JP4470959B2 - Recording / playback device - Google Patents

Description

  The present invention relates to a recording / reproducing apparatus that compresses and records an input signal such as a video signal or an audio signal on a recording medium.

A recording / reproducing apparatus that records an input signal such as a video signal or an audio signal uses a magnetic disk, an optical disk, or the like as a recording medium.
When recording an input signal, the recording / reproducing apparatus compresses the input signal at a predetermined compression rate and records it on a recording medium.
At the time of reproduction, the input signal is restored by reproducing and expanding the compressed and recorded signal.

  In the recording / reproducing apparatus, for example, when two compression rates are prepared, an input signal can be recorded for a long time by using a large compression rate, and an input signal can be recorded in a short time by using a small compression rate. Can be recorded over. When a large compression rate is used, when the input signal is restored, the quality (image quality and / or sound quality) of the input signal obtained by the restoration may be deteriorated.

Japanese Patent Laid-Open No. 10-257422 (Patent Document 1) discloses an invention of an image recording / reproducing apparatus.
In this publication, in the image recording / reproducing apparatus, during recording of a moving image, the recorded image data is decoded and re-encoded with different compression characteristics without interrupting the recording of the moving image, and the same recording medium Re-recording is disclosed.

Japanese Patent Laid-Open No. 6-76474 (Patent Document 2) discloses an invention of a digital data recording apparatus and a digital data recording method.
In this publication, there are taken-in means for taking in a capacity capable of recording information on a recording medium and the length of information to be recorded, compression means for compressing data obtained by digitizing information to be recorded, An invention of a digital data recording apparatus having a compression rate control means for controlling a compression rate of data in the compression means corresponding to an output and a recording means for recording digital data compressed by the compression means on the recording medium is disclosed. Has been.

Japanese Patent Laid-Open No. 10-257422 JP-A-6-76474

In a recording / reproducing apparatus having a plurality of recording modes with different compression rates, for example, a disc camcorder, the user of the recording / reproducing apparatus may not recognize the recordable recording capacity (remaining amount) of the recording medium, and may be used. In some cases, a person does not prepare a spare recording medium.
For this reason, the recording area of the recording medium in use may be used up and the signal may be recorded on the recording medium only halfway.
An object of the present invention is to provide a recording / reproducing apparatus capable of extending a recording time for recording a signal on a recording medium in accordance with a recordable recording capacity (remaining amount) of the recording medium.

According to the present invention, there is provided a recording / reproducing apparatus for compressing an input signal and recording it on a recording medium,
A first compressing means for generating a compressed signal by compression of the input signal,
A first buffer memory in which the compressed signal the first compression means has generated is subjected fed,
Recording means for recording the compressed signal supplied to the first buffer memory in a recording area of the recording medium;
If record possible remaining in the recording area of the recording medium is less than a set amount, reading means for reading the compressed signal from the recording area of the recording medium,
A third buffer memory to which the compressed signal read from the reading means is supplied when the capacity that can be recorded in the recording area of the recording medium is less than a set amount ;
Decompression means for decompressing the compressed signal supplied from the third buffer memory when the recordable capacity in the recording area of the recording medium is less than a set amount ;
Wherein when a recordable capacity in the recording area of the recording medium is less than the set amount, the input signal restored by said expansion means, said first compressing means when the remaining amount is equal to or greater than the set value Second compression means for generating a compressed signal by compressing at a compression rate greater than the compression rate;
A second buffer memory that is supplied with the compressed signal generated by the second compressing means and outputs the supplied compressed signal to the recording means;
Have
When the remaining amount of the recording medium is equal to or greater than the set value,
The first compression means compresses the input signal at a first compression rate, and transfers the compressed signal to the first buffer memory at a first transfer rate corresponding to the first compression rate;
When the remaining amount of the recording medium is less than the set value,
The first compression means compresses the input signal at a second compression rate larger than the first compression rate, and the compressed signal is compressed at a second transfer rate corresponding to the second compression rate. Transfer to the first buffer memory,
The second compression means compresses the signal read by the reading means at a third compression rate larger than the second compression rate, and the compressed signal is converted into a third compression rate corresponding to the third compression rate. Transfer to the second buffer memory at a transfer rate;
When the transfer speed at which the compressed signal read by the reading means is supplied to the decompression means is n times the transfer speed during normal reproduction, the remaining amount of the recording medium is less than the set value. The transfer speed (R3) for transferring the signal compressed by the first compression means to the first buffer memory is:
[(R1-R2) × n] is a positive value less than or equal to
However,
R1 is a transfer rate for transferring a compressed signal from the first compression means to the first buffer memory;
R2 is a transfer rate for transferring a compressed signal from the second compression means to the second buffer memory.
A recording / reproducing apparatus is provided.

