JPH04141855A - Method and device for retrieving sound signal - Google Patents

Abstract

PURPOSE:To retrieve a necessary track in spite of a mode where sound is recorded by realizing reproduction for program searching for prescribed time which is previously decided in spite of a compression ratio. CONSTITUTION:A timing control circuit 53 is controlled by a system controller 11 and it compresses or extends a sound signal on a time base at the time of recording and reproducing the sound of a disk D. The sound signal recorded in the disk D is FM-demodulated by a sound recording/reproducing circuit 31 at the time of reproducing sound, and/is stored in a sound memory 33. The stored sound signal is time-extended by the operation of the sound memory 33, the timing control circuit 53 and a D/A converter 52 and is outputted as an analog signal. A device is constituted in such a way that it reproduces the sound signal for prescribed time in spite of the compression ratio in the recording of the sound signal. Thus, the desired track can surely be retrieved in spite of the mode where sound is recorded (compression ratio).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video floppy disk used as a recording medium for electronic still video cameras, etc., and particularly relates to a method and apparatus for searching audio signals recorded on this disk. .

[Conventional technology]

In this type of video floppy disk, each track on which an audio signal is recorded is usually divided into four sectors, and the beginning of the audio signal is determined for each track as disclosed in Japanese Patent Laid-Open No. 1-269292. This is done by demodulating the audio signal recorded in the sector located at the beginning of the data and sequentially outputting it as audio.

Audio signals can be recorded and reproduced in modes of approximately 20 seconds, approximately 10 seconds, and approximately 5 seconds per track depending on the compression ratio. As mentioned above, since one track is composed of four sectors, the recording/reproducing time per sector in each mode is about 5 seconds, about 2.5 seconds, and about 1.2 seconds, respectively.

[Problem to be solved by the invention]

However, if the audio is recorded in the above-mentioned modes, for example in a mode of about 5 seconds per track, the playback time is as short as about 1.2 seconds, making it difficult to hear the reproduced audio and making it difficult to track the desired track. There is a problem that it becomes difficult to search for.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for searching an audio signal, which makes it easy to reliably search for a desired track, regardless of the mode in which the audio was recorded.

[Means to solve the problem]

A first search method according to the present invention is a method of searching for an audio signal by reproducing an audio signal recorded at a predetermined compression ratio and cueing a series of audio signals. It is characterized by being able to be played for a certain period of time to find the beginning.

The second search method according to the present invention is characterized by changing the playback amount for cueing according to the compression ratio.

Further, the first search device according to the present invention includes a means for detecting that an audio signal is recorded on a recording medium, a means for detecting the beginning of a series of audio signals, and a means for detecting a beginning of a series of audio signals, regardless of the compression ratio of the audio signal. , and means capable of reproducing the audio signal for a certain period of time from the beginning.

A second search device according to the present invention includes means for detecting that an audio signal is recorded on a recording medium, means for detecting the beginning of a series of audio signals, and means for detecting a compression ratio of the audio signal. , and means capable of reproducing the audio signal from the beginning by an amount corresponding to the compression ratio.

〔Example〕

The present invention will be explained below with reference to illustrated embodiments.

FIG. 3 is a circuit diagram of a disc recording and reproducing apparatus to which the audio signal retrieval method and apparatus according to an embodiment of the present invention are applied. The system controller 11 is a conventionally known microcomputer that controls the entire apparatus, and an operating section 12 for performing various operations, a voice search button 13, a stop button 14, etc. are connected to the system controller 11. Further, a display section 15 for displaying various displays is connected to the system controller 11.

The video recording/reproducing circuit 16 is controlled by the system controller 11, and divides a video signal input via a video camera (not shown) into a color difference signal and a luminance signal, and performs FM modulation on each of them, and outputs the video signal to a video floppy disk D via a switch 17. to be recorded. Video recording and playback circuit 16
is also connected to a video output terminal, and by connecting a playback device (not shown) to this terminal, the video recorded on the video floppy disk D can be viewed.

The switch 17 is controlled by the system controller 11, and is closed to the video recording and reproducing circuit 16 when recording and reproducing video, and is closed to the audio recording and reproducing circuit 31, which will be described later, when recording and reproducing audio.

The disk device includes a magnetic head 21 and this magnetic head 2.
a tracking circuit 22 for driving and controlling the video floppy disk D; a spindle motor 23 for rotationally driving the video floppy disk D; and a servo circuit 2 for driving and controlling the motor 23.
4, and a PG coil 25 for detecting the rotational angular position of the video floppy disk D. The PC coil 25 is connected to the servo circuit 24, and the servo circuit 24 and the tracking circuit 22 are connected to the system controller 11.

