JPH0832066B2 - Audio / video recorder - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio / video recording device used for a video tape recorder, an optical disc, or the like.

2. Description of the Related Art In recent years, development and commercialization of a device in which audio and video are integrated has been active, and as one example, a device for recording or reproducing audio and video on a tape or an optical disc has been commercialized. There is. For example, in a consumer video tape recorder, in addition to the video signal, the analog stereo audio signal is FM.
There are some that can be recorded and played back, and that FM or digitized audio is frequency-multiplexed with an image on an optical disc with a diameter of 30 cm.

Problems to be Solved by the Invention However, in this consumer video tape recorder, only video and audio can be recorded at the same time, and post-recording and audio or individual editing of video is impossible. Moreover, since the horizontal resolution of the video is about 330, dissatisfaction remains in the era of high image quality such as EDTV and HDTV, which are being considered for introduction in the near future. Further, the optical disc has a horizontal resolution of 400 or more, which is relatively high image quality, and although the voice is digitized, it has a drawback that the consumer cannot freely record it.

In view of the above problems, the present invention does not have a crosstalk between a luminance signal and a chrominance signal in recording audio and video, and does not use a color subcarrier, so that a linear or non-linear distortion is not strictly required. The present invention provides an audio / video recording device capable of independent recording / erasing of images and having a system expandability easily by a mode identification code such as a standard image quality mode, a high image quality mode, a standard sound quality mode, and a high sound quality mode.

In order to achieve this object, the audio / video recording apparatus of the present invention separates a video signal into a luminance signal and a chrominance signal, and separates each of them.
A / D converted and written to memory, time-axis compression time-division multiplexed, and configured to be time-division multiplexed with a time-axis-compressed audio signal prepared separately from this, and mode identification code, code / character signal Has been done.

With this configuration, since color signals and luminance signals of audio and video signals do not exist at the same time, and there is no color subcarrier, the requirements for linear and non-linear distortion are not strict, and audio, color, and Since each luminance signal is time-division multiplexed, independent recording and erasing of audio and video is possible, and the format can be switched by changing the time compression ratio of each signal according to the content of the mode identification signal, and the sound quality can be selected. It has an effect.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a signal processing block diagram of an audio / video recording apparatus according to an embodiment of the present invention.

In FIG. 1, 1 is a video signal input terminal, 2 is a luminance signal color signal separation circuit for separating a video signal into a luminance signal and a color signal, and 3 and 4 are A / D conversions for A / D converting the luminance and color signals. 5 and 6 are time base compression memories, 7 and 8 are write control circuits for the time base compression memories 5 and 6, 9 and 10 are read control circuits for the time base compression memories 5 and 6, and 11 is a selection for selecting data. Circuit, 12 D / A conversion circuit, 13 FM modulation circuit, 14 mode identification code input terminal, 15 code / character input terminal, 16 voice signal input terminal, 17 mode identification code generation circuit, code, character Audio processing / modulation circuit including data generation circuit, 18 sampling period / quantization bit number control unit, 19 time axis compression ratio control unit, 20 synchronization signal generation circuit, 21 changeover switch, 22 time division multiplexing An output terminal for outputting a recording signal.

The operation of the audio / video recording device configured as described above will be described below.

First, a video signal obtained from a VTR or a TV camera is input to the video input terminal 1, and the luminance signal color signal separation circuit 2
Are separated into luminance signal and chrominance signal by A / D converters 3 and 4, respectively.
Are sampled and quantized by and are written in the time axis compression memories 5 and 6 by the write control circuits 7 and 8 of the time axis compression memories 5 and 6. The signal once written is time-axis-compressed and read by the memory read control circuits 9 and 10, time-division multiplexed by the selection circuit 11, converted into an analog waveform by the D / A converter 12, and then the FM modulator 1
At 3, it becomes a video recording signal. On the other hand, analog processing / digital processing of audio signals, number of channels, analog FM modulation /
The mode identification code that specifies the digital modulation, the compression ratio of the luminance signal and the color signal on the time axis, etc. is input to the mode identification code input terminal 14, the code / character data is input to the code / character input terminal 15, and the audio signal is It is input to the audio signal input terminal 16. Here, the voice signal is a mode identification code generation circuit / code / character data generation circuit / voice signal processing / modulation circuit according to the contents of the input terminal 14.
It is processed in 17 and sent to the changeover switch 21 together with the mode identification code and the code / character data. The changeover switch 21 uses the output of the FM modulation circuit 13 and the sync signal generation circuit.
The output of 20 and the signal from the mode identification code generation circuit, code, character generation circuit / voice signal processing, modulation circuit 17 are switched and sent to the recording signal output terminal 22. Here, the sampling frequency according to the content of the mode identification code 14, and the sampling frequency and the number of quantization bits corresponding to each mode in the quantization bit number control unit 18 are switched, and similarly, the mode identification code According to the contents of 14, the time axis compression ratio control unit 19 controls the compression ratios of the voice, luminance and color signals.

Next, how the video / audio signal is recorded in this embodiment will be described.

