JPS61246986A - Digital dubbing error detecting method - Google Patents

Abstract

PURPOSE:To detect easily sound jumping by assuming that a dubbing error is present when a period from the start of dubbing and the time specified by sub-coding included in digital data transmitted from a compact disk device are discontinuous. CONSTITUTION:The CD device 11 transfers the digital data read out of a compact disk CD to an R-DAT 12 and a current time ta is set to zero. Simultaneously the CRC check of the sub-coding is carried out at every prescribed time DELTAT. If the sub-coding has an error, a processor 12a updates the current time by ta+DELTAT ta: otherwise, the processor 12a compares the ta with the time ts specified by the sub-coding. When they are discontinuous, the error is displayed, assuming that there is a dubbing error and dubbing error detection processing is stopped. Accordingly the sound jumping can be easily detected.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a digital dubbing error detection method, and particularly to a method for digitally recording audio data on a magnetic tape with a rotating head and reading audio data from the magnetic tape. The present invention relates to a method for detecting digital dubbing errors in a digital audio device for playback.

<Prior art> A digital audio device (referred to as an R-DAT device) that digitally records audio data on a magnetic tape using a rotating head, and also reads and reproduces audio data from the magnetic tape.
There is. In such an R-DAT, similar to a video tape recorder (VTR), recording/reproducing heads are provided at intervals of 180° from each other to form a rotating head, and the traveling locus of each head on the tape surface is parallel to the longitudinal direction of the magnetic tape. It is constructed so as to be inclined with respect to the direction, and is configured to record 16-bit linear AD-converted audio data on a magnetic tape using a rotary head, and to reproduce and output the audio data read from the magnetic tape.

Furthermore, some R-DATs record not only audio data from analog sources but also audio data from digital sources such as compact disc devices (CD devices) (referred to as digital dubbing).

This is because some CD devices have recently become available that have a digital output terminal that directly outputs digital data read from a compact disc.

<Problems to be Solved by the Invention> By the way, in the case of playback using an analog record player, if there is a skip in the sound, an abnormal sound is generated and the skip can be easily detected. However, in the case of playback using a CD device, even if there is a skip, no abnormal sound is generated, so it is often possible to dub without noticing the skip. Furthermore, when dubbing is performed without listening to the reproduced sound, it is of course impossible to detect abnormalities such as skipping.

If digital dubbing is performed on a magnetic tape with skipping abnormalities, it is naturally impossible to record audio of good quality. However, conventionally, it has not been possible to easily detect skipping during digital dubbing.

In light of the above, an object of the present invention is to provide a digital dubbing error detection method that can easily detect the occurrence of skipping.

Means for Solving the Problems> The present invention is a method for detecting digital dubbing errors in a digital audio device that digitally records audio data on a magnetic tape and also reads and reproduces audio data from the magnetic tape. (b) Compares the current time with the time indicated by the sub-coding included in the digital data sent from the compact disc device, and (c) detects discontinuity between both times. In this case, it is determined that a dubbing error has occurred.

Function> The time ta from the start of dubbing is monitored, and the time ts specified by subcoding included in the digital data sent from the compact disc device is compared with the time ts, and if both times are discontinuous, It is assumed that there is a dubbing error, and an error due to sound skipping during digital dubbing is detected. Note that the time comparison is performed using a predetermined time ΔT.
If the time difference 1ts-tal is within the allowable range, it is considered continuous, and if it is not within the allowable range, it is considered discontinuous. Then, in the case of continuous, the current time ta is updated with the time ts specified by the subcorporate (ts-+t
a) l, . . . From then on, time comparison is performed every ΔT.

<Example> Fig. 1 is a schematic configuration diagram of a system that realizes the present invention, Fig. 2
The figure is a flowchart of processing according to the present invention.

In FIG. 1, 11 is a CD device, and 12 is an R-DAT. The CD device 11 has a digital output terminal 11.
a is provided, and digital data read from a compact disc (CD) is sent as is to the R-DAT 12 via a signal line SL connected to this terminal. Therefore, if the R-DAT 12 is set to digital dubbing mode by operating a switch (not shown), the R-DAT's processor 12a transfers the digital data to the built-in RAM 12.
Thereafter, the digital data is read from the RAM in synchronization with a predetermined clock of the R-DAT and recorded on the magnetic tape via the rotary head 12c. In FIG. 1, 13 is an analog source (for example, a record player), and 12d is an AD conversion blade.

The digital dubbing error detection process according to the present invention will be explained below with reference to FIG.

(1) When digital dubbing starts, the CD device 11
reads the digital data from the CD into R-DAT 1
Transfer to 2.

(2) When the digital data is transferred, the R-DAT12 controller immediately sets the current time ta to zero (0→ta), and thereafter sets the current time ta to zero for a predetermined time ΔT.
CRC check of subcoding is performed every time.

(31 If there is an error in the subcoding by the CRC check, the processor updates the current time using the following formula % formula % and performs a CRC check every ΔT thereafter.

(If there is no error in the sub-coding according to the 41 CRC check, the processor compares the current time ta with the time (absolute time from the start of the performance) ts indicated by the sub-coding.

(5) Compare the current time ta and the time ts specified by subcoding, and if both times are discontinuous, it is assumed that there was a dubbing error due to skipping, and if they are continuous, it is assumed that there was no dubbing error. I reckon.

In addition, when the time difference between both L t s - t a l is calculated and the time difference is within the allowable range, in other words, when the following formula 6 formula % holds true, time is considered continuous, and when it does not hold, time is considered discontinuous. . However, Ta is the allowable time.

(6) If the time is continuous, the processor 12a updates the current time ta with the time ts specified by the subcoding (ts-4ta), and thereafter repeats the processing from step (1) onwards.

(7) However, if the time is discontinuous, an error display is output and the dubbing error detection process is stopped. Incidentally, in addition to the fact that there was a skip, the error display can also display the skip time. Also, even if an error is detected, the error detection process is not stopped, and the number of error occurrences E is updated (
E+ 1-E) may be displayed and the processing may be continued as ts→ta.

<Effects of the Invention> According to the present invention, the time from the start of dubbing is monitored, and the time is compared with the time indicated by the sub-coding included in the digital data sent from the compact disc device. If the times are discontinuous, it is assumed that a skipping dubbing error has occurred, so skipping during digital dubbing can be easily detected.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a system to which the present invention can be applied, and FIG. 2 is a flowchart of processing according to the present invention. 11...CD device, 12...R-DATl 12a...processor, 12b
・RAM112c ・One-turn head patent applicant
Alpine Co., Ltd. agent
Patent attorney Chiki Saito! figure

Claims (3)

[Claims] (1) In a digital dubbing error detection method for a digital audio device that digitally records audio data on a magnetic tape and also reads and plays audio data from the magnetic tape, the time from the start of dubbing is monitored, and the time and the compact disc are A digital dubbing error detection method characterized by comparing the time indicated by sub-coding included in digital data sent from a device and determining that a dubbing error has occurred if both times are discontinuous. . (2) The time difference is compared at predetermined time intervals, and if the difference between the two times is within an allowable range, it is considered to be continuous, and if it is not within the allowable range, it is considered to be discontinuous. 1) Digital dubbing error detection method described in section 1). (3) The digital dubbing error detection method according to claim (1) or (2), characterized in that, in the case of continuous occurrence, the current time is updated with the time indicated by subcoding.