JP2001148159A - Audio processing device and method, and computer- readable recording medium recorded with program to make computer execute audio processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an audio encoding processor which can reproduce second without causing the sudden changes of sound levels nor generating noise due to the changes. SOLUTION: This audio processor 30 includes a dual port memory 31, which stores the audio data supplied from an audio input pin, a register 32 which holds a pause indication signal, a register 33 which holds an audio-encoding indication signal, a processor 35 which applies the audio encoding processing to the audio data stored in the memory 31, an audio frame pulse generator 36 which generates an audio frame pulse and generates an interrupt to the processor 35 to start the audio encoding processing, a FIFO(first in first out) memory 34 which stores the audio encoding data processed by the processor 35 and outputs these data in a FIFO system via an audio-processing data output pin and a memory 37 which holds various parameters.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio processing apparatus and method, and a computer-readable recording medium on which a program for causing a computer to execute the audio processing method is recorded. In particular, the present invention relates to an audio processing apparatus and method that does not generate noise during audio reproduction, and a computer-readable recording medium that stores a program for causing a computer to execute the audio processing method.

[0002]

2. Description of the Related Art Conventionally, digital audio PCM (Puls
e Code Modulation) There is a recording device that uses a data encoding device. As audio encoding processing,
MPEG1 audio compression processing, which is internationally standardized by the Moving Picture Experts Group (MPEG), and AC-3 compression processing developed by Dolby are used.

[0003] The recording device naturally supports a pause function for temporarily stopping the recording operation. For example, in order for the user to play back music recorded on two different audio sources and record continuously, the recording operation is paused when recording from one audio source is completed, and the audio source is switched to the next. After switching to the audio source, recording is resumed.

An example of a recording operation using a pause function will be described with reference to FIG. In the figure, audio frames to be processed (hereinafter referred to as “frames”) are numbered A0 to A8. When the audio encoding instruction signal is L (Low), the audio encoding process is performed for each frame in the recording device. When the pause instruction signal is L, audio encoding is performed regardless of the value of the audio encoding instruction signal. Processing is stopped.
In the example shown in FIG. 11, when the processing of the frame A2 is completed, the pause instruction signal becomes L, and the pause is performed. The frames A3 and A4 input while the pause instruction signal is at L are not subjected to audio encoding processing. At the time when the frame A5 is processed, the pause instruction signal becomes H (H
i), the audio encoding process is restarted for the frames after the frame A5.

By using such a pause function, frames A0, A1, A
Reproduction is performed in the order of 2, A5, A6,.

[0006]

However, before and after the recording operation is temporarily stopped, there may be a difference in the reproduced sound level. If the difference between the reproduced sound levels, that is, the difference between the reproduced sound levels between the frames A2 and A5 in the example shown in FIG. 11, is large, noise is generated at the time of reproducing the audio.

[0007] For example, in a television program, CM
(Commercial Message) or the like, switching from stereo sound to monaural sound is performed. There is a device that pauses and unpauses the recording by using the voice switching as a trigger. However, video signals and audio signals do not always correspond exactly. For this reason, if a pause operation is performed with audio switching as a trigger, in a normal audio encoding process, due to a shift between the video signal and the audio signal, the audio corresponding to the video after the pause is reproduced when the video is reproduced before the pause. In some cases, a signal is reproduced, and vice versa.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and has as its object to prevent a sudden change in the sound level during reproduction and without causing noise accompanying the change.
An object of the present invention is to provide an audio encoding processing device and method capable of reproducing audio, and a computer-readable recording medium recording a program for causing a computer to execute the audio processing method.

Another object of the present invention is to provide an audio encoding processing apparatus and method capable of avoiding a mismatch in reproduction timing when a plurality of devices are used, and a program for causing a computer to execute the audio processing method. Is to provide a computer-readable recording medium on which is recorded.

[0010]

According to a first aspect of the present invention, there is provided an audio processing apparatus for instructing an audio data encoding process to selectively take one of a first value and a second value. Audio data in frame units based on a first signal and a second signal for instructing to temporarily stop encoding processing of audio data that selectively takes one of a third value and a fourth value; Is encoded. The audio processing device is connected to a memory having a first port to which audio data of a frame unit is input and a second port to which audio data is output, and when the audio data is input to the memory, the memory Audio data encoding means for reading audio data with a delay from the audio data, and selectively executing either audio data encoding processing or non-encoding processing based on the history of the first and second signals; Audio data encoding means coupled to the audio data encoding means for eliminating an audio level difference between the audio data in frames before and after a period in which the audio data encoding means does not encode the audio data based on the history of the second signal; A sound level controlling the gain of audio data encoded by the encoding means. And a le control unit.

