously, a means that can grasp the time axis of the audio signal is required.

〔the purpose〕

An object of the present invention is to provide a video/audio simulation method that can solve the above problems and control the time difference between a video signal and an audio signal.

Furthermore, the present invention is intended to be realized by adding only a small number of functions without requiring any complicated equipment or the like.

[Means for solving problems]

According to the present invention, when an audio signal is digitized and recorded in a memory, a vertical synchronization signal of a video signal is added and recorded, and this signal is used during playback to control the time difference.

That is, video/audio converts a video signal and an audio signal into AD and records them in a video memory and an audio memory, respectively, and converts the signals recorded in the video memory and audio memory into a DA to obtain a video output signal and an audio output signal. The simulation method is characterized in that a vertical synchronization signal of a video signal is written in redundant bits of the audio memory, and the vertical synchronization signal is detected to control the time axis of the video signal and the audio signal.

This achieves synchronization between the video signal and the audio signal.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. An analog video signal is input from a video input terminal, processed by an input circuit 11, and converted into a digital signal by an AD converter 12. This digital signal is written and recorded in a video memo using an IC memory.

During playback, the digital signal of the video memo January 3 is read out, converted into an analog video signal by the DA converter 14, and processed in the output circuit 15 to obtain a video output.

Similarly, an analog audio signal is input from the audio input terminal, processed by the input circuit 21, and converted into a digital signal by the AD converter 22. This digital signal is written and recorded in the audio memory 23 using an IC memory.

During playback, the digital signal in the audio memory 23 is read out, converted into an analog audio signal by the DA converter 24, and processed in the output circuit 25 to obtain an audio output.

The video signal is constantly generated from the sampling signal generator 31, and in the case of the NTSC system, the horizontal synchronization signal (HD) is 15.
750H2, the vertical synchronization signal (VD) is 5Qllz. When the +10 signal is multiplied by 2.8, it becomes 44,100 tlz, and the audio is sampled at this frequency. by this,
Between l frames, L470 phonemes can be obtained.

When processing video and audio signals as described above, data compression is performed, and the time axis is changed before being recorded in memory. Therefore, the time axis is corrected during playback.
In other words, it is necessary to control the time difference.

In the video signal, a vertical synchronization signal is recorded between each field. Since there is no such signal in the audio signal, a marker synchronized with the vertical synchronization signal (VD) of the video signal is added and recorded. That is, the sampling signal generator 31
A marker signal is written into the redundant bit of the audio memory 23 according to the signal.

Audio quantization is set to 16 bits due to dynamic range. In cases where dynamic range is important, a relative address is written into the audio memory and when read out, a redundant bit is provided and one field marker is written there.

As a marker signal, as shown in FIG.
1, a method such as writing eight consecutive O pulses 42 may be adopted.

During playback, this marker signal (pulse) is detected, a time axis is created by the counter 32, and transmitted to the processing computer 33 by an interrupt or status signal, and the processing computer 33 controls the time difference between the video signal and the audio signal. .

As a result, the time difference between the video signal and the audio signal is corrected during playback, and perfect synchronization can be achieved.

The present invention can be applied to any system in which synchronization of vertical synchronization signals differs, such as NTSC, PAL, and HDTV.

〔effect〕

According to the present invention, synchronization during reproduction of a video signal and an audio signal;
In other words, the time difference can be controlled. Therefore, a device capable of simultaneously simulating video signals and audio signals can be easily obtained.

Another advantage is that it can be realized by adding only a small number of functions without requiring any special means.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram of signal waveforms. 11.21... Input circuit 12.22... AD converter 13... Video memory 23...
...Audio memory 14.24...DA
Converter 15.25...Output circuit 32...Counter 33...Processing computer system 1 diagram

Claims (1)

[Claims] In a video/audio simulation method in which a video signal and an audio signal are respectively AD converted and recorded in a video memory and an audio memory, and the signals recorded in the video memory and audio memory are DA converted to obtain a video output signal and an audio output signal. A video/audio simulation method, comprising: writing a vertical synchronization signal of a video signal into redundant bits of the audio memory, and detecting the vertical synchronization signal to control the time axis of the video signal and the audio signal.