JP2012089217A - Audio reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve switching noise and switching timing delay in switching audio signals to be output, in such a device for reproducing a video signal or audio signal as a video server system.SOLUTION: In response to an instruction to switch audio signals to be output, a time when a first reproduced audio signal that is currently being output is to be switched is determined. On the basis of the determined switching time, fade-out processing is performed at the end of the first reproduced audio signal. Furthermore, in response to the instruction, fade-in processing is performed at the beginning of a second reproduced audio signal that is read out and the signal is stored in a buffer memory. At the switching time, the audio signal to be output is switched from the first reproduced audio signal to the second reproduced audio signal.

Description

  The present invention relates to an audio playback device, and more particularly to an audio playback device that reduces noise when switching audio output.

In a video server system and other video signal and audio signal playback apparatus (hereinafter referred to as information signal together), information signals recorded on a plurality of recording media including magnetic tape, optical disk, and hard disk In accordance with an instruction from the user, and has a function of providing the user to the user via a communication line, for example.
For this purpose, the playback device has a function of receiving a control instruction generated by another device or the device itself as needed and responding thereto. Further, the information signal is reproduced by switching from one recording medium to another recording medium, or the information signal is reproduced by switching to another position in the same recording medium.

Further, the reproducing apparatus includes a buffer memory for accumulating a certain amount of information signal reproduced from the recording medium so as not to cause a problem that the reproduced signal is interrupted during reproduction of the information signal. . Information signals stored in the buffer memory are sequentially read out and provided to the user.
Patent Document 1 discloses a method for automatically cuing at a device when an information signal from another device is filed on a recording medium for a non-linear bank system as an example of such a playback device. .

Japanese Patent Laying-Open No. 2005-210490

However, in such a playback apparatus, as will be described later, the information signal is switched from one recording medium to another recording medium for playback, or switched to another position in the same recording medium for switching to an audio output signal. There is a factor that generates noise. When switching noise is generated, there is a problem that a user who hears this noise causes discomfort.
In view of the above-described problems, an object of the present invention is to provide an audio reproduction device that reduces noise during audio output switching.

In order to solve the above-mentioned problems, the present invention is an audio reproduction device that switches and outputs audio signals read from a plurality of recording media,
A first reproduction processing unit for processing an audio signal read from the first recording medium, a first buffer memory for accumulating the first reproduction audio signal processed by the first reproduction processing unit, A second reproduction processing unit for processing the audio signal read from the second recording medium, a second buffer memory for accumulating the second reproduction audio signal processed by the second reproduction processing unit, An output processing unit that processes the first reproduced audio signal accumulated in the first buffer memory and the second reproduced audio signal accumulated in the second buffer memory and outputs either one; and the audio A control unit for controlling the operation of the playback device;
When switching the playback audio signal output from the output processing unit from the first playback audio signal to the second playback audio signal, the control unit controls the output processing unit and the second playback processing unit. Then, the second reproduction processing unit performs a fade-in process on the start portion of the second reproduction audio signal read from the second recording medium based on the control of the control unit, and performs the second buffer. The output control unit determines a switching time point of the reproduced audio signal to be output based on the control of the control unit, and terminates the first reproduced audio signal read from the first buffer memory. The reproduction audio signal output at the time of switching is switched to the second reproduction audio signal stored in the second buffer memory.

The present invention also relates to a method for switching audio output in an audio reproduction apparatus that switches and outputs a plurality of audio signals written to a recording medium along with a video signal and read from the recording medium,
A determination step for determining whether or not a command for switching the playback audio signal to be output has been issued, and a determination in the determination step that it is determined that a command for switching the playback audio signal to be output has been issued A fade-out process for determining a playback audio signal switching point based on the frame of the video signal and a terminal portion of the first playback audio signal being output based on the switching point determined in the determination step And a second reproduction sound different from the first reproduction sound signal when it is determined that a command for switching the reproduction sound signal to be output is issued as a result of the determination at the fade-out step and the determination step. A fade-in step of reading a signal from the recording medium and fading in a start portion of the second reproduced audio signal;
At the time of switching determined in the determining step, the output audio signal is switched from the first reproduced audio signal to the second reproduced audio signal.

  ADVANTAGE OF THE INVENTION According to this invention, the audio | voice reproduction apparatus which reduced the noise at the time of switching of audio | voice output can be provided, and there exists an effect that it can contribute to cancellation of a user's discomfort.

It is a block diagram of the audio | voice reproduction apparatus in one Example of this invention. It is a wave form diagram which shows an example of the conventional reproduction | regeneration audio | voice signal. It is a wave form diagram which shows the reproduction | regeneration audio | voice signal in one Example of this invention. It is a flowchart which shows the switching method of the audio | voice output in one Example of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram of an audio reproducing apparatus according to an embodiment of the present invention. As described above, the audio reproduction apparatus may have a configuration requirement for transmitting an audio signal via, for example, a communication line. Here, the audio reproduction apparatus reproduces and outputs an audio signal from a plurality of recording media. Only the components are shown. Of course, the audio reproducing apparatus may have a function of reproducing and outputting a video signal from a recording medium.

