JP2988968B2 - Digital signal playback device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reproducing a digital video signal and a digital audio signal for a moving image recorded at the same time.

[Prior Art] Current digital audio tape recorders (hereinafter referred to as "DATs") record and reproduce only digital audio signals.

[Problem to be Solved by the Invention] However, it is very convenient if not only a digital audio signal but also other signals, for example, a digital video signal for a moving image can be simultaneously recorded and reproduced.

When a digital video signal for a moving image is recorded in this way, if not only moving image display by normal reproduction but also special reproduction, for example, fast-forward reproduction, can be performed more easily.

Therefore, according to the present invention, when a digital video signal and a digital audio signal for a moving image recorded at the same time are reproduced, fast forward reproduction is enabled.

[Means for Solving the Problems] According to the present invention, a predetermined unit period is set as a compression reference period, and a digital signal is sequentially divided in units of N bits (N is an integer) for each compression reference period. The N-bit signal portion includes an image area, an audio area, and a control area that are independent of each other. In the image area in the compression reference period, reference image data corresponding to the first screen of the compression reference period is arranged. Subsequently, differential compressed image data from the reference image data corresponding to the remaining screens of the compression reference period are arranged, audio data for the compression reference period is arranged in the audio region in each compression reference period, and control in the compression reference period is performed. In a digital signal reproducing apparatus for reproducing and processing an area in which data used for signal reproduction is arranged, a reproduction at a normal speed and a reproduction at a predetermined speed are performed. Means for performing expansion processing of reference image data separated from an image area of a signal obtained by reproducing at a normal speed, and image data for one screen obtained by expansion processing. Means for repeatedly outputting.

[Operation] In the configuration described above, the reproduction at the normal speed and the reproduction at the predetermined double speed are alternately performed, the predetermined image data reproduced at the normal speed is decompressed, and the decompressed image data for one screen is processed. Can be repeatedly output, and as a result, a fast-forward image can be displayed on the monitor.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. In this example, a DAT is taken as an example of a recording / reproducing apparatus.

FIG. 2 shows the format of a digital signal recorded and reproduced in this embodiment. In the digital signal, a signal of a compression reference period is sequentially divided in units of, for example, 16 bits, 12 bits of bits [b15 to b4] are an image area, 3 bits of bits [b3 to b1] are an audio area, and bit [b0]. Of 1
The bit is used as a control area.

Here, the conventional audio sampling clock is 48 kHz
In z, as in the case of recording digital audio signals of two channels on the left and right, if the transmission rate of DAT is 48 kHz x 2 x 16 bits = 1536 kbps, the transmission rate of the image area is 48 kHz x 2 x 12 bits = 1152 kbps, The transmission rate in the voice area is 48 kHz × 2 × 3 bits = 288 kbps, and the transmission rate in the control area is 48 kHz × 2 × 1 bits = 96 kbps (see FIG. 3).

The recording data is configured as a predetermined period, in this example, one second as a unit period (hereinafter, referred to as a “compression reference period”). That is, in each compression reference period, the image area is 11
52000 bits, audio area 288000 bits, control area 960
It becomes 00 bits.

In this example, an NTSC video signal is used,
In the image area in each compression reference period, image data for 30 frames is arranged. In this case, the image data of 30 frames has too much information as it is. For example, 1
When the pixel data of the frame is 256H × 240V and the luminance signal Y, red color difference signal U, and blue color difference signal V are each 8 bits, the information amount for 30 frames is 256 × 240 × 8 × 30 × 3 = 44236800 bits.

Therefore, the image data for 30 frames is compressed within 1152000 bits.

For example, pixel data of 256 × 240 V is halved by the sub-sampling process.

A total of 24 bits of the luminance signal Y, red color difference signal U, and blue color difference signal V are compressed to 9 bits. Thus, the information amount for one frame is 256 × 240 × 1/2 × 9 = 276480 bits.

Further, the image data of the second frame to the 29th frame are each differential compressed image data using the image data of the first frame as reference image data, and the information amount of the differential compressed image data is, for example, 27200 bits. .

 Therefore, the information amount for 30 frames is 276480 × 1 + 27200 × 29 = 1065280 bits, which is within 1152000 bits.

The remaining 86720 bits are used for fixed length adjustment.

FIG. 4 shows a configuration example of recording data. At the beginning of the image area of each compression reference period, reference image data VB1, VB2,... Corresponding to the image data of the first frame are arranged, and then the difference corresponding to the image data of the second to 29th frames is provided. Compressed image data Δc1, Δc2, ..., Δc29
Are sequentially arranged.

In the audio area in each compression reference period, audio data for the compression reference period is allocated.

This audio data is data within 288000 bits.

For example, the ADPCM system is adopted as the audio data encoding system, and data compression is performed.

Thus, when the sampling frequency is 32 kHz, the sample is 4 bits, and the channel is 2 channels (stereo or monaural 2 channels), the information amount is 32 kHz × 4 bits × 2 channels = 256000 bits, which is data within 288000 bits. .

Note that the remaining 32000 bits are used for frequency adjustment.

As described above, the 16 bits b15 to b0 of the digital signal
The audio area is formed by 3 bits b3 to b1 of the above, and the transmission rate of the audio area is 96 kHz × 3 bits = 288 kbps (see FIGS. 2 and 3).

This can be considered as 32 kHz × 9 bits = 288 kbps. Therefore, for example, as shown in FIG. 5, audio data is allocated to 8 bits out of 9 bits, and the bit rate is adjusted. That is, 32 kHz × 8 bits = 256 kbps.

Further, a synchronization code section, a mode code section, and a control code section are provided in the control area in each compression reference period.

A plurality of synchronization code portions are provided in each compression reference period, and in this example, four synchronization code portions are provided at intervals of 0.25 seconds. For example, a 64 × 1 bit area is secured in each synchronization code section. A framing code is used as the synchronization code, and the four synchronization code parts are different types of synchronization code 1 respectively.
~ 4 are arranged.

As shown in FIG. 4, a synchronization code 1 is allocated to a synchronization code portion corresponding immediately before the next compression reference period, and synchronization codes 4 to 3 are assigned to three synchronization code portions earlier than the synchronization code portion.
Two are placed.

The mode code section is provided following each synchronization code section. That is, four compression reference periods are provided at intervals of 0.25 seconds. For example, a 64 × 1 bit area is secured in each mode code section.

In this case, the end of the mode code part arranged following the synchronization code part having the synchronization code 1 is arranged so as to be located at the beginning of the next compression reference period.

The same data is allocated to the four mode code parts in each compression reference period. In the mode code portion, data relating to image data, audio data, and the like to be distributed in the next compression reference period is allocated.

The following can be considered as data relating to image data.

Resolution data 256H × 240V 512H × 480V 768H × 480V Other Frame data 30 frames / sec 24 frames / sec 20 frames / sec 10 frames / sec Other Signal type data Luminance signal Y, red color difference signal U, blue color difference signal V Red signal R, green signal G, blue signal B and other data 24 bits (8 [Y, R] +8 [U, G] +8 [V, B]) 16 bits (6 [Y] +5 [U] +5 [ V]) 9 bits (compressed data of Y, U, V or R, G, B) Others The following can be considered as data relating to audio data.

Encoding data ADPCM PCM (linear) PCM (non-linear) Other bit data 4 bits, 6 bits, 8 bits, 10 bits, 12 bits, 16 bits, other Sampling frequency data 16 kHz, 32 kHz, 44.1 kHz, 48 kHz, Other Data of the number of channels 1 channel, 2 channels, etc. In addition to the data relating to the image data and the audio data described above, when there is a scene change in the next compression reference period as described later, Data indicating the presence or absence is also provided.