Preferably, the recording means and the reading means have a first operation for recording the compressed signal from the first buffer memory and a second operation for recording the compressed signal from the second buffer memory. And a third operation for reproducing the compressed signal from the recording medium and supplying the compressed signal to the decompression means in a time-sharing manner, wherein the first buffer memory is configured to perform the second operation and / or the third operation. The compressed signal generated by the first compression unit during operation is held, and the second buffer memory is stored in the second compression unit during the first operation and / or the third operation. The generated compressed signal is held.

Preferably, the transfer rate at which the first buffer memory supplies the compressed signal to the recording unit, the transfer rate at which the second buffer memory supplies the compressed signal to the recording unit, and the reading unit include The transfer speed for reproducing the signal and supplying it to the decompression means is set to a value that does not interrupt the recording of the input signal.

Preferably, the recording / reproducing apparatus sets the first compression rate of the first compression unit to the same value as the second compression rate when the remaining amount of the recording medium is less than the first set value. And a control circuit to be set.

Preferably, the recording / reproducing apparatus further includes a microphone that is supplied with an audio signal and outputs the audio signal as the input signal to the first compression unit.
Preferably, the recording / reproducing apparatus further includes a speaker that is supplied with the input signal restored by the decompression unit and outputs the supplied input signal as a sound.
More preferably, the recording / reproducing apparatus further includes an imaging circuit that generates a video signal and outputs the video signal as the input signal to the first compression unit.

Preferably, the recording medium is a magnetic disk, the recording means is a hard disk device, and the first and second buffer memories are semiconductor memories.

Preferably, the recording medium is a phase change type optical disc, the recording means is an optical disc apparatus, and the first and second buffer memories are semiconductor memories.

Preferably, the recording medium is detachable from the recording / reproducing apparatus, and the recording / reproducing apparatus comprises a disc camcorder.

In the recording / reproducing apparatus according to the present invention, the recording means records the compressed signal from the second buffer memory by overwriting the recording area when the remaining amount of the signal that can be recorded on the recording medium is less than the set value. In this way, an empty area is secured in the recording area, and the compressed signal from the first buffer memory is recorded in the remaining area of the recording area and the empty area, so the recording time of the input signal is extended by using the empty area. Is possible.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

First Embodiment FIG. 1 is a schematic block diagram showing a first embodiment of a recording / reproducing apparatus according to the present invention.
The recording / reproducing apparatus 1 includes an imaging circuit 2, a microphone 3, an A / D conversion circuit 4, a first compression circuit 5, a first buffer memory 6, a second buffer memory 13, and a third buffer. The buffer memory 10, the decompression circuit 11, the second compression circuit 12, the D / A conversion circuit 14, the output device 15, the control circuit 16, the remaining amount detection circuit 8, and the disk device 7. For example, a disc camcorder.

The image pickup circuit 2 has a CCD (Charge Coupled Device), picks up an image of a subject using the CCD, generates an analog video signal, and outputs the video signal to the A / D conversion circuit 4.
The microphone 3 is supplied with audio signals in analog form, the microphone 3 outputs the audio signal to be electro-acoustic conversion into an electrical signal from the acoustic signal A / D conversion circuit 4.

The A / D conversion circuit 4 converts the audio signal from the microphone 3 from an analog signal to a digital signal and outputs the signal to the first compression circuit 5.
The A / D conversion circuit 4 converts the video signal from the imaging circuit 2 from an analog signal to a digital signal and outputs the converted signal to the first compression circuit 5.

The first compression circuit 5 is supplied with the video signal and the audio signal from the A / D conversion circuit 4 as input signals, and the first compression circuit 5 compresses the input signal with the first compression rate C11 to obtain a compressed signal. The MPEG2 signal is generated, and this MPEG2 signal is output to the first buffer memory 6.
The first compression circuit 5 outputs the MPEG2 signal to the first buffer memory 6 as an MPEG2 signal having a transfer rate of, for example, a first transfer rate R11 = 14 Mbps (megabits / second). The first compression circuit 5 converts the MPEG2 signal at a transfer rate (first transfer rate R11) that is at least three times the minimum transfer rate (or average transfer rate) required for recording the input signal in real time. The data is output to the first buffer memory 6 .

The first buffer memory 6 stores the MPEG2 signal transferred from the first compression circuit 5, and the stored MPEG2 signal is stored in the disk device 7 via the switching circuit 9 before the first buffer memory 6 overflows. Output intermittently.

The disk device 7 records the MPEG2 signal from the switching circuit 9 in the recording area of the disk type recording medium 100. As an example, the disk type recording medium 100 is a magnetic disk, and the disk device 7 is a hard disk device.
This hard disk device is preferably a type that can be replaced with a spare part, for example, a replaceable device or a removable hard disk device that complies with PCMCIA (Personal Computer Memory Card International Association), but may be a normal fixed hard disk device.

