JPS58225784A - Disk reproducing device - Google Patents

Abstract

PURPOSE:To reproduce even a video signal from a compact disk from which a digital audio signal is reproduced, by outputting the digital audio signal on real- time basis and outputting the digital video signal from a memory. CONSTITUTION:A signal reproduced optically from the compact disk is supplied to an input terminal and the clock reproducing circuit 25 of a PLL extracts a bit clock synchronizing with reproduced data. Then, P-channel and Q-channel data in subcodes obtained from a decoder 39 are supplied to a system controller 40 and used for program searching, random program selection, etc. A time code in the Q-channel is supplied to and displayed on a display part 41. Further, data in R-W channel data in subcodes are converted by a D/A converter 42 into analog data, which are led out to an output terminal 44 through a low-pass filter 43. This display signal is supplied to a CRT display.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical disc reproducing apparatus. As an optical disc, a video disc that rotates in a frame and plays back an FM-modulated video signal is known. . A single frequency modulated audio signal is superimposed on this video signal. Some video discs record digital audio signals intermittently.In addition to optical discs, digital audio discs (called compact discs) are also known.

Since digital audio signals are recorded on compact discs, the recording density can be increased, and audio signals with high quality in terms of dynamic range, S/N, etc. can be reproduced.

The object of the present invention is to realize a disc playback device that can also play back video signals from a compact disc that plays all of the digital audio signals.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 7 shows a configuration for generating a signal to be recorded on a compact disc and recording it on a master tape. In FIG. 1, 1 and 2 indicate input terminals to which two-channel audio signals such as stereo are supplied.

Audio signals of each channel are supplied to sample and hold circuits 5 and 6 via p-bus filters 3 and 4.

Further, the two-channel audio PCM signal, in which l samples are converted into 7t bits by A/D converters 7 and 8, is supplied to a multiplexer 9.

Further, 10 indicates an input terminal to which a video signal is supplied,
This video signal is supplied to the sample and hold circuit M11, and the A/D converter 12 converts l samples into bits and writes them into the frame memory 13. This frame memory 13 includes television cameras, VTRs, etc.
A predetermined/frame of a video signal from a video signal source such as is written. The digital still video signal read from frame memory 13 is supplied to multiplexer 9.

Reference numeral 14 denotes a crystal oscillator. A master clock is supplied from the crystal oscillator 14 to a timing generation circuit 15, and licks, timing signals, etc. necessary for processing on the recording side are formed. In other words.

The digitization of the audio signal, the digitization of the video signal, the clock of the frame memory 3, and the control pulse of the multiplexer described later are formed. The two-channel digital audio signal is sent to the multiplexer 9.
/ channel. Further, the bit rate of the digital video signal read from the memory 3 to the array is set to be equal to the bit rate of the digital audio signal set as this /channel. -For example, an I/7 frame (30 seconds) digital video signal is
The recording time is approximately 2 seconds on a compact disc.

The multiplexer 9 converts the two channels of audio data into /channels, time-division multiplexes the audio data and video data by selecting them at a predetermined timing, and supplies them to the error correction encoder 16. The error correction encoder 16 performs error-correctable encoding processing on the audio data or video data output from the multiplexer 9. The output of this error correction encoder 16 is supplied to the multiplexer 11.

Furthermore, data (called a subcode) for controlling random access and displaying a 9 is inserted into the compact disc. Reference numeral 18 indicates a subcode encoder that generates this subcode, and the subcode is also subjected to error-correctable encoding. This subcode encoder.

The subcodes from 18 are fed to multiplexer 17 . The output of the multiplexer 17 is supplied to the digital modulation circuit 19 and subjected to EFM modulation of (g→c0 conversion). In this case, 7 framesyncs from the synchronization signal generation circuit 20 are mixed.

It is taken out to the output terminal 21. This output terminal 21 has
An optical cutting device is connected, and the recording laser beam is modulated according to the recording signal.

FIG. 2 shows the structure of a frame of a signal recorded on a compact disc, in which a subcode is located after a frame synchronization signal, and data is further located after that.

