JPH06105276A - Video and voice signal recorder - Google Patents

Abstract

PURPOSE:To prevent the generation of an uncomfortable noise by turning on a voice output suppression bit when a voice signal is turned to an error in an MUSE system just before a reproduction end, just before a power source turning-off, and just before a specific reproduction. CONSTITUTION:An error correction code is added to a compressed audio signal from a DANCE encoder 4, a bit interleave is operated, a control code and a sink are added, and an audio frame is constituted. The control code to be added includes a mute flag(voice output suppression bit), the control code is generated from a control signal generating circuit 7, and transmitted to a signal processing and control signal adding circuit 5. That is, the recording of one program is operated, and whether or not the instruction of the recording end of the program is applied from an input terminal 6 is judged. When the recording end is instructed, the mute flag is turned on. Then, the recording of the mute flag is operated in a prescribed time, and the recording is ended after the recording of the mute flag is operated in the prescribed time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video / audio signal recording apparatus of the MUSE system, and more particularly to a video / audio system capable of preventing an abnormal sound generated when the reproduction is interrupted in a MUSE system video disc player. The present invention relates to a signal recording device.

[0002]

2. Description of the Related Art Development of a video disc player for reproducing an optical disc on which a video signal of the MUSE system is recorded is under way. In the MUSE system, an audio signal is digitized, compression-coded, time-division multiplexed in the vertical blanking period of a video signal, and transmitted.

That is, in the MUSE audio transmission system, there are two audio modes, A mode and B mode.
Types are prepared. The A mode is a mode for supporting surround sound. The B mode is a mode for performing high quality stereo reproduction.

In the A mode, the input audio signal has four channels. The 4-channel audio signal is digitized with a sampling frequency of 32 kHz and a quantization bit number of 15 bits. Audio signal bandwidth is 15k
Hz is secured. Then, this digital audio signal is compression-encoded into 8 bits by the audio compression encoder.

In the B mode, the input audio signal has two channels. This 2-channel audio signal has a sampling frequency of 48 kHz and a quantization bit number of 16
Digitized in bits. The voice signal bandwidth is 20
kHz is secured. Then, this digital audio signal is compression-encoded into 11 bits by the audio compression encoder.

The voice band compression is a system based on differential PCM (quasi-instantaneous compression). By such voice compression, the voice data is compressed to about 65%.
As a result, high-quality audio reproduction suitable for high-quality video can be performed.

FIG. 4 shows the transmission format in the A mode, and FIG. 5 shows the transmission format in the B mode. As shown in FIGS. 4 and 5, the audio data is transmitted in units of one frame (audio frame). The data amount of one frame is 1350 bits, which is the same in both the A mode and the B mode. A 16-bit frame sync is provided at the beginning of the audio frame. The pattern of this frame sync is (0001001101011110).

A 22-bit control code is provided following the frame sync. FIG. 6 shows the structure of the control code. As shown in FIG. 6, this control code includes
It is used to transmit information such as audio mode, stereo / monaural format, and scrambling. Further, the control code includes a bit (mute flag) for suppressing audio output. The audio output suppression bit is located at the 16th position of the 22-bit control code. When the audio output suppression bit is "0", reproduction is performed on the MUSE decoder side. When the audio output suppression bit is "1", audio reproduction is muted by the MUSE decoder.

As shown in FIG. 4, in the A mode,
Following this, range bits of audio A1 and A2 are arranged, and audio data A1 and A2 for two channels are arranged. The range bit indicates a compression range. Then, the range bits of the audios A3 and A4 are arranged, and the audio data A3 and A4 for two channels are arranged. Following this, 12
Independent data for 8-bit reserve is provided and an error correction code is added.

As shown in FIG. 5, in the B mode,
Subsequent to the control code, range bits of audio B1 and B2 are arranged, and audio data B1 and B2 for two channels are arranged. Following this, 112
Independent data for the reserve of bits is provided, and
An error correction code is added.

In order to cope with the burst error, this frame is interleaved every 16 bits except the sync signal and the control code. Such interleaving is called bit interleaving.

FIG. 7 shows bit interleaving in the A mode. The data is two-dimensionally arranged in (16 × 82), written in the horizontal direction, and transmitted in the vertical direction. As a result, interleaving is applied every 16 bits.

FIG. 8 shows bit interleaving in the B mode. Also in B mode,
The data is arranged two-dimensionally in (16 × 82), written in the horizontal direction, and transmitted in the vertical direction. This gives 16
Interleave is applied for each bit.