The control code section is provided following each mode code section. That is, four are provided in each compression period. For example, an area of 23136 × 1 bit is secured in each control code section.

The same data is allocated to the four control code parts in each compression reference period. The control code section is provided with microcodes for expanding image data, which are allocated in the next compression reference period, so that any compression method can be used during reproduction.

Although not shown in FIG. 4, a 736-bit guard area in which “0” is allocated to each bit is provided between the control code section and the synchronization code section.

As described above, the same data is allocated to the four mode code portions and the control code portion, so that at the time of reproduction,
The mode code and the control code can be efficiently obtained from any position, and the operation of the reproduction signal processing system described later can be smoothly controlled.

FIG. 6 shows the structure of recording data when a scene change has occurred.

When there is a scene change, the recording state of the image data is reset in the middle of the compression reference period (see time tc in FIG. 6). That is, from time tc, the reference image data VBN + 2 after the scene change and the differentially compressed image data Δc1, Δc2,... Are sequentially arranged and recorded in the image area.

Accordingly, the recording state of the data in the control area is also reset, and a synchronization code section having a synchronization code 1 is provided immediately before the reference image data VB N + 2. And, in the mode code part of the compression reference period before the scene change,
Data indicating that there is a scene change is provided.

FIG. 1 shows an example of a signal processing device used when recording and reproducing the recording data shown in FIGS. 4 and 6 by DAT.

 First, the recording system will be described.

The NTSC color video signal SV supplied to the video-in terminal 11 is amplified by an amplifier 12 and then decoded by a decoder 13.
Supplied to The decoder 13 outputs a luminance signal Y, a red color difference signal U, and a blue color difference signal V.
Supplied to

Further, the video signal SV output from the amplifier 12 is supplied to the synchronization separation / clock generation circuit 15. From the circuit 15, the frequency 8f sc / 3 (f
A clock CKR1 of 3.58 MHz (sc is a sub-carrier frequency for sc) is output, and this clock CKR1 is supplied to the A / D converter 14 as a sampling clock.

In the A / D converter 14, each of the signals Y, U, and V is 1
Sampling is performed so that the number of samples in the effective horizontal period becomes 256, and converted into a digital signal with 8 bits per sample.

The signals Y, U, and V output from the A / D converter 14 are supplied to the movable terminal of the changeover switch 16. Although the control line is not shown, the changeover switch 16 is switched and controlled by the controller 110 having a CPU.
, B, c, a,...

The fixed terminals on the a to c sides of the changeover switch 16 are RAMs 17a to 17
Connected to the input side of c. The writing and reading of the RAMs 17a to 17c are controlled by the RAM controller 120. In addition,
The operation of the RAM controller 120 is controlled by the controller 110.

The clock CCK1 output from the circuit 15 is supplied to the RAM controller 120, and the vertical synchronization signal VDR and the horizontal synchronization signal HDR are supplied as reference synchronization signals. The controller 110 is supplied with a clock CKR2 having a frequency of 8fs and output from the circuit 15 as a master clock, and is supplied with a vertical synchronization signal VDR and a horizontal synchronization signal HDR as reference synchronization signals.

Further, the controller 110 receives a bit clock BCK (shown in FIG. 7B) and a clock LRCK (shown in FIG. 7A) for switching the left and right channels from the DAT 130 by the DAT 130.
It is supplied as a reference clock for taking a timing of 30.

The operation of the DAT 130 is controlled by the controller 110.

In each of the RAMs 17a to 17c, 256 sample data in the horizontal direction and 240 sample data in the vertical direction are written for the signals Y, U, and V in one frame period connected to the changeover switches a to c, respectively. . 256H × for each of the signals Y, U, and V written to these RAMs 17a to 17c.
The 240 V data is repeatedly read twice in the following two frame periods.

The signals read from the RAM 17a are changeover switches 18a, 1
8b and 18c are supplied to the fixed terminals on the a side, a side and c side, respectively. The signal read from the RAM 17b is supplied to fixed terminals b, b, and a of the changeover switches 18a, 18b, 18c, respectively. The signals read from the RAM 17c are c-side, c-side, and b-side of the changeover switches 18a, 18b, and 18c, respectively.
Supplied to the fixed terminal on the side.

Although the control line is not shown, the changeover switches 18a to 18c are
Switching is controlled by the controller 110. When the changeover switch 16 is sequentially connected to the a side, the b side, the c side, the a side,... Every frame period, the changeover switches 18a to 18c are connected to the c side, the a side, the b side, and the c side. ,... Are sequentially connected.

Output signals of the changeover switches 18a to 18c are supplied to the image compression unit 19, respectively. The operation of the image compression unit 19 is controlled by the controller 110.

The image compression section 19 performs the following processing on the image data of the first frame among the image data of 30 frames constituting each compression reference period (1 second). First,
Sub-sampling processing is performed, and the number of samples in one frame for each of the signals Y, U, and V is reduced to half. Next, the 24-bit data is compressed to 9 bits. Thereby, the reference image data VBN is formed.

For the image data of the second to the 30th frames,
The following processes are respectively performed. First, a sub-sampling process is performed, and the number of samples in one frame for each of the signals Y, U, and V is reduced to half. Next, the 24-bit data is compressed to 9 bits. Further, a difference from the reference image data is obtained. As a result, differential compressed image data Δc1 to Δc29 are formed.

The reference image data VBN and the difference compressed image data Δc1 to Δc29 formed by the image compression unit 19 in each compression reference period are:
Video RA via connection switch 20 and changeover switch 21
The signals are supplied to M22a to M22c and sequentially written to a predetermined address.

Although the control lines are not shown, the connection switch 20 and the changeover switch 21 are controlled by the controller 110.
The connection switch 20 is turned on during recording. Selector switch
21 is a side, b side, c side, a side,
Are sequentially connected.

The writing and reading of the video RAMs 22a to 22c are controlled by the RAM controller 120.

In the video RAMs 22a to 22c, the reference image data VBN and the difference compressed image data Δc1 to Δc29 formed by the image compression unit 19 are written in one compression reference period in which the changeover switch 21 is connected to the ac side, respectively. It is.

The reference image data VBN and the differential compressed image data Δc1 to Δc29 written in the video RAMs 22a to 22c are read out in one subsequent compression reference period.

Reference image data V read from video RAMs 22a to 22c
The BN and the differential compressed image data Δc1 to Δc29 are supplied to the mixing circuit 24 via the changeover switch 23, and are arranged in the image area of the recording data.

Although the control line is not shown, the changeover switch 23 is controlled by the controller 110. The changeover switch 23 is
During the period during which the image data is read from the video RAMs 22a to 22b, they are connected to the a side to the c side, respectively. The operation of the mixing circuit 24 is controlled by the controller 110.

The left and right channel audio signals SA L and SAR supplied to the audio-in terminal 31 are amplified by an amplifier 32 and then supplied to an audio digital signal processor (audio DSP) 33.

The operation of the audio DSP 33 is controlled by the controller 110. In the audio DSP 33, the left and right channel audio signals SA L and SAR are sampled with a clock of 32 kHz, respectively, and furthermore, the RAM 34 is used.
Coding is performed by the ADPCM method so that one sample has 4 bits. As a result, audio data of 256000 bits is formed corresponding to each compression reference period.