Next, a circuit for recording and reproducing audio will be explained.

The audio recording/reproducing circuit 31 is a circuit that performs FM modulation, FM demodulation, etc., and is connected to the magnetic head 21 via a switch 17. The emphasis circuit 32 is a circuit that emphasizes the high frequency range of the audio signal transmitted from the audio memory 33 when recording audio on the disc D and outputs it to the audio recording/reproducing circuit 31. It is connected to the audio memory 33 via the device 35. The de-emphasis circuit 36 is a circuit that suppresses the high frequency range of the audio signal output from the audio recording/reproducing circuit 31 when reproducing the audio recorded on the disc D. It is connected to the audio memory 33.

The microphone 41 is connected to a switch 45 via an amplifier 42, and the speaker 43 is connected to a switch 45 via an amplifier 44. The switch 45 is controlled by the system controller 11, and is closed on the microphone amplifier 42 side when recording audio, and closed on the speaker amplifier 44 side when audio is reproduced. The switch 45 is connected to a noise reduction circuit 46, and the noise reduction circuit 46 is connected to a low-pass filter 47.

The low-pass filter 47 is connected to the A/D via a switch 48.
It is connected to the converter 51 and the D/A converter 52, and the A/D
The converter 51 and the D/A converter 52 are connected to the audio memory 33.
connected to. Switch 48 is system controller 1
1, and is closed on the A/D converter 51 side when recording audio, and closed on the D/A converter 52 side when audio is reproduced.

Note that the noise reduction circuit 46 and the low-pass filter 47 are also controlled by the system controller 11.

A timing control circuit 53 is connected to the audio memory 33, A/D converter 51, and D/A converter 52.

This timing control circuit 53 is controlled by the system controller 11 and cooperates with the audio memory 33, the A/D converter 51, and the D/A converter 52, and when recording and reproducing audio on the disk D, the timing control circuit 53 converts audio signals into time signals. Compress or expand about an axis.

When recording audio, the audio input from the microphone 41 passes through the amplifier 42, the noise reduction circuit 46, and the low-pass filter 47, and is input to the A/D converter 51. This audio signal is time-compressed by the action of the A/D converter 51, the audio memory 33, and the timing control circuit 53.
After being D/A converted by a D/A converter 35, the signal passes through a low-pass filter 34, has its high frequencies emphasized by an emphasis circuit 32, is FM modulated by an audio recording/reproducing circuit 31, and is recorded on a disc D.

Further, when playing back audio, the audio signal recorded on the disc D is FM demodulated by the audio recording/reproducing circuit 31, and then the high frequencies are suppressed by the de-emphasis circuit 36.
The signal passes through a low-pass filter 37 and an A/D converter 38 and is stored in the audio memory 33. The audio signal stored in the audio memory 33 is time-expanded by the actions of the audio memory 33, the timing control circuit 53, and the D/A converter 52, and is output as an analog signal. The signal passes through the amplifier 44 and is reproduced by the speaker 43.

FIG. 4 shows a video floppy disk D used in the disk recording and reproducing apparatus of FIG. This video floppy disk D is, for example, a 2-inch magnetic disk. The 1st to 50th tracks from the outside of the video floppy disk D are recording tracks on which digital data such as video and audio are recorded, the 51st track has nothing recorded, and the 52nd track is a so-called cue signal. This is a cue track for recording. A track on which audio signals are recorded is divided into four sectors.

FIG. 5 shows the relationship between tracks and sectors of the video floppy disk D. In this example, Section 6.7.9.10.
Video signals are recorded on each of the 12 tracks, and audio signals are recorded on the 5th, 8th, 11th, and 13th tracks. The video signal is recorded with one track as one unit. On the other hand, there are 4 tracks on which audio signals are recorded.
The audio signal is recorded with each sector as a unit, and a series of audio signals is formed by connecting several sectors as will be described later.

There are four types of signal recording formats in sectors containing audio signals. Type 1 (■ in Figure 5) is a sector in which audio signals are also recorded in the following sectors, type 2 (■)
■) in Figure 5 is a sector where the audio signal continues on a different track, type 3 (■ in Figure 5) is a sector where a series of audio signals ends, and type 4 (■ in Figure 5) is a sector where the audio signal is recorded. This is a sector that has not been That is, in the example of FIG. 5, the audio signal continues from sector #2 of the fifth track to the eighth track, from sector #3 of the eighth track to the eleventh track, and from sector #1 to the thirteenth track of the eleventh track.
It ends following sector #0 of the track. In other words, a series of audio signals are recorded over a predetermined trunk of the 5.8th, IL13th track.

FIG. 6 schematically shows a recording state of a signal in one sector including an audio signal.

Each sector records a signal that starts with a start flag F1 and ends with an end flag F2. Immediately after the start flag F1, a control code C1 for recording various information is recorded.
The audio waveform signal C2 is recorded between the end flag F2 and the end flag F2.

In the type 1 signal recording format, as shown in FIG. 6, the start flag F1 is a high level signal and the end flag F2 is a high level signal.
is a low level signal. Type 2 is also indicated by the start flag F1 being a high level signal and the end flag F2 being a low level signal, but the position of the end flag F2 is different from Type 2. Type 3 is indicated by the fact that the start flag Fl and end flag F2 are both low level signals, and type 4 is indicated by the start flag Fl being a low level signal and the end flag F2 being a high level signal.

FIG. 1 is a flowchart showing a first method for searching for audio signals. This routine is activated by pressing the voice search button 13.

In step 101, it is determined whether the magnetic head 21 is currently facing the 50th track of the video floppy disk D, that is, the innermost track of the recording tracks. The video floppy disk D is read from the outer circumferential side to the inner circumferential side, and the magnetic disk 2
When the number 1 is located on the 50th track, reading of the recording track has been completed, so this routine ends.

If the 50th track has not been played yet,
Tracking is performed in step 102, and the magnetic head 21 is moved to one track on the inner circumferential side. In step 103, it is determined whether the track that is currently being reproduced is a track on which an audio signal has been recorded. This is determined by an output signal from a synchronization signal separation circuit (not shown). If the track is not a track on which an audio signal has been recorded, the process returns to step 101, but if the track is a track on which an audio signal has been recorded, in step 104,
By reading the control code cl (Figure 6),
It is determined whether or not it is the beginning of a sequence, that is, a series of audio signals. The track number and sector number of the first sector are recorded in the control code C1 in each sector of a series of audio signals, and by reading this,
It is determined whether the sector is the beginning of a series of audio signals. If the currently reproduced track is not the beginning of a series of audio signals, the process returns to step 101, but if the track is the beginning of a series of audio signals, steps 105 and subsequent steps are executed.

In step 105, a time limit is set in a timer (not shown), and in step 106, this timer is started.

Next, in step 111, reproduction of the audio signal is started. In step 112, it is determined whether or not the 7 button 14 (FIG. 3) has been pressed. If the stop button 14 is pressed, the timer is stopped in step 119, and this routine is forcibly terminated in this state, but if it is not pressed, steps 113 and subsequent steps are executed.

In other words, whether the sector currently being played is type 3 or not.
In other words, it is determined whether or not it is the last of a series of audio signals. If not type 3, in step 114 step 106
The timer started in step 105 is checked and it is determined whether the timer has expired, that is, whether the time limit set in step 105 has elapsed. If the time limit has not yet elapsed, in step 115 it is determined whether the currently playing sector is of type 2, that is, whether the audio signal continues to a sector of another track. If it is not type 2, return to step 111, but
In the case of type 2, in step 116 the magnetic head 2
1 to subsequent tracks, step 11
Return to 1.

Steps 111 to 116 are repeatedly executed to reproduce audio signals for several sectors. Thereafter, if it is determined in step 113 that the sector being reproduced is of type 3, or if it is determined in step 114 that a predetermined time has elapsed, step 11
At step 7, the reproduction of the audio signal is stopped, and at the same time, at step 118, the timer is stopped.

The routine then returns to step 101, and the same process as described above is repeated, and the next series of audio signals is played back, ie, the cue is found.

As described above, this embodiment is configured to reproduce the audio signal for a certain period of time regardless of the compression ratio in recording the audio signal. Therefore, even in a mode in which about 5 seconds of audio is recorded per track, the playback time is secured, for example, about 2.5 seconds or about 5 seconds. Therefore, the playback time is long enough to hear the audio, making it easy to search for a desired track. Furthermore, according to this embodiment, even if audio signals with different recording modes are mixed on one video floppy disk, the audio signals can be played back for a fixed period of time, making it possible to reliably search for a desired track. I can do it.

FIG. 2 is a flowchart showing a second method of searching for audio signals, and this routine is started by pressing the audio search button 13.

The processes in steps 201, 202, 203 and 204 are the same as steps 101, 102, 103 and 104 in FIG. 1, respectively, and their explanation will be omitted.

In step 205, a reference value N indicating the number of sectors to be reproduced is set to "1". This is just an example, and it may be set to "2" or more if necessary. In step 206, it is determined whether the audio signal is recorded in the first mode (a mode in which about 20 seconds of audio is recorded per track). If the mode is not the first mode, it is determined in step 207 whether the audio signal is recorded in the second mode (a mode in which about 10 seconds of audio is recorded per track). Second
In the case of the mode, the reference value N is set to 2 in step 208.
Changed to N. If it is not the second mode, that is, if it is the third mode (a mode in which approximately 5 seconds of audio is recorded per track), the reference value N is set to 4 in step 209.
Changed to N.

Next, in step 210, the counter M is set to "1", and the audio is reproduced in steps 211 and subsequent steps.

In step 211, one sector is played back and the audio is played back. In step 212, it is determined whether or not the stop button 14 (Fig. 3) has been pressed. If it has been pressed, this routine is forcibly terminated in this state.
If not pressed, steps 213 and subsequent steps are executed. First, in step 213, it is determined whether the sector currently being reproduced is of type 3, that is, whether it is the last of a series of audio signals. If it is type 3, the series of audio signals has ended and the process immediately returns to step 201, but if it is not type 3, it is determined in step 214 whether or not the counter M has reached the reference value N. Counter M
If it has reached the reference value N, that is, if reproduction of a predetermined number of sectors has been completed, the process returns to step 201 and the next audio cue is found.

On the other hand, if the playback of the predetermined number of sectors has not yet been completed and the counter M has not reached the reference value N, the counter M is incremented by rlJ in step 215, and then the current playback is performed in step 216. It is determined whether the sector in question is of type 2, that is, whether the audio signal follows a sector of another track. Type 2
If not, the process returns to step 211, but in the case of type 2, the magnetic head 21 is tracked to the following track in step 217, and the process returns to step 211.

Steps 211 to 217 are repeatedly executed to reproduce audio signals for a predetermined number of sectors. If it is determined in step 213 that the sector being reproduced is type 3, or if it is determined in step 214 that reproduction of a predetermined number of sectors has been completed, the routine returns to step 201 and is similar to that described above. This process is repeated to reproduce the next series of audio signals.

As described above, this embodiment is configured such that the amount of audio signal playback is changed according to the compression ratio in recording the audio signal, and the smaller the compression ratio, the more sectors are played for cueing. The number is increasing. Therefore, 1
Even in a mode with a low compression ratio where approximately 5 seconds of audio is recorded per track, the playback time is sufficiently long.
It becomes easier to hear the audio, and the desired track can be reliably searched. Furthermore, according to this embodiment, even if audio signals of different recording modes are mixed on one video floppy disk, the number of sectors corresponding to each mode is always played back, so the desired track can be reliably searched. be able to.

Although each of the above embodiments uses a video floppy disk as a recording medium, the present invention is not limited to this, and can also be applied to devices using magnetic tape, magnetic drums, etc. as a recording medium. .

[Effects of the Invention] As described above, according to the present invention, it is possible to reliably search for a desired track regardless of the mode (compression ratio) in which audio was recorded.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a first method of searching for an audio signal, FIG. 2 is a flowchart showing a second method of searching for an audio signal, and FIG. 3 is a flowchart showing a second method of searching for an audio signal. FIG. A circuit diagram showing a disk recording and reproducing apparatus to which the signal search method and device are applied; FIG. 4 is a diagram showing a video floppy disk; FIG. 5 is a diagram showing the relationship between trunks and sectors of the video floppy disk; The figure is a diagram schematically showing the recording state of audio signals in one sector. video floppy disk

Claims (6)

[Claims] (1) In a method of reproducing an audio signal recorded on a recording medium at a predetermined compression ratio, and searching for the audio signal by cueing a series of audio signals, a predetermined constant A method for searching for an audio signal, characterized in that playback for cueing is possible for a certain period of time. (2) In a method of reproducing an audio signal recorded on a recording medium at a predetermined compression ratio and searching for an audio signal by cueing a series of audio signals, the amount of playback for cueing is adjusted to the above compression ratio. A method for searching for an audio signal, which is characterized in that the search method changes the audio signal accordingly. (3) The recording medium is divided into multiple sectors,
3. The method of retrieving an audio signal according to claim 2, wherein the number of sectors reproduced for cueing changes in accordance with the compression ratio. (4) means for detecting that an audio signal is recorded on a recording medium; and means for detecting the beginning of a series of audio signals;
An audio signal search device comprising: means capable of reproducing the audio signal for a certain period of time from the beginning regardless of the compression ratio of the audio signal. (5) means for detecting that an audio signal is recorded on a recording medium; and means for detecting the beginning of a series of audio signals;
An audio signal search device comprising: means for detecting a compression ratio of the audio signal; and means capable of reproducing the audio signal from the beginning by an amount corresponding to the compression ratio. (6) The recording medium is divided into multiple sectors,
6. The audio signal retrieval device according to claim 5, wherein said audio signal reproducing means is capable of reproducing audio signals for a number of sectors corresponding to said compression ratio.