JPH11167396A - Voice recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a voice recording and reproducing device suitable to more extensive purposes including a language learning by reproducing voice signals of two channels while alternately changing over the voice signals at frame positions expressing silence. SOLUTION: Inputted voice signals of two chammels are judged whether they are sound or silence in a frame length unit having a prescribed time length and judgement results and voice data are recorded on a record medium 10. When a system control part 9 detect that a reproduction button is pressed, it moves to reproduction processing and it inputs voice data of the channel of one side being in the two channels from the recording medium 10 in the frame unit to check the states of added sound and silence flags. Then, when the voice data are silence frame, it changes over the reproduction channel of the voice data to be inputted from the medium 10 and also inserts a silence frame having a prescribed length behind the silence frame and outputs voice data to which the silence frame is added to a digital signal processing part 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an audio recording / reproducing apparatus.

[0002]

2. Description of the Related Art As one type of audio recording / reproducing apparatus, an audio recording / reproducing apparatus capable of recording and reproducing information of a bilingual (audio multiplex) broadcast has been conventionally known. In such an audio recording and reproducing apparatus, Japanese Patent Laid-Open Publication No.
In order to solve the problem that it is difficult to hear when languages are reproduced from both channels at the same time, a device for outputting only one of the sounds simultaneously from both channels is disclosed.

[0003]

However, in the above-mentioned Japanese Patent Application Laid-Open No. 5-145878, whether only one of the audios is simultaneously output from both channels is determined.
Alternatively, only one of the sounds can be output from only one of the channels, so the use is limited, and the reproduction is not suitable for use in, for example, language learning.

The audio recording / reproducing apparatus of the present invention has been made in view of such a problem. An object of the present invention is to be able to alternately reproduce a two-channel audio signal at a frame position indicating silence. Thus, an object of the present invention is to provide a voice recording / reproducing apparatus suitable for a wider range of uses including, for example, language learning.

[0005]

In order to achieve the above object, an audio recording / reproducing apparatus according to a first aspect of the present invention comprises: an audio input unit capable of inputting an audio signal of two channels; Determining means for determining whether the audio signal is sound or no sound in frame units having a predetermined time length, recording means for recording the determination result and the audio data by the determining means on a recording medium, and audio data recorded on the recording medium And reproduction control means for alternately switching the audio data corresponding to each channel at a frame position indicating silence and sequentially reproducing the audio data.

The audio recording / reproducing apparatus according to a second aspect of the present invention is the audio recording / reproducing apparatus according to the first aspect of the present invention, wherein the audio recording / reproducing apparatus further comprises a reproducing speed adjusting means capable of independently adjusting the reproducing speed of the audio data corresponding to each channel. Have.

Further, in the audio recording and reproducing apparatus according to a third aspect of the present invention, in the audio recording and reproducing apparatus according to the first or second aspect, the determining means determines that a time length from a silent frame to a silent frame is a predetermined time. If not, the subsequent silent frame is determined to be a sound frame.

That is, in the audio recording / reproducing apparatus according to the first invention, it is determined whether the audio signal of each channel input from the audio input unit is sound or silence in a frame unit having a predetermined time length. The result of the determination and the audio data are recorded on a recording medium. When the audio data recorded on the recording medium is reproduced, the reproducing operation is controlled so that the audio data corresponding to each channel is alternately switched at frame positions indicating silence and sequentially reproduced.

Further, according to the audio recording / reproducing apparatus according to the second invention, in the audio recording / reproducing apparatus according to the first invention, the reproduction speed of the audio data corresponding to each channel is adjusted independently.

[0010] The audio recording and reproducing apparatus according to a third aspect of the present invention is the audio recording and reproducing apparatus according to the first or second aspect, wherein the time length between silent frames is shorter than a predetermined time. Is determined that the subsequent silent frame is a voiced frame.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of a digital audio recording and reproducing apparatus to which the audio recording and reproducing apparatus of the present invention is applied. In FIG. 1, channel terminals of an audio input unit 1 for inputting audio signals of two channels are respectively provided with amplifiers (AMP) 2, 3 and a low-pass filter (L).
PF) 4, 5 and a digital signal processor (DSP) 8 via A / D converters (A / D) 6, 7. The speaker 16 includes an amplifier (AMP) 15 and
A low-pass filter (LPF) 14 and a D / A converter (D / A) 13 are connected to a digital signal processing unit (DSP) 8 as a determination unit.

The digital signal processing section 8 is connected to a system control section (CPU) 9. The system control unit 9 has a function as a reproduction unit and a reproduction control unit.

