JP2523364B2 - Digital signal recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to recording and reproducing digital signals, and more particularly to a MIDI signal processing device for controlling an electronic musical instrument.

[Prior Art] There is a MIDI standard for driving and controlling various electronic musical instruments with digital signals according to a predetermined format. this
Keyboard devices and electronic musical instruments that comply with the MIDI standard have already been put into practical use, and by operating a single keyboard device,
It can drive many electronic musical instruments. In addition, the applicant of the present invention is based on the MIDI standard, which is 8-bit data (hereinafter referred to as MIDI
A word has been recorded on a magnetic tape in advance, and by reproducing this, a digital information recording and recording / reproducing system for driving one or a plurality of electronic musical instruments without operating a keyboard has been developed and applied for a patent. This is JP 62-14
As shown in Japanese Patent No. 6470, digital information regarding musical instrument performance, that is, musical instrument control information such as pitch, scale, and duration of a musical instrument is recorded in advance as a MIDI word in a helical scan type magnetic recording / reproducing apparatus. , Play this and add start bit and stop bit
It sends MIDI signals to each musical instrument to drive it.

[Problems to be Solved by the Invention] If the above magnetic recording / reproducing apparatus is used, an 8-bit MIDI word obtained by removing a start bit and a stop bit from a MIDI signal composed of a total of 10 bits including a start bit and a stop bit is used as it is. It can be recorded and played on magnetic tape, but it was not possible to record MIDI words in the subcode of a compact disc and play them on a compact disc player. This is because one MIDI word is composed of 8 bits, but one part of the subcode of a compact disc (hereinafter referred to as CD) is R, S except for 2 bits used for time code. … W
Because it consists of 6 bits consisting of, it is not possible to record the MIDI word as it is on the subcode channel of the CD. The transmission rate is 3,600 BPS (byte per second), that is, 28,800 bps, which is 31,250 bps.
The ps MIDI signal cannot be recorded as it is.

In addition, the MIDI standard does not consider the case where a MIDI signal is interrupted while it is being given to an electronic musical instrument, so the MIDI signal playback device is put in a state other than the playback state, such as when it is stopped, or the signal is dropped out. MI with impossible error
If the DI signal is not accurately transmitted, there is a problem in that the sound source such as an electronic musical instrument keeps producing sound or the pitch is changed.

In order to solve such a problem, the present applicant can record a MIDI signal in a subcode channel of a CD prior to the present invention and reproduce it on a CD player to generate an original MIDI signal. A bit map corresponding to the turned-on note number is set and reset when the same note number is turned off, and when a playback signal is lost or an uncorrectable error occurs, or a stop operation other than the normal playback state In the case of time, etc., a MIDI signal demodulating device for reading out the bit map and artificially sending out a note-off message of a note number corresponding to the set bit map to prevent the sound from continuing to sound Has been developed and a patent application (Japanese Patent Application No. 63-294407) has been filed.

In this way, in a MIDI signal demodulating device for decoding a MIDI signal recorded in advance on a digital signal recording medium such as a CD or DAT to drive an electronic musical instrument and sending a note-off message when an uncorrectable error occurs, It is possible to prevent the sound from being left off due to the original note-off data being lost due to an error, but note-on messages are accepted only once for one note number, so notes of the same note number are accepted. On message is 2
Connected MIDI when played back and sent to a MIDI instrument
Depending on the musical instrument, the pronunciation may not stop unless two note-off messages with the same note number are received. In such a case, the MIDI standard requires that the number of note-on and note-off messages must be the same, including the case of the same note number, and in this case, two note-off messages with the same note number are sent. . Normally I don't send note-on of the same note more than once,
In the case of CD-MIDI, note-on messages with the same note number may be duplicated when creating or editing a disc, so it is desirable to comply with the MIDI standard.

Therefore, according to the present invention, when an uncorrectable error occurs during MIDI data demodulation, or even when a part of the MIDI data is lost due to stop, search operation, etc., the sound continues to sound, various sound control is abnormal. It is an object of the present invention to provide a MIDI signal recording / reproducing device capable of preventing such a situation.

