JP3329336B2 - Digital data playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital data reproducing apparatus suitable for application to, for example, a VTR apparatus for recording, as digital data, an audio signal or a still image signal recorded together with a video signal.

[0002]

2. Description of the Related Art Conventionally, a VTR device capable of recording a digital audio signal together with an analog video signal has been put to practical use. FIG. 11 is a diagram showing a recording format of a system called 8 mm video as an example of such a VTR device. In the drawing, reference numeral 1 denotes a magnetic tape, on which a slanted track rotates. Recording is performed by sequentially forming magnetic heads attached to the head drum. In this case, 22 of the peripheral surface of the rotary head drum
The magnetic tape 1 is wound around 1 ° for recording / reproduction,
The first 36 of tracks formed by this 221 ° scan
Digital audio signal (PCM audio signal) in the range of °
Is recorded, and recording of a video signal (analog video signal) is performed in a subsequent range of 180 °. Note that digital data other than the digital audio signal can be recorded in the recording area of the digital audio signal. For example, a still image signal converted into digital data can be recorded. When recording the still image signal, the still image signal for one frame is divided into a plurality of tracks and recorded.

[0003] By recording digital data such as a digital audio signal and a video signal in separate areas in this way, the video signal and the digital data can be recorded and reproduced individually.

In the case of 8 mm video, a so-called multi-PCM mode for recording digital data instead of a video signal in a video signal recording area is provided.
FIG. 12 is a diagram showing a recording format of the multi-PCM mode.
It is divided and each divided area is used as a digital audio signal recording area. In this case, the first to sixth sets of six digital audio signal recording areas are formed together with a digital audio signal recording area prepared separately from the video signal recording area, and six different sets of digital audio signals (or other sets) are provided. Digital data) can be recorded.

[0005] In addition to the system for recording the digital audio signal and the video signal in different areas, there is also a system for simultaneously recording the digital audio signal and the video signal by frequency multiplexing.

[0006]

By the way, when digital data is recorded in this way, when an error rate of reproduced data is deteriorated at the time of reproduction, the reproduced signal to be outputted is determined to be in a mute state as a reproduction failure. I have to do it. In other words, when a digital audio signal is being reproduced, the state of reproduction from the magnetic tape deteriorates for some reason, and the error rate of the reproduced signal deteriorates to such a degree that it cannot be almost completely processed by error correction, interpolation, or the like. A sound signal in a silent state is output instead of a reproduction signal, thereby preventing noise such as an abnormal sound different from the reproduction sound from being reproduced due to erroneous data. Also, when reproducing a magnetic tape on which a digital still image signal is recorded instead of a digital audio signal, the reproduced video signal to be output is similarly set to a mute state in which the entire screen becomes black due to the deterioration of the error rate. I have to do it.

[0007] Such a mute state is automatically set when the error rate is deteriorated during the reproduction. However, the reproduced sound or the reproduced image is suddenly interrupted, and the person who monitors the reproduced sound or the reproduced image is ineffective. However, there is a risk that the device may be mistaken for a failure.

[0008] It is an object of the present invention to provide an operator of this type with a simple configuration when an error rate is deteriorated in such a reproducing apparatus.

[0009]

According to the present invention, as shown in FIG. 1, for example, in a digital reproducing apparatus for reproducing video or audio digital data recorded on a predetermined recording medium 1, the digital data is reproduced from the recording medium 1. Playback from digital data
Error condition is higher than specified or specified in media
The presence or absence of recorded data is determined to improve the normal playback state.
The playback process for normal playback output.
The normal reproduction output stored in the predetermined memories 31 and 32 in advance can be performed in accordance with any of them.
Reads the predetermined data indicative of the absence, predetermined playback exits the read data as video or audio
It is designed to be output instead of force data .

[0010] By doing so, the normal reproduction output is
When the state can not be performed, since data read from the memory is output as video or audio, in video or audio due to data read from the memory, the normal reproduction
It is notified that output cannot be performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
This will be described with reference to FIG. In this example, an example is shown in which the present invention is applied to a VTR device of a standard called 8 mm video, which records and reproduces a digital audio signal in a time-division manner with a video signal.
It is configured as a TR-integrated video camera device.

In FIG. 1, reference numeral 1 denotes a magnetic tape. The magnetic tape 1 is wound around a rotary head drum 2. On the rotary head drum 1, magnetic heads 3 and 4 having an angular interval of 180 ° are arranged. In this case, the rotary head drum 2 is rotated at a frame frequency by a servo circuit (not shown) in synchronization with the luminance signal of the recording video signal.