There is no difference in audio level between audio frame data before and after the audio data encoding process is temporarily stopped. For this reason, audio reproduction can be performed without a sudden change in the audio level at the time of reproduction, and without generating noise accompanying the change.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the audio level control means is coupled to the audio data encoding means, and based on the history of the second signal, First fade-out means for reducing the gain of the audio level of the audio data to a reference value during a first predetermined frame period before the frame at which the audio data encoding means stops encoding, and audio data encoding means; And fade-in means for increasing the gain of the audio level of the audio data from the reference value in a second predetermined frame period after the frame in which the audio data encoding means resumes encoding based on the history of the second signal. including.

[0013] The gain of the audio level of the audio data decreases to the reference value just before the audio data encoding process is paused, and the gain of the audio level of the audio data of the frame whose pause has been released is reduced from the reference value. To increase. For this reason, audio reproduction can be performed without a sudden change in the audio level at the time of reproduction, and without generating noise accompanying the change.

According to a third aspect of the present invention, in addition to the configuration of the second aspect, the first fade-out means includes:
A second audio signal encoding unit configured to reduce the audio level gain of the audio data to a reference value in one frame immediately before the audio data encoding unit stops encoding, based on the history of the second signal; Including fade-out means.

According to a fourth aspect of the present invention, in addition to the configuration of the second aspect, the first fade-out means includes:
The audio data encoding unit is coupled to the predetermined frame two or more frames before the frame at which the audio data encoding unit stops encoding based on the history of the second signal. A second fade-out means for reducing the gain of the audio level to a reference value according to a predetermined method, and an audio data encoding means, based on a history of the second signal,
And mute means for maintaining the gain of the audio level of the audio data of the frame after the predetermined frame and before the audio data encoding means stops encoding at the reference value.

For example, in a television program, switching from stereo sound to monaural sound is performed at the timing of switching to CM or the like. There is a device that pauses and unpauses the recording by using the voice switching as a trigger.
However, video signals and audio signals do not always correspond exactly. For this reason, if a pause operation is performed with audio switching as a trigger, in a normal audio encoding process, due to a shift between the video signal and the audio signal, the audio corresponding to the video after the pause is reproduced when the video is reproduced before the pause. In some cases, a signal is reproduced, and vice versa. However, for several frames before the pause is performed, the audio level is set to the reference value. For this reason, if this reference value is set low, an audio signal corresponding to the video after the pause will not be generated at the time of video reproduction before the pause, and the reproduction timing will not be correct when using multiple devices. Matching can be avoided.

According to a fifth aspect of the present invention, there is provided an audio processing method, comprising: a first signal for instructing an audio data encoding process for selectively taking one of a first value and a second value; The audio data is encoded in frame units based on a second signal for instructing to temporarily stop encoding processing of the audio data that selectively takes one of the third and fourth values. The audio processing method includes the steps of: delaying input audio data; and determining, based on the history of the delayed audio data and the second signal, an audio level difference of the audio data between frames before and after a period in which the audio data is not encoded. Controlling the gain of the audio data to be encoded so as to eliminate the error, and encoding or not encoding the audio data based on the delayed audio data and the history of the first and second signals. Selectively performing the operation.

There is no difference in audio level between audio frame data before and after the audio data encoding process is temporarily stopped. For this reason, audio reproduction can be performed without a sudden change in the audio level at the time of reproduction, and without generating noise accompanying the change.

According to a sixth aspect of the present invention, in addition to the configuration of the fifth aspect of the present invention, the step of controlling the gain comprises:
Reducing the gain of the audio level of the audio data to a reference value in a first predetermined frame period before a frame in which encoding of the audio data is stopped based on the delayed audio data and the history of the second signal. And increasing the gain of the audio level of the audio data from the reference value in a second predetermined frame period after the frame in which the encoding of the audio data is restarted, based on the delayed audio data and the history of the second signal. Steps.

Just before the audio data encoding process is paused, the audio level gain of the audio data decreases to the reference value, and the audio level gain of the audio data of the frame whose pause has been released is reduced from the reference value. To increase. For this reason, audio reproduction can be performed without a sudden change in the audio level at the time of reproduction, and without generating noise accompanying the change.

According to a seventh aspect of the present invention, in addition to the configuration of the sixth aspect, the step of reducing the gain to the reference value is based on the delayed audio data and the history of the second signal. And reducing the gain of the audio level of the audio data to the reference value in one frame immediately before the stop of the encoding of the audio data.

According to an eighth aspect of the present invention, in addition to the configuration of the sixth aspect, the step of reducing the gain to the reference value is based on the delayed audio data and the history of the second signal. Reducing the gain of the audio level of the audio data to a reference value according to a predetermined method for a predetermined frame two or more frames before the frame at which the encoding of the audio data is stopped; Audio data and second
Maintaining the gain of the audio level of the audio data of the frame after the predetermined frame and before the encoding of the audio data is stopped, based on the signal history of Including.

