JP2666566B2 - Digital signal processor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital signal processing apparatus, and more particularly to a digital signal recording / reproducing apparatus having a function of editing a digital audio signal and a control method thereof.

[0002]

2. Description of the Related Art As an example of a conventional digital signal recording / reproducing apparatus which also considers editing of a block digital audio signal, a digital V-2 format of D-2 format is used.
There is TR. For D-2 format, SMPT
From page 586 of the E-Journal July 1990 issue
It is published on page 7 and the "Propos"
ed American National Stan
dard for television digit
al recording-19-mm type D
-2 composite format-helic
aldataand control records
(SMPTE 247M) "on page 15 describes an edit flag added to an edit point of an audio signal. In the D-2 format, an edit flag is added to the first block and the last block of an audio signal block inserted by editing. In addition, by detecting this at the time of reproduction, it is possible to perform processing so that noise such as a pop sound is not generated due to discontinuity of a signal at an editing point. The so-called V-fade is performed to reduce the reproduction level immediately before the point and to raise the reproduction level again immediately after the edit point.

[0003]

The above-mentioned conventional D-2
Since the format device has no connection to the audio signal before and after the edit point and does not have overlap recording, it is not possible to take measures to prevent noise generation due to more advanced crossfading during playback. He was dissatisfied.

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-performance audio signal recording system such as the D-2 format, which enables editing by cross-fading of an audio signal and is compatible with a device having a conventional V-fade function. To provide a digital signal recording / reproducing apparatus.

[0005]

In order to perform cross-fade in a signal recording type apparatus in which the audio signal before and after the edit point is not connected and overlap recording is not performed, such as the D-2 format, This can be achieved by performing a crossfade process during recording. This is achieved by providing a reproducing head preceding the recording head, or D-2.
In a helical scan type apparatus such as a VTR, a reproducing head is used as a moving head, and a signal recorded on a tape in advance can be read by setting the reproducing head to a pre-read mode. Then, the recording mode is entered before the editing start point. Before the editing start point, the pre-read signal reproduced from the tape is recorded at the original recording position as it is, and the level of the pre-read signal is gradually reduced at the editing start point. At the same time, the level of the input signal to be inserted or added is gradually increased and added to this pre-read signal to perform crossfade, and only the input signal is recorded after the crossfade section at the editing start point. In the case of insertion, the reverse operation is performed at the editing end point, and after the cross-fade section at the editing end point, the pre-read signal is again recorded as it is at the original recording position, and then the recording mode is ended.

However, when the above insertion recording is performed, in the D-2 format, an edit flag is added to the first audio block at the recording start point and the last audio block at the recording end point. However, in actuality, only the signal that was originally recorded was re-recorded near the recording start point and the recording end point.
The audio signal is continuous. Therefore, if V-fade is performed by an edit flag at the time of reproduction as in a normal D-2 VTR, a reproduction signal is lost at an unnecessary part, which causes a problem in compatibility. Further, the information becomes inappropriate as information indicating a point at which the signal is switched. Therefore, in the present method, an edit flag is added in the same manner as in the past in the case of normal editing, and the edit flag is not added to the recording start point and the recording end point in the case of performing a cross fade. In that case, the edit flag can be moved and added to the audio block of each cross-fade section as needed. Also, of course, no edit flag may be added.

[0007]

When a crossfade is performed, an edit flag is not added, so that unnecessary reproduction sound is not lost even if V-fade is automatically performed by the edit flag during reproduction. . In a system in which the V-fade function at the time of reproduction can be selected, information indicating a point at which a signal is switched is correctly stored by moving an edit flag from an editing start point and an end point to a cross-fade section. be able to. As described above, by performing V-fade recording using so-called look-ahead editing and performing an operation on an edit flag indicating an edit point, it is possible to perform high-accuracy sound editing without generating editing noise, and to perform the conventional D-2.
Compatibility with a device such as a VTR having only a V-fade function at the time of reproduction can be maintained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to embodiments.
FIG. 1 shows a digital VTR of a D-2 format according to the present invention.
FIG. 6 is a block diagram of an embodiment when applied to the audio recording / reproducing unit of FIG. In FIG. 1, 1 is an input terminal to which a digitized audio signal is input, 2 is a digital level controller composed of a multiplier for adjusting the recording level of the input signal, and 3 is a digital adder for adding two digital audio signals. , 4 is a recording signal processing circuit for processing a digital audio signal in accordance with a D-2 format according to the D-2 format, 5 is a recording head attached to a cylinder, 6 is a magnetic tape, 7 is a reproducing head attached to a cylinder, 8 Is a reproduction signal processing circuit for processing a reproduction signal from a tape according to the D-2 format and outputting it as a reproduction digital audio signal; and 9, a digital level controller comprising a multiplier for adjusting the output level of the reproduction digital audio signal. 10 is the output digital audio signal An output terminal 11, a control circuit for controlling the editing of digital audio signals, a flag generation circuit 12 for generating an edit flag defined in the D-2 format, and a gate circuit 13 for controlling the output of the edit flag It is.

