JPH04301283A - System for double speed dubbing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-speed dubbing system for video tape dubbing.

0002

2. Description of the Related Art In a conventional double-speed dubbing system, as shown in FIG. 6, the rotational speed of the cylinder and capstan of a master VTR 1 is increased to twice that of recording, and the master tape is played back on-track, and the reproduced signal is reproduced. coaxial cable 2
, distributor 3, and the master VTR via the coaxial cable 4.
A commonly used method is to record with a slave VTR 5 whose cylinder and capstan rotational speeds are doubled as in 1, thereby dubbing at twice the speed in half the recording time of the master tape.

0003

However, with the above conventional configuration and method, when a digital VTR with high image quality and high sound quality is used as a master VTR, the cylinder rotation speed is as high as 90 to 150 Hz during normal playback. Even if on-track reproduction is performed at double speed, the rotational speed must be increased to 180 to 300 Hz. If a master tape is played back under such conditions, the vibration and durability of the cylinder, the contact state of the tape head, the frequency characteristics of the head, etc. will deteriorate, and the image and sound quality will deteriorate. Furthermore, solving these problems requires huge development costs, making it difficult to put them into practical use within the framework of conventional methods, and the advantages of digital VTRs, such as high image quality and high sound quality, cannot be taken advantage of. It had

The present invention solves the above-mentioned conventional problems, and even if a VTR such as a digital VTR, which has a high cylinder rotation speed during normal playback, is used as a master VTR,
To provide a double speed dubbing system capable of dubbing at double speed.

[0005]

[Means for Solving the Problems] In order to achieve this object, the double speed dubbing system of the present invention replaces the master VTR 1 of the conventional double speed dubbing system with N (N is a positive integer) recording the same information. master tape, and N master tapes each having one of the master tapes placed thereon and playing back at mutually different phases at a tape speed that is N times the recording speed.
TR and N discontinuous video or audio playback signals obtained from the N master VTRs are input,
/N, and a rate converter that outputs one continuous video or audio signal that is time-base compressed.

[0006]

[Operation] With the above-described structure, the double-speed dubbing system of the present invention reproduces N master tapes on which the same information is recorded by N master VTRs at N times the speed and in mutually different phases, and reproduces the N pieces of discontinuous By compressing the time axis of each playback signal to 1/N in a rate converter and splicing them in the recording order on the master tape, the N of the master VTR 1 in the conventional double speed dubbing system is
By converting double-speed on-track playback into a single continuous playback signal in the same format and using the above N master VTRs and rate converter in place of the master VTR 1 of the conventional double-speed dubbing system, N master VTR
Dubbing can be done in 1/N of the recording time of the master tape without increasing the cylinder rotation speed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numerals 6 and 7 digitally record and reproduce digital NTSC video signals that are sampled at four times the frequency of the color subcarrier (4 fsc) and quantized in 8 bits using three tracks per field. 8 is a master VTR, 8 is a digital cable, 9 is a rate converter for splicing the reproduced data of the two master VTRs 6 and 7 into one, 10 and 12 are coaxial cables, 11 is a distributor, and 13 is a slave VTR.

The operation of the double-speed dubbing system of this embodiment configured as described above will be explained below.

First, master tapes with the same content recorded on the master VTRs 6 and 7 are placed one by one, and variable mode (a method in which a playback head is mounted on a piezo element and the recorded tracks are tracked and controlled) is performed. Different phases, for example, different fields, are played back in parallel at twice the speed of the variable speed playback mode (variable speed playback mode). In this embodiment, the master VTR 6 is used to reproduce odd fields.
The master VTR 7 is assigned to play even fields.

FIG. 2 shows the reproduction track at this time. The upper row in FIG. 2 shows the reproduction track of the master VTR 6, and the lower row shows the reproduction track of the master VTR 7. Since the master VTRs 6 and 7 used in this embodiment use three tracks for recording one field, three consecutive tracks are the unit of reproduction. Therefore, during double-speed playback in variable mode, the tracks indicated by three consecutive solid lines in FIG. This is a playback track. That is, the master VTR
6 plays the 1st, 3rd, and 5th fields, and the master VTR 7
represents that 2, 4, and 6 fields are reproduced.

