JPH1032777A - Digital video recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record a still picture with high picture quality during moving image recording. SOLUTION: When recording the still picture just after the moving image recording in a long time (SDL) mode, while turning a signal processing system to a high picture quality (SP) mode, the SDL mode of a servo system is kept. A mode flag P-LSF for signal processing system and a mode flag S-LSF for servo system are set to sub codes and recorded on a magnetic tape together with image information. At the time of reproducing, according to the reproduced mode flags P-LSF and S-LSF, the operating modes of the signal processing system and the servo system are set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital video recording / reproducing apparatus, and more particularly, to a digital video recording / reproducing apparatus for recording / reproducing a digital video signal in which a moving image and a still image are mixed.

[0002]

2. Description of the Related Art In a system for digitally transmitting or digitally recording and reproducing image data, image transmission without deterioration in S / N and recording and reproduction without change over time are realized. Such digital image processing apparatuses are usually provided with a data memory capable of storing at least one screen of image data to be input / output or to be processed. The representation format of the image data, that is, the format, is a display format or a reference input / output format in which pixel signals are arranged in the scanning direction like a monitor output or a camera input, a recording format of a magnetic recording medium, and individual transmission of a transmission path. There are transmission / reception formats according to the rules. FIG. 9 shows a format (basic format) in which each pixel data is arranged in the order of horizontal scanning and vertical scanning, and FIG.
1 shows a recording format of a magnetic tape in a video tape recorder (VTR).

When transmitting or recording image data, compression coding by DCT transform and Huffman coding is usually performed on block data of n × n pixels together with shuffling of the image data. An error correction code is added to the encoded data, and a synchronization signal SYNC, an identification signal ID, and the like are also added for each N-byte synchronization block.

In a conventional digital VTR, a moving image is recorded in addition to a high image quality mode (hereinafter, referred to as an SP mode) in which image quality is prioritized and a long time recording mode (hereinafter, referred to as an SDL mode) in which recording time is prioritized. And a still image mode for recording a still image. In one conventional example, one frame of image data in the SP mode requires 10 tracks in the case of the NTSC system and 12 tracks in the case of the PAL system. On the other hand, the information is compressed to about 1/2 of the SP mode, and the tape feed speed is reduced to 1/2 of that of the SP mode
In the double SDL mode, one frame of image data requires five tracks in the case of the NTSC system and six tracks in the case of the PAL system.

[0005]

Here, consider a case where a still image is recorded in the middle of recording a moving image in the SDL mode. FIG. 11 is a diagram showing a track format and mode transition when an intermediate still image is recorded in the SDL mode.
FIG. 12 is a diagram showing a track format and mode transition when an intermediate still image is recorded in the SP mode.
11 and 12, Fn is a frame number, Tn is a track number in one frame, Q is a processing mode of a servo system,
P indicates the processing mode of the signal processing system.

In FIG. 11, the last one frame (F1, T1) of an SDL mode moving image is recorded on a magnetic tape as a recording medium.
To T5), the SDL mode still image includes two frames ((F2, T1 to T5), (F3, T1 to T5)),
Subsequently, a moving image in the SDL mode is composed of one frame (F1, T
1 to T5) are recorded. At this time, the processing mode of the servo system and the processing mode of the signal processing system remain in the SDL mode. Still images recorded in SDL mode are:
The number of data to be sampled as compared with the still image in the SP mode is reduced to 3/4 in the horizontal direction in the case of, for example, a luminance signal and is highly compressed, so that the image quality is low.

In FIG. 12, the last one frame (F1, T1) of a moving image in the SDL mode is recorded on a magnetic tape as a recording medium.
To T5), the processing mode of the servo system and the processing mode of the signal processing system are switched to the SP mode, and a still image in the SP mode is one frame (F2, T1 to T10). The processing mode of the processing system is switched to the SDL mode, and a moving image in the SDL mode is recorded in one frame (F3, T1 to T5). In this case, the still image recorded in the SP mode has high image quality,
As described above, when switching from the still image recording in the SP mode to the moving image recording in the SDL mode, the tape feed speed changes as described above.
2, T9) is overwritten by the tracing operation of the first track of the moving image recorded next in the SDL mode. As a result, even if a still image recorded in the SP mode is reproduced, the image quality of the SP mode cannot be obtained, and the image quality is significantly deteriorated.

An object of the present invention is to provide a digital video recording / reproducing apparatus which solves such a problem.

Another object of the present invention is to provide a digital video recording / reproducing apparatus capable of obtaining high reproduction quality of a still image when a moving image and a still image are mixedly recorded.

[0010]

According to the present invention, there is provided a digital video signal processing apparatus which adds a synchronous signal, identification data for channel identification and address data to a digital video signal for each predetermined sample, and comprises a plurality of rotary heads. A digital video recording and reproducing apparatus that records and reproduces a plurality of inclined tracks on a magnetic tape by forming
In response to a still image recording instruction after the long recording mode, the servo system is fixed to the long recording mode and the signal processing system is set to the high image quality mode.

Thus, even when a still image is recorded during a moving image in the long-time recording mode, the still image can be recorded with high image quality, and the first track of the subsequent moving image recording is a still image recording track. The image quality of a still image is not deteriorated because the image is not covered with the image.

[0012]

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

FIG. 1 is a schematic block diagram showing an embodiment of the present invention applied to a digital VTR.

Reference numeral 10 denotes a data I / O block for controlling data line input / output, 12 denotes an image data input / output block for performing Y / C separation of image data and the like, 14 denotes an audio processing block for processing an audio signal, and 16 Is an encoding / decoding block for performing variable-length encoding / decoding of image data using a discrete cosine transform, 18 is an error correction block for performing error correction encoding and decoding, and 20 is encoded data to be recorded. Encoded data input / output block for converting to tape format and reverse format conversion during playback, 2
2 is an encoded data input / output block 2 in the recording mode.
This is an electromagnetic conversion processing block in which data to be recorded from 0 is magnetically recorded on the magnetic tape 24, and in a reproduction mode, a recording signal on the magnetic tape 24 is reproduced and supplied to the encoded data input / output block 20. The blocks 12 to 20 can read and write data in the memory 28 via the address conversion circuit 26.

A system control CPU 30 controls an internal electric system.
To 20. Numeral 34 denotes a servo CPU for controlling the servo system.
/ O block 10 and electromagnetic conversion processing block 22 are controlled. The bus 32 and the bus 36 are connected via an interface 38, and the system control CPU 30 is also connected to the interface 38. External CPUs are connected to the buses 32 and 36.
Can also be connected.

Blocks 10 to 22 correspond to the CPUs 30 and 34.
And is controlled according to a predetermined command from an external CPU, and operates in a time sharing manner. Blocks 12 to 20 are CPU
The memory 28 can be accessed at a desired timing while being controlled by the CPU 30 and the external CPU. A memory control circuit (not shown) arbitrates the access requests of the CPUs 30 and 34, the external CPU, and the blocks 10 to 22.

Each of the processing blocks 12 to 20 includes an SD
The corresponding image data and audio data can be processed in real time. In this embodiment, processing blocks 12 to 2
0 are arranged in parallel, and the image data and the audio data are supplied to each of the processing blocks 12 to 20 in a time-division manner to be processed.
HD-compatible image data and audio data that is twice as large as the corresponding image data can be processed in real time.

Here, the pixel configuration of one frame of image data will be briefly described. In the case of the NTSC system in the high image quality mode (hereinafter, referred to as SP mode), as shown in FIG. 2, the luminance signal Y is 720 × 480 pixels, and the color difference signal is C.
Both r and Cb are composed of 180 × 480 pixels. In the case of the PAL system in the SP mode, as shown in FIG.
Is 720 × 576 pixels, and the color difference signal is 3 for both Cr and Cb.
It consists of 60 × 288 pixels. Long time mode (hereinafter SD
It is described as L mode. 4), in the case of the NTSC system, as shown in FIG. 4, the luminance signal Y is 540 × 480 pixels, and the color difference signal is 180 × 240 pixels for both Cr and Cb. In the case of the PAL system in the SDL mode, as shown in FIG. 5, the luminance signal Y is composed of 540 × 576 pixels, and the color difference signal is composed of 180 × 288 pixels for both Cr and Cb.

The data amount in the SDL mode is halved from the data amount in the SP mode by high compression processing. Therefore, the image data shown in FIGS. 2 to 5 is compressed and coded, and then, on a magnetic tape, 10 tracks / 1 frame in the case of the NTSC system in the SP mode, and the PA in the SP mode.
12 tracks / 1 frame in the case of the L system, 5 tracks / 1 frame in the case of the NTSC system in the SDL mode, S
In the case of the PAL system in the DL mode, recording is performed over 6 tracks / 1 frame.

FIG. 6 shows a moving picture / still picture mode and SP / S
FIG. 2 is a schematic block diagram showing a reconfigured block shown in FIG. 1 focusing on switching and detection of the DL mode. 50
Is an image data input terminal to which image data from the data I / O block 10 is input. The input image data is supplied to the image compression / decompression processing circuit 52. The image compression / decompression processing circuit 52 includes an image data input / output block 12, an audio processing block 14, and an encoding / decoding block 16
And executes these processes. The recording / reproduction processing circuit 54 corresponds to the error correction block 18, the coded data input / output block 20, and the electromagnetic conversion processing block 22, and executes these processes. 56 is an electromagnetic conversion processing block 2
Is a rotary head located between the magnetic tape 2 and the magnetic tape 24, magnetically records information while forming a plurality of inclined tracks on the magnetic tape 24, and converts a magnetic signal recorded on the magnetic tape 24 into an electric signal. .

Reference numeral 58 denotes an SP / SDL mode switch, and reference numeral 60 denotes a moving image / still image mode switch. The output of the switch is applied to the control circuit 62. Control circuit 6
2 is a system control CPU 30 and a servo system CPU 34
Are collectively described, and each mode signal determined by each mode switching signal is converted into an image compression / decompression processing circuit 52, a recording / reproduction processing circuit 54, and a rotating head 5.
6 and a mechanism driving circuit 64 for driving the feed mechanism of the magnetic tape 24. Although not shown, each mode signal is supplied to the image compression / expansion processing circuit 52 by a frame synchronization signal having a 1/30 second cycle (in the case of the NTSC system) or a 1/25 second cycle (in the case of the PAL system). The recording and reproduction processing circuit 54 and the mechanism drive circuit 64 are set in synchronization with a synchronization signal of a track unit having a period of 1/300 second in both the NTSC system and the PAL system.

In recording, the control circuit 62 controls the SP
/ SDL mode signal, mode flag P_LSF for signal processing system and mode flag S_L for servo system
An SF is generated and supplied to the recording / reproducing processing circuit 54. The recording / reproducing processing circuit 54 sets the mode flags P_LSF, S_L to predetermined bits of the subcode to be recorded on the magnetic tape 24.
The LSF is set, and the subcode is taped together with the encoded image data. The control circuit 62 also supplies the generated mode flag S_LSF to the mechanism drive circuit 64.

On the other hand, at the time of reproduction, the recording / reproduction processing circuit 54
Detects the mode flags P_LSF and S_LSF in the subcode from the data string reproduced by the rotating head 56 and supplies them to the control circuit 62, and sets the internal signal processing system to a processing mode corresponding to the mode flag P_LSF. Set. The control circuit 62 controls the mode flag P_LSF
Is set in the image compression / decompression processing circuit 52, and the processing mode determined by the mode flag S_LSF is set in the mechanism drive circuit 64.

Therefore, the mechanism drive circuit 64, that is, the servo system, operates during recording / reproduction in accordance with the processing mode determined by the mode flag S_LSF, and the signals of the image compression / decompression processing circuit 52 and the recording / reproduction processing circuit 54 are transmitted. The processing system operates according to the processing mode determined by the mode flag P_LSF.

FIG. 7 shows a correspondence table between the moving image / still image mode, the SP / SDL mode, and the mode flags S_LSF and P_LSF. M in the moving image / still image mode column indicates a moving image mode, and S indicates a still image mode. As can be seen from FIG. 7, the mode flag S_LSF is SP / SDL
Although the mode flag P_LSF corresponds to the mode set by the mode changeover switch 58, when the still image mode is set by the moving image / still image mode changeover switch 60, the mode flag P_LSF is set regardless of the setting mode of the SP / SDL mode changeover switch 58. Instead, it becomes "0".

The recording operation of this embodiment in the case of the NTSC system will be described. FIG. 8 shows the track pattern and the mode transition. SP / SDL mode switch 60
Outputs a mode signal indicating the SDL mode, and the moving image / still image mode switch 58 outputs a mode signal indicating the moving image mode. The control circuit 62 includes switches 58 and 6
According to the mode signal from 0, the operation mode of the mechanism drive circuit 64 (servo system) (hereinafter, referred to as S_mode) and the operation mode of the image compression / decompression processing circuit 52 (hereinafter, P_m)
ode. ) Are set to the SDL mode.

The control circuit 62 further includes a recording / reproduction processing circuit 5
4 is “1” as the mode flag P_LSF.
Is set to “1” as the mode flag S_LSF. As a result, the recording / reproducing processing circuit 54, as shown in FIG.
To T5), the moving image in the SDL mode and the mode flag P_
A subcode signal in which LSF and S_LSF are set to predetermined bits is recorded.

When the moving image recording in the SDL mode is completed in one frame and the mode is changed to the still image mode in the SDL mode, the control circuit 62 sets the P_mode to the SP mode while holding the S_mode in the SDL mode.
Mode flag P_LS for the recording / reproducing processing circuit 54
F is set to “0” and the mode flag S_LSF is set.
As the still image mode in the SDL mode, "1" is set as in the previous state. As a result, as shown in FIG. 8, the recording / reproduction processing circuit 54 records a still image in the SP mode and a subcode signal in which the mode flags P_LSF and S_LSF are set to predetermined bits. Since the signal processing system operates in SP mode, the amount of data to be recorded is SD
The frame number F2 in FIG.
A high-quality still image is recorded over ten tracks of track numbers T1 to T10.

When the mode changes to the moving image mode again after the end of the still image recording, the control circuit 62 sets the P_mode
Is returned to the SDL mode, and normal moving image recording in the SDL mode is executed.

At the time of reproduction, the operation is as follows. That is,
Mode flag P_LS in the reproduced subcode
F and S_LSF are transmitted from the recording / reproduction processing circuit 54 to the control circuit 6
2 is supplied. The control circuit 62 outputs the reproduced mode
According to the flags P_LSF and S_LSF, the signal processing system
An operation mode corresponding to the reproduced mode flag P_LSF is set, and the servo system is set to the reproduced mode flag S.
Set to the operation mode determined by _LSF.

[0031]

As can be easily understood from the above description, according to the present invention, when a still image is recorded in the long-time recording mode, the still image can be recorded and reproduced with high image quality.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of an embodiment of the present invention.

FIG. 2 shows a pixel configuration in the case of an NTSC system in a high image quality mode.

FIG. 3 shows a pixel configuration in the case of a PAL system in a high image quality mode.

FIG. 4 shows a pixel configuration in the case of an NTSC system in a long-time recording mode.

FIG. 5 shows a pixel configuration in the case of a PAL system in a long-time recording mode.

FIG. 6 is a schematic block diagram of the reconstructed embodiment of the present invention.

FIG. 7 is a correspondence table of a moving image / still image mode, an SP / SDL mode, and mode flags S_LSF and P_LSF.

FIG. 8 is a diagram illustrating an example of a track pattern and a mode transition according to the present embodiment.

FIG. 9 shows a basic format of image data.

FIG. 10 shows a recording format of a magnetic tape.

FIG. 11 is a diagram showing a recording track pattern and mode transition of a conventional example.

FIG. 12 is another diagram showing a recording track pattern and a mode transition in the conventional example.

[Explanation of symbols]

 10: Data I / O block 12: Image data input / output block 14: Audio processing block 16: Encoding / decoding block 18: Error correction block 20: Encoded data input / output block 22: Electromagnetic conversion processing block 24: Magnetic tape 26: Address conversion circuit 28: Memory 30: System control CPU 32: CPU bus 34: Servo CPU 36: CPU bus 38: Interface 50: Image data input terminal 52: Image compression / expansion processing circuit 54: Recording / reproduction processing circuit 56: Rotating head 58: SP / SDL mode changeover switch 60: Moving image / still image mode changeover switch 62: Control circuit 64: Mechanism drive circuit

Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location H04N 5/92 H04N 5/92 H 9/804 9/80 B 9/808

Claims (1)

[Claims] A digital video signal is recorded in such a manner that a synchronization signal, identification data for channel identification and address data are added to each predetermined sample, and a plurality of inclined tracks are formed on a magnetic tape by a plurality of rotary heads. ,
A digital video recording / reproducing apparatus for reproducing, characterized in that a servo system is fixed to a long time recording mode and a signal processing system is set to a high image quality mode in response to a still image recording instruction after a long time recording mode. Digital video recording and playback device.