FIG. 2 is a diagram showing a 1H section of an NTSC video signal.
FIG. A shows, for example, a block obtained by dividing the 1H section into 12 equal parts for time division multiplexing. As a recording method, for example,
The 1H section is equally divided into 12 blocks, and each block is voiced by the mode identification code at the beginning.
Assigned to luminance and color signals. Here, the luminance signal band is 4.
2MHz, chrominance band 1.2MHz, voice sampling 3 × fH
(= 47.2KHz), 16-bit quantization, 2c channels
If h, redundancy is 1.5 times, and the modulation method is (2,7) RLLC, the bandwidth will be about 0.755 MHz. Therefore, each block is assigned to luminance, color, and audio at a ratio of 7: 2: 3, and the upper limit frequency that can be recorded is significantly lower than 9.2 MHz of a commercially available laser disk 7.
If 2 to 8.0MHz, the luminance signal band is 4.2MHz × 12/7 = 7.2
MHz and color signal band are 1.2MHz × 12/2 = 7.2MHz, and audio signal band is 0.755MHz × 12/3 = 3.02MHz. This frequency is the band that can be recorded on both optical discs and VTRs. Here, it is preferable to make the same for each band, but it is unavoidable that they become non-uniform due to the clock rate of the modulation method of the audio signal. The recording in this case is as shown in FIG. Here, a mode identification code is provided at the beginning of each 1H section, and the compression ratio and arrangement of each signal are uniquely determined by this identification code. This will be described later.

Next, as an example of expanding the system, for example, when voice is not needed, a block of a voice section is assigned to a luminance signal or a chrominance signal, and when assigned to a luminance signal, a luminance signal band × 12 / (7 + 3) = 7.2MHz, luminance signal band is 6MHz
Becomes Further, when the color signals are assigned, the color signals are 3 MHz from the color signal band × 12 / (2 + 3) = 7.2 MHz, and the resolution is improved to 480 lines. An example of this case is shown in FIGS. 2c and 2d.

Further, when the quality of voice is lowered and the portion is assigned to the luminance signal or the color signal, the block of the voice section is changed from 3 blocks to 1 block, and the rest is assigned to the luminance signal. Band x 12 / (7 + 2) =
From 7.2MHz, the luminance signal band becomes 5.4MHz, and if it is assigned to the color signal, the color signal band x 12 / (2 + 2) = 7.2MH
From z, the color signal band is 2.4 MHz, and in this case, there is sound and a high resolution of 440 lines can be obtained. An example of this case is shown in FIGS. 2e and 2f.

As described above, a high image quality can be obtained by allocating a block in the voice section to a luminance signal or a chrominance signal. However, the voice is divided from three blocks to one block, and even one block has a sampling frequency and a quantization bit number. Many systems will be constructed by combining the number of channels.

FIG. 3 shows the relationship between each mode and the audio signal. In the example shown in FIG. 3, up to 12 channels of digitally processed audio signals are obtained. Further, in the E mode of FIG. 3, when analog FM modulation is performed, the voice band is set to 15 KHz, and the center carrier frequency of FM is determined to be 32 × n KHz, and many channels can be obtained. Further, FIG. 4 shows an example of an 8-bit mode identification code.

EFFECTS OF THE INVENTION As described above, according to the present embodiment, the 1H section of NTSC is divided into n equal parts, and the luminance signal and the chrominance signal of audio and video are time-division multiplexed based on their respective time compression ratios, and By providing a mode identification code that manages each allocation at the beginning of the 1H section, there is no crosstalk between the luminance signal and the chrominance signal, and since subcarriers are not provided, the requirements for linear / non-linear distortion are not strict, and voice, or Can realize an audio-video recording device capable of independently recording and erasing video and having system expandability corresponding to a mode identification code.

[Brief description of drawings]

FIG. 1 is a signal processing block diagram of an embodiment of the present invention, and FIG.
Figures a, b, c, d, e, and f are 1H of the video signal for time division multiplexing processing.
FIG. 3 is a block diagram showing allocation of each signal in a section, FIG. 3 is a correspondence diagram showing a relationship between a voice signal and modes, and FIG. 4 is a correspondence diagram showing an example of an 8-bit mode identification code. 2 ... Luminance signal / color signal separation circuit, 3,4 ... A / D converter,
5,6 …… Time axis compression memory, 7,8 …… Write control circuit,
9, 10 ... Read control circuit, 11 ... Selection circuit, 12 ...
D / A converter, 13 ... FM modulation circuit, 17 ... Mode identification code generation circuit / code character generation circuit / voice signal processing modulation circuit, 18 ... Sampling period / quantization bit number control unit,
19 ... Time axis compression ratio control unit, 20 ... Synchronization signal generation circuit,
21 ... switch.

Claims (1)

[Claims] 1. A means for separating a video signal into a luminance signal and a chrominance signal; first and second means for sampling and quantizing the separated luminance signal and chrominance signal respectively; , First and second memories for storing the signals obtained by the second means, first and second write control means for controlling the timing of writing the signals in the first and second memories, and The signals from the first and second memories and the first and second read control means for controlling the timing of time-compressing the signals written in the first and second memories and reading the signals are input respectively. And means for selecting one of
A means for D / A converting the selected signal, a means for FM-modulating the D / A converted output, a mode identification signal, a code / character signal and a time axis compression which are created separately from the video signal. Means for producing an FM or digitized audio signal or the like, means for generating a video signal synchronizing signal, and a signal obtained from the video synchronizing signal generating means,
Means for switching between the signal obtained from the FM modulation means, the mode identification signal, the code / character signal, and the signal obtained from the means for creating the FM signal or digitized voice signal which has been time-axis compressed, and said mode Means for changing the time axis compression ratios of the luminance signal, the chrominance signal, and the audio signal according to the content of the identification signal, and sampling for the first and second sampling and quantization means according to the content of the mode identification signal. An audio / video recording apparatus comprising: means for changing a cycle and the number of quantization bits.