  The audio signal recorded on the first recording medium 11A is read by a sensor (not shown) such as a magnetic head and an optical pickup according to the type of the recording medium, and is reproduced by the first reproduction processing unit 12A. It becomes a baseband audio signal and is stored in, for example, the first buffer memory 13A using a semiconductor memory. Similarly, the audio signal recorded on the second recording medium 11B is read by a sensor (not shown) and reproduced by the second reproduction processing unit 12B to become a baseband audio signal, and the second buffer memory 13B. Accumulated in. The control unit 16 controls the overall operation of the audio reproduction device 1, and gives a command related to the reproduction operation to, for example, the first reproduction processing unit 12A and the second reproduction processing unit 12B.

The output processing unit 14 selects an audio signal stored in either the first buffer memory 13A or the second buffer memory 13B based on a command from the control unit 16, or synthesizes them to output terminal 15 And supply it to the user via a communication line if necessary. The output processing unit 14 may be a component such as an HD-SDI (High Definition Serial Digital Interface) board which is a digital interface standard for video signals and audio signals. In this case, the output terminal 15 may also be a standardized HD-SDI output terminal.
Here, a case where the control unit 16 performs control so as to switch the audio signal output to the output processing unit 16 in accordance with an instruction from the user will be described with reference to FIG.

FIG. 2 is a waveform diagram showing an example of a conventional reproduced audio signal. Here, a case where the audio signal output from the output processing unit 14 to the output terminal 15 is switched from the audio signal processed by the first reproduction processing unit 12A to the audio signal processed by the second reproduction processing unit 12B is shown. . Conventionally, switching noise is often generated at the time of switching regardless of the presence or absence of the first buffer memory 13A and the second buffer memory 13B, and the user is often uncomfortable. For example, at the moment of switching, the audio signal processed by the first reproduction unit 12A is at the maximum amplitude in the positive direction as shown by (1) in FIG. 2, and the audio signal processed by the second reproduction unit 12B is shown in FIG. Assume that the maximum amplitude is in the negative direction as shown in (2) of 2. At this time, a sudden waveform change as shown in (3) of FIG. 2 is caused at the moment of switching, and the user hears this as switching noise.
The same phenomenon occurs when the sound signal processed by the same playback processing unit continues to be played, when returning from the end point on the recording medium in loop playback (endless playback), or suddenly from a silent state to a large volume. Also occurs when the voice rises.

  Therefore, one embodiment of the present invention is characterized in that the occurrence of this switching noise is eliminated. Another feature is that, by reducing the occurrence of noise, for example, the adverse effect of delaying the switching timing so that the user feels uncomfortable is eliminated. Hereinafter, these matters will be described with reference to FIG.

FIG. 3 is a waveform diagram showing a reproduced audio signal in one embodiment of the present invention.
First, as shown in the figure, the output of the first buffer memory 13A indicated by (1A) in the figure is a reproduced audio signal read from the first recording medium 11A and processed by the first reproduction processing unit 12A. A is output. When the user instructs to switch from the reproduced audio signal processed by the first reproduction processing unit 12A to the reproduced audio signal processed by the second reproduction processing unit 12B, the control unit 16 responds accordingly. At least, the illustrated “switching command” is sent to the second reproduction processing unit 12B and the output processing unit 14.

  The output processing unit 14 refers to the reproduced audio signal A stored in the first buffer memory 13A and determines a switching time point. For example, if the reproduced audio signal is an audio signal recorded along with the video signal, the time point at which the audio signal is switched is determined by determining the final frame of the video signal. After receiving the above switching command, the output processing unit 14 outputs the playback audio signal A having the specified number of samples up to the switching point of the final frame to the output terminal 15 while fading out as shown by (2A) in FIG. . That is, the fade-out process described above is performed by the output processing unit 14 including, for example, an HD-SDI board.

  On the other hand, the second reproduction processing unit 12B that has received the previous switching instruction starts to read the audio signal from the second recording medium 11B. The reproduced audio signal B immediately after being read by the second reproduction processing unit 12B is shown by (1B) in FIG. Next, the second reproduction processing unit 12B processes the rising portion of the reproduced audio signal B so as to fade in as indicated by (2B) in FIG. 3, and stores it in the second buffer memory 13B. That is, the fade-in process described above is performed by the second reproduction processing unit 12B.

  The time point described as “switching” in FIG. 3 corresponds to the switching time point determined by the output processing unit 14 as described above. At this time, the output processing unit 14 switches the reproduced audio signal output to the output terminal 15 to the reproduced audio signal read from the second buffer memory 13B shown by (3B) in FIG. As a result, the audio signal output to the output terminal 15 is switched from the reproduced audio signal A to the reproduced audio signal B as shown by (4) in FIG. Since the fade-out process and the fade-in process described above are performed, the waveform of the audio signal does not change sharply, and the problem of generating unpleasant switching noise at the time of switching as in the prior art is solved.