The remaining amount detection circuit 8 monitors the recording capacity (remaining amount) that can be recorded in the recording area of the disk type recording medium 100 and supplies a signal indicating the remaining amount to the control circuit 16.

The control circuit 16 is a controller that controls the entirety of the recording / reproducing apparatus 1, and is configured by, for example, a microcomputer.
The control circuit 16, when the small lost than the first set amount of recordable recording capacity in the recording area of the disk-type recording medium 100 (the remaining amount) is set in advance, the first compression circuit 5 first 1 compression ratio, twice the compression ratio C11 values when the remaining amount is first set amount or more, i.e., is increased to C12 (= 2 × C11), corresponding to the change of the compression ratio C12 to half the transfer rate of the MPEG2 signal, from top Symbol transfer speed R11 of value when the remaining amount is first set amount or more (14 Mbps) from the first compression circuit 5 to the first buffer memory 6 Transfer rate R12 = R11 / 2, for example, 7 Mbps.

Further, the control circuit 16, when the small lost than the first set amount of recordable recording capacity in the recording area of the disk-type recording medium 100 (the remaining amount) is set in advance, the first reproduction command signal Generate and output to the disk device 7.
Based on the first reproduction command signal, the disk device 7 reads and reproduces the MPEG2 signal compressed at the compression ratio C11 recorded when the remaining amount is equal to or greater than the first set amount. Is output to the third buffer memory 10 via the switching circuit 9. The disk device 7 reads, reproduces, and outputs the MPEG2 signal at a triple speed, which is three times the normal reproduction speed, for example.

The third buffer memory 10 is supplied MPEG2 signal disk device 7 is reproduced, the third buffer memory 10 is output to the decompression circuit 11 accumulates the MPEG2 signal.
Decompression circuit 11 decompresses the MPEG2 signal inputted from the third buffer memory 10, is compressed by the first compression circuit 5 to restore the signals stored in the disk device 7, the reconstructed signal second To the compression circuit 12 and the D / A conversion circuit 14.

The D / A conversion circuit 14 is supplied with the signal restored by the decompression circuit 11 during normal reproduction, converts the supplied signal from a digital signal to an analog signal, and outputs the converted signal to the output device 15.
The output device 15 includes a display device 15D and a speaker 15S. The display device 15S displays an image of the video signal included in the signal from the D / A conversion circuit 14 on the display screen. The speaker 15S performs electroacoustic conversion of an audio signal included in the signal from the D / A conversion circuit 14 from an electric signal to an acoustic signal and outputs the audio.

The second compression circuit 12 is supplied with the MPEG2 signal compressed by the compression ratio C11 restored by the decompression circuit 11 , and compresses this signal at the compression ratio C21 to generate an MPEG2 signal which is a compressed signal. The MPEG2 signal thus output is output to the second buffer memory 13.
The second compression circuit 12 outputs the generated MPEG2 signal to the second buffer memory 13 as an MPEG2 signal having a transfer rate R21 of 7 Mbps, for example.
The second compression circuit 12 outputs the MPEG2 signal to the second buffer memory 13 at a transfer rate R21 that is at least three times the minimum transfer rate necessary for recording the signal restored by the decompression circuit 11 in real time. To do.
As an example, the compression ratio C21, the compression ratio C12 of the first compression circuit 5 recordable recording capacity in the recording area of the disk-type recording medium 100 (the remaining amount) of time less than the first set amount ( = 2 × C11) , that is, C21 = 2 × C12 (or C21 == 4 × C11 ).

The second buffer memory 13 stores the MPEG2 signal compressed at the compression rate C21 from the second compression circuit 12, and switches the stored MPEG2 signal before the recording capacity of the second buffer memory 13 overflows. Output intermittently to the disk device 7 via the circuit 9.

The disk device 7 receives the MPEG2 signal from the second buffer memory 13 when the recording capacity (remaining amount) that can be recorded in the recording area of the disk type recording medium 100 is less than a preset first setting value. A free area is generated in the recording area by overwriting the corresponding recording area of the disc type recording medium 100 for recording.
Then, the MPEG2 signal from the first buffer memory 6 compressed by the first compression circuit 5 and transferred to the first buffer memory 6 is converted into the remaining area of the recording area of the disk type recording medium 100 and the Record in free space.

When the recording capacity (remaining amount ) that can be recorded in the recording area of the disk type recording medium 100 becomes less than the second set amount, the control circuit 16 sets the compression rate compression rate C12 of the first compression circuit 5 to the disk type recording. The compression rate C11 when the remaining amount of the medium 100 is equal to or larger than the first set amount is set to four times (C12 = 4 × C11) , and the second reproduction command signal is output to the disk device 7.
Based on the second reproduction command signal, the disk device 7 reproduces the MPEG2 signal recorded on the disk type recording medium 100 when the remaining amount is equal to or larger than the second set amount, and this MPEG2 signal is sent to the switching circuit 9. To the third buffer memory 10.