Also, the video period T during which the digital video signal is recorded
The video period Tv and the audio period Ta in which the digital audio signal is recorded are arranged alternately as shown in FIG. It is considered a thing.

Video data of /frame is inserted into the video period TV, so that one still image can be played back. Moreover, the audio period Ta is.

Audio information related to this still image is recorded. For example, a painting is recorded in the video period 'rv, and an audio explanation thereof is recorded in the audio period Ta. Furthermore,
In order to distinguish between the video period TV and the audio period Tat, a predetermined identification signal may be recorded together with the data, and on the playback side, the video data and audio data may be separated using this identification signal.

FIG. 1 shows the configuration of a reproducing system in an embodiment of the present invention, in which a signal optically reproduced from a compact disc is supplied to an input terminal 22.

This reproduced signal is passed through the waveform shaping circuit 23 to the digital demodulation circuit 24. Clock regeneration circuit 25 and synchronization detection circuit 2
6. Clock regeneration circuit 25 with PLL configuration
A pit clock synchronized with the reproduced data is extracted. Further, the synchronization detection circuit 26 is configured to detect frame sync and generate a timing signal synchronized with reproduction data, and supplies a predetermined timing signal to each circuit of the reproduction system.

Among the outputs of the digital demodulation circuit 24, main channel data undergoes error detection, error correction, and interpolation processing in an error correction circuit 27. Further, the subcode is subjected to error detection and error correction processing in the decoder 39.

This error correction circuit 27 performs error correction on video data and audio data, and its output is supplied to a demultiplexer 28. This demultiplexer 2
The audio data separated by 8 is passed through a D/A converter 29, 30 and a low pass filter 3 for each channel.
1.32, and the reproduced audio signals of each channel appear at output terminals 33.34.

Further, the video data separated by the demultiplexer 28 is written into the frame memory 35.

When writing to the frame memory 35 is completed, this becomes a read operation, and video data is read out at a regular sampling rate. This frame memory 35
The video data read out is converted into analog by the D/A converter 36.

The signal is taken out to the output terminal 3B via the low-pass filter 37. This output terminal 38 has one terminal (not shown).

A monitor receiver is connected.

Further, the P channel and Q channel data of the subcode obtained from the decoder 39 is supplied to a system controller 40 made up of a microcomputer, and is used to perform operations such as cueing and random music selection.

The time code included in the Q channel is displayed on the display section 41.
is supplied and displayed. Further, the data included in the R channel to W channel of the subcode is converted into analog by the D/A converter 42, and the data contained in the R channel to W channel of the subcode is
3 to the output terminal 44.

This display signal is supplied to the CRT display. As can be understood from the description of one embodiment above.

According to the present invention, it is possible to reproduce high quality continuous audio signals along with video information from optical discs, thus expanding the range of applications of optical discs compared to reproducing only audio signals. be able to. In other words, along with the music, it can display explanations of landscape paintings and songs, display illustrations, generate audio of the explanations, and use it like an illustrated encyclopedia, or for educational and learning purposes. can. Moreover, by making both the audio signal and the video signal have the same signal configuration, it is possible to prevent the hardware of the regenerated yarn from becoming complicated.

Note that the present invention is not limited to frame still images, but may be field still images, and the capacity of the memory may be increased to reproduce a plurality of still images.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a recording system in one embodiment of the present invention, FIGS. 2 and 3 are route maps showing the structure of data recorded on a compact disc, and FIG. FIG. 2 is a block diagram showing the configuration of a reproduction system in one embodiment. 9.17...Multiplexer, 22...
- Reproduction signal input terminal, 27...Error correction circuit. 28...Demultiplexer, 13.35...
...Frame memory. Agent Masato Sugiura

Claims (1)

[Claims] In a disc playback device that plays back an optical disc in which a video signal period in which a digital video signal is recorded and an audio signal period in which a digital audio signal is recorded are included in the same signal track, the digital Separating a video signal and a digital audio signal, storing the digital video signal in a memory, and outputting the digital audio signal in real time. A disc playback device configured to output a digital video signal from the memory.