JPH0689507A - Multichannel digital audio recorder system - Google Patents

Abstract

PURPOSE:To record and reproduce audio signals in multi-channels with high quality and to remarkably prolong the longest continuous recording and reproducing time by utilizing an existing digital VTR using a cassette type magnetic tape as it is while being small-sized, light-weighted and low-cost. CONSTITUTION:An existing digital VTR is made a digital data recorder 1, and an encoder 3 converting plural digital video data capable of recording plural channels sound inputs to a video sector part in the tape 2 is connected to the input side of the digital data recorder 1 through a transmission line 4. Further, a decoder 5 converting the digital video data reproduced from the video sector part to original plural channels sound signals and outputting them is connected to the output side through the transmission line 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applicable to the production of stage broadcasts and concert broadcasts at broadcasting stations.
The present invention relates to a multi-channel audio recorder system used when a multi-channel audio signal is picked up by using a large number of microphones at a recording site such as a concert relay as a pre-stage of mixing in a station.

[0002]

2. Description of the Related Art In producing a program at a broadcasting station or the like, in the video field, by popularizing a digital VTR using a magnetic tape of a tape format such as D-2, high quality recording / playback can be easily performed. In the audio field, the need for high-quality, multi-channel audio recording is increasing in the recording field such as stage broadcasting.

As such a multi-channel audio tape recorder (hereinafter referred to as MTR),
Conventionally, an analog MTR that records and reproduces multi-channel audio signals such as 24 channels using a wide (2 inch) tape and a narrow width {(1 /
2) inch} tapes have been used to record and reproduce multi-channel audio signals such as 48 channels.

[0004]

All of the conventional MTRs described above are of an open reel type because of the width of the tape used and the like. Not only is it difficult to carry and install, but the longest continuous recording / playback time is about 60 minutes.
The recording capacity was small, but the cost was high. Also, the tape used is wide,
Moreover, its large diameter makes it inconvenient to handle and manage.

The present invention has been made in view of the above circumstances, and it is possible to effectively use an existing digital VTR, which has been remarkably popularized in the video field, to be small in size and light in weight and low in cost. It is an object of the present invention to provide a digital MTR capable of recording / reproducing a high-quality audio signal of a channel and significantly increasing the longest continuous recording / reproducing time as compared with the conventional one.

[0006]

In order to achieve the above object, a digital MTR according to the present invention has a plurality of helical tracks in which a video sector and an audio sector are respectively arranged and data for one field period is digitally recorded. A digital data recorder including an existing digital VTR having a magnetic tape as a recording medium, and a digital audio input signal of a plurality of channels connected to the input side of the digital data recorder via a transmission path and capable of recording the digital audio input signals in the video sector. An encoder for converting into a form of digital video data, and a decoder connected to the output side of the digital data recorder through a transmission line for converting the digital video data into original digital audio signals of a plurality of channels and outputting it It is a thing.

In the digital MTR according to claim 1, an A / D converter for A / D converting analog audio inputs of a plurality of channels is provided as the encoder, or a digital video transmitted from a digital data recorder as the decoder. It may be provided with a D / A converter for D / A converting data into analog audio of a plurality of channels, and at least two of the encoder, the decoder and the digital data recorder are integrated. May be.

Further, in the digital MTR according to claim 1, as the transmission path, RP-defined in the SMPTE standard is used.
125X parallel interface standard or 259
Any of the M serial interface standards may be used.

[0009]

According to the present invention, a plurality of channels of audio signals picked up by a plurality of microphones installed at a recording site such as a concert relay are input to the encoder. After being converted into one-channel digital data, that is, a digital pseudo video signal, it is transmitted and input to a digital data recorder including an existing digital VTR via a transmission line. The digital data input to the digital data recorder is recorded in the video sector portion of the helical track on the cassette-formed magnetic tape in accordance with the recording operation of the digital data recorder.

Next, regarding reproduction of the audio data recorded as described above, along with the reproduction operation of the digital data recorder, the digital video data recorded in the video sector portion of the cassette magnetic tape is transmitted through the transmission path. Is transmitted to and input to a decoder, and in this decoder, the digital video data is converted into the original audio signals of a plurality of channels and reproduced and output.