The audio data formed by the audio DSP 33 is supplied to the mixing circuit 24 and arranged in the audio area of the recorded data as shown in FIG.

In this case, the audio data output from the audio DSP is controlled so as to correspond to the image data supplied to the mixing circuit 24.

Reference numeral 25 denotes a circuit for generating control data such as a synchronization code, a mode code, and a control code. The operation of the generation circuit 25 is controlled by the controller 110. Generator 2
The control data output from 5 is supplied to the mixing circuit 24 and is arranged in the control area of the recording data.

In this way, in the mixing circuit 24, recording data as shown in FIG. 4 is formed, and this recording data is supplied to the DAT 130 and recorded in the DAT format.

26 is a scene change detection circuit. The detection circuit 26 is provided with changeover switches 18a to 18c by the image compression unit 19.
Are supplied to two consecutive frames.
Then, based on the comparison position signal from the RAM controller 120, data at a plurality of sample points is compared, and it is determined whether or not the difference exceeds a specified value. When the predetermined number or more exceeds the specified value, it is determined that a scene change has occurred, and the determination signal is supplied to the controller 110 and the RAM controller 120.

If there is a scene change, the signal processing state is reset even during the one second compression reference period. That is, in the image compression unit 19, the formation of the reference image data VBN is started by the image after the scene change, and the switch 21 is also switched to the next video REM.

Note that the signal processing state of the audio system is also reset similarly to the video system. The operation of the control data generation circuit 25 is also controlled, so that the generation timing of the synchronization code is controlled, and data indicating a scene change is allocated to the mode code of the compression reference period before the scene change.

Thus, when there is a scene change, the mixed circuit
At 24, recording data as shown in FIG. 6 is formed, and this recording data is supplied to the DAT 130 and recorded in the DAT format.

FIG. 8 is a timing chart of a recording system for a video signal and an audio signal.

FIGS. 7A and 7B show a video signal SV and audio signals SAL and SAR supplied to terminals 11 and 31, respectively. VG1, VG
.., AG1, AG2,... Are video signals and audio signals in each compression reference period, respectively.

In the video RAMs 22a to 22c, compressed image data CVG1, CVG2,...
Are sequentially written.

In addition, even if not described above, the RAM 34 stores the video RAM 22 described above.
Similarly to the areas a to 22c, areas of the RAMs a to c are provided, and as shown in FIG. D, compressed audio data CAG1, CAG2,...

As described above, the video signal and the audio signal are processed at the same timing, and the DAT 130 stores the compressed image data CVG1 and CV
G2,... And the compressed audio data CAG1, CAG2,.

 Next, a reproduction system will be described.

Data reproduced from the DAT 130 as shown in FIGS. 4 and 6 is supplied to the separation circuit 41. The operation of the separation circuit 41 is controlled by the controller 110, and the image data, the audio data, and the control data are separated from the reproduction data.

The control data separated by the separation circuit 41 is supplied to a control data discrimination circuit 42, and a synchronization code, a mode code,
The control code is determined, and the result of the determination is supplied to the controller 110. Then, under the control of the controller 110, an image decompression unit and an audio DSP
And the like, processing corresponding to the format and compression method of the reproduced image data and audio data is performed.

This makes it possible to deal with any case of reproduced image data and audio data. In addition,
Hereinafter, a case where data as shown in FIG. 4 or FIG. 6 is reproduced will be described.

Reference numeral 43 denotes a synchronization signal and clock generation circuit. The operation of the generation circuit 43 is controlled by the controller 110. Then, the frequency 4f sc /
3 clocks CK P1, vertical sync signal VD P, horizontal sync signal HD
P and a clock CK P2 having a frequency of 8fsc are output.

The clock CK P1 output from the generation circuit 43 is supplied to the RAM controller 120, and the vertical synchronization signal VD
P and the horizontal synchronizing signal HDP are supplied as reference synchronizing signals. In addition, the controller 110 is supplied with a clock CK P2 having a frequency of 8fs output from the generation circuit 43 as a master clock, and is supplied with a vertical synchronization signal VD P and a horizontal synchronization signal HD P as reference synchronization signals.

In addition, the reference image data VBN and the difference compressed image data Δc1 to Δc2 of each compression reference period separated by the separation circuit 41.
9 is supplied to the video RAMs 22a to 22c via the connection switch 44 and the changeover switch 45, and is sequentially written to a predetermined address.

Although the control line is not shown, the connection switch 44 and the changeover switch 45 are controlled to be switched by the controller 110.
The connection switch 44 is turned on during reproduction. Selector switch
45 is a side, b side, c side, a side,
Are sequentially connected.

The writing and reading of the video RAMs 22a to 22c are controlled by the RAM controller 120. In the RAMs 22a to 22c, the reference image data VB separated by the separation circuit 41 during one compression reference period in which the changeover switch 45 is connected to the ac side respectively.
N and differential compressed image data Δc1 to Δc29 are written.

The reference image data VBN and the differential compressed image data Δc1 to Δc29 written in the video RAMs 22a to 22c are read out in one subsequent compression reference period.

Reference image data V read from video RAMs 22a to 22c
The BN and the differential compressed image data Δc1 to Δc29 are supplied to the image decompression unit 46 via the changeover switch 23. Although the control line is not shown, the changeover switch 23 is controlled by the controller 110. The changeover switch 23 is connected to the video RAM 22a to
The period during which image data is read from 22c is a
Side to c side.

The operation of the image decompression unit 46 is controlled by the controller 110 based on the control code as described above, and
The processing opposite to 9 is performed.

In the image decompression unit 46, for the reference image data VBN,
The following processing is performed. First, 9-bit data is expanded into 8-bit signals Y, U, and V, respectively. Next, an interpolation process is performed to double the number of samples in one frame for each of the signals Y, U, and V. Thereby, the image data of the first frame is formed.

Further, for the differential compressed image data Δc1 to Δc29,
The following processes are respectively performed. First, the difference data is returned to 9-bit data using the reference image data. Next, the 9-bit data is 8 bits for each of the signals Y, U, and V.
Expanded to bits. Further, interpolation processing is performed, and the number of samples in one frame for each of the signals Y, U, and V is doubled. As a result, image data of the second frame to the thirtieth frame is formed.

The signals Y, U, V output from the image decompression unit 46 are supplied to a matrix circuit 47, and the primary color signals R, G, B output from the matrix circuit 47 are supplied to a D / A converter 48. The clock CK P1 is supplied from the generation circuit 43 to the D / A converter 48. Then, the analog primary color signals R, G, and B output from the D / A converter 48 are led to video-out terminals 49R, 49G, and 49B, respectively.

A terminal 50 is an output terminal for a synchronization signal. A decoding synchronization signal SYNC output from the generation circuit 43 is derived from the terminal 50.

The audio data separated by the separation circuit 41 is supplied to the audio DSP 33, where the ADPCM signal is demodulated. Then, the left and right audio signals SA L and SAR output from the audio DSP 33 are led out to an audio out terminal 36 via an amplifier 35.

If a scene change occurs, the signal processing state is reset even during the one-second compression reference period.
That is, the changeover switch 45 is switched, and the next video
Writing to RAM starts. Regarding the processing of the image decompression unit 46 performed after one compression reference period, the formation of the image data of the first frame is started from the reference image data VBN after the scene change.

Note that the signal processing state of the audio system is also reset similarly to the video system.

FIG. 9 shows a timing chart of a reproduction system relating to a video signal and an audio signal.

From DAT130, the compressed image data CVG for each compression reference period
, And the compressed audio data CAG1, CAG2,... Are reproduced correspondingly (see FIG. 9A).