In the D-2 format, a digital audio signal is recorded as a block composed of a signal corresponding to one-third of one field of a video signal (referred to as a segment) for each channel. Therefore, a recording operation for editing or the like must be performed at least in units of blocks (= segments). In a normal D-2 system, since it is a VTR, audio editing is also performed on a field or frame basis. Therefore, when performing insert editing, for example, as shown in the segment diagram in FIG. 4, recording is started before a point (in the figure, indicated as a cross-fade section) that is to be actually started to be connected by editing. Stop recording after the point where you want to end the connection. That is, the signal on the tape is rewritten from the point indicated by IN to the point indicated by OUT in the drawing. Here, in the ordinary D-2 system, a signal delay of one field is caused by the recording signal processing, the reproduction signal processing, the recording, and the reproduction head. That is, from the entrance of the recording signal processing circuit 4 of FIG.
The signal delay from the reproduction signal processing circuit 8 to the output of the adder 3 via the level controller 9 is one field. However, when the reproducing head 7 attached to the rotary cylinder is a moving head, it is possible to read out the signal one field before by moving the reproducing head 7 in a direction perpendicular to the recording track on the magnetic tape 6. it can. As a result, the delay amount of the signal loop can be reduced to 0, the gain of the level controller 9 on the reproduction side is set to 1 and the gain of the level controller 2 on the recording side is set to 0. When recording is performed on the magnetic tape 6 as it is at 5, the signal read from the magnetic tape 6 is written to the original position as it is. In this way, for example, recording is started from the IN point in FIG. 4, and the gain of the level controller 2 on the recording side is gradually increased until it becomes 1 on the way, and at the same time, the gain of the level controller 9 on the reproduction side is gradually decreased until it becomes 0. After that, in a predetermined section, the gain of the level controller 2 on the recording side is set to 1 and the gain of the level controller 9 on the reproducing side is set to 0 to record the insertion signal from the input terminal 1. The gain of the controller 2 is gradually decreased until it becomes 0, and at the same time, the gain of the level controller 9 on the reproduction side is gradually increased until it becomes 1, and finally, the gain of the level controller 9 on the reproduction side is set to 1, and the level controller 2 on the recording side is finally set. If the recording is terminated at the OUT point after setting the gain of 0 to 0, the output of the adder 3 becomes the signal from the input terminal 1 and the reproduction signal from the magnetic tape 6. The will to cross-fade the signal, you can insert edited by cross-fade. In the segment diagram of FIG. 4, A, B,
At the place where the signals of C, D, E, F, G, H, I, J, and K were recorded, the recording as described above is started from the segment of B, and the segment of E is started from the middle of the segment of C. A crossfade is performed halfway between the input signals c, d, and e, and the input signals f and g are subsequently recorded. The cross-fade is again performed between the read-ahead G, H, and I signals, and the state of the recorded signal formed on the tape when editing is completed at the point where the J signal from the tape was finally recorded is shown. ing.

When digital audio is edited in the D-2 format, hexadecimal hexadecimal values are added to edit flag data (4 bits) attached to the data of the first segment as shown in flag (a) of FIG. A flag B is added, and a hexadecimal E flag is added to the last segment. Therefore, if the edit flag is recorded as it is, although the edit flag is certainly attached in accordance with the operation of the edited apparatus, it cannot correspond to the content of the actually recorded signal. Therefore, for example, in order to prevent the occurrence of noise due to the discontinuity of the audio signal at the editing point on the playback device side, so-called V-fade processing by fade-out and fade-in is performed with reference to the edit flag. However, even if the recorded signal is actually continuous, a V-fade occurs at the time of reproduction, which causes a compatibility problem.