Then, the magnetic tape 1 is caused to run obliquely at a constant speed over an angular range slightly over 221 ° with respect to the rotating peripheral surfaces of the magnetic heads 3 and 4, and the video signal of the video signal is rotated within an angular range of about 180 °. Recording and reproduction are performed, and recording and reproduction of the digital audio signal are performed in an angular range of about 36 °.

Next, a recording system circuit will be described. In the figure, reference numeral 11 denotes a solid-state image pickup device (CCD) as an image pickup means, which converts image pickup light into an electric image pickup signal. Then, the image pickup signal output from the CCD 11 is supplied to an image pickup processing circuit 12, and this processing circuit 12
The video signal is converted into a video signal of a predetermined standard such as a system. Then, the video signal output from the imaging processing circuit 12 is supplied to the video recording processing circuit 13. Further, this VTR device has an external video input terminal 14, and supplies a video signal obtained at this input terminal 14 to the video recording processing circuit 13.

The video recording processing circuit 13 performs recording modulation and the like, and the processed recording video signal is output to the mixer 15.
To supply. The video recording processing circuit 13 is supplied with storage data (image data) from a ROM 31 and a RAM 32 to be described later, and superimposes the image data supplied from the ROM 31 or the RAM 32 on a video signal. In addition, in some cases, this image data can be output as a video signal for recording, instead of the video signal supplied from the imaging processing circuit 12 or the input terminal 14. This superimposition and replacement with stored image data are performed using this VT
This is performed under the control of the system controller 10 that controls the operation of the R device.

Here, the ROM 31 and the RAM 32 will be described. The ROM 31 has image data for performing a superimposition such as a preset title, and image data and audio data for notifying that the input signal is not recorded. And image data and audio data for notifying a reproduction failure or the like used at the time of reproduction described later. The RAM 32 allows the user to arbitrarily store image data and audio data (a circuit for storing the data is not shown). When the stored data is read from the ROM 31 or the RAM 32 under the control of the system controller 10, a switch 33 for switching between the memories 31 and 32, a switch 34 for switching between the recording system and the reproducing system, and a video processing circuit side. The video recording processing circuit 1 is switched via the changeover switch 35 for switching the audio processing circuit side.
3 or a digital recording processing circuit 25 described later.

In FIG. 1, reference numeral 21 denotes a microphone device, which supplies a sound picked up by the microphone device 21 to an audio frequency modulation recording processing circuit (hereinafter, referred to as an AFM recording processing circuit) 22. A recording process such as frequency modulation is performed. Further, this VTR device has an external audio input terminal 27, and an audio signal obtained at the input terminal 27 is supplied to the AFM recording processing circuit 22. Then, the modulated audio signal output from the AFM recording processing circuit 22 is supplied to the mixer 15.

The image signal and the FM signal are mixed by the mixer 15.
An audio signal is mixed by frequency multiplexing, and the mixed signal is supplied to a changeover switch 16. The changeover switch 16 switches between a circuit connected to one magnetic head 3 and a circuit connected to the other magnetic head 4. Is supplied to one magnetic head 3 via the recording amplifier 6 and the rotary transformer 5. When the switch is switched to the other by the changeover switch 16, the output of the mixer 15 is supplied to the other magnetic head 4 via the recording amplifier 7 and the rotary transformer 5.
To supply. Then, the output of the mixer 15 is applied to the magnetic tape 1.
In the video signal recording area (see FIG. 11).

The audio signal picked up by the microphone device 21 and the audio signal obtained at the external audio input terminal 27 are supplied to an analog / digital converter 23, and the digital audio signal converted by the analog / digital converter 23 is supplied. Is supplied to the digital recording processing circuit 25 via the changeover switch 24. Then, the digital recording processing circuit 25 performs digital signal processing based on the recording method, and supplies the processed digital audio signal to the recording amplifiers 6 and 7 via the changeover switch 26. Then, the recording amplifiers 6 and 7
Then, the digital audio signal is supplied to one and the other magnetic heads 3 and 4 via a rotary transformer 5 to record a digital audio signal in a digital audio signal recording area (see FIG. 11) of the magnetic tape 1. Note that a recording signal is also supplied from the digital recording processing circuit 25 side to each recording area in the multi PCM mode.

When the digital audio signal is not recorded, a digital still picture signal can be recorded. That is, the video signal output from the imaging processing circuit 12 or the video signal obtained at the external video input terminal 14 is supplied to the still image recording processing circuit 17, and the still image recording processing circuit 1
In step 7, a predetermined one-frame video signal is converted into digital data, and the data is divided into data to be recorded on one track and sequentially output. Then, the still image recording processing circuit 1
7 is supplied to a digital recording processing circuit 25, and the digital recording processing circuit 25 performs recording processing in the same manner as the digital audio signal, and the digital recording processing circuit 25 sends the signal to the magnetic heads 3 and 4 instead of the digital audio signal. A digital still image signal is supplied and recorded in a digital audio signal recording area of the magnetic tape 1.