Reproduced compressed image data CVG1, CVG2,... Are sequentially written into the video RAMs 22a to 22c as shown in FIG.

Further, in the areas of the RAMs a to c of the RAM 34, the reproduced compressed audio data CAG1, CAG2,... Are sequentially written as shown in FIG.

As described above, the compressed image data and the compressed audio data are processed at the same timing, and the terminals 49R to 49B and 36 have
Video signals VG1, VG2,... And audio signals AG1, AG2,... In each compression reference period are output correspondingly (see FIGS. D, E).

FIG. 10 is a flowchart showing the operation of the video system during normal reproduction.

In the figure, when the reproduction key of the keyboard 140 is turned on, in step 51, the synchronization code 2 or 3 or 4
Is determined.

When any of these synchronization codes is input, in step 52, the mode code and the control code arranged following the synchronization code are taken into the control area, and the image decompression unit 46 and the like convert the compressed image data to be reproduced. It is set to perform the corresponding operation.

Next, in step 53, it is determined whether or not the synchronization code 1 has been input. When the synchronization code 1 is input, at step 54, any of the video RAMs (video RAMs 22a to 22c
), The input of compressed image data for one compression reference period is started.

Next, in step 55, it is determined whether or not the synchronization code 1 has been input. When the synchronization code 1 is input, in step 56, input of compressed image data for one compression reference period to the next video RAM is started.

Next, at step 57, the video RAM
Are sequentially read out, and the image expansion unit 46 starts expansion processing. Then, an image is displayed on a monitor (not shown) connected to terminals 49R-49B.

Next, at step 58, it is determined whether or not the synchronization code 1 has been input. When the synchronization code 1 is inputted, it is determined in a step 59 whether or not the stop key of the keyboard 140 is turned on.

If the stop key is not on, the process returns to step 56 to repeat the above-described operation, while if the stop key is on, the reproducing operation is stopped.

Note that the decompression processing in step 57 starts processing for the subsequent compression reference period after the decompression processing of the compressed image data written in any of the video RAMs 22a to 22c in the previous compression reference period.

Therefore, when there is a scene change in the middle, during the period in which the compressed image data of a certain compression reference period is read out from one video RAM and decompressed, the processing of writing the compressed image data over the other two video RAMs is performed. (See the scene change section in FIGS. 9C and D). That is,
Compressed image data (CVG N + 1) before the scene change is written to one of the two video RAMs, and compressed image data (CVG N + 2) after the scene change is written to the other. In this sense, three video RAMs 22a to 22c are used.

Even if not described above, the compression processing in the image compression unit 19, the image decompression unit
As the IC for performing the decompression processing in 46, for example, there is an IC for compression and decompression [82750PB] of Intel Corporation.

Next, special reproduction such as still reproduction and strobe reproduction will be described.

First, still reproduction will be described. The playback tape running speed in still playback is the same as in normal playback.

FIG. 11 is a flowchart showing the operation of still playback (first still playback) in which still images based on reference image data are sequentially displayed by manual operation.

In the figure, when the first still reproduction is designated by operating the keyboard 140, it is determined in a step 61 whether or not the synchronization code 2 or 3 or 4 has been inputted.

When any one of these synchronization codes is input, in step 62, the mode code and the control code arranged following the synchronization code are taken into the control area, and the image decompression unit 46 and the like convert the compressed image data to be reproduced. It is set to perform the corresponding operation.

Next, in step 63, it is determined whether or not the synchronization code 1 has been input. When the synchronization code 1 is input, at step 64, any of the video RAMs (video RAMs 22a to 22c
Are sequentially used) to write the reference image data.

Next, in step 65, the reference image data is read from the video RAM, the image is expanded by the image expansion unit 46 to form one frame of image data, and the one frame of image data is stored in the memory. Then, one frame of image data is repeatedly read out from this memory, and the terminals 49R to 49R
The still image based on the reference image data is displayed on the monitor connected to 9B.

Next, at step 66, the DAT 130 is brought into a playback pause state.

Next, in step 67, it is determined whether or not the reproduction key of the keyboard 140 is on. If the reproduction key is ON, the reproduction pause state of the DAT 130 is released in step 68, and the process returns to step 61. Then, by the same operation as described above, a still image based on the reference image data in the next compression reference period is displayed.

If the reproduction key is not on in step 67, it is determined in step 69 whether the stop key of the keyboard 140 is on. If the stop key is not on, the process returns to step 67.

In step 69, when the stop key is on, the first
Stops the still playback operation.

FIG. 12 is a flowchart showing a still playback (second still playback) operation in which still images based on reference image data immediately after a scene change are sequentially displayed by manual operation.

In the figure, when the second still reproduction is designated by operating the keyboard 140, it is determined in a step 71 whether or not the synchronization code 2 or 3 or 4 has been inputted.

When any of these synchronization codes is input, in step 72, a mode code arranged following the synchronization code is fetched into the control area, and in step 73, based on data indicating the presence or absence of a scene change of the mode code. ,
It is determined whether there is a scene change. If there is no scene change, the process returns to step 71.

If there is a scene change, in step 74, a control code distributed following the mode code is fetched.
Then, based on the mode code and the control code, the image decompression unit 46 and the like are set to perform an operation corresponding to the compressed image data to be reproduced.

Next, in step 75, it is determined whether or not the synchronization code 1 has been input. When the synchronization code 1 is input, at step 76, any of the video RAMs (video RAMs 22a to 22c
Are sequentially used), the reference image data immediately after the scene change is written.

Next, in step 77, the reference image data is read from the video RAM, the image is expanded by the image expansion unit 46 to form one frame of image data, and the one frame of image data is stored in the memory. Then, one frame of image data is repeatedly read out from this memory, and the terminals 49R to 49R
The still image based on the reference image data immediately after the scene change is displayed on the monitor connected to 9B.

Next, in step 78, the DAT 130 is brought into a playback pause state.

Next, in step 79, it is determined whether or not the reproduction key of the keyboard 140 is on. When the reproduction key is on, the reproduction pause state of the DAT 120 is canceled in step 80, and the process returns to step 71. Then, by the same operation as described above, a still image based on the reference image data immediately after the next scene change is displayed.

If the reproduction key is not on in step 79, it is determined in step 81 whether the stop key of the keyboard 140 is on. If the stop key is not on, the process returns to step 79.

In step 81, when the stop key is on, the second
Stops the still playback operation.

FIG. 13 shows still playback (see FIG. 3) in which still images based on reference image data are automatically and sequentially displayed at predetermined time intervals.
3 is a flowchart showing an operation of the still reproduction. No.
Steps corresponding to those in FIG. 11 are denoted by the same reference numerals.

In the figure, after the DAT 130 is set to the playback pause state in step 66, it is determined in step 91 whether the time t has elapsed.

When the time t has elapsed, it is determined in a step 92 whether or not the stop key of the keyboard 140 is on. If the stop key is not on, the playback pause state of the DAT 130 is canceled in step 68, and the process returns to step 61.

In step 92, when the stop key is on, the third
Stops the still playback operation.

 Others are the same as the example of FIG.

In the third still reproduction, still images based on the reference image data of each compression reference period are automatically and sequentially displayed on the monitor at time intervals determined by the time t.

FIG. 14 shows still playback (see FIG. 4) for automatically displaying still images based on reference image data immediately after a scene change.
3 is a flowchart showing an operation of the still reproduction. No.
Steps corresponding to those in FIG. 12 are denoted by the same reference numerals.