In the present invention, such a problem is solved by the following configuration and operation. The editing operation described above is performed by setting the mode in the control circuit 11 including the addition of the edit flag. Control circuit 1
1 fetches a tape timer signal or a time code signal from the reproduction signal processing circuit 8 and compares it with a set value to output a level control signal to the recording-side and reproduction-side level controllers 2 and 9 to perform a cross-fade operation. Or
When the mode is set to a mode in which no cross-fade is performed, the control simply starts the recording from the IN point and ends the recording at the OUT point, or sends a flag generation command signal to the flag generation circuit 12. The flag generation circuit 12 controls the editing IN according to a command from the control circuit 11.
Hexadecimal B and E edit flags respectively corresponding to the point and the OUT point are generated and sent to the recording signal processing circuit 4 via the gate circuit 13. The recording signal processing circuit 4 records the edit flag together with the audio signal to be edited and recorded on the tape 6 via the recording head 5. When the editing mode of the audio signal is set to perform the crossfade editing, the control circuit 11
A command signal for stopping the output of the edit flag is sent to 3, the gate circuit 13 stops the output of the edit flag, and sends a 0 flag to the recording signal processing circuit 4. By the above operation, when the audio signal is edited by cross-fade, the edit flag added to the recording signal becomes all 0 as shown in the flag (b) of FIG. 4, and the device having the normal V-fade function No need to perform unnecessary V-fade processing even if playback is performed on the. In this embodiment, the gate circuit 13 is provided at the output of the flag generation circuit 12 for the sake of simplicity of explanation. However, the control circuit 11 outputs a flag generation command signal during cross-fade editing. It is good also as composition which does not do. The same applies to other embodiments described below, but it goes without saying that all of these operations can be realized by software control.

Next, another embodiment of the present invention will be described. FIG. 2 is a block diagram of another embodiment in which the present invention is applied to a voice recording / reproducing section of a digital VTR of a D-2 format, as in the previous embodiment. In FIG. 2, 14
Is a control circuit for controlling the editing of the digital audio signal and the like, and 15 is a switching circuit for switching a command signal to the flag generation circuit 12.

As in the above-described embodiment, in this embodiment, the editing operation is performed by setting the mode to the control circuit 14 including the addition of the edit flag. Control circuit 1
Reference numeral 4 denotes a level control signal to the recording-side and reproduction-side level controllers 2 and 9 by taking in a tape timer signal and a time code signal from the reproduction signal processing circuit 8 and comparing them with a set value, thereby performing a cross-fade operation. Or
When the mode is set to a mode in which crossfade is not performed, only control for starting recording from the IN point and ending recording at the OUT point is performed. The switching circuit 15 has an IN point, an OUT point,
Then, a total of four timing signals of two points for performing the cross fade are output. Further, when the editing mode of the audio signal is set to perform the crossfade editing, the control circuit 14 sends a command signal for switching the operation to the switching circuit 15. The switching circuit 15 uses these timing signals and command signals to perform cross-fading at the IN point and the OUT point when the mode is set not to perform cross-fading and at the IN point and OUT point when the mode is set to perform cross-fading. At these two points, a flag generation command signal is sent to the flag generation circuit 12.
As described above, the edit flag is output from the flag generation circuit 12 to the recording signal processing circuit 4 in accordance with the editing mode, and the flag of the recording signal when cross-fading is performed is the flag (c) in FIG. As shown, IN point, OUT point
The edit flag of the point is moved and added to the cross-fade point. As a result, a flag corresponding to the point at which the signal is actually switched is added. In a reproducing apparatus having a normal V-fade function, V-fade is performed at the signal-switch point, while the V-fade function is used. In a reproducing apparatus capable of stopping the reproduction or a reproducing apparatus having no V-fade function, so-called upward compatibility in which cross-fade reproduction according to a recording signal is performed can be obtained. In the flag (c) of FIG. 4, the edit flag is moved to and added to the center segment of the cross-fade section. However, as shown in the flag (d) of FIG. , Or vice versa, or at the beginning or end of each other, the effect of the present invention is not impaired.

Further, another configuration of the present invention will be described with reference to an embodiment. FIG. 3 is a block diagram showing another embodiment of the present invention. In FIG. 3, reference numeral 16 denotes a mode signal input terminal for setting whether to add an edit flag,
17 is a gate circuit.