Further, the bit interleaved frame is interleaved every 25 frames including the sync signal and the control code. Such interleaving is called frame interleaving.

FIG. 9 is for explaining the frame interleaving process. In FIG. 9, shift registers 61-1, 61-2, ... 61-23, 61-24
Are shift registers for 1350 bits (corresponding to one audio frame). The output between the stages of these shift registers 61-1, 61-2 ... Is the selector 6.
2 is supplied. Shift registers 61-1 and 61-2 ...
25 frames of data P1, P2, P
3 is obtained respectively.

First, the selector 62 is switched so that the data P1 is selected. Below, the selector 62
Are sequentially switched so that the data P1, P2, P3 ... Are output. As a result, interleaving between frames is applied every 25 frames.

The double interleaved data of the bit interleave and the frame interleave is binary / ternary converted according to the table shown in FIG.

In FIG. 10, 3-bit binary data is shown on the left side, and corresponding 2-sample 3-valued data is shown on the right side. By thus performing the binary / ternary conversion, the transmission rate can be reduced.

That is, as shown in FIG. 11A, binary 3-bit data is converted into ternary 2-bit data as shown in FIG. 11B.
Converted to sample data. Cycle t1 for binary
As can be seen by comparing with the period t2 in the case of three values,
When binary / ternary conversion is performed, even if data of the same amount of information is transmitted, a long period can be taken and the transmission rate can be reduced.

The rate of the data that has undergone the binary / ternary conversion and the frequency conversion is 12.15 MHz. So that this data can be multiplexed during the vertical blanking period of the video signal,
The frequency is converted and multiplexed in the vertical blanking period of the video signal.

FIG. 12 shows a transmission format of a signal transmitted in one frame of the MUSE system. As shown in FIG. 12, lines 3 to 42 and 5
From line 65 to line 604, audio data is inserted following the horizontal synchronizing signal period. On lines 43 to 46 and lines 605 to 608, audio data is inserted together with the chroma signal.

[0022]

In the conventional system using the video disk player for MUSE, an unpleasant noise is generated from the speaker immediately before the end of reproduction, immediately before power off, or just before special reproduction. There is a problem. This is because in the MUSE method, compression encoding based on DPCM is performed, and when the reproduction is suddenly interrupted,
This is because the audio data becomes an error.

That is, even if a small error occurs in the digital audio signal, the result affects the analog output after decoding to generate a large noise. Therefore, it is generally coded using an error correction code having a high error correction capability. 1 for MUSE audio signal
Error correction coding is performed for each audio frame corresponding to m seconds of data, and even if an error occurs, the error is corrected within the correction capability.

However, M suddenly input to the decoder
When the USE signal is interrupted, an error exceeding the error correction capability range occurs. Therefore, an unpleasant noise is output immediately before the end of reproduction.

Therefore, it is conceivable to detect the end of reproduction, and mute the audio reproduction when the end of reproduction is detected. However, in the MUSE method, the relationship between the audio frame and the video frame is indefinite. Therefore, it is difficult to specify the position of the mute flag. Therefore, it is difficult to change ON / OFF of the mute flag after the recording is finished.

That is, the voice data is, as described above,
The binary / ternary value is converted and transmitted. The data rate at the time of this binary / ternary conversion is 12.15 MHz.
This binary / ternary converted data is time division multiplexed into a 16.2 MHz video signal.

An audio frame has 1350 bits, and 900 samples (1350 × 1350 ×) by binary / ternary conversion.
(2/3) = 900 samples), and 1200 samples (900 × 16.2 / 12.15) by frequency conversion.
= 1200 samples). That is, an audio frame consists of 1200 samples at the rate of the video signal frequency of 16.2 MHz.

In the MUSE signal, only audio data is inserted from the 3rd line to the 42nd line and from the 565th line to the 604th line. The amount of audio data that can be inserted into 40 lines from 3 lines to 42 lines and 565 lines to 604 lines is 464 bits.

From line 43 to line 46 and 605
From line 608 to line 608, voice data is inserted together with the chroma signal. The amount of audio data that can be inserted into the 4 lines from 43 lines to 46 lines and from 605 lines to 608 lines is 360 bits.

Therefore, the audio data amount in each vertical blanking period is (464 bits × 40) + (360 bits × 4) = 20.
It becomes k bits.