In FIG. 7, after the DAT 130 is set to the reproduction pause state in step 78, it is determined in step 94 whether the time t has elapsed.

If the time t has elapsed, it is determined in step 95 whether the stop key of the keyboard 140 is on. If the stop key is not on, the reproduction pause state of the DAT 130 is canceled in step 80, and the process returns to step 71.

In step 95, when the stop key is on,
Stops the still playback operation.

 Others are the same as the example of FIG.

In the fourth still reproduction, the next scene change is detected after the elapse of time t, and still images based on the reference image data immediately after the scene change are sequentially and automatically displayed on the monitor.

In a state where the normal playback operation shown in the flowchart of FIG. 10 is being performed, for example, when the pause key of the keyboard 140 is turned on to set the playback pause state, the playback is performed based on the image of one frame formed by the image decompression unit 46 immediately before. Still images can be configured to be displayed on a monitor, so that still images of arbitrary frames can be monitored.

Next, flash reproduction will be described. The playback tape running speed in strobe playback is the same as in normal playback.

FIG. 15 is a flowchart showing the operation of flash reproduction.

In the figure, when the strobe reproduction is designated by operating the keyboard 140, it is determined in a step 151 whether or not the synchronization code 2 or 3 or 4 has been inputted.

When any of these synchronization codes is input, in step 152, the mode code and the control code arranged following the synchronization code are taken into the control area, and the image decompression unit 46 and the like convert the compressed image data to be reproduced. It is set to perform the corresponding operation.

Next, in step 153, it is determined whether or not the synchronization code 1 has been input. When synchronization code 1 is input,
In step 154, any of the video RAMs (video RAM 22a to
22c is sequentially used), input of compressed image data for one compression reference period is started.

Next, in step 155, it is determined whether or not the synchronization code 1 has been input. When synchronization code 1 is input,
In step 156, N = 0 is set, and in step 157,
L = 1 is set, and in step 158, input of compressed image data for one compression reference period to the next video RAM is started.

Next, at step 159, the video RAM
Reads the reference image data written in the
The extension process is performed at 46. Then, a still image based on the reference image data is displayed on a monitor (not shown) connected to the terminals 49R to 49B.

Next, in step 160, N = N + 1 is set, and the differentially compressed image data ΔcN is read from the video RAM and expanded.

Next, at step 161, it is determined whether N is equal to L × M + 1. Here, M is the number of frame skips in strobe display, and is preset by the keyboard 140.

If they are not equal in step 161, the process returns to step 160, and the same processing as described above is performed. On the other hand, when they are equal, in step 162, the difference compressed image data ΔcN
Is displayed on the monitor.

Next, at step 163, it is determined whether or not the synchronization code 1 has been input. If the synchronization code 1 is not input, at step 164, L = L + 1 is set, and at step 160
Then, the same operation as described above is performed.

When the synchronization code 1 is input in step 163, it is determined in step 165 whether or not the stop key of the keyboard 140 is on.

If the stop key is not on, the process returns to step 156 to repeat the same operation as described above, while if the stop key is on, the flash playback operation is stopped.

In such a strobe reproducing operation, in each compression reference period, still images based on image data of frames every M frames are sequentially displayed on a monitor, and so-called strobe display is performed.

 Next, fast forward reproduction will be described.

FIG. 16A shows reproduced image data during normal reproduction. VB1, VB2,... Are reference image data in each compression reference period, and are reproduced at one-second intervals during normal reproduction.

In this example, when certain reference image data, for example, VB1, is reproduced, the reproduction tape running speed of the DAT 130 is made twice as high as the normal speed, and the DAT 130 is run for 2 seconds. The reference image data is reproduced (shown in FIG. B).

 Hereinafter, the same operation is repeated.

The reason for returning the reproduction tape running speed to normal before reproducing the reference image data is to make the rotating head scan correctly without crossing the recording track.

By the above-described reproduction operation, as shown in FIG. C, the reference image data VB1, VB6, VB1
1,... Are reproduced. In the portion indicated by the broken line,
Since the rotating head scans across the recording track, correct image data cannot be obtained.

The reference image data VB1, VB6, VB1 thus reproduced
, Are video RAMs 22a to 22c as shown in FIG.
Are written sequentially.

Then, the reference image data written in the video RAMs 22a to 22c is read, supplied to the image decompression unit 46, and decompressed to form one frame of image data. Then, a still image based on the image data for one frame is
The display is continued until one frame of image data is formed by the next reproduced reference image data (illustrated in FIG. E).

As described above, at the time of normal reproduction, the contents displayed at intervals of 5 seconds (for example, images based on the reference image data VB1 and VB6) are displayed at intervals of 3.15 seconds by the above-described reproduction operation. Therefore, fast forward reproduction of about 5 / 3.15 ≒ 1.6 times is performed.

FIG. 17 is a flowchart showing this fast-forward playback operation.

In the figure, when fast-forward playback is designated by operating the keyboard 140, the DAT 130 is controlled by the controller 110 in step 171 to set a normal speed playback state.

Next, in step 172, it is determined whether or not the synchronization code 2 or 3 or 4 has been input.

When any one of these synchronization codes is input, in step 173, the mode code and the control code arranged following the synchronization code are taken into the control area, and the image decompression unit 46 and the like convert the compressed image data to be reproduced. It is set to perform the corresponding operation.

Next, in step 174, it is determined whether or not the synchronization code 1 has been input. When synchronization code 1 is input,
In step 175, any of the video RAMs (video RAM 22a ~
22c is used sequentially), and writes the reference image data.

Next, in step 176, the reference image data is read from the video RAM, the image is expanded by the image expansion unit 46 to form one frame of image data, and the one frame of image data is stored in the memory. Then, one frame of image data is repeatedly read out from this memory, and the terminals 49R to 49R
The still image based on the reference image data is displayed on the monitor connected to 9B.

Next, at step 177, DAT1
30 is controlled, and the tape traveling speed is set to double speed.

Next, in step 178, it is determined whether two seconds have elapsed. If two seconds have elapsed, it is determined in step 179 whether the stop key of the keyboard 140 is on. If the stop key is not on, the process returns to step 171 to perform the same operation as described above. If the stop key is on, fast-forward playback is stopped.

In the above description, an example in which the fast-forward reproduction is performed about 1.6 times is performed. However, by adjusting the speed of the reproduction tape traveling speed and the traveling time, fast-forward reproduction at an arbitrary speed becomes possible.

 Next, slow reproduction will be described.

FIG. 18A shows reproduced image data at the time of normal reproduction, and CVG1, CVG2,... Represent compressed image data (reference image data VBN and differential compressed image data Δc1 to Δc29) in each compression reference period. In normal reproduction, the data is sequentially reproduced every second.

In this example, after the DAT 130 is set to the normal speed reproduction state for the three compression reference periods, the DAT 130 is set to the reproduction pause state for the same period as that period, and this is repeated thereafter.

By the operation of the DAT 130 as described above, the compressed image data (CVG1 to CVG1 to CVG1 to CVG
3) are successively reproduced, and then, after the same period, the compressed image data (CVG4 to CVG6) of the subsequent three compression reference periods is continuously reproduced. Hereinafter, the same is repeated.

The compressed image data CVG1, CVG2,... Of each compression reference period reproduced in this way are, as shown in FIG.
The data is sequentially written to the RAMs 22a to 22c.

