JPH01302577A - Video and sound track discriminating method - Google Patents

Abstract

PURPOSE:To easily discriminate the both track of a sound and an image by muting a video signal output according to the existence of a flag or a code, which is added to a sound signal, and muting a sound output in the other case. CONSTITUTION:A CPU 12 has function to discriminate the presence and absence of the flag or control code to be added to the sound signal and the presence and absence of an ID signal to be added to a video signal. When the flag or control code is detected in the CPU 12, since the track is the sound track, the mute of the video signal is loaded in a mute circuit 14 by a command from the CPU 12. On the other hand, when the ID signal is inputted to the CPU 12, the track is the image track and the mute of the sound signal is loaded in the circuit 14 by the command from the CPU 12. When the input of the ID signal is not executed in field recording, since the flag or control code is not detected by the CPU 12, the mute of the sound signal is loaded in the circuit 14.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Denominator> The present invention relates to a video and audio track discrimination method when not only video but also audio is recorded on a video floppy used in a methyl video system, for example.

<Prior art and its problems> A video floppy has 52 concentric tracks with a diameter of 47 mm.

And from &1 track (outermost track) to Nl1
Video signals and audio signals are recorded on 50 tracks, &5
One track is an empty track, and the NrL52) rack is a track for cue signals. Note that the video signal and the audio signal are recorded on separate tracks.

On such a video floppy, video and audio signals that are related to each other are recorded as a pair and played back simultaneously. If you want to freely form video tracks and audio tracks on a video floppy, for example, if you want to record video signals and audio signals on empty tracks in order in response to recording requests without distinguishing between video and audio, you can create either a video track or an audio track. It is necessary to determine whether For this reason, the present invention provides a novel method for performing the above-mentioned discrimination, but before explaining the method, some characteristics of the audio signal will be explained.

Due to their nature, audio signals are time-compressed and recorded on a video floppy, and are time-expanded during playback. To explain the recording format of the audio signal, as shown in FIG. 3, the video floppy 1 has four sectors $$O, #
1°#2. #3, and the time-compressed audio signal is divided into these sectors and recorded. A series of related audio signals may be recorded over one track or multiple tracks. FIG. 4 shows a series of related audio signals in sectors #0 # #1 of the fifth track. #2 → 8th
Truck sector #0. #1. #2. #3→Sector #0 of the 11th track. #1 → Sector #0 of the 13th track
An example is shown in which data is recorded separately in each sector in this order. When recording audio signals on multiple tracks as shown in this example, the multiple tracks do not necessarily have to be adjacent, and it is not necessary to record in all four sectors on each track, but is always recorded in sector #
Must start from 0. When audio is recorded in this way, the usage of each sector can be divided into the following four types.

Taibuto: Continue recording to the next sector of the same track.

Type 2: Finish recording on that track and continue recording on sector #O of the following track.

Type 3: Recording ends in that sector.

Type 4: Unused sector.

The signal arrangement of the audio signals for the sectors is as shown in FIG. Start flag and end flag levels (
The characteristics (high level, low level) are set as shown in the following table according to the sector types 1, 2, 3, and 4 described above.

The control code attached to each sector within the same track is the same. The control code includes information for synchronization and error checking, as well as 9 words of information.

W,・W2. '#, , person, W5. Has Otori, Swear, and W6. Each word information is composed of 8 pits and has the following meaning.

Wo: Indicates the track number.

W D Indicates the track number of the first track among the tracks on which a series of related audio signals are recorded.

W D Indicates the track number of the subsequent track following the relevant track when a series of related audio signals are recorded on multiple tracks. Therefore, this word information W2 has no meaning in a track containing a type 3 sector, ie, a track where a series of related audio signals has been recorded.

W: Indicates the number of the track on which the video signal is recorded when the video signal is recorded as a pair in relation to the audio signal. In the case of field still image recording, the relevant video track number is shown, and in the case of frame still image recording, the outer video track number is shown.

w: (il! Not used.

W Indicates Nibray back mode, time compression rate and option code.

w6. w, , W is a niobium code and is used for dates, etc. as necessary.