The third buffer memory 10 is supplied again with the MPEG2 signal reproduced by the disk device 7, and the third buffer memory 10 accumulates the MPEG2 signal and outputs it to the decompression circuit 11.
The decompression circuit 11 decompresses the MPEG2 signal from the third buffer memory 10, restores the input signal again, and supplies the restored signal to the second compression circuit 12.

The second compression circuit 12 is supplied reconstructed signal by the decompression circuit 11, a second compression circuit 12 is again compressed and the compressed signal at a compression rate C22 set to 4 times the compression ratio C11 the signal Is generated in real time, and this MPEG2 signal is output to the disk device 7 via the second buffer memory 13.
The second compression circuit 12 outputs the MPEG2 signal as an MPEG2 signal having a transfer rate R22 of 3.5 Mbps, for example.

When the recording capacity (remaining amount) that can be recorded in the recording area of the disk type recording medium 100 is less than the second set value, the disk device 7 receives the MPEG2 signal from the second buffer memory 13 as the disk type recording medium. By overwriting again in the 100 recording area and recording again, an empty area is secured again in the recording area. Then, the MPEG2 signal from the first buffer memory 6 is recorded in the empty area.

The disk device 7 includes a first recording operation for recording the MPEG2 signal from the first buffer memory 6, a second recording operation for recording the MPEG2 signal from the second buffer memory 13, and a disk-shaped recording medium 100. ck operation and you supplied to the third buffer memory 10 to reproduce the MPEG2 signal from, performed by time division.
The control circuit 16 controls the switching circuit 9 to switch between the first to third buffer memories 6, 13, and 10 and the disk device 7 by using the switching circuit 9.
First buffer memory 6, the second recording operation during and / or holds the MPEG2 signal generated by the first compression circuit 5 during playback operation.
Second buffer memory 13, the first recording operation during and / or holds the MPEG2 signal generated by the second compression circuit 12 during playback operation.

Transfer rate and supplies the first buffer memory 6 is MPEG2 signal in the disk device 7, the transfer rate and supplies the second buffer memory 13 is MPEG2 signal in the disk device 7, and the disk device 7 reproduces the MPEG2 signal The transfer speed supplied to the third buffer memory 10 is set to a value that does not interrupt the recording of the input signal onto the disk type recording medium 100 .

As an example, when the recording capacity (remaining amount) that can be recorded in the recording area of the disc type recording medium 100 is less than the first set value , the MPEG2 signal reproduced by the disc device 7 passes through the third buffer memory 10. When the transfer rate supplied to the decompression circuit 11 is n times the transfer rate during normal reproduction, the following relationship is established.
0 <R13 ≦ (R12−R21) × n .
However,
R11 is a transfer speed at which the first compression circuit 5 outputs the MPEG2 signal to the first buffer memory 6 when the remaining amount of the disk type recording medium 100 is equal to or greater than the first set value .
R12, when a disk-type recording medium 100 remaining is less than the first set value, a transfer rate first compression circuit 5 outputs the MPEG2 signal to a first buffer memory 6,
R1 3 is a disk-type recording medium 100 remaining amount is less than the first set value, in the case of more than the second set value, transfers a first compression circuit 5 outputs the MPEG2 signal to a first buffer memory 6 Speed ,
R21 operates when the remaining amount of the disk type recording medium 100 is less than the first set value, and the second compression circuit 12 compresses the signal reproduced by the disk device 7 and decompressed by the decompression circuit 11. This is the transfer rate at which a signal is output to the second buffer memory 13 .
In the case of n = 1, there is an advantage that the decompression circuit 11 can perform the decompression operation at the operation speed at the normal reproduction, and the cost of the decompression circuit 11 can be reduced.

2 to 4 are explanatory diagrams showing recording areas of the disk type recording medium 100. FIG.
The recording area 120 of the disc type recording medium 100 in FIG. 2 has a written area 102 and a remaining area 103. In the recording area 120, signals are recorded from the inner circumference side to the outer circumference side. Note that a center hole 101 is formed in the disk type recording medium 100.
The MPEG2 signal from the first buffer memory 6 is supplied to the disk device 7 at a transfer rate R11 = 14 Mbps, and the supplied MPEG2 signal is recorded in the area 102.
The remaining area 103 is an area where no MPEG2 signal has been recorded yet.