Then, the compressed image data written in the video RAMs 22a to 22c is read, supplied to the image decompression unit 46, and decompressed. In this case, the image data VG1, VG2,... For 30 frames are respectively formed from the compressed image data CVG1, CVG2,.

Then, a moving image based on the image data VG1, VG2,... Is displayed on the monitor, but the same screen is displayed continuously for every two frames. That is, image data VG1, VG2,
The time axis of the moving image is doubled and displayed (shown in FIG. D).

Thus, the time axis of the moving image displayed on the monitor is 2
Since the image is expanded twice, the monitor displays a 1/2 slow image.

FIG. 19 is a flowchart showing the slow reproduction operation.

In the figure, when slow playback is designated by operating the keyboard 140, the DAT 130 is controlled by the controller 110 in step 181 to bring the playback speed to the normal speed.

Next, at step 182, it is determined whether the synchronization code 2 or 3 or 4 has been input.

When any of these synchronization codes is input, in step 183, a mode code and a control code arranged following the synchronization code are taken into the control area, and the image decompression unit 46 and the like convert the compressed image data to be reproduced. It is set to perform the corresponding operation.

Next, after N = 0 is set in step 184, it is determined in step 185 whether or not the synchronization code 1 is input.

When the synchronization code 1 is input, step 186 is executed.
After N is set to N + 1, in step 187, N = 2
It is determined whether or not. If N = 2, step 18
Proceeding directly to step 8 and when N = 2, proceeding to step 188 via step 189.

In step 189, reading of compressed image data for three compression reference periods continuously written to the video RAMs 22a to 22c is started, and the image decompression unit 46 starts decompression processing.
The moving image is displayed on a monitor (not shown) connected to 9B. In this case, the same screen is displayed continuously for every two frames.

In step 188, one of the video RAMs (video RAM2
2a to 22c are sequentially used), input of compressed image data for one compression reference period is started.

Next, at step 190, it is determined whether or not the synchronization code 1 has been input. When synchronization code 1 is input,
At step 191, it is determined whether N = 3. N =
If not 3, the process returns to step 186, and the same operation as described above is repeated.

When N = 3, in step 192, the DAT 130 is controlled by the controller 110, and a reproduction pause state is set. At this point, the video RAMs 22a to 22c have three consecutive
The compressed image data for the compression reference period is written.

Next, at step 193, it is determined whether or not the same time T3 as the above-mentioned three compression reference period has elapsed. Here, the reason why the time is not set to 3 seconds is that when there is a scene change described above,
This is because the three compression reference periods may be shorter than three seconds.

Next, in step 194, DAT1
30 is controlled, the playback pause state is released, and step 19
After setting N = 0 in step 5, in step 196, the keyboard
It is determined whether the 140 stop key is on.

If the stop key is not on, the process returns to step 186 to repeat the above-described operation, while if the stop key is on, the slow reproduction operation is stopped.

In the above description, an example in which the normal speed reproduction state in the three compression reference periods and the reproduction pause state in the same period are repeated is described. However, the three compression reference periods correspond to the three video RAMs 22a to 22c. And is not limited to this. For example, one compression reference period or two compression reference periods may be used.

In the above description, an example in which 1/2 slow reproduction is performed has been described. However, by adjusting the pause period, slow reproduction can be performed at an arbitrary speed. For example, the pause period is twice as long as the compression reference period during normal speed reproduction,
If the same screen of three frames is displayed, the time axis of the moving image displayed on the monitor is extended three times,
1/3 slow playback.

 Next, the reverse reproduction will be described.

In order to realize reverse reproduction, the recording data is configured as shown in FIG. The data structure of the control area is changed from the example of FIG.

That is, in each compression reference period, four synchronization codes 1A to 4A
And mode codes 1A to 4A. These are the fourth
These are the same as the synchronization code and the mode code in the figure.

In the one shown in FIG. 20, the synchronization codes 1A to
4A, synchronization codes 1B to 4B, mode code 1B at positions symmetric to mode codes 1A to 4A (in the example of the control code in FIG. 4).
~ 4B are arranged.

The synchronization codes 1A to 4A and the mode codes 1A to 4A can be detected during normal playback, while the synchronization codes 1B to 4B and the mode codes 1B to 4B can be detected during reverse playback.

As with the mode codes in the example of FIG. 4, data corresponding to the next compression reference period of the normal reproduction method is allocated to the mode codes 1A to 4A.

Data corresponding to the next compression reference period in the reverse reproduction direction is allocated to the mode codes 1B to 4B. In this, in addition to the data similar to the mode codes 1A to 4A, in the next compression period, the data amount fluctuation data of the differential compressed image data Δc1 to Δc29, and whether or not it is the period immediately before the scene change occurs , Data of the period in that case, and the like.

In the above description, the data amount of the differential compressed image data Δc1 to Δc29 is fixed, and therefore, the arrangement position of each differential compressed image data is fixed. However, the difference compressed image data Δc1 to Δc29
May be changed to improve the performance of the image data. In this case, the arrangement position of each differential compressed image data changes. Therefore, as described later, during reverse playback,
In order to control the addresses of the video RAMs 22a to 22c and to write the reproduction data from the reverse direction to exactly the same address as in normal reproduction, it is necessary to consider the data amount of each of the differential compressed image data Δc1 to Δc29.

This is the mode code that contains the differential compressed image data Δc1 ~
This is the reason why the variation data of the data amount of Δc29 is allocated. The change in the data amount will be described later.

By configuring the recorded data as shown in FIG. 20, during normal playback, the synchronization codes 1A to 4A and the mode code
The playback operation is performed using 1A to 4A.

At the time of reverse reproduction, a reproduction operation is performed using the synchronization codes 1B to 4B and the mode codes 1B to 4B. In this case, the video RAMs 22a to 22a are determined based on the variation data of the data amount of the differential compressed image
The address 22c is controlled, and the reproduction data is written from the reverse direction to the exact same address as in normal reproduction.

As a result, subsequent expansion processing and the like in the image expansion section 46 are performed in the same manner as in the case of normal reproduction, and a screen for reverse reproduction is displayed on the monitor.

Note that, with the configuration of the recording data as shown in FIG. 20, still playback in the reverse direction, fast-forward playback, and slow playback can be performed in the same manner.

Next, a variation in the data amount of the differential compressed image data Δc1 to Δc29 will be described.

FIG. 21 shows an example of realizing a change in the data amount.

As the area of the reference image data, 276480 bits are provided as in the case where the data amount is fixed as described above.

Further, as an area of the differential compressed image data Δc1 to c29,
31 areas B1 to B31 each having 27200 bits are provided. The total area is 843200 bits.

27200 × 31 = 843200 bits The image area for one compression reference period is as described above.
1152000 bits, and the remaining 32320 bits are used for fixed length adjustment.

Reference image data is arranged in the area of the reference image data. This is the same as the case where the data amount is fixed.

Also, basically, the difference compressed image data Δc1 to Δc29
Are arranged in the regions B1 to B29, respectively, but when the image with little motion rapidly changes to an image with large motion and the difference compressed image data cannot be contained in the 27200-bit region, two or more Space is used.

When two or more areas are used for one piece of differentially compressed image data, the information is arranged and recorded, for example, at the head of the control code as shown in the figure.

In the block number portion, data 1 to 29 indicating differential compressed image data using two or more areas are arranged. Also,
Data indicating the number of areas to be used (for example, two “0” and three “1”) is arranged in the number part.

For example, when two areas are used for the differential compressed image data Δc5 and Δc20, respectively, “5” is used as the data of the first block number part, “0” is used as the number part data, and the data of the next block number part is used. And “0” as the number part data.