In this embodiment, a ROM 3 described later is used.
1. The storage data (audio data or image data) is supplied from the RAM 32 side.
Alternatively, audio data or image data supplied from the RAM 32 can be output instead of a digital audio signal supplied from the analog / digital converter 23 or a signal supplied from the still image recording processing circuit 17. is there. That is, when the supply of the audio signal from the analog / digital converter 23 is interrupted in the digital audio signal recording mode, the audio data supplied from the ROM 31 and the RAM 32 is replaced with the input digital audio signal. The audio data is recorded in the digital audio signal recording area of the magnetic tape 1. When the supply of the still image signal from the still image recording processing circuit 17 is interrupted in the digital still image signal recording mode, the image data supplied from the ROM 31 and the RAM 32 is input to the input digital still image. The image data is output in place of the signal, and the image data is recorded in the digital audio signal recording area of the magnetic tape 1. Replacement with this memory data
The operation is performed under the control of the system controller 10 that controls the operation of the VTR device.

Next, the reproduction system circuit will be described. A reproduction signal output from the magnetic heads 3 and 4 is transmitted to a changeover switch 4 via a rotary transformer 5 and reproduction amplifiers 8 and 9.
1 and the changeover switch 41 controls the two magnetic heads 3,
4 is switched for each field and supplied to a video reproduction processing circuit 42 and an audio FM modulation reproduction processing circuit (hereinafter referred to as an AFM reproduction processing circuit) 43. Then, each of the reproduction processing circuits 42 and 43 performs a reproduction process of the video signal and the FM audio signal recorded in the corresponding frequency band, and outputs the processed video signal and audio signal to the video signal output terminal 4.
4 and an audio signal output terminal 45.

A reproduction signal output from the magnetic heads 3 and 4 is supplied to a changeover switch 51 via a rotary transformer 5 and reproduction amplifiers 8 and 9.
At 1, the reproduction outputs of the two magnetic heads 3 and 4 are alternately switched and supplied to the digital reproduction processing circuit 52. The digital reproduction processing circuit 52 performs a predetermined reproduction process on the digital audio signal or digital still image signal reproduced from the digital audio signal recording area of the magnetic tape 1. As the reproduction processing, error detection, error correction, interpolation, expansion of the time axis, and the like of reproduction data are performed.

In this case, an error rate discriminating circuit 61 is connected to the digital reproduction processing circuit 52, and an error occurrence state detected by the digital reproduction processing circuit 52 is evaluated to determine an error rate. Then, the data of the determined error rate is supplied to the digital reproduction processing circuit 52, and when the error rate is equal to or higher than a predetermined value, a process of muting is performed. That is, when the digital audio signal is in the reproduction mode and the error rate of the digital audio signal reproduced from the magnetic tape 1 is deteriorated to a level that cannot be processed by error correction or interpolation, the reproduced signal is not output. Further, when the digital still image signal is in the reproduction mode and the error rate of the digital still image signal reproduced from the magnetic tape 1 is deteriorated to such a degree that it cannot be processed by error correction or interpolation, the reproduced signal is not output. .

Further, the error rate data is transmitted from the error rate determination circuit 61 to the system controller 10.
When mute processing is performed at an error rate equal to or higher than a predetermined value, data replacing the reproduction data is stored in the ROM 31.
Alternatively, it is read from the RAM 32. In this case, the data read from the ROM 31 and the RAM 32
The signals are supplied to the digital reproduction processing circuit 52 via the changeover switches 33 and 34.

Then, the digital audio signal subjected to the reproduction processing by the digital reproduction processing circuit 52 is transferred to a changeover switch 53.
To the digital / analog converter 54, and the analog audio signal converted by the digital / analog converter 54 is supplied to the audio signal output terminal 55. Further, the digital still image signal subjected to the reproduction processing by the digital reproduction processing circuit 52 is supplied to a still image reproduction processing circuit 56 via a changeover switch 53, and the still image reproduction processing circuit 56 outputs one frame of an analog still image. The signal is assembled, and the still image signal is supplied to the output terminal 57.