In the recording / reproducing operation of a plurality of channels as described above, when the audio signal input to the encoder is analog audio, the analog audio is input to the A / D converter before being input to the encoder. If analog audio output is required when outputting from the decoder, digital audio data should be passed through a D / A converter and converted into analog by converting. Good.

Further, if at least two of the encoder, the decoder and the digital data recorder are integrated, the whole system can be easily carried and installed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram of a digital MTR according to an embodiment of the present invention. In FIG. 1, reference numeral 1 is the most popular D-type among existing digital VTRs.
It is a digital data recorder composed of a two-format digital VTR. The specifications of the D-2 format digital data recorder (digital VTR) are as shown in Table 1. However, since these are well known, detailed description thereof will be omitted. Further, the tape format of D-2 is as shown in FIG. 4, and the magnetic tape 2 has six helical tracks T for recording data of one field period and an analog cue track CU.
E, has a time code track TIME CODE and a traveling control track CTL.
As shown in FIG. 5, a video sector VS for writing a video signal and an audio sector AS for writing 4-channel audio data are arranged on the helical track T, and the timing of editing between the sectors VS, AS. The edit gap EG is provided in consideration of the error. In FIG. 3, E is a preamble and P is a postamble.

Returning to FIG. 1, reference numeral 3 is an encoder, which converts analog audio inputs of a plurality of channels (CH1 to CH60) into digital video data recordable in the video sector VS of the magnetic tape 2 and converts the digital data recorder 1 into digital video data. RP-1 specified in the SMPTE standard on the input side of
25X parallel interface standard or 259M
They are connected via a transmission line 4 of the serial interface standard. A decoder 5 is connected to the output side of the digital data recorder 1 via a transmission line 6 of the RP-125X parallel interface standard or the 259M serial interface standard, and the digital video transmitted from the digital data recorder 1 is transmitted. It converts data to original analog audio of multiple channels and outputs it. A video burst sync signal (hereinafter referred to as VBS) for generating a reference clock signal is input to the encoder 3 and the digital data recorder 1.

FIG. 2 is a block diagram showing a concrete configuration example of the encoder 3, and in FIG. 2, 7-1 to 7-
Reference numeral 60 is an A / D converter for A / D converting the analog audio inputs of the above-mentioned plurality of channels (CH1 to CH60), and 8 is a memory, and the A / D converters 7-1 to 7-
Digital audio data A / D converted by 60 (1A _M , 1A _L , 1B _M , 1B _L ... to 60A _M , 60A _L , 60B _M , 6
The 0B _L ...), write clock Lc output from the clock generation circuit 9 in synchronism with the sync burst component of the VBS
Store in synchronization with k. Here, each of the A / D converters 7-1 to 7-60 has a resolution of 1 sample of 16 bits, and therefore, the A / D converted digital audio data (1A _M , 1A _L , 1B). _M , 1B _L … ～ 60A
_M , 60A _L , 60B _M , 60B _L ...), for example, 1A _M is A of CH1.
The uppermost 8 bits data of the th sampling are shown, and 60B _L shows the Bth lower 8 bits data of CH60.

Reference numeral 10 denotes a sync / burst addition circuit, which is one-channel digital video data (1A _M , 1A _L , 2A _M , 2A _L ... 60B _M , 60B) read from the memory 8.
A sync component and a burst component after passing the VBS through the A / D converter 11 are added to _L ) to output a digital pseudo video signal corresponding to the video signal as shown in FIG. This digital pseudo video signal is input to the digital data recorder 1 via the transmission path 4 and recorded in the video sector VS of the helical track T on the magnetic tape 2 described above.