As a result, the image data Δc to Δc4
B1 to B4, the image data Δc5 is arranged in the areas B5 and B6, and the image data Δc6 to Δc19 are arranged in the areas B7 to B20, respectively.
, The image data Δc20 is arranged in the areas B21 and B22, and the image data Δc21 to Δc29 are arranged in the areas B23 to B31, respectively.
Is shown.

At the time of reproduction, this information is taken into the controller 110, the addresses of the video RAMs 22a to 22c are controlled, and the reproduction signal processing is performed correctly as in the case where the data amount of each differential compressed image data is fixed. You.

FIG. 22 shows another example for realizing a change in the data amount.

As the area of the reference image data, 276480 bits are provided as in the case where the data amount is fixed as described above.

In addition, the areas of the differential compressed image data Δc1 to Δc29 are provided with only bits corresponding to the respective data amounts.

Then, the difference compressed image data Δ provided in the image area
In the control area, address information of the video RAMs 22a to 22c to be written at the time of reproduction is arranged as, for example, 18-bit data corresponding to each of the areas c1 to Δc29.

At the time of reproduction, this address information is taken into the controller 110, the addresses of the video RAMs 22a to 22c are controlled, and the reproduction signal processing is performed correctly, as in the case where the data amount of each differentially compressed image data is fixed. To be.

By changing the data amount as shown in FIGS. 21 and 22, differential compressed image data having a data amount corresponding to the image state can be recorded and reproduced, and the performance of the image data can be improved. .

From the viewpoint that the image area can be used effectively,
Although the example of FIG. 22 is superior, the example of FIG. 21 is superior from the viewpoint of effective use of the control area.

 Next, the time code will be described.

Even without the above, it is conceivable to arrange a time code in the control area of the recording data.

In the above example, the synchronization code part is 64 bits, but for example, as shown in FIG. 23, the synchronization code part is 48 bits,
A 16-bit time code part is provided between the synchronization code part and the mode code part.

This time code part, like the synchronous code part and the mode code part, is, for example, four times in one compression reference period (one second).
However, the same data is allocated to four of them.

The 16-bit data of the time code section represents, for example, an absolute time (second). In this case, each digit of the decimal number is represented by a 4-bit binary number.
Hex) data, it can represent the time from 0 to 9999 seconds. Also, assuming that the 19-bit binary data is 0 to (2 ¹⁶ −
1) It can represent time in seconds.

At the time of reproduction, by capturing the time code recorded in this way, it can be used for control such as search, display of the remaining amount of tape, position adjustment at the time of editing, and the like.

By using the time code described above,
The search can be performed with an accuracy of 1 second, but the search can be performed with an accuracy of 1 to 4 seconds by using different types of synchronization codes 1 to 4.

Further, as described above, by using the variation data of the differential compressed image data arranged in the control area, it is possible to perform a search up to the frame accuracy, which is effective for, for example, screen adjustment at the time of editing.

The configuration, arrangement position, and number of bits of the time code are as follows.
It is not limited to the example of FIG. For example, “hour, minute, and second” may be represented as the configuration of the time code.

Next, by using the signal processing device of FIG. 1, the signal having the data configuration of FIG. 4 or FIG.
An example of digital dubbing of a tape recorded with T using two DATs will be described.

FIG. 24 shows a configuration for digital dubbing using two DATs.

In the figure, reference numeral 201 denotes a master-side DAT, and reference numeral 202 denotes a slave-side DAT. These DATs 201 and 202 are connected by a so-called digital audio interface DAI, and a synchronization signal such as a bit clock BCK is supplied from the DAT 201 to the DAT 202 to synchronize them. Further, various control flags for controlling the operation of the DAT are supplied from the DAT 201 to the DAT 202.

In addition, the DAT 201 includes, among the signal processing devices of FIG.
At least a video playback system circuit is provided, and a monitor 203 is connected to a video output terminal.

The DAT 201 has a dubbing start key 201a and a dubbing stop key in addition to a normal recording / playback key (not shown).
201b and a dubbing period setting key 201c are provided.

First, an example of executing dubbing for an arbitrary period while monitoring the playback screen will be described with reference to the flowchart of FIG. In this example of dubbing,
As shown in FIG. 20, it is necessary that, in addition to the synchronization codes 1A to 4A, the synchronization codes 1B to 4B for reverse playback are arranged and recorded.

When the dubbing start key 201a is turned on and dubbing is instructed while the DAT 201 is in a normal playback state and a moving image is displayed on the monitor 203, a recording pause flag is supplied from the DAT 201 to 202 in step 211. Thus, the DAT 202 is in a recording pause state.

Next, in step 212, the frame image data at the time when the dubbing start key 201a is turned on is
The still images are sequentially read from the monitor 46 and displayed on the monitor 203.

Next, in step 213, the DAT 201 starts reverse playback. Even during the reverse playback, the still image is continuously displayed on the monitor 203.

Next, in step 214, it is determined whether or not the synchronization code 1B has been input. When synchronization code 1B is input,
In step 215, it is determined whether the synchronization code 4B has been input. When synchronization code 4B is input,
At 216, it is determined whether the synchronization code 3B has been input.

When the synchronization code 3B is input in step 216, the reverse reproduction of the DAT 201 is stopped in step 217.

Next, in step 218, the pause release flag is supplied from the DAT 201 to the DAT 202, and the DAT 202 is set to the recording state.

Next, in step 219, normal reproduction of the DAT 201 is started, reproduction data is supplied to the DAT 202 via the digital audio interface DAI, and recording is started.

Then, in step 220, the display of the moving image on the monitor 203 is started.

Next, in step 221, it is determined whether the dubbing stop key 201b is on. When the dubbing stop key 201b is on, it is determined in step 222 whether or not the synchronization code 1A has been input. When the synchronization code 1A is input, it is determined in step 223 whether the synchronization code 2A has been input.

When the synchronization code 2A is input, step 224
Then, a recording stop flag is supplied from DAT201 to 202, and DAT20
2 is stopped, and the recording is stopped.

Then, in step 225, the reproduction of the DAT 201 is stopped, and the dubbing operation ends.

According to the dubbing example of FIG. 25, the dubbing start key
Since a still image is displayed by the frame image data at the time when 201a is turned on, an image at which dubbing is started can be confirmed. In addition, by controlling based on the synchronization code, the recording is performed from the part immediately before the synchronization codes 4A and 4B, and the recording is performed from the part immediately after the synchronization codes 2A and 2B, so that the necessary part can be efficiently recorded.

Next, an example of executing dubbing for an arbitrary period while monitoring the playback screen will be described with reference to the flowchart of FIG. In addition, this dubbing example can be applied to those recorded by either of the configurations shown in FIGS. 4 and 20. Synchronization codes 1 to 4 in the figure correspond to synchronization codes 1A to 4A in the example of FIG.

When the dubbing start key 201a is turned on and dubbing is instructed while the DAT 201 is in a normal playback state and a moving image is displayed on the monitor 203, a recording pause flag is supplied from the DAT 201 to 202 in step 231. Thus, the DAT 202 is in a recording pause state.

Next, in step 232, it is determined whether or not the synchronization code 3 has been input. When synchronization code 3 is input,
In step 233, the pause release flag is supplied from the DAT 201 to the DAT 202, and the DAT 202 is set to the recording state. This allows the DAT201 to be connected via the digital audio interface DAI.
Recording of the supplied reproduction data is started.

