JPH0348594B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital audio editing device for editing a tape recorded by a digital recording/playback device.

Conventionally, in editing analog recorded tapes, manual editing has been carried out, in which necessary parts of the recorded tape are cut by hand and then spliced together to form a single tape. This situation is shown in FIG. In other words, in Figure 1, 1 and 2 are parts of the recorded tape, part A of 1 is a necessary part, part B is an unnecessary part, part C of 2 is an unnecessary part, and D is a necessary part. It is. The edited tape 3 can be obtained by cutting these tapes and mechanically joining the necessary parts. At this time, the cutting positions of tapes 1 and 2, that is, A, B, and C.
It is necessary to find the boundary between and D (hereinafter referred to as the editing point), but for this purpose the following work is required.

In other words, first put the tape recorder in playback mode, stop it at a position that seems to be the edit point while listening to the playback sound, and then manually move the take-up reel and supply reel of the tape recorder in the same direction relative to each other in order to find a more accurate edit point. , the tape is reversed, the editing point is judged and determined by listening to the playback sound, and the editing point is manually cut out using the tape position where it is in contact with the gap of the playback head as the editing point.

Such editing work is indispensable when creating music tapes, etc., but difficult problems arise when applying it to digital recording and playback devices that have been put into practical use in recent years. That is, when a digital recording/reproducing apparatus reproduces a music signal on a tape, the tape speed must be approximately constant because the data is once written into a buffer memory and then read and reproduced at a constant clock. Therefore, variable speed playback and reverse playback are difficult, and editing points cannot be finely adjusted by manually rotating the reel. This means that editing digitally recorded tapes is difficult. This means that it cannot be done with traditional hand-cut editing.

Also, digital recording and playback devices, such as
In a PCM (Pulse Code Modulation) type PCM recording/playback device, the recorded signal on the tape is made up of dozens of samples of information bits with error correction codes added to form one PCM frame, so manual editing is required. , data was lost in units of 1 PCM frame, and the signal was discontinuous before and after the editing point, which had a detrimental effect on the reproduced sound.

Therefore, in a digital audio editing device, the recorded tape is not cut mechanically, but two digital recording and playback devices are used, and the first digital recording and playback device plays back the unedited tape, and the first Two digital recording and reproducing devices are used to record only necessary portions of a first tape onto a second tape to create one edited tape.
In other words, 1 and 2 are the first
These are different parts of one tape installed in the second digital recording/playback device, and 3 is the tape installed in the second digital recording/playback device. Therefore, the operation is to play part 1 of the first tape loaded in the first digital recording/playback device, and then start the second digital recording until it passes the boundary between A and B and slightly enters the area B. Record on a second tape attached to a playback device. This situation is shown in FIG. When the editing point, the boundary between parts A and B, and the boundary between parts C and D are determined accurately, the first tape is played from a length L ₁ before the boundary between C and D, and at the same time the second tape is played back. is played from L ₂ before the boundary between A and B. Here, L ₁ L ₂ is assumed, and this value is such that at the moment when the playback head of the first digital recording/playback device comes into contact with the boundary between C and D of tape 1, the second It is sufficient that the length is sufficient to run the tapes 1 and 2 synchronously so that the recording head of the digital recording/playback device comes into contact with them. In this way, if tapes 1 and 2 are run synchronously, D of tape 1 will be moved from the boundary between A and B of tape 2.
can be recorded. At this time, at the boundary between A and D, a fade-out of A and a fade-in of D are performed by digital calculation.

In order to realize an electronic editing system based on the above concept, the audio signals before and after the editing points, that is, the border between A and B and the border between C and D in Figure 1, are stored in memory and edited by memory processing. It is necessary to perform fine adjustment of the editing point by reproducing the audio signal before and after the point at variable speed and in the reverse direction. The amount of memory employed in most digital audio editing devices is enormous and weighs heavily on the structure and cost of the device.

Therefore, in order to reduce memory capacity, methods have been adopted in which digital data reproduced by a digital recording and reproducing device is bit-compressed in units of samples or thinned out every N samples when writing to memory. However, the method using bit compression has its limitations because the dynamic range decreases and the S/N ratio becomes a problem when checking editing processing using memory. In addition, in the method of thinning out every N samples, if sample data such as click noise is included in the sample data that has been thinned out, the original signal on the tape will not be completely reproduced in memory, and editing processing in memory will be delayed. When checking, problems such as clicking noises and the like may be overlooked.