  After the switching is performed, the reproduction process of the audio signal recorded on the first recording medium 11A in the first reproduction processing unit 12A may be stopped. Further, in FIG. 3, there is a slight time delay accompanying the synchronization with the video switching from the time when the switching command is generated to the time when the audio signal is actually switched. It is a time delay and the user will not feel uncomfortable. Of course, the switching from the reproduced audio signal B to the reproduced audio signal A is exactly the same as described above, and thus the description thereof is omitted here.

Next, an audio output switching method in the present embodiment will be described.
FIG. 4 is a flowchart showing the audio output switching method according to the embodiment of the present invention. In an audio reproducing apparatus having a plurality of recording media and a corresponding reproduction processing unit, the first reproduction processing unit 12A reproduces and outputs the audio signal recorded on the first recording medium 11A.

In step S401, the control unit 16 determines whether or not a command is issued to switch the audio signal to be reproduced and output. If it is determined that the command has not been issued (No in the figure), the same determination is repeated again.
As a result of the determination in step S401, if it is determined that the command has been issued (Yes in the figure), the control unit 16 transmits the command to the second reproduction processing unit 12B and the output processing unit 14 at least. Then, the process proceeds to step S402. First, consider a case where the audio signal being reproduced is recorded on a recording medium along with the video signal.

In step S <b> 402, the output processing unit 14 determines a final frame of the video signal to be reproduced in response to a command from the control unit 16. For example, the frame of the video signal when receiving the command is determined as the final frame.
In step S403, the output processing unit 14 detects the final frame of the video signal determined in step S402 from the video signal stored in the first buffer memory 13A.
Further, in step S404, the output processing unit 14 detects the reproduced audio signal corresponding to the final frame detected in step S403 from the audio signal stored in the first buffer memory 13A.

In step S405, the output processing unit 14 performs a fade-out process on the terminal portion of the reproduced audio signal detected in step S404, and outputs the reproduced audio signal subjected to the fade-out process to the output terminal 15 in step S406.
Needless to say, when the audio signal being reproduced is recorded on the recording medium irrespective of the video signal, the audio signal switching time may be determined without determining the final frame.

As a result of the determination in step S401, when it is determined that the command has been issued, the second reproduction processing unit 12B separately reads out the audio signal recorded in the second recording medium 11B in step S407. start.
In step S408, the second reproduction processing unit 12B performs a fade-in process on the start portion of the read audio signal, and accumulates it in the second buffer memory 13B.

In step S409, the output processing unit 14 switches the audio signal output to the output terminal 15 from the reproduced audio signal subjected to the fade-out process in step S406 to the reproduced audio signal subjected to the fade-in process in step S408. Thereby, the switching operation of the audio signal is completed.
As described above, according to the present embodiment, the output audio signal can be switched without an unpleasant switching noise or a sense of incongruity due to a delay in switching timing. This eliminates the need for manpower for switching, and does not require expensive and highly functional peripheral devices, which can contribute to a reduction in price.
The embodiments described so far are merely examples, and do not limit the present invention. Although different embodiments can be considered based on the spirit of the present invention including the block diagram of FIG. 1 and the flowchart of FIG. 4, both are within the scope of the present invention.

  1: audio reproduction device, 12A: first reproduction processing unit, 12B: second reproduction processing unit, 13A: first buffer memory, 13B: second buffer memory, 14: output processing unit, 15: audio output Terminal 16: Control unit.

Claims (1)

An audio reproduction device that switches and outputs audio signals read from a plurality of recording media,
A first reproduction processing unit for processing an audio signal read from the first recording medium;
A first buffer memory for accumulating the first reproduction audio signal processed by the first reproduction processing unit;
A second reproduction processing unit for processing an audio signal read from the second recording medium;
A second buffer memory for accumulating the second reproduced audio signal processed by the second reproduction processing unit;
An output processing unit that processes the first reproduced audio signal accumulated in the first buffer memory and the second reproduced audio signal accumulated in the second buffer memory, and outputs either one;
A control unit for controlling the operation of the audio reproduction device;
When switching the playback audio signal output from the output processing unit from the first playback audio signal to the second playback audio signal, the control unit controls the output processing unit and the second playback processing unit. And
The second reproduction processing unit performs a fade-in process on the start portion of the second reproduction audio signal read from the second recording medium based on the control of the control unit, and stores the fade-in process in the second buffer memory. Accumulate,
The output control unit determines a switching time point of the reproduced audio signal to be output based on the control of the control unit, and performs a fade-out process on a terminal portion of the first reproduced audio signal read from the first buffer memory. An audio reproduction apparatus characterized in that the reproduced audio signal output at the time of switching is switched to the second reproduced audio signal stored in the second buffer memory.

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