[Means for Solving the Problems] The present invention has been made to achieve the above object,
Demodulation means for reading a signal from a digital signal recording medium in which MIDI data is recorded in the auxiliary signal recording area and performing EFM demodulation,
A means for generating a control signal when an uncorrectable error occurs, a non-playback state or a signal loss, and an initial value that does not exist as a note number in a predetermined area of a readable / writable memory in which at least 1 byte is assigned to one note number. Means for initializing, and a writing means for sequentially writing a value corresponding to the note number in a predetermined area of the memory that is initialized when the MIDI data reproduced by the demodulating means is a note-on message, When the reproduced MIDI data is a note-off message, if a value corresponding to the note number is written in the predetermined area, the value is initialized, and there is no initialized area in the predetermined area. When the control signal is generated, the note-on message is prohibited from being transmitted to the MIDI output, and the predetermined area is searched to be initialized. Digital signal recording and reproducing apparatus and a control unit that generates and sends the note number of the note-off message to the MIDI output corresponding to the value written to have regions is provided.

[Operation] Since the MIDI signal recording / reproducing apparatus of the present invention has the above-mentioned configuration, when the MIDI data reproduced by the demodulating means is a note-on message, at least 1 byte is assigned to one note number and read / write is possible. When a note-off message is received and the value corresponding to the note number is sequentially written in the recording area of the appropriate memory, only the byte of the corresponding channel is searched, and if the same note number is found, the address is recorded. By initializing the area, note-off can be surely performed even when a plurality of same note numbers of the same channel are turned on.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a digital signal recording / reproducing apparatus of the present invention. The signal recording / reproducing apparatus is an optical pickup 2 for reading CD data from a CD 1 as a digital recording / reproducing medium, and amplifies the read data via a photodetector preamplifier 3 and inputs the data. Audio data as main data recorded in the recording area and subcode data recorded in the auxiliary signal recording area are respectively subjected to audio data error correction, and the output of the interpolating circuit 5 is converted to digital / analog audio data through the audio data buffer 6. (D / A) D / A conversion circuit 7 for conversion and output, subcode signal processing circuit 9 for bit conversion of subcode data through subcode data error correction circuit 8 and demodulation of MIDI data, demodulated MIDI data buffer for MIDI data
MIDI modulation circuit 11, which receives via 10 and sends out MIDI output,
Operation switch for stop, search, fast forward, play, etc. 1
2. The audio data buffer 6, the subcode data error correction circuit 8, the subcode signal processing circuit 9, the MIDI data buffer 10, and the MIDI data buffer 10 are controlled and operated based on the operation command from the operation switch 12. MIDI
It is connected to the modulation circuit 11 and executes processing based on data transfer, and when the uncorrectable error occurs or some operation such as stop or search causes a part of the MIDI data to be lost and the sound may be left off, When the rhythm does not stop, the rhythm is out of synchronization, or various sounding controls become abnormal, the microcomputer 14 has a control operation for preventing this.

The MIDI output from the MIDI modulation circuit 11 is converted into an audio output via the MIDI musical instrument 15, and is input to the audio mixer 16 together with the audio output via the D / A conversion circuit 7, and then a speaker via the audio amplifier 17 Output by 18.

FIG. 2 is a diagram showing a storage state of data for one pack of the subcode channel of the CD, that is, data from frame 0 to frame 23. 6-bit data from R to W is stored for each frame.
The data is stored from frame 4 to frame 19. Each frame has a 6-bit structure, and the MIDI data stored as described above is a byte, that is, 8 bytes.
It is a bit unit. 1 byte of MIDI data is, for example, 6 bits shown by a ₀ of R to W of frame 4 and frame 5
It consists of 8 bits in total, 2 bits indicated by a ₀ ′ in R and S. In embodiments hereinafter Similarly 1-byte data by a combination of four bits b ₀ 'remaining in the R~U of 4 bits of b ₀ and the frame 6 T～W frame 5 is constructed, the frame from the frame 4 12 bytes of MIDI data are stored over 16 frames up to 19.

FIG. 3 is a signal waveform diagram of 1 byte of MIDI data to be finally sent out. A start bit of logical 0 is added to the head of 8-bit MIDI data and a stop bit of logical 1 is added to the end.

FIG. 4 shows the structure of MIDI data in one pack to be sent out. A ₀ , a ₀ ′, b _0, etc. in FIG. 4 indicate the correspondence with the data in the subcode in FIG. A brief explanation of the MIDI standard is that MIDI data is transmitted at a rate of 3125 bytes per second. The subcode in Fig. 2 shows one pack consisting of 24 frames, but since 300 packs are reproduced from the CD per second, the MID
I data is 6 bits x 16 frames x 300 packs = 28800bps
Will be played. When this is expressed in bytes, 28800bps / 8 =
It becomes 3600 BPS and exceeds the MIDI data of 3125 BPS.
Therefore, 12 bytes MI per pack for all packs
Storing DI data is not allowed by the MIDI standard.

Therefore, as a countermeasure, it is necessary to devise beforehand when recording on the subcode of the CD so that 300 packs will be 3125 bytes. 2 out of every 12 packs, for example 300 packs
Divide into 5 and maximum 1 MIDI data for each group of 12 packs
5 packs containing 1 byte, maximum 1 MIDI data
If 7 packs contain 0 bytes, the maximum total number of MIDI bytes in this group is 125 bytes, and the total of 300 packs can be 3125 bytes or less.

However, most of the MIDI data are note-on commands and note-off commands, and these are each composed of 3 bytes, so it is better to consider 12 bytes which is a multiple of 3 as a reference. Therefore, it is preferable to put 12 bytes in some packs and 11 bytes or less in the remaining packs in each group so that the total is 125 bytes or less.

5 to 10 show the microcomputer shown in FIG.
FIG. 5 (a) illustrates a processing flow by the 14 CPUs, and when the reproduced MIDI data is a note on / off message, a readable and writable memory (RAM that allocates 1 byte to one note number). ), A main routine for explaining writing, reading and sending processing to a predetermined storage area,
FIG. 6B shows an interrupt process which is executed immediately when MIDI data is input to the reception buffer and transfers the data to the queue buffer. In the main routine of FIG. 5 (a), first, the storage area of the RAM is initialized with an initial value that does not exist as a note number. The MIDI data decoded by the subcode signal processing circuit 9 in FIG. 1 is sequentially processed by the microcomputer 14 and temporarily stored in the MIDI data buffer 10. In order to perform the processing at high speed and to prevent data loss, writing to the buffer uses a method of writing to the queue buffer by interrupt processing as shown in FIG. 5 (b). In the main routine, it is determined whether the queue buffer is empty. When the queue buffer is empty, the loop is repeated until data is stored. If it is not empty, the data once stored is sequentially read and the error occurrence flag is detected. Here, the error occurrence flag is detected when the subcode data error correction circuit 8 of FIG. 1 detects that there is an uncorrectable error in the subcodes of the subcode channels of the predetermined frames of the plurality of packs reproduced from the CD 1. When the reproduced digital output does not exist for a predetermined time or when the operation switch 12 is in the non-reproduced state, a mute signal is obtained by the microcomputer 14, and when this signal is generated, the RAM (in this embodiment, M
This error occurs when it is set to a predetermined address on a partial storage area of the IDI data buffer 10 (the error occurrence flag is monitored by polling in this embodiment, but an interrupt may be generated by a mute signal). If the flag is 0, processing according to the status type is executed.

That is, when the error occurrence flag is not set in the error occurrence flag determination step, the processing according to the read data is performed according to the running status processing routine shown in detail in FIG. Here, if the read data is the system message from F0 to FF or the data bytes that follow it, for example, if it is a rhythm start message FA, set the flag of the rhythm start buffer in RAM and exit to EXIT2 to read the data. Send FA as it is as MIDI output. In the case of channel messages from 80 _H to EF, they are stored in the status buffer on RAM. The number of data bytes that follow depends on the status type, and is stored in the 1st or 2nd byte data buffer until the required number of bytes of data is prepared, and a specified number of data bytes are prepared. Then, the process exits EXIT3 and proceeds to each on-buffer writing routine shown in detail in FIG. 7, and proceeds to the next note-on / off determination routine.

If the data stored in the status buffer has a status indicating note-on or note-off, the routine proceeds to the note-on buffer write routine shown in detail in FIG. Note that, in FIG. 8, a portion surrounded by a broken line (a) is a note-on writing routine (specific contents of note-on buffer setting and sending processing in FIG. 7), and (b) is a note-off writing routine. This is a routine (specific contents of the reset and send processing of the note-on buffer in FIG. 7), note-off is 8n _H (n is channel number 0 to F _H ) and note-off is the second byte of data byte is 0. There is provided a determination routine for either of the note-on statuses (Note that A, B, L and HL in FIG. 8 indicate register names).

The note-on storage state written by the processing routine shown in FIG. 8, which is the main content of the present invention, will be described below.
The details will be described with reference to the drawings. Fig. 9 is an explanatory diagram of the note-on buffer on the RAM map that is sequentially written with 1 byte as one note number. It shows the recording area from A000 _H to A0FF _H.
256 bytes are provided on the MIDI data buffer 10 in FIG. 1, and are divided into areas of 16 bytes each from the beginning, and note-on note numbers of channels 1 to 16 are written. Note number first be initialized to this area FF _H to a value impossible as note numbers because a value in the range of 0～7F _H by the MIDI standard. In FIG.
First, the center C sound of the first channel 1 (note number 3C)
Status message and 1
90 _H , 3 in the data buffer of the second byte and the second byte
The note-on status byte of C _H and 40 _H and 3 bytes of key number and velocity value are stored. Since it is a note-on message, proceed to the processing of the part in Fig. 8 (a). Since the lower 4 bits of the status byte are 0, address A000 _H 16 bytes are read from and the address which is initialized (address where note number is not written) is searched. in this case,
Since FF _H is detected immediately, the first byte of the data buffer (note number 3C _H ) is written to address A000 _H , and subsequently the status byte and the first and second data bytes are sent out via MIDI output and the main routine from EXIT. Return to. Next, when 3E _H, 40 _H from the data buffer is read, rewritten only 3E _H, 40 _H data buffer without rewriting the status buffer by running status processing, in a manner similar to that described above, note-on buffer Is written to. In this case, the already A000 _H addresses the address is incremented so 3C _H are written, the contents of the address is FF _H is the initial value 3E _H to the A001 _H address is written.

On the other hand, when a note-off message is received, the contents of the 16-byte address from the beginning of the address of the corresponding channel are read by the processing routine in the part (b) of the figure, and if there is the same note number, that address is read. FF _H is written to and the contents of the status buffer and the first and second data buffers are sent to the MIDI output. If the same note number is turned on twice in the same channel, the same value data is written in another address in the same channel area of the note on buffer. Also, if you receive only 16 note-on in a row, the note-on buffer will be full, so at that time, it is not written to the note-on buffer and is not sent to MIDI output. There is no possibility that more than 16 notes will be turned on at the same time on the same channel, but the number of simultaneous polyphony for connected MIDI instruments is 16
Even if the same tone color that is limited to the sound level is pronounced at the same time, it is hard to hear.
If 16 channels are summed up, 256 sounds will be produced at the same time, which is sufficient for musical expression.

Next, in FIG. 5, when the error occurrence flag is set, the reading and sending processing of the note-on buffer is executed. The detailed flow of this part is shown in FIG.
(Note that A, B, D, E, L, and HL in FIG. 10 are register names).
To explain this with reference to FIG. 9, the contents of the buffer are read for 16 channels in 16-byte units from the start address A000 _H of the note-on buffer. If the data is not FF, a note-off message is sent and The running status flag (RUNSTF) is set to 0 in order to change the channel number every 16 times, and the running status flag (RUNSTF) is set to 1 when the status is sent, and the next message sends only the data byte. . To speed up MIDI transfer, the second byte of the data byte is set to 0 and the note-on status 9n _H is sent. After sending Note-off, FF _H is written to that address to initialize it.

After that, when the reading and sending process of the note-on buffer is completed, the process returns to the main routine of FIG.
In order to restore various sound controls other than note-on, MIDI messages such as pitch bend off, rhythm stop, reset all controller and end of exclusive are continuously sent to the MIDI output and the error occurrence flag is cleared.

Although the above embodiment has been described only note-on buffer, it provided a buffer for storing reception on event for each other messages e.g. control changes or rhythm start such status to A100 after _H in FIG. 9, when an error occurs By reading the respective buffers and turning off only the statuses that are on, it is possible to prevent unnecessary off messages from being sent.

Further, in the above embodiment, the case where one byte is allocated to a predetermined area of the memory for one note number has been described, but the present invention can be applied to a MIDI message of a note number to which one or more bytes are allocated. Of course.

[Effect of the Invention] As is apparent from the above description, in the digital signal recording / reproducing apparatus of the present invention, note numbers are sequentially registered in the note-on buffer in which at least 1 byte is allocated to one note number, When an off message is received, only the bytes of the corresponding channel are searched, and if there is the same note number, the buffer is initialized to a value that does not exist as a note number, so the same note number of the same channel is repeated multiple times. Even if it is turned on, you can reliably turn off the note, and even if some MIDI data is lost due to an uncorrectable error occurrence or operation such as stop, search, etc. It is possible to prevent the pronunciation control from becoming abnormal.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a digital signal recording / reproducing apparatus of the present invention, FIG. 2 is a diagram showing one pack of R to W channels of CD subcode, and FIG. 3 is an MI to be transmitted.
Waveform diagram of 1 byte of DI signal, FIG. 4 is a diagram in which the MIDI data in the 1-pack subcode of FIG. 2 is a 12-byte MIDI signal, and it is in accordance with the waveform diagram of FIG. 5 is a flowchart showing the processing of the microcomputer 14 of FIG. 1, FIG. 6 is a detailed flowchart of the running status processing of FIG. 5, and FIG. 7 is the note-on buffer of FIG. 5 and the on-buffer of other messages. Flowchart of Write to Message and Message Sending Process, Eighth
FIG. 7 is a detailed flowchart of the note-on-buffer setting, resetting, and sending process of FIG. 7, and FIG. 9 is an explanatory diagram showing the state of the on-buffer processed in FIGS. 7 and 8.
FIG. 10 is a detailed flowchart of the reading and sending process of the note-on buffer of FIG. 1 ... CD, 4 ... PLL EFM demodulation circuit, 8 ... subcode data error correction circuit, 9 ... subcode signal processing circuit, 10 ... MIDI
Data buffer, 12 ... Operation switch, 14 ... Microcomputer.

Claims (1)

(57) [Claims] 1. A demodulation means for reading a signal from a digital signal recording medium having MIDI data recorded in an auxiliary signal recording area and performing EFM demodulation, and a control signal when an uncorrectable error occurs, in a non-reproducing state or when a signal is lost. Means for initializing a predetermined area of a readable / writable memory in which at least 1 byte is allocated to one note number with an initial value which does not exist as a note number, and the demodulating means reproduces the data.
When the MIDI data is a note-on message, writing means for sequentially writing a value corresponding to the corresponding note number in a predetermined area of the memory that has been initialized, and the reproduced MI.
When the DI data is a note-off message, if the value corresponding to the note number is written in the predetermined area, the value is initialized, and if there is no initialized area in the predetermined area, the note-on is performed. In addition to prohibiting sending of messages to MIDI output, when the control signal is generated, the predetermined area is searched to generate a note-off message with a note number corresponding to the value written in the uninitialized area. And a digital signal recording / reproducing apparatus having a control means for transmitting to a MIDI output.