As in the embodiment of FIG. 2, in this embodiment, the editing operation is performed by setting the mode in the control circuit 14 including the addition of an edit flag. The control circuit 14 fetches a tape timer signal or a time code signal from the reproduction signal processing circuit 8 and compares it with a set value to output a level control signal to the level controllers 2 and 9 on the recording side and the reproduction side, thereby performing a cross-fade operation. When the mode is set not to perform crossfade, only control for starting recording from the IN point and ending recording at the OUT point is performed. Then, the switching circuit 15 outputs a total of four timing signals of an IN point, an OUT point, and two points for performing crossfading in the editing and recording operation. Further, when the editing mode of the audio signal is set to perform the crossfade editing, the control circuit 14 sends a command signal for switching the operation to the switching circuit 15. When the switching circuit 15 is set to a mode in which no cross-fade is performed, the timing signal and the command signal cause the switching circuit 15 to output the signal IN.
When the cross-fade mode is set at the point and the OUT point, a flag generation command signal is sent to the flag generation circuit 12 via the gate circuit 17 at the two points where the cross-fade is performed. Further, a command signal sent from the control circuit 15 to the switching circuit 15 is also sent to the gate circuit 17. A mode signal for setting whether or not to add an edit flag at the time of cross-fade is input from the mode signal input terminal 16 to the gate circuit 17, and the gate circuit 17 is set when the mode for adding the edit flag is set.
Transmits the edit flag from the flag generation circuit 12 to the recording signal processing circuit 4 as it is, and performs the same operation as in the embodiment of FIG. On the other hand, when the mode is set so that no edit flag is added during crossfade,
The gate circuit 17 determines whether or not the mode is a cross-fade mode according to a command signal from the control circuit 14. When the mode is the cross-fade mode as in the embodiment of FIG. 1, the edit flag from the flag generation circuit 12 is recorded as a signal. Not transmitted to the processing circuit 4. As described above, in this embodiment, any one of the operations in FIGS. 1 and 2 described above can be selected by setting from the mode signal input terminal 16.

Although the insert editing has been described in the above embodiment, the same operation is performed in the case of assemble editing in which the OUT point does not exist and the second crossfade does not exist. Needless to say.
Further, when the edit flag is moved to the cross-fade section, the edit flag is set to another value, that is, a value other than B, E, or 0 in hexadecimal in the example of D-2 described above, so that the normal editing is performed. Indicates that V-fade is not performed during reproduction.

[0017]

According to the present invention, it is possible to prevent the occurrence of abnormal sounds due to crossfade editing even in an audio signal recording system such as D-2 format, which performs editing without overlapping sections in block units. Compatible with a device having the V-fade function.

[0018]

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram showing another embodiment of the present invention.

FIG. 3 is a block diagram showing another embodiment of the present invention.

FIG. 4 is a conceptual diagram for explaining the operation of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Input terminal, 2 ... Level controller, 3 ... Digital adder, 4 ... Recording signal processing circuit, 5 ... Recording head, 6
... magnetic tape, 7 ... reproduction head, 8 ... reproduction signal processing circuit, 9 ... level controller, 10 ... output terminal, 11 ...
Control circuit, 12: flag generation circuit, 13: gate circuit,
14 control circuit, 15 switching circuit, 16 mode signal input circuit, 17 gate circuit.

Claims (3)

(57) [Claims] 1. A signal block is constructed and transmitted or recorded / reproduced for each fixed amount of a digital sampling signal which is continuous in chronological order, and an editing operation such as replacement or insertion of a transmitted or recorded signal is performed for each signal block. In the digital signal processing device, control information adding means (11, 12) for adding control information indicating the first and last blocks to the first and last blocks of a plurality of signal blocks to be continuously replaced and inserted, respectively. And switching means (13) for switching the control information of the control information adding means (11, 12), wherein the first and last blocks of the signal block to be replaced and inserted are at the same position before the replacement and insertion. When equal to the content of a signal block, control information is not added to these blocks. Digital signal processor that. 2. A signal block is formed and transmitted or recorded / reproduced for each fixed amount of a digital sampling signal which is continuous in chronological order, and editing operations such as replacement or insertion of a transmitted or recorded signal are performed in units of the signal block. In a digital signal processing device, control information adding means (12, 12) for adding control information indicating that the block is a signal switching point block to a predetermined block among a plurality of signal blocks to be continuously replaced and inserted. 14) and changing means (15) for changing the position of the control information adding means (12, 14) at which the control information is added, wherein the signal blocks to be replaced and inserted have the same position before the replacement and insertion. Digital signal processing characterized in that control information is not added to these blocks in a section equal to the contents of the signal blocks. Apparatus. 3. The digital signal processing device according to claim 2, wherein said changing means (15) comprises said control information adding means (12, 1).
Selection means (1) that can be set to stop adding control information instead of changing the position where control information is added in 4).
7) so that a mode in which the control information is not added to blocks in a section in which the signal block to be replaced or inserted is not equal to the content of the signal block at the same position before the replacement or insertion can be selected. 3. The digital signal processing device according to claim 2, wherein: