JPH03207184A - Video signal recording system - Google Patents

Abstract

PURPOSE:To easily record a specific sound which is generated separately and prevent its continuity from being spoiled by providing a means which compresses the amount of information of an audio signal and a means which expands the information amount of the audio signal. CONSTITUTION:An information compressor 38 compresses data digitized by an A/D converter 37 and supplies it to a memory 39. Then the compressed audio data read out of the memory 39 is restored to the original sound data by an information expander 43 consisting of an ADPCM demodulator, etc. The audio signal is stored while its information is compressed, so the sound which is generated separately can be recorded for a long time only by providing a storage means with relatively small capacity. Even when the recording of a video signal is stopped temporarily, part of the expanded audio signal is stored, so the audio signal can be expanded and restored even at the restart of the recording according to the stored audio signal, thereby maintaining the continuity of the sound.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video signal recording system, and more particularly to a system for recording a video signal together with an audio signal.

[Prior Art] A so-called camera-integrated video table recorder (VTR) has been known as a video signal recording system of this type, and will be explained below by taking this camera-integrated VTR as an example.

In camera-integrated VTRs, so-called after-recording is well known as a method of adding other sounds such as BGM (background music) to the captured video images and sounds.

On the other hand, in recent years, it has been proposed to perform recording called VOS (video on sound) using a depth recording method.

Since the above-mentioned post-recording is a well-known method, the VOS will be briefly explained below.

VOS involves listening to music that has been previously recorded in the deep layer of a magnetic recording medium, taking images in time with the music, and recording a video signal on the surface layer of the medium.

First, as shown in FIG. 7, an audio signal a1 is pre-recorded in the deep layer of a recording medium, and an audio signal a2 having the same content is correspondingly recorded on a linear track of a tape-shaped recording medium a3.

Then, the audio recorded on the linear track a2 is played back by the fixed head a4, the playback circuit a8, and the amplifier a9 at the time of shooting, and the content of the audio signal is deep recorded by listening to the output audio signal from the output terminal 10. While checking the image sensor all and camera signal processing circuit al
Using the camera section consisting of 2, take a picture of the screen in accordance with the audio output from Mizuko alo, switch the video signal from the camera section with switch al3, and record the video signal from the camera section al3.
4. Amplify with al5. This video signal is then sent to the deep recording track al using rotary heads a6-A and a6-B.
The video track a7 is recorded on top.

In this way, by shooting while listening to the BGM etc. recorded in advance, the shooting of the screen that matches the BGM etc. is completed.

[Problems to be Solved by the Invention] However, in the above-mentioned dubbing method, BGM etc. are recorded after the shooting is completed, so recording is performed twice on the same tape, and the camera In addition to the body type VTR, other audio playback devices must be operated in synchronization, which is very cumbersome to operate.

Furthermore, in the above-mentioned VOS method, recording is performed twice on the same tape, and furthermore, the recording time is restricted by the time of the pre-recorded audio signal, which is not preferable. .

Against this background, the present invention enables easy recording of long-time audio that is separately formed when recording a video signal, and allows the predetermined audio to be continuously recorded even at the joint portion of the video signal. It is an object of the present invention to provide a video signal recording system capable of recording in a reproducible manner.

[Means for Solving the Problems] To achieve this purpose, the video signal recording system of the present invention includes a device for recording an audio signal and a video signal on a recording medium, and a device for compressing the information amount of the audio signal. a first storage means capable of storing a so-called period of audio signals compressed by the compression means; and an expansion means for expanding the information amount of the audio signal read from the first storage means. a second recording medium capable of recording the audio signal outputted from the decompression means on the recording medium together with the video signal, and storing a part of the audio signal decompressed by the decompression means in response to stopping of the recording; A storage means was provided.

[Operation] With the above-described configuration, even when recording a video signal, the audio signal stored in the first storage means is decompressed and recorded together with the video signal, so that the BG
Separately formed sounds such as M can also be recorded. Moreover, since the audio signal is stored in a compressed state, it has become possible to record separately formed audio over a long period of time simply by providing a storage means with a relatively small capacity. In addition, even when video signal recording is temporarily stopped, a part of the audio signal expanded in response to the stop is stored, so when recording is resumed after stopping, this stored audio signal is followed. Stretch the audio signal. Since it can be restored, the continuity of the audio can be maintained.

[Example] Examples of the present invention will be described in detail below.

Figure 1 shows a camera-integrated VTR as an embodiment of the present invention.
1 is a diagram showing the configuration of a recording system of a VTR, which includes a camera section consisting of a lens 1 for taking pictures, an image sensor 2, and a camera processing circuit 3, and a camera section for recording a video signal output from the camera section. a video signal processing circuit 5, a microphone 8 for recording audio, a microphone amplifier 9, an audio signal section from the audio signal processing circuit 14, and an adder 6 for recording the audio signal and video signal; Recording amplifier 7, head switches 1 5-A, 15-B, and the rotating head 16- on the drum 22 which is switched and selected thereby.
The video signal . An audio signal is recorded.

Further, this VTR has the following servo mechanism necessary for recording. First, the cab stan servo system includes a pinch roller 19 and a cab stan 1 that presses the table 17 together with the pinch roller 19.
8. FG sensor 2 that detects the rotation of the cab stun 18
5. A rotation servo circuit 34 that controls the rotation speed of the cab stan motor CM according to the FG signal output from the sensor 25.
, a cab stan motor CM driven by a control signal from the servo circuit.

The drum servo system for controlling the rotation of the rotating drum 22 in synchronization with the vertical synchronization signal of the video signal includes a PG generator 23 for detecting the rotational phase of the rotating drum 22, an FG generator 24 for detecting the rotational speed, and the PG generator 24 for detecting the rotational speed. It consists of a servo circuit 34 that controls the rotation speed and phase of the drum 22 based on output signals from the generators 23 and 24, and a drum motor DM driven by the control signals.

The rotary servo circuit 34 generates a head switching pulse (HSP) having a constant phase relationship with respect to the drum PG output from the PG generator 23, and this HSP is supplied to the head switching pulse generator 20. Head changeover switch 1 5-A, 1 5-
B overlap each other and are switched at the cycle of video vertical synchronization.

With the configuration of the servo system as described above, the heads 16-A and 16-B during normal recording of video signals and audio signals
The relative position between the table 17 and the table 17 is determined.

Next, the operation of storing audio such as specific BGM in the memory 39 will be explained.

The audio signal input from the external input terminal 35 and the audio signal corresponding to the sound collected by the microphone 8 are input to the selection switch 38, and the audio signal output from the switch 38 is input to the A/D converter 37. 1
It is converted into digital data with a sampling period of 5 KHz to 48 KHz and a quantization level of about 8 to 16 bits.

The information compressor 38 compresses the data digitized by the A/D converter 37 using a well-known method such as ADPCM.
The data is supplied to the memory 39. At this time, in the ADPCM method, it is necessary to output uncompressed sample data (hereinafter referred to as a reset value) in addition to compressed sample data (ADPCM data). In this embodiment, it is assumed that the compressor 38 outputs n reset values at the beginning of each audio piece such as BGM. Here, the value of n is determined by the compression method.

In this way, the reset value is output from the compressor 38. When outputting compressed data, turn on the memory key 47 of the operation unit 42.
The system control microcomputer 41 is the memory control circuit 4
0 to put the memory 39 into a write state, and write digital audio data for a predetermined period into the memory 39.

The memory 39 is removable from the main body of the device in the form of a memory unit 55 including a memory control circuit 40. On the main body side, there is a memory voice port pO, an output port p1, and an interface between the memory control circuit 40 and the system control microcomputer. Connection ports p2 and p3 for exchanging information are provided. As will be described later, the memory control circuit 40 determines addresses and switches the write/read mode of the memory 39 at one track level.

Next, the recording operation of audio read out from the memory 39 in the VTR of this embodiment will be explained.