A detachable memory is connected to the system control unit 9 as a recording medium 10, and operation buttons are
As a record button REC, a play button PLAY, a stop button STOP, a CHANGE button as a sound / silence flag change button for changing the state of a sound / silence flag described later, and a silence frame detection button for detecting a silence frame SEAR
A CH button and the like are connected. Also, a reproduction speed adjusting means 11 comprising an operation switch is connected. As the reproduction speed adjusting means 11, a slide type switch, +,
A button or the like can be used. The recording medium 10
May be a built-in type memory instead of a detachable type.

The system control unit 9 controls the operations of the digital signal processing unit 8 and the recording medium 10 according to the operation of the plurality of operation buttons and operation switches. This recording medium 1
As 0, for example, a flash memory, a magneto-optical disk, a magnetic disk, or the like is used. In this embodiment, a flash memory is used. An address, which is information indicating a recording position of audio information, is recorded on the recording medium 10.

In the above configuration, the recording process will be described first with reference to FIG. FIG. 2 is a flowchart for explaining the operation of the system control unit 9 during the recording process. When the system control unit 9 detects that the recording button REC is pressed, the system control unit 9 initializes the digital signal processing unit 8 and resets the number N of the counter of the digital signal processing unit 8 that counts the number of sound frames ( N = 0) (step S1). This counter counts the number of frames determined to have sound during the silence determination processing described later. Note that the initialization of the digital signal processing unit 8 and the reset of the counter accompanying the initialization need not be performed at this time, but may be performed any time before the digital signal processing unit 8 performs the silence determination processing.

In parallel with the above processing, for example, audio signals of two channels of bilingual broadcasting recorded on a television or a video are input from an audio input unit 1 such as an audio terminal. Here, the two-channel audio signals are a main audio and a sub audio, respectively. The input audio signal is amplified by the amplifiers 2 and 3 for each channel, and the low-pass filters 4 and 5
In order to prevent the generation of aliasing noise, unnecessary frequency bands are cut.

Next, the audio signals from the low-pass filters 4 and 5 are converted into digital signals by the A / D converters 6 and 7, and then input to the digital signal processing unit 8. The digital signal processing unit 8 is controlled by the system control unit 9, and first decomposes the input audio signals of both channels into frame units (in this embodiment, data sampled during 20 msec is regarded as one frame).

At this time, the system control unit 9 instructs the digital signal processing unit 8 to start the silence judgment processing and the encoding processing, and performs the silence judgment processing and the encoding processing for each channel. (Step S2). Next, the system control unit 9 enters a recording operation process for reading the free space and the recording position of the recording medium 10 and writing the recording start position in order to record sound on the recording medium 10 (step S3).

Next, the system control unit 9 inputs the encoded audio data from the digital signal processing unit 8 via the internal buffer (step S4), and outputs the input audio data to the recording medium 10. (Step S5). After that, the current address position is updated (step S
6). Then, the system control unit 9 determines whether or not the stop button STOP has been pressed (step S7).
When it detects that is pressed, it exits the recording process,
Otherwise, the series of operations (steps S4, S5,
S6) is repeated.

FIG. 3 is a flowchart showing the details of the silence determination processing and the encoding processing in the digital signal processing section 8 described above. Hereinafter, the silence determination processing and the encoding processing will be described with reference to this flowchart.

First, one frame of audio data is input (step S10). Then, the energy level of the audio data is determined for each frame (step S11), and it is determined whether or not the input audio data frame is a silent frame based on the energy level at this time (step S12). Here, if the input frame has energy greater than a predetermined level, a sound frame,
If the level is equal to or lower than the predetermined level, it is determined that the frame is a silent frame.

If it is determined in step S12 that the input frame is a speech frame, a speech / silence flag for discriminating between a speech frame and a silence frame is set to 1 (step S12). S13) The number N of the counter for counting the number of sound frames is incremented (N = N + 1) (step S14). Next, an encoding process (step S15) is performed, and the process returns.

On the other hand, if it is determined in step S12 that the input frame is a silent frame,
It is determined whether the number N of the counter is 25 or more (step S16). If N is less than 25, the process proceeds to step S13, and the sound / silence flag is set to 1.

On the other hand, if the number N of the counter is 25 or more, the sound / silence flag is set to 0 and the counter is reset (N = 0) (steps S17 and S1).
8). Next, an encoding process (step S15) is performed, and the process returns.

At the time of reproduction, the system controller 9 can easily determine whether the audio data frame is a voice frame or a voiceless frame by detecting the status of the voice / non-voice flag on a frame basis. Also, as can be seen from the above steps, in the present embodiment, after a certain frame is determined to be a silent frame, several sound frames continue, and if a silent frame is subsequently detected, the first detected frame is detected. If the time length between the detected silence frame and the silence frame detected thereafter is less than a predetermined time, here the time corresponding to 25 frames, the silence frame detected later is determined as a speech frame. Like that. As a result, the audio data can be reproduced as a sound frame having a certain time length.

FIG. 4 shows that an identification signal of 1 or 0 is written in a voice / non-voice flag added to a voice data frame in accordance with a determination whether the voice data frame is a voice frame or a voice frame. It is a figure showing a situation.

Next, the reproduction process will be described with reference to FIG. FIG. 5 is a flowchart for explaining the operation of the system control unit 9 during the reproduction process. First, upon detecting that the play button PLAY has been pressed, the system control unit 9 shifts to a reproducing process, and first detects a reproducing position of the recording medium 10 (step S20). Next, audio data of one of the two channels is input from the recording medium 10 via the internal buffer of the system control unit 9 in frame units (step S21). Then, the state of the sound / silence flag added to each audio data frame is checked to determine whether or not the input frame is a sound frame (if the frame is a sound frame, the sound / silence flag becomes 0). ing)
(Step S22) If the frame is a silence frame, the reproduction channel of the audio data input from the recording medium 10 is switched (Step S23), and a silence frame having a predetermined length (1 in this embodiment) is added after the silence frame.
(4 frames) are inserted (step S24). Then, the audio data to which the silence frame of the predetermined length is added is output to the digital signal processing unit 8 (step S2).
5).

As described above, when a channel is switched, a silence frame of a predetermined length is inserted to provide an interval of a predetermined time, so that the reproduced sound becomes more audible. In addition, since the audio data of each channel is sequentially reproduced by the channel switching in the silent frame, there is no portion where the reproduction is cut.

On the other hand, if it is determined in step S22 that the input frame is a sound frame (if the frame is a sound frame, the sound / silence flag is set to 1), the frame is left as it is. Output to the digital signal processing unit 8 (step S25).

Next, the system control unit 9 outputs a decoding start command to the digital signal processing unit 8 (step S26), and causes the digital signal processing unit 8 to decode audio data. Thereafter, the current address position is updated (step S27). Next, the system control unit 9 determines whether the stop button STOP has been pressed (step S2).
8) While the stop button STOP is not pressed, the above series of processing is repeated, and when it is detected that the stop button STOP is pressed, the processing returns from the reproduction processing.

The audio data decoded by the digital signal processing unit 8 is converted into an analog signal by the D / A converter 13, and an unnecessary frequency band is cut by the low-pass filter 14 in order to reduce quantization noise. Next, the signal is input to the amplifier 15 and amplified to a signal capable of driving the speaker 16. The audio signal amplified by the amplifier 15 is converted into audio by the speaker 16 and output.

When the user changes the state of the reproduction speed adjusting means 11 during the above-mentioned reproduction operation or during the stop, the system control section 9 detects this and performs the following processing.

That is, the user sets the reproduction speed adjusting means 1
In the case where the reproduction speed is set to a high value by using TDHS (Time Domain Harmonic Compressor) from the current address position in the digital signal processing unit 8 in accordance with the set value.
on) The time axis compression process is performed in frame units by the method.
In this case, the user can change the compression ratio on the time axis in accordance with the set value of the playback speed adjusting means 11, and can adjust the playback speed in several steps accordingly.

On the other hand, if the user sets a slower playback speed, the digital signal processing unit 8 performs the time axis decompression process from the current address position in frame units by the TDHS method according to the set value. In this case, the user can change the elongation rate of the time axis according to the set value of the playback speed adjusting means 11, and can reduce the playback speed to 、 ４, 4
It can be adjusted in steps of a fraction.

The user can adjust the reproduction speed adjusting means 11
Can be used to set the playback speed for each channel. In this case, the setting of each channel is stored in the internal memory of the system control unit 9 in advance. At the time of reproduction, the system control unit 9 determines which channel data is referred to by referring to the settings of each channel, and controls the digital signal processing unit 8 to switch the reproduction speed according to the channel.

Since the playback speed can be adjusted independently for each channel in this way, for example, efficient playback of a foreign language that is difficult to hear is performed slowly, or fast when no time is available. Can study languages.

Further, in the present embodiment, the user can easily change the state of the sound / non-sound flag by operating the CHANGE button as the determination result changing means during the recording process. As a result, the reproduction position of the audio signal of the two channels can be switched with higher accuracy, and reproduction suitable for language learning can be performed.

First, a case will be described in which a sound / silence flag = 0 is newly added to an audio data frame to change the channel switching position. When the user presses the CHANGE button at a position where the user wants to change the channel switching position during playback or stop, the system control unit 9 sets
Upon detecting that the GE button has been pressed, the digital signal processing unit 8 sets the sound / silence flag of the current audio data frame to 0.
Is recorded on the recording medium 10.