Next, in step 234, it is determined whether the dubbing stop key 201b is on. When the dubbing stop key 201b is on, it is determined in step 235 whether or not the synchronization code 1 has been input. When the synchronization code 1 is input, it is determined in step 236 whether the synchronization code 2 has been input.

When synchronization code 2 is input, step 237
Then, a recording stop flag is supplied from DAT201 to 202, and DAT20
2 is stopped, and the recording is stopped.

Then, in step 238, the reproduction of the DAT 201 is stopped, and the dubbing operation ends.

In the dubbing example shown in FIG. 26 as well, the control based on the synchronization code causes recording from the portion immediately before the synchronization code 4 and recording to the portion immediately after the synchronization code 2, so that the necessary portion can be recorded efficiently.

Next, an example of executing dubbing for a set dubbing period will be described with reference to the flowchart of FIG. In addition, in this dubbing example, as shown in FIG. 23, the present invention can be applied to a device in which a time code is recorded.

First, in step 241, the dubbing start time and the dubbing end time are set using the dubbing period setting key 201c. The time is input in, for example, “hour, minute, second”.

Next, in step 242, when the dubbing start key 201a is turned on, in step 243, a recording pause flag is supplied from the DAT 201 to 202, and the DAT 202 is set to a recording pause state.

Next, in step 244, the reproduction of the DAT 201 is started, and in step 245, it is determined whether or not the time code detected from the control area of the reproduced data is “dubbing start time−1 second”. If the time code is "dubbing start time minus one second", it is determined in step 246 whether or not the synchronization code 3 has been input.

When the synchronization code 3 is input in step 246, the pause release flag is supplied from 202 to the DAT 201 in step 247, and the DAT 202 is set to the recording state. This allows
DAT via digital audio interface DAI
Recording of the reproduction data supplied from 201 is started.

Next, in step 248, it is determined whether or not the time code detected from the control area of the reproduction data is “dubbing end time + 1 second”. When the time code is “dubbing end time + 1 second”, in step 249, the DAT201
Then, a recording stop flag is supplied to the DAT 202, the DAT 202 is stopped, and the recording is stopped.

Then, in step 250, the reproduction of the DAT 201 is stopped, and the dubbing operation ends.

According to the dubbing example of FIG. 27, dubbing for a set period can be automatically performed. Further, by controlling based on the synchronization code, the data is recorded from the part immediately before the synchronization code 4 and also recorded to the part immediately after the synchronization code 2, so that the necessary part can be efficiently recorded.

In the example shown in FIG. 24, the key operation is performed by the DAT 201 on the master side.
It is also possible to provide an operation key in the keypad 02 and operate the key.

By the way, in the above-described example, an example is shown in which only data in a moving image is recorded as image data, but it is also possible to record image data for a still image by switching.

In this case, as shown in FIG. 28, after certain moving image compressed image data is arranged, still image data S1, S2,
Is recorded.

Recording of the image data S1, S2,... For still images can be easily realized by the signal processing device shown in FIG.

That is, the image data of each frame sequentially input to the RAMs 17a to 17c is read, and the read image data is allocated as still image data in the data area and recorded.

In this case, the image compression unit 19 performs a compression process to make the image data S1, S2,... For the still image the same as the reference image data VBN for the moving image, and also a compression ratio. By recording an enlarged area without reducing or compressing it, it is possible to record higher quality still image data.

According to the signal processing device of the example shown in FIG.
Since it has M17a to 17c, even if the image data for a still image is of high image quality, recording of at least three consecutive frames,
So-called continuous shooting of three images becomes possible.

Further, as shown in FIG. 28, the image data S for still image
A synchronization code section and a mode code section are provided in the control area corresponding to immediately before the start of each of 1, S2,. In the mode code portion, data indicating the still image mode is allocated.

At the time of reproduction, control is performed so as to shift from the reproduction processing of the moving image to the reproduction processing of the still image based on the data indicating the still image mode detected from the control area of the reproduction data.

In the example shown in FIG. 28, the image data S for a still image
Are arranged continuously, but they may be arranged at predetermined intervals.

In the above-described embodiment, 12 bits are used for the total number of bits of the digital signal 16 bits recorded and reproduced in the DAT.
Bits are used as an image area, 3 bits are used as an audio area,
Although one bit is used as a control area, it is needless to say that the number of bits and the arrangement position are not limited to this.

Also. In the above embodiment, NTSC is used as the video signal.
Although an example of handling a system signal is shown, video signals of another system such as the PAL system or the SECAM system can be handled similarly. In that case, a change is required according to the number of frames and the like. For example, when the number of frames is 25 frames / sec, the differential compressed image data is Δc1
Δc24.

Further, in the above embodiment, the recording / reproducing apparatus is an example of the DAT, but the present invention can be similarly applied to an apparatus in which a recording medium is recorded on a disk or optically.

[Effects of the Invention] As described above, according to the present invention, the reproduction at the normal speed and the reproduction at the predetermined double speed are alternately performed, and the predetermined image data reproduced at the normal speed is decompressed, and the decompression process is performed. Since the image data for one screen can be repeatedly output, a fast-forward image can be displayed on the monitor as a result. Moreover, this fast forward image has
Unlike a conventional VTR fast-forward playback, no noise bar is generated in the horizontal direction, and the image is very easy to see. In this way, fast-forward playback is possible, so that a user-friendly device such as a DAT can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of a signal processing apparatus according to the present invention, FIGS. 2 to 6 are diagrams for explaining recording data, and FIGS.
FIG. 1 is a diagram for explaining the example of FIG. 1, FIG. 10 is a flowchart showing an operation at the time of normal reproduction, FIGS. 11 to 15 are a flowchart showing an operation of still reproduction, and FIG. , FIG. 17 is a flowchart showing the operation of fast-forward reproduction, FIG. 18 is an explanatory diagram of the operation of slow reproduction, FIG. 19 is a flowchart showing the operation of slow reproduction, and FIG. 20 is for realizing reverse reproduction. 21 and 22 are diagrams showing the configuration of recording data when the data amount is varied, FIG. 23 is a diagram for explaining time codes, and FIG. 24 is a diagram showing digital dubbing. 25 to 27 are flowcharts showing a dubbing operation, and FIG. 28 is a diagram showing the configuration of recording data when switching between a moving image and a still image for recording. 17a to 17c, 34 RAM 19 Image compression unit 22a to 22c Video RAM 24 Mixing circuit 25 Control data generation circuit 26 Scene change detection circuit 33 Audio DSP 41 Separation circuit 42 Control data discriminating circuit 46 Image decompression unit 110 Controller 120 RAM controller 130, 201, 202 DAT 140 Keyboard 203 Monitor

Claims (1)

(57) [Claims] A predetermined unit period is set as a compression reference period,
The digital signal is sequentially divided in units of N bits (N is an integer) for each compression reference period, and the N-bit signal portion is composed of an image area, a sound area, and a control area which are independent of each other. In the image area in the period, the reference image data corresponding to the first screen of the compression reference period is arranged, and then the difference compressed image data from the reference image data corresponding to the remaining screen of the compression reference period. The audio area of the compression reference period is provided with audio data of the compression reference period, and the control area of the compression reference period is provided with data used for signal reproduction. In the digital signal reproducing apparatus, the reproduction at the normal speed and the reproduction at the predetermined double speed are alternately performed, and the reproduction at the normal speed is performed. Means for expanding the reference image data separated from the image area of the signal obtained by the above processing, and means for repeatedly outputting one screen of image data obtained by the expansion processing. Digital signal reproducing device.