The compressed audio data read from the memory 39 is ADPCM
The information decompressor 43 consisting of a demodulator etc. restores the original audio data. The audio data from the decompressor 43 is restored to an analog audio signal by a D/A converter 45, and this restored analog audio signal is sent to an audio mixer (balancer) 10.
is connected to the volume 10a. The balancer 10 includes a volume 10a for setting the volume on the memory side, a volume 10b for setting the volume on the microphone side, and an adder 12 for mixing the signals of both volumes, and the two volumes are connected so as to set the volume complementary to each other. There is. In other words, if you turn the volume all the way to one end, only one audio will be output and the other audio will not be output. Further, at an intermediate position between both ends, a mixed audio signal with a volume balance corresponding to that position is output.

Music such as BGM stored in the memory prior to shooting is played back from the memory during shooting using the above configuration and operation, so that the audio signal output from the adder 12 is processed by the audio processing circuit described earlier. The signal is processed and recorded on the tape 17 together with the video signal.

Note that the external audio signal from the terminal 35 and the audio signal from the adder 12 mentioned above are selected by the changeover switch 13,
6 and the aforementioned camera signal processing circuit 3.
output is selected by the changeover switch 4. The changeover switches 4 and 13 are normally connected to the B side, and when external human power is available, they are connected to the A side.

The memory control during continuous shooting of the camera-integrated VTR of this embodiment will be explained below.

The mode and address of the memory 39 described above are controlled by a memory control circuit 40, and the memory control circuit 40 is controlled by a system control microcomputer 41 (hereinafter referred to as system controller).

The system controller 41 changes the control contents as appropriate using the operation unit 42. The operation section is configured to accept the following various operation keys. That is, the operation section includes a memory key 47 for storing music prior to camera shooting, a BGM key 46 for setting whether or not to play back audio from the memory 39 such as BGM audio, and a camera-integrated VTR. includes a trigger key 48 for starting or stopping recording.

In the splicing operation, the above-mentioned servo loop is controlled in accordance with instructions from the system controller 41 to form a track pattern on the tape as shown in FIG. 2C. In Figure 2, shooting scene A
When a video track is formed by splicing and shooting scene B, track An is the final track of scene A and track B. is the first track of scene B. In a 5° portion at the end of each track, the signals recorded in the 180° portions of the previous and succeeding tracks are recorded in an overlapping manner.

Here, the video changes as the scene changes, but the audio such as BGM is on track A. It is desirable that there is no interruption at track B1. In the VTR of this embodiment, the system controller 41 implements memory control that enables uninterrupted audio recording of BGM and the like during scene switching.

FIG. 3 is a conceptual diagram showing the concept of memory control in this embodiment.

The upper row shows the recording state when the camera is photographed by turning the trigger key 48 ON and OFF, and the diagonally shaded period shows the state in which recording is being performed, with the horizontal axis representing time.

Correspondingly, the memory control circuit 40 operates to read audio data from the audio memory 39 only when the trigger key 48 is ON. This situation is shown in the middle row with the address of the memory 39 on the horizontal axis.

The lower row shows the state of the playback screen corresponding to the audio from the memory during playback, with the horizontal axis representing time.

Furthermore, detailed timing regarding memory addresses is shown in FIG. In FIG. 4, (a) shows the HSP (head switching pulse), which is inverted every unit of track formation (one field period), and FIG. 4(b) shows the instruction pulse from the trigger key 48, ( C) is a recorder mode, and the recorder mode control signal (d) is a recorder mode control signal that inverts REC (recording) and REC Bose (recording standby) in synchronization with the inversion of HSP every time a trigger pulse (b) is input. A servo motor control signal that switches the tape between running (RUN) and stopping (STOP) in response to signal (C);
(e) is a memory mode control signal instructed from the memory control circuit 40 to the memory 39, and this signal (e) stores the audio signal in the memory only when a track is formed in accordance with the servo mode control signal (d). This is a mode signal that switches between an RE (read enable) mode in which reading is possible from the track 39 and an REInv (read prohibited) mode, which is the opposite, on a track-by-track basis. ．． FIG. 4(f) shows the address control signal of the audio memory 39 in the memory control circuit 4.
This signal indicates the address specified to the memory 39 from 0. The upper bits of this address correspond to each track, and the lower bits are reset at each HSP inversion timing. Note that the dotted address slanted line conceptually shows, as in Figure 3, how the tape is stopped during recording (corresponding to the arrow) and the time during playback is clogged and the tape is played back continuously. .

As is clear from Fig. 4, only when the tape is running to record the video signal from the camera, the mote of the memory 39 is set to read mode and the memory address is counted up, so that the audio such as BGM can be transferred to the memory address during continuous shooting. Continuous reading is possible.

Next, the operation of the system controller 41 during continuous shooting as described above will be explained with reference to the flowchart of FIG. 5 and the timing chart of FIG. 6.

First, when the system controller 41 starts operating according to the flowchart in FIG. 5 by turning on a power key (not shown), the memory control circuit 40 resets the address of the memory 39.
(Step Sl). And after this,
When the trigger key 48 is turned on (step S2), an instruction to start tape running is output to the servo circuit 34 (step S3). After the tape starts running, when the servo circuit 34 detects that the tape speed is locked to a predetermined speed (step S4), the mode of the VTR is set to recording mode in synchronization with the HSP (step 35), and the data is stored in the memory 39. data can be read (step S6). still,
In this flowchart, it is assumed that the BGM key 46 is on, that is, the VTR is set to a mode in which data is read from the memory 39.

In this state, as described above, the audio signal processing circuit 14
, the video signal from the video signal processing circuit 5 , and the pilot signal for tracking control from the pilot signal generation circuit 33 are added by the adder 6 and recorded on the table 17 . The pilot signal generation circuit 33 cyclically switches and outputs four types of pilot signals every one field period according to, for example, HSP. In addition, in this state, the system control microcomputer supplies information indicating that the audio from the memory 39 is being recorded to the character generation circuit 30, and the circuit 30 converts this information into a video signal corresponding to a visually recognizable character. is converted into and supplied to the adder 32. As a result, while recording audio from the memory 39, the electronic viewfinder (EVF) 31
The above character is displayed together with the image being photographed.

In this state, the address counter in the memory control circuit 40 counts (step S7). Also, P.G.
Each time the edge of
The n expanded data output from 3 and the upper bits of the address data currently being counted are written to the memory 44 (
Step S9). At this time, the upper bits of the address data written into the memory 44 become those at time t-1 in FIG.

When a stop key (not shown) or the like is turned on in step SIO in the recording state, the VTR enters the stop mode and ends the process.

On the other hand, when the trigger key 48 is turned on again, the recording of the second field video signal recorded on the even track is completed at the next rising timing of HSP (the timing shown in FIG. 6), but in reality, the switch 15- B is t. It is turned off after a period in which the rotary head rotates 5 degrees from the timing of . 6(C) and (d) are heads 1 6-A,
16-B shows the supply timing of the recording signal. Therefore, the recording on the tape 17 is configured to end after the recording on the even numbered tracks An is completely completed.

Here, since the mode of the memory 39 is controlled on a track-by-track basis, the falling timing of the next HSP (T in FIG.
, the reading of the audio information from the memory 39 is stopped (step S11) and the counting of the address counter is also stopped (step S12), thereby stopping the reading of audio information from the memory 39.

Then, the servo circuit 34 is used to rewind the tape 17 by a predetermined amount, and the amount rewound at this time is set to the above-mentioned t. The timing is set to O and stored as several tracks (step S13).

At this point, the VTR is set to a recording pause mode (step S14) and waits for the trigger key 48 to be turned on again.