Next, a case where the channel switching position is changed by deleting the channel switching position will be described. Here, the index mark is used as a mark for detecting a silent frame. When the user presses the SEARCH button, the system control unit 9 detects the index mark at a high speed in response thereto, thereby detecting a silent frame. If the user wants to delete the detected silent frame, the user presses the CNANGE button. In response, the system control unit 9 instructs the digital signal processing unit 8 to change the sound / non-sound flag of the current audio data frame to 1, and records the same on the recording medium 10.

According to the above-described embodiment, since the audio signals of two channels can be alternately reproduced at the position of the silent frame, the present audio recording / reproducing apparatus can be used for a wider range of applications including, for example, language learning. Can be used.

The invention having the following configurations (1) to (4) is derived from the above specific embodiment.
The effects of each invention are as follows. (1) An audio input unit capable of inputting an audio signal of two channels, determining means for determining whether the input audio signal of each channel is sound or silence in a frame unit having a predetermined time length, and determining means Recording means for recording the determination result and the audio data on the recording medium, reproducing means for reproducing the audio data recorded on the recording medium, and sequentially reproducing the audio data corresponding to each channel by switching alternately at frame positions indicating silence And a reproduction control means for causing the sound recording / reproducing apparatus to perform. (2) The audio recording / reproducing apparatus according to configuration (1), further including a determination result changing unit that can arbitrarily change the determination result recorded on the recording medium. (3) The audio recording / reproducing apparatus according to (1), wherein the reproduction control means inserts a silence of a predetermined length at the time of switching. (4) Processing audio data of a recording medium in which audio data for two channels is recorded together with an identification signal for discriminating between sound and silence in a frame unit having a predetermined time length. Reproduction means for reproducing the recorded audio data; and reproduction control means for switching the audio data corresponding to each channel alternately at a frame position indicating silence to sequentially reproduce the audio data of each channel. Audio processing device.

According to the invention described in the configuration (1), it is possible to provide a voice recording / reproducing apparatus suitable for a wider range of uses including, for example, language learning. According to the invention described in the configuration (2), in addition to the effect of the invention described in the configuration (1), the reproduction position of the 2-channel audio signal is switched with higher accuracy, and is more suitable for, for example, language learning. An audio recording / reproducing device capable of reproducing can be provided.

According to the invention described in the configuration (3),
In addition to the effect of the invention described in the configuration (1), the sound reproduced at the time of channel switching becomes more audible. Further, according to the invention described in the configuration (4), it is possible to provide a speech processing device suitable for a wider range of uses including, for example, language learning.

[0044]

According to the first aspect of the present invention, it is possible to provide a voice recording / reproducing apparatus suitable for a wider range of uses including, for example, language learning. According to the second aspect, in addition to the effects of the first aspect, more efficient language learning can be performed. According to the third aspect of the invention, in addition to the effect of the first aspect, the audio data can be reproduced as a sound frame having a predetermined time length.

[Brief description of the drawings]

FIG. 1 is a block diagram of a digital audio recording and reproducing apparatus to which an audio recording and reproducing apparatus of the present invention is applied.

FIG. 2 is a flowchart illustrating an operation of a system control unit during a recording process.

FIG. 3 is a flowchart illustrating details of silence determination processing and encoding processing in a digital signal processing unit.

FIG. 4 is a diagram showing how an identification signal of 1 or 0 is written in a voice / silence flag in accordance with a determination whether a voice data frame is a voice frame or a voice frame.

FIG. 5 is a flowchart for explaining the operation of a system control unit during a reproduction process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Audio input part, 2, 3 ... Amplifier (AMP), 4, 5 ... Low-pass filter (LPF), 6, 7 ... A / D converter, 8 ... Digital signal processing part (DSP), 9 ... System control part, DESCRIPTION OF SYMBOLS 10 ... Recording medium, 11 ... Reproduction speed adjustment means, 13 ... D / A converter, 14 ... Low-pass filter (LPF), 15 ... Amplifier (AMP), 16 ... Speaker.

Claims (3)

[Claims] 1. An audio input unit capable of inputting audio signals of two channels, determining means for determining whether the input audio signals of each channel are sound or silence in a frame unit having a predetermined time length, Recording means for recording the determination result and the audio data on the recording medium, reproducing means for reproducing the audio data recorded on the recording medium, and alternately switching the audio data corresponding to each channel at a frame position indicating silence. An audio recording / reproducing apparatus, comprising: reproduction control means for sequentially reproducing. 2. The audio recording / reproducing apparatus according to claim 1, further comprising a reproducing speed adjusting means capable of independently adjusting the reproducing speed of the audio data corresponding to each channel. 3. The method according to claim 1, wherein when the time length between the silent frame and the silent frame is less than a predetermined time, the determining unit determines the subsequent silent frame as a voice frame.
An audio recording / reproducing device according to claim 1.