Since the data amount of one audio frame is 1200 samples at the rate of the frequency of 16.2 MHz, and the audio data amount of the vertical blanking period is 20 kbit, the number of audio frames in each vertical blanking period is determined. When calculated, it becomes 20k / 1200 = 16 + 2/3.

That is, the number of audio frames in one vertical blanking period is 16 frames and 2/3 frames. Therefore, in one frame of the video signal, twice as many (33 + 1/3) audio frames are inserted.

As described above, in the MUSE system, the relationship between the data amount of each audio frame and the data amount inserted in each vertical blanking period is not an integer relationship. The relationship between the start position of each blanking period and the start position of the audio frame is also not specified.

Therefore, an object of the present invention is to provide an audio / video signal recording device capable of preventing the generation of unpleasant noise at the end of reproduction.

[0035]

According to the present invention, in a video / audio signal recording apparatus for recording a time-division multiplexed video / audio signal in which a video frame period and an audio frame period do not match in a recording medium, an audio signal immediately before a recording operation is stopped. It is a video and audio signal recording device that stops a recording operation after setting an audio suppression flag included therein.

In the present invention, the voice suppression flag is PCM.
It is included in the control code of the converted audio data.

In the present invention, the voice suppression flag should be at least 3
The recording operation is stopped after standing for 6 audio frames.

[0038]

Before the recording of one program is completed, the mute flag is recorded for at least the master frame (36 audio frames) or more. Since the change of the voice control state is performed for each master frame by the majority vote of the state of the flag for each frame in the immediately previous master frame, the mute flag is recorded at least at least the master frame immediately before the recording of the program is finished in this way. If so, the sound is muted just before the end of the reproduction of one program at the time of reproduction, and the generation of abnormal noise can be prevented.

[0039]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a master video disc creating system to which the present invention is applied. In FIG. 1, a high-definition video signal is supplied to the input terminal 1 and an audio signal is supplied to the input terminal 2. The video signal from the input terminal 1 is supplied to the MUSE encoder 3. The audio signal from the input terminal 2 is supplied to the DANCE encoder 4.

The MUSE encoder 3 encodes the high-definition video signal from the input terminal 1 into a video signal of the MUSE system, and compresses the high-definition video signal of about 20 MHz band to about 8 MHz band. Further, the DANCE encoder 4 compresses the audio data to about 65% by the voice compression method (quasi-instantaneous compression) based on the differential PCM.

The output of the DANCE encoder 4 is supplied to the signal processing / control signal adding circuit 5. The signal processing / control signal adding circuit 5 performs error correction coding processing and multiplexing processing. That is, an error correction code is added to the compressed audio signal from the DANCE encoder 4, bit interleaving is performed, and a control code and a sync are added to form an audio frame. The added control code includes the mute flag (audio output suppression bit) as shown in FIG. This control code is generated from the control signal generation circuit 7 and sent to the signal processing / control signal addition circuit 5. Then, frame interleaving is performed, binary / ternary conversion is performed, and frequency conversion is performed so as to be multiplexed in the vertical blanking period of the video signal. The output of the signal processing and control signal adding circuit 5 is supplied to the MUSE encoder 3 and multiplexed in the blanking period.

The output of the MUSE encoder 3 is supplied to the disk recording device 8. The disc recording device 8 is a recording device that creates a master of a video disc for MUSE, for example. The disc recording device 8 creates a master disc on which a MUSE signal is recorded.

As described above, the mute flag is included in the control code added by the signal processing and control signal adding circuit 5. The mute flag is controlled by the recording end signal from the input terminal 6 as shown in FIG.

One program is recorded (step 11), and it is judged whether or not an instruction to end the recording of the program is given from the input terminal 6 (step 1).
2). When the recording end is instructed, the mute flag is turned on (step 13). Then, the recording of the mute flag is performed for a predetermined time (at least one master frame or more). When the recording of the mute flag is performed for a predetermined time (step 14), the recording is finished (step 1).
5).

In the MUSE decoder, the change of the voice control state is performed for each master frame by the majority decision of the flag state for each frame in the immediately preceding master frame. The master frame consists of 36 audio frames. Therefore, the mute flag must be turned on for at least one master frame (36 audio frames) or more. Therefore, in step 14, it is determined whether or not a predetermined time has elapsed, and the mute flag is turned on for one master frame or more.