When the trigger key 48 is turned on, the mode of the VTR is first set to playback mode, and the servo circuit 34 is controlled to restart tape running (step S16). Then, the current number T of rewinding tracks is corrected by counting down from the above-mentioned number of tracks by the number of tracks that have advanced as the tape runs. Then, when T=-1 (step 318) and completion of servo lock is confirmed (
Step 319), n pieces of expanded data and the upper bits of the address data stored in the memory 44 are fetched (Step S20), and this data is set in the address counter in the memory control circuit 40 (Step S21). As a result, reading from the memory 39 is started from the timing when T=-1 (shown in FIG. 6 τ-1) (step S
22), the read address at this time is determined by using the upper bits of the address data stored in the memory 44 at timing t-1 and resetting the lower bits. When the memory 39 starts reading, the counting operation of the address counter is restarted (step S23), and the reading from the memory 39 is restarted. At this time, the decompressor 43 decompresses the audio data using n decompressed data from the system control microcomputer 41. It is decoded and supplied to the D/A converter 45.

After this, the switch 15-A is turned on earlier than the next HSP rise timing τ0 by the period during which the rotary head rotates 5 degrees, and the recording of the signal by the head 16-A is started.
The device returns to recording mode (step S5). As a result, signal recording starts from the overlapping portion of track B in FIG. 2, and the same audio signal corresponding to the diagonal portion in FIG. 6 is recorded redundantly in track An and track B. become.

By the above-described procedure, the audio signal stored in the memory can be recorded as a continuous audio signal even at the joint portion of the video signal, and the audio signal can be recorded in an overlapping manner between adjacent tracks.

Further, at this time, since the read address of the memory 39 is always controlled on a track-by-track basis, the control determination of the address of the memory 39 can be performed extremely easily.

[Effects of the Invention] As is clear from the description of the embodiments described above, according to the video signal recording system of the present invention, it is possible to easily record predetermined audio that is separately formed even when recording a video signal.
Moreover, the continuity is not impaired. Furthermore, it is possible to record separately formed audio for a relatively long time without increasing the capacity of the recording means.

[Brief explanation of drawings]

Figure 1 shows a camera-integrated VTR as an embodiment of the present invention.
Figure 2 shows the schematic configuration of the recording system of the VTR shown in Figure 1.
Figure 3 is a diagram conceptually showing the continuous shooting operation of the VTR shown in Figure 1, Figure 4 is a diagram showing detailed timing regarding the address of the VTR shown in Figure 1, and Figure 5 is Figure 1 is a flowchart to explain the operation of the VTR, Figure 6 is a timing chart to explain the operation of the VTR in Figure 1 during continuous shooting, and Figure 7 is an example of conventional additional recording of audio signals. It is a figure for explaining. In the figure, 5 is a video signal processing circuit, 8 is a microphone, and 10 is a video signal processing circuit.
is a balancer, 14 is an audio signal processing circuit, 16-A
, 16-B is a magnetic head, 17 is a magnetic tape, 18 is a cab stan, 35 is an external audio input terminal, 37 is an A/D converter, 39 is an audio memory (first storage means), and 40 is a memory control circuit. , 41 is a system control microcomputer,
42 is an operation unit, 44 is a memory (second storage means), 55
is a memory unit. A brave figure

Claims (2)

[Claims] (1) A device for recording an audio signal and a video signal on a recording medium, a compression means for compressing the information amount of the audio signal, and a first storage capable of storing a so-called period of audio signals compressed by the compression means. and an expansion means for expanding the information amount of the audio signal read from the first storage means, the audio signal output from the expansion means can be recorded on the recording medium together with the video signal, and . A video signal recording system comprising: second storage means for storing a part of the audio signal expanded by the expansion means in response to stopping of the recording. (2) In the system according to claim (1), the device is a device that performs recording while forming a large number of parallel tracks on the recording medium, and the device is a device that performs recording while forming a large number of parallel tracks on the recording medium, and The video recording apparatus is characterized in that it comprises a control means capable of controlling the read address in units of one track, and the second storage means stores the read address and a part of the expanded audio signal in association with each other. Signal recording system.