FIG. 3 shows a state in which the remaining recordable amount in the recording area 120 of the disc type recording medium 100 is less than the first set amount.
In this case, the MPEG2 signal from the first buffer memory 6 is supplied to the disk device 7 at a transfer rate R12 = 7 Mbps, and the supplied MPEG2 signal is recorded in the area 104. This area 104 corresponds to the first set amount.

The disk device 7 reads out and reproduces the MPEG2 signal from the innermost periphery of the used area 105, and the reproduced MPEG2 signal is compressed again through the decompression circuit 11 and the second compression circuit 12, and the second buffer memory. 13 is supplied. The recompressed MPEG2 signal is supplied from the second buffer memory 13 to the disk device 7 at a transfer rate R21 = 7 Mbps. The supplied MPEG2 signal is overwritten from the innermost periphery of the area 105 and recorded in the area 106. An empty area 107 is generated in the area 105.
In this way, the MPEG2 signal once compressed is expanded, compressed by the second compression circuit 12 at a higher compression rate, and recorded again in the corresponding area of the disk type recording medium 100, thereby recording area 105. An empty area 107 can be generated in the disk, and even when the recording area on the outer periphery side of the disk is exhausted, the signal can be further recorded and the recording time can be extended.

In FIG. 4, when the remaining amount of the disk type recording medium 100 is less than the first set amount, the MPEG2 signal supplied from the first buffer memory 6 to the disk device 7 at a transfer rate of 7 Mbps is recorded in the area 107. Has been.
The disk device 7 reads out and reproduces the MPEG2 signal from the innermost periphery of the used area 108, and the reproduced MPEG2 signal is compressed again through the decompression circuit 11 and the second compression circuit 12, and the second buffer memory. 13 is supplied. The recompressed MPEG2 signal is supplied from the second buffer memory 13 to the disk device 7 at a transfer rate of 7 Mbps, and the supplied MPEG2 signal is overwritten from the innermost periphery of the area 108 and recorded in the area 109. An empty area 110 is generated in the area.
In this way, the free space 110 can be generated in the area 108 by reading the MPEG2 signal once compressed from the disk type recording medium 100, decompressing it, compressing it at a higher compression rate, and recording it again. Even if the recording area on the outer circumference side of the disk is used up, the signal can be further recorded by using the empty area 110, and the recording time can be extended.

Second Embodiment FIG. 5 is a schematic block diagram showing a second embodiment of the recording / reproducing apparatus according to the present invention.
The recording / reproducing apparatus 21 includes an imaging circuit 2, a microphone 3, an A / D conversion circuit 4, a compression circuit 27, a fourth buffer memory 25, a fifth buffer memory 32, and a sixth buffer memory. 35, a decompression circuit 31, a D / A conversion circuit 14, an output device 15, a control circuit 36, a remaining amount detection circuit 8, a disk device 7, and switching circuits 26 and 28, for example, a disk It consists of a camcorder.
In the recording / reproducing apparatus 21 of FIG. 5, the same components as those of the recording / reproducing apparatus 1 of FIG.

The A / D conversion circuit 4 converts the audio signal from the microphone 3 from an analog signal to a digital signal and outputs it to the fourth buffer memory 25.
The A / D conversion circuit 4 converts the video signal from the imaging circuit 2 from an analog signal to a digital signal and outputs the converted signal to the fourth buffer memory 25.

  The fourth buffer memory 25 is supplied with the video signal and the audio signal as input signals from the A / D conversion circuit 4, accumulates the input signals, and passes the accumulated MPEG2 signal through the switching circuit 26 before overflowing. This is supplied to the compression circuit 27.

The compression circuit 27 is supplied with an input signal from the fourth buffer memory 25, compresses this input signal at the fourth compression rate C 14 to generate an MPEG2 signal that is a compression signal, and the generated MPEG2 signal is switched to the switching circuit 28. To the disk device 7 at a transfer rate R14 .
The compression circuit 27 outputs the MPEG2 signal to the disk device 7 as an MPEG2 signal having a transfer rate R14 of 14 Mbps, for example. The compression circuit 27 outputs the MPEG2 signal at a transfer rate R14 that is at least three times the minimum transfer rate required to record the input signal to the disk device 7 in real time.

The disk device 7 records the MPEG2 signal from the switching circuit 28 in the recording area of the disk type recording medium 100.
The remaining amount detection circuit 8 monitors the remaining amount that can be recorded in the recording area of the disk type recording medium 100 and supplies a signal indicating the remaining amount to the control circuit 36.

The control circuit 36 is a controller that controls the entire recording / reproducing apparatus 21 and is configured by, for example, a microcomputer.
The control circuit 36, when it becomes less remaining amount of the disk-type recording medium 100 than the first set amount that is set in advance, the remaining amount The compression ratio of the compression circuit 27 is first set amount or more Is increased to twice the value (C14), and the transfer rate of the compression circuit 27 is changed from 14 Mbps to 7 Mbps correspondingly .