As described above, in the master video disc creating system to which the present invention is applied, the mute flag is inserted for at least one master frame or more at the end of the program recording. Therefore, it is possible to prevent an abnormal noise from being generated at the end of reproduction in the video disc thus created.

That is, FIG. 3 shows processing at the time of reproduction. In FIG. 3, the program is reproduced (step 21), and it is determined whether the mute flag is turned on during the reproduction of the program (step 22). It is determined whether or not the mute flag is detected during reproduction (step 22). When the mute flag is detected, the sound is muted (step 23) and the reproduction of the program ends (step 24). Then, it is judged whether to reproduce the next program or to end the reproduction (step 25). If the next program is to be reproduced, the procedure returns to step 21. If the reproduction is to be ended, the reproduction is terminated (step 25). Step 26).

As described above, the mute flag is turned on at the end of the program during recording. Therefore,
At step 22, the mute flag is detected at the end of the reproduction of one program. When the mute flag is detected, the sound is muted. Therefore, it is possible to prevent abnormal noise from being generated at the end of the program reproduction.

In the above-described embodiment, the case of creating the master of the video disk for MUSE has been described, but the present invention is applicable to other MUS such as VTR for MUSE.
The same applies to the recording device for E.

[0050]

According to the present invention, the audio output suppression bit is turned on in the case where the audio signal is in error in the MUSE system, such as immediately before the end of reproduction, immediately before power off, or immediately before special reproduction. It Therefore, it is possible to prevent unpleasant noise from occurring immediately before the end of reproduction, immediately before power-off, immediately before special reproduction, or the like. Further, since the audio is muted by turning on the audio output suppression bit, it can be applied to any MUSE decoder.

Further, according to the present invention, when it is desired to detect the position of the audio output suppression bit from the MUSE system signal with a reliable and simple circuit configuration and to mute the audio signal, the audio output is performed. The suppress bit can be turned on.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flow chart used to explain an embodiment of the present invention.

FIG. 3 is a flowchart used to describe an embodiment of the present invention.

FIG. 4 is a schematic diagram used to describe a MUSE voice transmission system.

FIG. 5 is a schematic diagram used to describe a MUSE voice transmission system.

FIG. 6 is a schematic diagram used for explaining a MUSE voice transmission system.

FIG. 7 is a schematic diagram used to describe a MUSE voice transmission system.

FIG. 8 is a schematic diagram used to describe a MUSE voice transmission system.

FIG. 9 is a block diagram used to describe a MUSE voice transmission system.

FIG. 10 is a schematic diagram used to describe a MUSE voice transmission system.

FIG. 11 is a waveform diagram used to describe a MUSE voice transmission system.

[Explanation of symbols]

 1 Video signal input terminal 2 Audio signal input terminal 3 MUSE encoder 4 DANCE encoder 5 Signal processing and control signal addition circuit

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[Procedure amendment]

[Submission date] March 17, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flow chart used to explain an embodiment of the present invention.

FIG. 3 is a flowchart used to describe an embodiment of the present invention.

FIG. 4 is a schematic diagram used to describe a MUSE voice transmission system.

FIG. 5 is a schematic diagram used to describe a MUSE voice transmission system.

FIG. 6 is a schematic diagram used for explaining a MUSE voice transmission system.

FIG. 7 is a schematic diagram used to describe a MUSE voice transmission system.

FIG. 8 is a schematic diagram used to describe a MUSE voice transmission system.

FIG. 9 is a block diagram used to describe a MUSE voice transmission system.

FIG. 10 is a schematic diagram used to describe a MUSE voice transmission system.

FIG. 11 is a waveform diagram used to describe a MUSE voice transmission system.

FIG. 12 is a schematic diagram used to describe a MUSE audio transmission system.

[Description of symbols] 1 video signal input terminal 2 audio signal input terminal 3 MUSE encoder 4 DANCE encoder 5 signal processing and control signal addition circuit

Claims (3)

[Claims] 1. A video / audio signal recording apparatus for recording a time-division multiplexed video / audio signal in which a video frame cycle and an audio frame cycle do not match, in a recording medium, an audio suppression flag included in the audio signal immediately before the recording operation is stopped. A video / audio signal recording device in which recording operation is stopped after standing up. 2. The video / audio signal recording apparatus according to claim 1, wherein the audio suppression flag is included in a control code of PCM-converted audio data. 3. The video / audio signal recording apparatus according to claim 2, wherein the audio suppression flag is set for at least 36 audio frames before the recording operation is stopped.