Further, the master VTRs 6 and 7 reproduce the assigned fields at the timings shown in the upper and middle rows of FIG. The horizontal axis in Figure 3 is time (seconds), T is the field period 1/59.94 seconds, and the upper row is the master VTR 6.
The data entered from and its field number,
The middle row shows data input from the master VTR 7 and its field numbers. Taking the period from 0 seconds to T seconds as an example, this indicates that the master VTR 7 is made to play field 2 at the same time as the master VTR 6 plays field 1.

The data outputted from the master VTRs 6 and 7 in this manner is transmitted to the rate converter 9 via the digital cable 8, respectively.

The detailed operation of the rate converter 9 will be explained with reference to block diagrams shown in FIGS. 4 and 5. Figure 4 shows the rate converter 9
FIG. 5 is a block diagram showing the internal configuration of the video signal processing section, and FIG. 5 is a block diagram showing the internal configuration of the audio signal processing section.

In FIG. 4, 14 and 15 are video data input terminals for inputting digital video data from master VTRs 6 and 7, respectively, and 16 and 17 are field memories for storing video data input from the video data input terminal 14. , 18 and 19 are field memories for storing video data input from the video data input terminal 15, 20 is a writing means for controlling the write address of the field memories 16 and 17, and 21 is a field memory 18 and 19.
22 is a reading means for controlling the read addresses of the field memories 16, 17, 18, 19, 23 is a process circuit for adding a synchronization signal and a color burst signal, 24 is a D /A converter,
25 is a video signal output terminal to the slave VTR. Note that between field memories 16 and 17 and between 18 and 19
Set so that there is no duplication of write addresses between them.

Further, in FIG. 5, 26 and 27 are audio data input terminals for inputting digital audio data;
29 is a field memory for storing data input from the audio data input terminal 26; 30 and 31 are field memories for storing data input from the audio data input terminal 27; 32 is for controlling write addresses of the field memories 28 and 29. Writing means 33 is field memory 30,3
1 is a write means for controlling the write address; 34 is a read means for controlling the read address from the field memories 28, 29, 30, 31; 35 is a D/A converter; and 36 is an audio signal output terminal. Note that the thick lines in FIGS. 4 and 5 indicate the flow of video data (signal) or audio data (signal), the dotted line indicates a clock signal, and the two-dot chain line indicates address designation to the field memory.

Since the rate converter of this embodiment configured as described above processes video data and audio data in the same manner, its operation will be explained below using video data as an example.

The video data reproduced by the master VTRs 6 and 7 by the above means has 8 bits per word and 4 fsc.
This is parallel data at a rate of 1, and is input via video data input terminals 14 and 15. Video data input terminal 1
The data input from 4 is stored in field memories 16 and 17.
The data inputted from the video data input terminal 15 to the writing means 20 is sent to the field memories 18, 19 and the writing means 2.
Sent to 1. The writing means 20 and 21 detect the sampling clock (4fsc) and horizontal and vertical synchronization signals from the video data, calculate the write address of the video data, and write the address to the field memory 16 or 17, 18 or 1, respectively.
Specify the address for either one of 9. The field memory designated with the write address stores video data at the address at a rate of 4 fsc. Here, between field memories 16 and 17 and 18 and 19
In order to avoid duplication of write addresses during the period, only one field memory is used for write operations.

Further, the reading means 22 receives the sampling clock and the write address from the writing means 21, generates a read address, and uses the read clock (8fsc) twice the sampling clock to perform the write operation. The read addresses are sequentially specified for the two field memories that are not currently in use. That is, by first sending a read address to the field memory 16 or 17 to read the data, and then sending the same read address to the field memory 18 or 19, data for two fields can be read at a rate of 8 fsc with one field period T seconds. Read out sequentially.