FIG. 3 is a block diagram showing a concrete example of the configuration of the decoder 5, in which FIG.
In the burst separation circuit, the above digital data recorder 1
Associated with the reproducing operation of the transmission path 6 read from the video sector VS of the helical track T on the magnetic tape 2.
The sync component and the burst component are separated from the digital pseudo video signal output via the. 13 is a memory,
The sync / burst separation circuit 12 stores digital video data (1A _M , 1A _L , 2A _M , 2A _L ... 60B _M , 60B _L ) from which the sync and burst components have been removed, and the sync / burst component Read clock Rc output from the clock generation circuit 14 in synchronization with
Synchronized with k, multiple channels of digital audio data (1A _M , 1A _L , 1B _M , 1B _L … ～ 60A _M .60A _L , 60
B _M, and outputs the conversion to 60B _L ...). 15-1 to 15-
Reference numeral 60 denotes a D / A converter, which is a digital audio data (1A _M , 1A _L , 1) read from the memory 13.
B _M , 1B _L ... to 60A _M , 60A _L , 60B _M , 60B _L ...) are respectively D / A converted in synchronization with the clock Rck and output as analog voices of the original plurality of channels (CH1 to CH60). .

The digital MTR having the above structure is
For example, analog audio of a plurality of channels picked up by a plurality of microphones (not shown) installed at a recording site such as a concert relay is input to the encoder 3.
The plural channels of analog audio input to the encoder 3 are first A / D converted by the A / D converters 7-1 to 7-60, and the digital audio data (1A _M , 1A _L , 1B _M , 1B _L … ～ 60A _M , 60A _L , 60B _M , 60B
_L ...) Is stored in the memory 8 in synchronization with the write clock Lck output from the clock generation circuit 9 synchronized with VBS. Next, digital video data (1A _M , 1A _L , 2A _M , 2A _L ... 6
The sync and burst are added to 0B _M , 60B _L ) to create and output a digital pseudo video signal. This digital pseudo video signal is input to the digital data recorder 1 via the transmission path 4 and recorded in the video sector VS of the helical track T on the magnetic tape 2 described above.

Next, the above digital data recorder 1
Associated with the reproducing operation of the transmission path 6 read from the video sector VS of the helical track T on the magnetic tape 2.
The digital pseudo video signal output via the
Entered in. The digital pseudo video signal input to the decoder 5 is first sync / burst separation circuit 12
, The sync component and the burst component are separated, and then the digital video data (1A _M , 1A _L , 2A _M , 2A
_L ...... 60B _M , 60B _L ) is input and stored in the memory 13. Next, digital audio data (1A _M , 1A _L , 1B _M , 1B _L ... ~) of a plurality of channels read from the memory 13 in synchronization with the read clock Rck.
60A _M , 60A _L , 60B _M , 60B _L ...) are respectively D / A converted by D / A converters 15-1 to 15-60 and output as analog voices of the original plural channels (CH1 to CH60). It

Now, as an existing digital VTR to be the above digital data recorder 1, taking the V-2 of the most popular D-2 format as an example, the result of examining the recording capacity will be described below. This D-
In the 2 format, 1 channel of digital video and 4 channels of digital audio are recorded on the helical track T of the cassette magnetic tape 2, and the total recording data rate is about 127 Mbp.
s, about 19% of which is a check code for error correction, and of the remaining about 102 Mbps, about 8 Mbps is 4
Channel audio recording data rate, about 9 remaining
4 Mbps is the video recording data rate.

As shown in Table 1, the sampling of video is performed at a sampling frequency of 4 fsc = 14.318 18
MHz, the number of quantization bits: 8 bits, and 910 samples per horizontal scanning period (1H), but 142 samples of the sync and burst signal portions are not recorded, so the actual recording is 768 samples per 1H. . Since the number of scanning lines to record is 255 per field, the data rate of video data is 8 (bits) × 768 (samples) × 255 (lines) × 59.94.
(Field / second) = 93.9091968 (Mbp
s), and this capacity can be used as a recording capacity for multi-channel digital audio data.

The characteristic distribution of the recording capacity is divided into the sampling frequency, the number of quantization bits, the number of channels, and the redundancy. Here, the sampling frequency and the number of quantization bits of the digital audio are 48 KHz and 16b.
Assuming that its, the bit rate per channel is 48 (KHz) × 16 (bits) = 768 (Kbp)
s), 93.9091968 (Mbps) / 768 (Kbp)
s) = 122.2776 (CH), which makes it possible to realize a digital MTR of 122 channels.