As described above, the present invention provides an audio track discrimination method for freely recording and reproducing video tracks and audio tracks on a video floppy, assuming the audio signal recording format as described above.

<Means for Solving the Problems> The present invention, which achieves the above-mentioned object, is an apparatus for demodulating and reproducing a video modulated signal and an audio modulated signal recorded on a video floppy. The present invention is characterized by determining the presence or absence of a flag or control code added to the video signal and an ID signal added to the video signal, and muting the video signal output depending on the presence of the flag or control code, and muting the audio output otherwise.

EMBODIMENTS> The present invention will now be described in detail with reference to FIGS. 1 and 2. FIG. 1 is a block diagram of the reproduction system. In FIG. 1, 1 is a playback head and 2 is a playback amplifier. This reproducing amplifier 2 is connected to three filters 3, 4, and 5. The bypass filter and equalizer circuit 3 pass the audio and luminance signals, the low-pass filter 4 passes the chroma signal, and the band-pass filter 5 passes the ID signal. passes. Furthermore, each filter 3, 4.5 has a demodulator 6.7.
8 for luminance FM demodulation and 7 for chroma FM demodulation.
MII modulation and ID demodulation are performed at 8.

The demodulator 6 is next connected to the audio signal processing circuit 9 and the luminance reproduction signal processing circuit ID, and the audio signal processing circuit 9
It has a de-emphasis function to improve the S/N ratio and a time expansion function to return to the original length. Further, the demodulator 7 is connected to the chroma reproduction signal processing circuit 11, and the demodulator 8 is connected to the chroma reproduction signal processing circuit 11.
Connected to PU12. The respective output terminals of the luminance reproduction signal processing circuit ID, the chroma reproduction signal processing circuit 11, and the CPU 12 which outputs a display signal for displaying the ID signal on the monitor are connected to the addition circuit 13. The adder circuit 13 is connected to the mute circuit 14 together with the audio signal processing circuit 9.

Further, the CPU 12 is connected not only to the output terminal of the amplifier 8 but also to the output terminal of the audio signal processing port g89. Here, the CPU 12 displays the ID on the screen mentioned above.
It has a function of outputting a signal for displaying a signal, as well as determining the presence or absence of a flag or control code added to the aforementioned audio signal, and determining the presence or absence of an ID signal. If the flag or control code is detected by the CPU 12, the track is an audio track, so the mute circuit 14 mutes the video signal in response to a command from the CPU 12.

On the other hand, when the ID signal included in the video signal is input to the CPU 12, the track is a video track and the CPU 1
The audio signal is muted in the mute circuit 14 according to the command from 2. Also, if no ID signal is input during field recording, a flag is sent to the CPU 12.

If no signal or control code is detected, the video signal track will be played during playback, so the mute
The audio signal is muted at Is14.

FIG. 2 is a flowchart for determining video/audio tracks in the CPU 12. That is, when playing a video floppy, it is determined whether or not there is an ID signal, and then flags and control codes are determined, and if these flags or codes are present, an audio signal processing output is output, and if not, an audio signal processing output is output. The video signal processing output is output. Note that the presence or absence of the ID signal differs depending on whether feed recording or frame recording is performed, so the broken line portion may be omitted.

<Effects of the Invention> In this way, the presence or absence of an audio signal can be detected by detecting the flag or control code, and it is possible to easily distinguish between an audio track and a video track.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a block diagram of the playback system, FIG. 2 is a determination flowchart 1-, and FIG. FIG. 4 is an explanatory diagram showing an example of the recording state of the audio signal, and FIG. 5 is an explanatory diagram showing the signal arrangement of the audio signal. In the figure, 6.7.8 is an IX adjuster, 9 is an audio signal processing circuit, 12 is a CPU, and 14 is a mute circuit. Patent application Agent: Fuji Photo Film Co., Ltd.

Claims (1)

[Claims] In a device that demodulates and reproduces a video modulated signal and an audio modulated signal recorded on a video floppy, a flag or control code added to the audio signal at the time of demodulation and an ID added to the video signal. A video/audio track discrimination method characterized by determining the presence or absence of a signal, and muting the video signal output depending on the presence of the flag or control code, and muting the audio output otherwise.