The present invention provides a digital audio editing device that does not cause the above-mentioned problems.

Embodiments of the present invention will be described in detail below, but first an outline of the editing method used in the apparatus of this embodiment will be explained.

In this method, a recorded tape is played back by a digital recording/playback device, and when the played back temporally continuous digital data is stored in memory, it is averaged in units of an arbitrary number of temporally continuous samples. This makes it possible to store N samples of information without losing their relationships, thereby reducing the amount of memory.

The apparatus of this embodiment is based on the above-mentioned technical idea, and an example of averaging every two samples will be explained in detail below with reference to FIGS. 3, 4, and 5.

In FIG. 3, a terminal 10 is an input terminal for digital data reproduced by a digital recording/reproducing device, 11 and 12 are latch elements that store or latch the digital data input from the input terminal 10, and 13 is a latch element 11, 12 is an adder that adds two temporally consecutive samples of digital data latched; 14 is a divider that divides the digital data added by adder 13 by the number of samples to be added; 15 is an input terminal 10; 16 is an address counter of the memory 15; 17 is a digital recording and reproducing device connected to the terminal 10; This is the terminal to which a clock signal synchronized with the ampoule data in the signal sent from the terminal is input. Reference numeral 18 denotes a control signal generation circuit that generates timing signals for controlling each element based on the clock signal input from the input terminal 17.

Next, the operation of this embodiment will be explained with reference to the timing chart shown in FIG. It is assumed here that the digital data input from the digital recording/reproducing device to the terminal 10 is 16 bits/sample and is transmitted in 16-bit parallel.

In FIG. 4, the sample data input from the terminal 10 (see FIG. 4a) is transmitted to the latch element 1 by a timing signal, as shown in FIG. 4b and c.
1 and 12 and input to the adder 13.
The sample data added by this adder 13 is input to a divider. Then, it instructs the divider 14 to perform division using the division signal and address counter up signal shown in FIG. The data is written into the memory 15 using the timing signal shown in FIG. 4e. Through this series of processing, two temporally consecutive samples are averaged, and the results are written and stored in memory. The situation is shown in FIG. In addition,
FIG. 4f shows the clock signal input to terminal 17.

In FIG. 5, a is temporally continuous original sample data, b is sample data latched by latch element 11, c is sample data latched by latch element 12, and d is latch element 11, 12.
This is the result of adding the sample data latched by the adder 13 and dividing by the divider 14, that is, the average value of the latched sample data.

As explained above, according to the digital audio editing device of the present invention, problems such as a decrease in dynamic range in the bit compression processing method of the conventional device and insufficient reproducibility of the original signal in the thinning method can be solved. The effects are significant, such as the ability to reduce memory capacity and thereby reduce costs.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the conventional analog audio editing method, FIG. 2 is a diagram for explaining the digital audio editing method that is the basis of the device of the present invention, and FIG.
The figure is a block diagram of a digital audio editing device according to an embodiment of the present invention, FIGS. 4a to 4f are waveform diagrams of the main parts thereof, and FIGS. It is a diagram. 10...Reproduction data input terminal, 11, 12...
latch element, 13... adder, 14... divider,
15...Memory, 16...Address counter, 1
7...Clock signal input terminal.

Claims (1)

[Claims] 1. A digital audio editing device that electronically edits a digital audio signal, comprising: a first latch means for capturing and holding a digital signal with an odd number of sample periods from among digital signals in time-series continuous sample units; a second latching means for capturing and holding a digital signal of an even number of sample periods that is one sample behind the digital signal latched by the latching means; and an adding means for adding the digital signals latched by the first and second latching means. a dividing means for dividing the digital signal added by the adding means into 1/2; a memory means for storing the digital signal divided by the dividing means; and a dividing means for storing the digital signal divided by the dividing means in the memory means. address counter means for updating and determining the storage location of the digital signal divided by the adding means; a latch control signal for latching the first and second latch means; a division control signal that causes a division means to perform a division operation; an address update control signal that causes an address counter that updates and determines a storage location of the memory means to update the storage location; and control signal generation means for generating a storage control signal to be stored in the memory means, and in order to search and determine the edit point on the memory, the digital signal in the vicinity of the edit point is generated in units of two temporally consecutive samples. A digital audio editing device characterized in that the average value is calculated for each time, and the average value is continuously written and stored in a memory means.