Next, the operation when recording / reproducing with the VTR device of this embodiment will be described. First, the operation at the time of recording will be described. This VTR apparatus has a plurality of recording modes. This recording mode is divided into a mode for recording digital audio signals in the digital audio signal recording area and a mode for recording digital still image signals in this area. Recording a signal (moving image) and an FM audio signal is defined by a standard. Here, when there is a corresponding signal input in each recording mode, each input signal is subjected to recording processing by each circuit shown in FIG. 1 and recorded on the magnetic tape 1.

In this example, when there is no input of any signal, the system controller 10 judges this, reads out the data stored in the ROM 31 or the RAM 32, and records this data instead. It is. Table 1 below shows a case where the data stored in the memories 31 and 32 is read out and recorded.

[0029]

[Table 1]

As can be seen from Table 1, when there is no audio signal input, data indicating that there is no audio signal input is read from the ROM 31 or the RAM 32, and the digital audio signal (in the digital audio recording mode). ) And the FM audio signal, this audio data is recorded. When there is no video signal input, data indicating that there is no video signal input is read from the ROM 31 or the RAM 32, and the digital still image signal (in the digital still image recording mode) and the analog video signal are read. This video data is recorded.

By recording in this way, when the magnetic tape 1 recorded at this time is reproduced, for example, when the magnetic tape 1 recorded without any audio input is reproduced, the recording of the input audio is performed. The fact that the message was not heard can be immediately determined by the reproduced voice message. Similarly, when the magnetic tape 1 recorded with no video input is reproduced, it can be immediately determined from the message indicated by characters or the like in the reproduced image that the input video has not been recorded.

In the case of the multi PCM mode, data read from the ROM 31 or the RAM 32 is recorded as shown in Table 2 below.

[0033]

[Table 2]

Next, at the time of reproduction, the ROM 31 or the RAM 32
2 will be described with reference to the flowchart of FIG. 2. When reproducing from the magnetic tape 1 attached to this VTR device, it is necessary to select a reproduction mode. That is, as shown in the flowchart of FIG. 2, first, whether or not to reproduce the digital signal recording area (PCM area) is selected (step 101). The reproduction of the digital signal recording area includes the reproduction of multi-PCM. When the reproduction of the digital signal recording area is not performed, the reproduction is performed without using the data stored in the ROM 31 and the RAM 32 in any case (Step 10).
2).

When reproducing the digital signal recording area, it is determined whether the reproduction of this area is in the audio mode or the still image mode (step 103). Then, in the audio mode in which the digital audio signal is reproduced, the error rate of the data reproduced from the corresponding digital signal recording area is determined by the error rate determination circuit 61, and it is determined whether the error rate at this time is lower than a predetermined value. (Step 104). At this time, if the value is equal to or less than the predetermined value, it is determined that good error processing is possible by processing such as error correction and interpolation, and processing for outputting the reproduced audio data is performed (step 102). Also,
When it is determined that the error rate is higher than a predetermined value and cannot be processed by the error correction or the interpolation, under the control of the system controller 10, audio data indicating that the reproduction state of the digital audio is defective is indicated by the ROM 31 or the RA.
M32 is read (step 105), and this audio data is output from the audio signal output terminal 55 instead of the reproduced audio (step 106), and the audio is notified that the reproduction state is defective. Until the error rate discriminating circuit 61 detects that the error rate has dropped below a predetermined value, the notification by voice is continued, and when the error rate drops, the process is switched to a process of outputting the reproduced audio data (step). 102).

When it is determined in step 103 that the digital still image signal is to be reproduced in the still image mode, it is determined whether the error rate at this time is lower than a predetermined value (step 108). At this time, if it is less than the predetermined value,
It is determined that good error processing is possible by processing such as error correction and interpolation, and processing for outputting the reproduced still image data is performed (step 102). When it is determined that the error rate is higher than a predetermined value and cannot be processed by error correction or interpolation, image data indicating that the reproduction state of the digital still image is defective is read from the ROM 31.
Alternatively, the image data is read from the RAM 32 (step 109), and this image data is output from the still image signal output terminal 57 instead of the reproduced still image (step 110), and a message in the image notifies that the reproduction state is defective. Until the error rate discriminating circuit 61 detects that the error rate has dropped below a predetermined value, the notification with this image is continued, and when the error rate drops, the processing is switched to a process of outputting reproduced still image data ( Step 10
2).

Here, FIG. 3 shows an example of an image informing that the reproduction state is defective as described above. In this case, "improper reproduction state" is displayed in some background by superimposition. Further, in the case of the multi PCM mode, as shown in FIG. 4, the character "Reproduction state failure" and the channel number are displayed. In this case, these display data are stored in ROM
31 in advance, and when a display different from those in FIGS. 3 and 4 is desired (for example, when a background image is to be changed), R
An image different from this display image may be stored in the AM 32.

In addition, due to factors other than the error rate defect,
Even when digital data cannot be reproduced, the ROM 31
Alternatively, display (or audio output) based on the data stored in the RAM 32 may be performed. For example, when the recording mode of the signal recorded on the magnetic tape 1 is unknown at the start of reproduction or the like, when the operation of discriminating the recording mode is performed, as shown in FIG. Let it. While the magnetic tape 1 is being rewound, "rewinding" is displayed as shown in FIG. When digital data is not recorded in some areas (channels) of the track divided into six in the multi-PCM mode, when the reproduction of the channel without the recording is performed, as shown in FIG. , "Multi 4 channel no recording" or the like. Also, this multi PC
When a channel recorded in the M mode is being searched, "multi-PCM channel searching" is displayed as shown in FIG. Further, when the characteristics of the equalizer for equalizing the reproduction data are adjusted at the time of starting the reproduction or the like, "automatic equalization in progress" or the like is displayed as shown in FIG.

It should be noted that, in addition to the notification by the image or the sound, a corresponding display may be performed on a display panel or the like of the VTR device. That is, as shown in FIG. 10, for example, an error, a still image, a multi-PCM, etc. are displayed on the panel surface, and corresponding pilot lamps are provided to discriminate the deterioration of the error rate, the still image recording mode, the multi-PCM mode, and the like. At this time, the corresponding pilot lamp may be turned on.

As described above, according to the VTR apparatus of the present embodiment, when a part of the input signal is lost during recording, data indicating this is recorded instead of the input signal. It is convenient because it is clear that the device is not out of order. In addition, at the time of reproduction, when good reproduction cannot be performed due to the deterioration of the error rate of the recorded digital data, this is notified instead of the reproduced sound or reproduced image. It is convenient. In this case, the memories (ROMs 31 and 32) for generating these data are also used for superimposing a title or the like at the time of shooting as a video camera, and use an empty area of this memory. It suffices to store voice and image data, which can be realized with a simple configuration, and a memory for superimposing titles and the like can be effectively used.

In the above-described embodiment, the video camera and the VTR device are configured as a single unit. However, the present invention can be applied to a single VTR device without a video camera. That is, in the configuration of FIG. 1, the CCD 11 constituting the video camera and the imaging signal processing circuit 1
If the microphone 2 and the microphone device 21 are removed, a normal VTR device is obtained.

In the above embodiment, the video signal and the digital data (digital audio signal or digital still image signal) are applied to the one that is recorded in another area of the magnetic tape. Can be applied to a VTR device that records the same on the same track by frequency multiplexing.

According to the present invention, normal reproduction output cannot be performed.
The data read from the memory is output as video or audio when the data is in the normal state.
There is a benefit to be announced that it cannot be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart for explaining one embodiment;

FIG. 3 is an explanatory diagram showing a display example when a reproduction state is defective according to one embodiment.

FIG. 4 is an explanatory diagram showing a display example when a reproduction state is defective according to one embodiment.

FIG. 5 is an explanatory diagram illustrating a display example during mode determination according to one embodiment;

FIG. 6 is an explanatory diagram showing a display example during rewinding according to one embodiment.

FIG. 7 is an explanatory diagram showing a display example at the time of non-recording according to an embodiment.

FIG. 8 is an explanatory diagram showing a display example during a channel search according to one embodiment.

FIG. 9 is an explanatory diagram illustrating a display example during automatic equalization according to one embodiment;

FIG. 10 is an explanatory diagram showing a display example of a panel surface according to one embodiment.

FIG. 11 is an explanatory diagram showing a recording format of 8 mm video.

FIG. 12 is an explanatory diagram showing a recording format of multi-PCM for 8 mm video.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic tape, 3, 4 ... Magnetic head, 10 *
..System controller, 13 video recording processing circuit, 22 audio frequency modulation recording processing circuit, 25
.Digital recording processing circuit, 31 ROM, 32.
· RAM, 52 · · · digital reproduction processing circuit, 61 · · ·
・ Error rate discrimination circuit

Claims (1)

(57) [Claims] 1. A digital reproducing apparatus for reproducing digital data of video or audio recorded on a predetermined recording medium, reproducing from the digital data reproduced from said recording medium gill
-The status is higher than the specified level , or
Discriminates the presence or absence of the predetermined recording data
To determine whether it will be good, or for normal playback output
The reproduction processing operation state is determined, and a normal reproduction output stored in a predetermined memory cannot be performed according to any of the states.
The predetermined data indicating the status is read out, and the read data is output as predetermined reproduction output data as video or audio.
Digital data reproducing apparatus so as to output to replace the motor.