Further, the control circuit 36 generates a first reproduction command signal and outputs it to the disk device 7 when the remaining amount of the disk type recording medium 100 becomes smaller than the first set amount.
Based on the first reproduction command signal, the disk device 7 reproduces the recorded MPEG2 signal when the remaining amount is not less than the first set amount, and this MPEG2 signal is sent to the decompression circuit 31 via the switching circuit 28. Output. For example, the disk device 7 reproduces and outputs the MPEG2 signal at a triple speed, which is three times the normal reproduction speed.

  The decompression circuit 31 decompresses the MPEG2 signal from the disk device 7 to restore the input signal, and supplies the restored input signal to the fifth buffer memory 32 and the sixth buffer memory 35.

The sixth buffer memory 35 is supplied with the input signal restored by the decompression circuit 31 during normal reproduction, and the sixth buffer memory 35 outputs the supplied input signal to the D / A conversion circuit 14.
The D / A conversion circuit 14 is supplied with an input signal from the buffer memory 35 of the 6, D / A conversion circuit 14 outputs the supplied signal to the output device 15 into an analog signal from a digital signal.
By providing the sixth buffer memory 35, it is possible to prevent the output device 15 from being interrupted when the output device 15 reproduces the input signal restored by the decompression circuit 31.

The fifth buffer memory 32 accumulates the input signal from the decompression circuit 31 and intermittently sends the accumulated input signal to the compression circuit 27 via the switching circuit 26 before the fifth buffer memory 32 overflows. Supply.
The compression circuit 27 is supplied with an input signal from the fifth buffer memory 32, compresses the input signal at the fifth compression rate C15 , generates an MPEG2 signal as a compressed signal in real time, and switches the MPEG2 signal to the switching circuit. The data is output to the disk device 7 via 28.
The compression circuit 27 outputs an MPEG2 signal obtained by compressing the input signal from the fifth buffer memory 32 at a transfer rate of 7 Mbps, for example. The compression circuit 27 outputs the MPEG2 signal at a transfer rate that is at least three times the minimum transfer rate (or average transfer rate) required to record the input signal restored by the decompression circuit 31 in real time.
As an example, the fifth compression rate C15 is set to be twice the fourth compression rate C14 when the remaining amount is less than the first set amount.

  When the remaining amount is less than the first set value, the disk device 7 records the MPEG2 signal generated by the compression circuit 27 compressing the input signal from the fifth buffer memory 32 on the disk-type recording medium 100. By recording over the area, an empty area is generated in the recording area. Then, the MPEG2 signal generated by compressing the input signal from the fourth buffer memory 25 by the compression circuit 27 is recorded in the remaining area and the free area of the recording area.

When the remaining amount becomes less than the second set amount, the control circuit 36 sets the fifth compression rate C15 to four times the fourth compression rate (C14) when the remaining amount is equal to or greater than the first set amount, 2 reproduction command signal is output to the disk device 7.
Based on the second reproduction command signal, the disk device 7 reproduces the recorded MPEG2 signal when the remaining amount is equal to or larger than the second set amount, and this MPEG2 signal is sent to the decompression circuit 31 via the switching circuit 28. Output.

The decompression circuit 31 decompresses the MPEG2 signal from the disk device 7, restores the input signal again, and supplies the restored input signal to the fifth buffer memory 32.
The fifth buffer memory 32 is supplied with the input signal restored again by the decompression circuit 31, accumulates this MPEG2 signal, and outputs it to the compression circuit 27 via the switching circuit 26.

  The compression circuit 27 is supplied with the input signal restored again by the decompression circuit 31 via the fifth buffer memory 32, and compresses the input signal again at the fifth compression ratio C15 to obtain the MPEG2 signal which is the compressed signal. The MPEG2 signal is generated and output to the disk device 7 via the switching circuit 28. The compression circuit 27 outputs the MPEG2 signal as an MPEG2 signal having a transfer rate of 3.5 Mbps, for example.

When the remaining amount is less than the second set value, the disk device 7 records the MPEG2 signal generated by the compression circuit 27 compressing the input signal from the fifth buffer memory 32 on the disk-type recording medium 100. By overwriting again in the area and recording, an empty area is secured in the recording area. Then, the MPEG2 signal generated by compressing the input signal from the fourth buffer memory 25 by the compression circuit 27 is recorded in the empty area.