When writing and reading are performed at the above-mentioned timing, the output of the rate converter 9 is as shown in the lower part of FIG. It becomes a spliced signal. For example, from 0 seconds to T
The playback signal of field 1 from the master VTR 6 and the playback signal of field 2 of the master VTR 7, which are input in seconds, are on the time axis at 1/2 between T seconds and 2T seconds when fields 3 and 4 are input. It is compressed and spliced and output as a single continuous video signal. This input/output relationship is the same for the following fields.

Finally, a synchronizing signal and a color burst signal are added to the video data read out as described above in the process circuit 23 of FIG.
It converts into an analog video signal using the clock generated in , and outputs it via the video signal output terminal 25.

The video signal thus outputted from the video signal output terminal 25 has the same format as the reproduction signal of the master VTR 1 in the conventional double speed dubbing system. Therefore, since conventional technology can be used for the coaxial cable 10, distributor 11, coaxial cable 12, and slave VTR 13 in FIG.
The explanation of the output stage and subsequent stages will be omitted, but the master V
Dubbing can be performed in half the recording time of the master tape without increasing the cylinder rotation speed of the TR.

Further, in FIG. 5, the audio data inputted through the audio data input terminals 26 and 27 has 64 bits per word for 2 channels, and has a sampling frequency of f.
s is serial data with a frequency of 48 KHz and a transfer rate of 64 fs. Since the audio data processing is performed only by the fact that there is no process circuit and the clock frequency is different, the block diagram of the audio data processing is only shown in FIG. 5, and the explanation thereof will be omitted.

In this embodiment, two master VTRs are used to explain the field-based variable mode, but as an application, the number of master VTRs can be increased to three, and playback at three times the variable mode and dubbing at three times the speed. It is also possible to perform double-speed dubbing using frame-by-frame variable mode. Furthermore, as a master VTR, analog VTRs with high cylinder rotation speeds such as high-definition VTRs can be used.
Even if N TRs are used, their output stage and rate converter 9
By providing an A/D converter between the two, dubbing can be performed at N times the speed, and the image quality of the dubbed tape can also be improved.

[0025]

As described above, according to the present invention, by providing a plurality of master VTRs and rate converters,
Since it is possible to obtain video or audio signals in the same format as the master VTR in a conventional double-speed dubbing system, there is no need to increase the cylinder rotation speed of multiple master VTRs, and the durability of the cylinders and the contact condition of the tape head can be improved. , it is possible to avoid technical issues such as deterioration of the frequency characteristics of the head, and the huge development investment associated with solving the issues, and it is also possible to easily perform dubbing at N times the speed while using conventional equipment for the master VTR. be able to.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of a double-speed dubbing system in an embodiment of the present invention.

[Fig. 2] Block diagram showing the internal configuration of the video rate converter in the same embodiment.

[Fig. 3] Block diagram showing the internal configuration of the audio rate converter in the same embodiment.

FIG. 4 is a tape pattern diagram for explaining the playback tracks of the master VTR in the same embodiment.

[Fig. 5] Time chart for explaining the operation of the double-speed dubbing device in the same embodiment.

[Figure 6] Block diagram showing the overall configuration of a conventional double-speed dubbing system

[Explanation of symbols]

6,7 Master VTR 8 Digital cable 9 Rate converter 10, 12 Coaxial cable 11 Distributor 13 Slave VTR

Claims (1)

[Claims] Claim 1: N master tapes (N is a positive integer) on which the same information is recorded and one master tape each are mounted, and the N master tapes are reproduced at a tape speed N times the recording speed and in mutually different phases. N discontinuous video or audio playback signals obtained from the N master VTRs are input, and the time axis is compressed to 1/N of that of the master tape recording to produce one continuous video or A double-speed dubbing system comprising a rate converter that outputs an audio signal and one or more slave VTRs that record the output of the rate converter.