However, in actual use, such a number of channels is not necessary, and about half the number of channels is sufficient from the viewpoint of the present application. Therefore, in order to improve reliability, a digital MTR of 60CH can be realized even if a redundancy of about 100% is taken. Furthermore, when combined with 4CH of digital audio of the D-2 format itself, 64CH of It is capable of recording and reproducing digital audio data, and is at a level equivalent to or higher than the maximum number of channels available in existing multi-channel audio recorders.

In the above embodiment, the multi-channel audio signal recorded on site was carried to the station by carrying the digital MTR for mixing and the like, but another application of the encoder / decoder is, for example, a concert. A multi-channel audio signal can be obtained by using a digital video transmission line capable of transmitting digital data between two points separated from each other, such as a venue and a broadcasting station, and installing the encoder 3 and the decoder 5 at both ends thereof. It is also possible to construct and use a system for transmitting.

[0025]

[Table 1]

[0026]

As described above, according to the present invention, D-
As a digital audio data recorder, existing digital VTRs that have been developed and widely used to easily perform compact and high-quality recording / reproducing by using cassette type magnetic tapes such as 2 format Compared to the conventional open reel type digital MTR shown at the beginning, 1) Small size, light weight, easy to carry, space saving and power saving at the time of installation. Therefore, maintenance can be reduced. 2) The longest continuous recording / reproducing time can be extended to several times that of the conventional digital MTR, for example, in the case of the D-2VTR, it can be up to 208 minutes. 3) By using a tape cassette, it is easy to handle and store the tape, and it is possible to easily determine whether or not recording is prohibited, and to quickly change the tape at the recording site. 4) The structure of the device is simple and it is easy to reduce the manufacturing cost. 5) Since the existing digital VTR can be used as it is, the introduction cost can be reduced, and since it can be used as it is as a digital VTR except when it is used as an MTR, there is no waste in terms of frequency of use and there is also a costly introduction risk. small. 6) Digital V
If there are two TRs, only one encoder is required. Also, if there are two digital VTRs, a print tape can be made without an encoder and a decoder. In particular, it can be used very effectively for multi-channel audio recording at the recording site when producing concert broadcasts or stage broadcast programs.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a digital MTR according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a specific configuration of an encoder in the embodiment.

FIG. 3 is a block diagram showing a specific configuration of a decoder in the embodiment.

FIG. 4 is a schematic diagram of a D-2 tape format used in the above embodiment.

FIG. 5 is an explanatory diagram of sector arrangement of a helical track on the same tape.

FIG. 6 is an explanatory diagram when a video signal is digitized and represented.

[Explanation of symbols]

1 Digital data recorder (existing digital VT
R) 2 magnetic tape 3 encoder 4 6 transmission line 5 decoder 7-1 to 7-60 A / D converter 8 13 memory 15-1 to 15-60 D / A converter

Claims (4)

[Claims] 1. A digital data recorder comprising an existing digital VTR having a magnetic tape as a recording medium having a plurality of helical tracks in which a video sector and an audio sector are respectively arranged and digitally records data in a field period. An encoder connected to the input side of the digital data recorder through a transmission line to convert digital audio input signals of a plurality of channels into a form of digital video data recordable in the video sector, and an output side of the digital data recorder. A multi-channel digital audio recorder system, comprising: a decoder connected through a transmission line to convert the digital video data into original digital audio signals of a plurality of channels and output the digital audio signals. 2. The encoder comprises an A / D converter for A / D converting analog audio inputs of a plurality of channels respectively, or the decoder has a plurality of channels of digital video data transmitted from a digital data recorder. D / A to D / A conversion to analog audio output
2. The multi-channel digital audio recorder system according to claim 1, further comprising an A converter. 3. The multi-channel digital audio recorder system according to claim 1, wherein at least two of the encoder, the decoder and the digital data recorder are integrated. 4. The multi-channel digital audio recorder system according to claim 1, 2 or 3, wherein the transmission line is the RP-125X parallel interface standard or the 259M serial interface standard defined in the SMPTE standard.