The disk device 7 includes a fourth recording operation for recording the MPEG2 signal generated by compressing the input signal from the fourth buffer memory 25 by the compression circuit 27, and a compression circuit for the input signal from the fifth buffer memory 32. fifth recording operation and that 27 records the MPEG2 signal generated by compressing, the playback operation and you supplied to the decompression circuit 31 to reproduce a MPEG2 signal from the disk-like recording medium 100 is performed by time division.
The control circuit 36 controls the switching circuit 26 to switch between the fourth and fifth buffer memories 25 and 32 and the compression circuit 27 by using the switching circuit 26.
The control circuit 36 also controls the switching circuit 28 to switch between the compression circuit 27 and the decompression circuit 31 and the disk device 7 by the switching circuit 28.
Fourth buffer memory 25, the fifth recording operation during and / or of holding the input signal input during playback operation.
Fifth buffer memory 32, the fourth recording operation during and / or of holding the MPEG2 signal generated by the decompression circuit 31 during playback operation.

  The transfer rate at which the fourth buffer memory 25 supplies the input signal to the compression circuit 27, the transfer rate at which the fifth buffer memory 32 supplies the input signal to the compression circuit 27, and the disk device 7 reproduces the MPEG2 signal. The transfer rate supplied to the decompression circuit 31 is set to a value that does not interrupt the recording of the input signal input to the fourth buffer memory 25.

  In the recording / reproducing device 21, the disk device 7 vacates the recording area by recording the compressed signal generated by the compression circuit 27 compressing the input signal from the fifth buffer memory 32 by overwriting the recording area. Create a region. Further, since the compressed signal generated by the compression circuit 27 compressing the input signal from the fourth buffer memory 25 is recorded in the remaining area and the empty area of the recording area, the recording of the input signal is performed by using the empty area. It is possible to extend the time.

In the recording / reproducing apparatuses 1 and 21, a setting switch for setting the minimum value of the transfer speed to 7 Mbps is provided by manual operation, and a signal indicating the setting state of the setting switch is supplied to the control circuits 16 and 36, thereby transferring the transfer speed. The minimum value may be controlled.
Further, an image detection circuit that detects the complexity of the input image based on the spatial frequency or the like is provided, and a signal indicating the complexity is supplied to the control circuits 16 and 36 to control the minimum transfer speed. Good. For example, an image detection circuit may be provided between the decompression circuit 31 and the fifth buffer memory 32 in the recording / reproduction device 21, and an image detection circuit may be provided between the decompression circuit 11 and the compression circuit 12 in the recording / reproduction device 1. It may be provided.

Similarly, in the recording / reproducing apparatuses 1 and 21, a setting switch for setting the maximum value of the compression rate to 7 Mbps by manual operation is provided, and a signal indicating the setting state of the setting switch is supplied to the control circuits 16 and 36. It is good also as a structure which controls the maximum value of a compression rate.
In addition, an image detection circuit that detects the complexity of the input image based on the spatial frequency or the like is provided, and a signal indicating the complexity is supplied to the control circuits 16 and 36 to control the maximum value of the compression rate. Good.

In the recording / reproducing apparatuses 1 and 21, the disk type recording medium 100 is a magnetic disk and the disk apparatus 7 is a hard disk apparatus. However, the present invention is not limited to this. For example, the disk type recording medium 100 is a magneto-optical disk. Yes, the disk device 7 may be a magneto-optical disk device.
Further, the disc type recording medium 100 may be a phase change type optical disc, and the disc device 7 may be an optical disc device.
The recording / reproducing apparatuses 1 and 21 may be configured so that the disk-type recording medium 100 can be attached and detached. The first to sixth buffer memories may be constituted by semiconductor memories.
In addition, the said embodiment is an illustration of this invention and this invention is not limited to the said embodiment.

1 is a schematic block diagram showing a first embodiment of a recording / reproducing apparatus according to the present invention. It is the 1st explanatory view showing the recording area of a disc type recording medium. It is the 2nd explanatory view showing the recording area of a disc type recording medium. It is a 3rd explanatory drawing which shows the recording area of a disk type recording medium. It is a schematic block diagram which shows 2nd Embodiment of the recording / reproducing apparatus which concerns on this invention.

  DESCRIPTION OF SYMBOLS 1,21 ... Recording / reproducing apparatus, 2 ... Imaging circuit, 3 ... Microphone, 4 ... A / D conversion circuit, 5 ... 1st compression circuit, 6 ... 1st buffer memory, 7 ... Disk apparatus, 8 ... Remaining amount Detection circuit, 9, 26, 28 ... switching circuit, 10 ... third buffer memory, 11, 31 ... expansion circuit, 12 ... second compression circuit, 13 ... second buffer memory, 14 ... D / A conversion circuit , 15 ... output device, 15S ... speaker, 15D ... display device, 16, 36 ... control circuit, 25 ... fourth buffer memory, 27 ... compression circuit, 32 ... fifth buffer memory, 35 ... sixth buffer memory , 100: Disc type recording medium, 101: Center hole, 102, 104, 105, 106, 108, 109 ... area, 103: Remaining area, 107, 110 ... Empty area, 120 ... Recording area.

Claims (12)

A recording / reproducing apparatus for compressing an input signal and recording it on a recording medium,
A first compressing means for generating a compressed signal by compression of the input signal,
A first buffer memory in which the compressed signal the first compression means has generated is subjected fed,
Recording means for recording the compressed signal supplied to the first buffer memory in a recording area of the recording medium;
If record possible remaining in the recording area of the recording medium is less than a set amount, reading means for reading the compressed signal from the recording area of the recording medium,
A third buffer memory to which the compressed signal read from the reading means is supplied when the capacity that can be recorded in the recording area of the recording medium is less than a set amount ;
Decompression means for decompressing the compressed signal supplied from the third buffer memory when the recordable capacity in the recording area of the recording medium is less than a set amount ;
Wherein when a recordable capacity in the recording area of the recording medium is less than the set amount, the input signal restored by said expansion means, said first compressing means when the remaining amount is equal to or greater than the set value Second compression means for generating a compressed signal by compressing at a compression rate greater than the compression rate;
A second buffer memory that is supplied with the compressed signal generated by the second compressing means and outputs the supplied compressed signal to the recording means;
Have
When the remaining amount of the recording medium is equal to or greater than the set value,
The first compression means compresses the input signal at a first compression rate, and transfers the compressed signal to the first buffer memory at a first transfer rate corresponding to the first compression rate;
When the remaining amount of the recording medium is less than the set value,
The first compression means compresses the input signal at a second compression rate larger than the first compression rate, and the compressed signal is compressed at a second transfer rate corresponding to the second compression rate. Transfer to the first buffer memory,
The second compression means compresses the signal read by the reading means at a third compression rate larger than the second compression rate, and the compressed signal is converted into a third compression rate corresponding to the third compression rate. Transfer to the second buffer memory at a transfer rate;
When the transfer speed at which the compressed signal read by the reading means is supplied to the decompression means is n times the transfer speed during normal reproduction, the remaining amount of the recording medium is less than the set value. The transfer speed (R3) for transferring the signal compressed by the first compression means to the first buffer memory is:
[(R1-R2) × n] is a positive value less than or equal to
However,
R1 is a transfer rate for transferring a compressed signal from the first compression means to the first buffer memory;
R2 is a transfer rate for transferring a compressed signal from the second compression means to the second buffer memory.
Recording / playback device. The recording means and the reading means include a first operation for recording the compressed signal from the first buffer memory, a second operation for recording the compressed signal from the second buffer memory, and A third operation of reproducing the compressed signal from the recording medium and supplying the compressed signal to the decompression means is performed in a time-sharing manner.
The first buffer memory holds the compressed signal generated by the first compression means during the second operation and / or the third operation;
The second buffer memory holds the compressed signal generated by the second compression means during the first operation and / or the third operation.
The recording / reproducing apparatus according to claim 1. A transfer speed at which the first buffer memory supplies the compressed signal to the recording means; a transfer speed at which the second buffer memory supplies the compressed signal to the recording means; and a reading means for reproducing the signal. The transfer rate supplied to the decompression means is set to a value that does not interrupt the recording of the input signal.
The recording / reproducing apparatus according to claim 2. A control circuit for setting the first compression rate of the first compression means to the same value as the second compression rate when the remaining amount of the recording medium is less than the first set value;
The recording / reproducing apparatus according to claim 1. The recording / reproducing apparatus according to claim 1, further comprising a microphone that is supplied with an audio signal and outputs the audio signal as the input signal to the first compression unit. A speaker that is supplied with the input signal restored by the decompression unit and outputs the supplied input signal as audio;
The recording / reproducing apparatus according to claim 5. An imaging circuit that generates a video signal and outputs the video signal as the input signal to the first compression unit;
The recording / reproducing apparatus according to claim 1. The display further includes a display device that is supplied with the input signal restored by the decompression unit and outputs the supplied input signal as an image.
The recording / reproducing apparatus according to claim 7. The recording medium is a magnetic disk;
The recording means is a hard disk device;
The recording / reproducing apparatus according to claim 1, wherein the first and second buffer memories are semiconductor memories. The recording medium is a magneto-optical disk;
The recording means is a magneto-optical disk device,
The recording / reproducing apparatus according to claim 1, wherein the first and second buffer memories are semiconductor memories. The recording medium is a phase change optical disc,
The recording means is an optical disc apparatus;
The recording / reproducing apparatus according to claim 1, wherein the first and second buffer memories are semiconductor memories. The recording medium is detachable from the recording / reproducing apparatus,
The recording / reproducing apparatus according to claim 1, wherein the recording / reproducing apparatus comprises a disc camcorder.

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