For example, in a television program, switching from stereo sound to monaural sound is performed at the timing of switching to CM or the like. There is a device that pauses and unpauses the recording by using the voice switching as a trigger.
However, video signals and audio signals do not always correspond exactly. For this reason, if a pause operation is performed with audio switching as a trigger, in a normal audio encoding process, due to a shift between the video signal and the audio signal, the audio corresponding to the video after the pause is reproduced when the video is reproduced before the pause. In some cases, a signal is reproduced, and vice versa. However, for several frames before the pause is performed, the audio level is set to the reference value. For this reason, if this reference value is set low, an audio signal corresponding to the video after the pause will not be generated at the time of video reproduction before the pause, and the reproduction timing will not be correct when using multiple devices. Matching can be avoided.

According to a ninth aspect of the present invention, there is provided a computer-readable recording medium according to the first aspect for instructing an audio data encoding process to selectively take one of a first value and a second value. On the basis of a signal and a second signal for instructing to temporarily stop encoding processing of audio data that selectively takes one of the third and fourth values.
A program for causing a computer to execute an audio processing method for encoding audio data in frame units is recorded. The audio processing method includes the steps of: delaying input audio data; and, based on the delayed audio data and the history of the second signal,
Controlling the gain of the audio data to be encoded so as to eliminate the audio level difference of the audio data in frames before and after the period in which the audio data is not encoded, and the history of the delayed audio data and the first and second signals And selectively performing either a process of encoding the audio data or a process of not encoding the audio data based on the audio data.

There is no difference in audio level between audio frame data before and after the audio data encoding process is temporarily stopped. For this reason, audio reproduction can be performed without a sudden change in the audio level at the time of reproduction, and without generating noise accompanying the change.

According to a tenth aspect of the present invention, in addition to the configuration of the ninth aspect of the present invention, the step of controlling the gain includes the step of controlling the audio data based on the delayed audio data and the history of the second signal. Reducing the gain of the audio level of the audio data to a reference value in a first predetermined frame period before the frame in which encoding of the audio data stops, and based on the history of the delayed audio data and the second signal, Increasing the gain of the audio level of the audio data from the reference value in a second predetermined frame period after the frame in which the encoding of the audio data is restarted.

[0027] The gain of the audio level of the audio data decreases to the reference value just before the audio data encoding process is paused, and the gain of the audio level of the audio data of the frame whose pause has been released is reduced from the reference value. To increase. For this reason, audio reproduction can be performed without a sudden change in the audio level at the time of reproduction, and without generating noise accompanying the change.

According to an eleventh aspect of the present invention, in addition to the configuration of the tenth aspect, the step of reducing the gain to the reference value is based on the delayed audio data and the history of the second signal. And reducing the gain of the audio level of the audio data to the reference value in one frame immediately before the stop of the encoding of the audio data.

According to a twelfth aspect of the present invention, in addition to the configuration of the tenth aspect, the step of reducing the gain to the reference value is based on the delayed audio data and the history of the second signal. Reducing the gain of the audio level of the audio data to a reference value according to a predetermined method for a predetermined frame two or more frames before the frame at which the encoding of the audio data is stopped; The gain of the audio level of the audio data of the frame after the predetermined frame and before the encoding of the audio data is stopped based on the history of the audio data and the history of the second signal. Maintaining.

For example, in a television program, switching from stereo sound to monaural sound is performed at the timing of switching to CM or the like. There is a device that pauses and unpauses the recording by using the voice switching as a trigger.
However, video signals and audio signals do not always correspond exactly. For this reason, if a pause operation is performed with audio switching as a trigger, in a normal audio encoding process, due to a shift between the video signal and the audio signal, the audio corresponding to the video after the pause is reproduced when the video is reproduced before the pause. In some cases, a signal is reproduced, and vice versa. However, for several frames before the pause is performed, the audio level is set to the reference value. For this reason, if this reference value is set low, an audio signal corresponding to the video after the pause will not be generated at the time of video reproduction before the pause, and the reproduction timing will not be correct when using multiple devices. Matching can be avoided.

[0031]

[First Embodiment] Referring to FIG. 1, an audio processing apparatus 30 according to an embodiment of the present invention will be described.
Is a two-port memory 31 in which one port is connected to an audio input pin, the other port is connected to a bus described later, and stores audio data supplied from the audio input pin. A register 32 for holding a pause instruction signal for instructing stop, and a register 33 for holding an audio encoding instruction signal for instructing audio data encoding.
And a processor 35 for performing audio encoding processing on audio data stored in the two-port memory 31, connected to the processor 35, generating an audio frame pulse, interrupting the processor 35 in response to the audio frame pulse, An audio frame pulse generator 36 for activating an audio encoding process, and audio encoded data processed by the processor 35 are stored,
FIFO (First In First Out) memory 34 for outputting from the audio processing data output pin in a first-in first-out manner
And a memory 37 for holding various parameters, and a bus for interconnecting the two-port memory 31, the register 32, the register 33, the FIFO memory 34, the processor 35, and the memory 37.

The register 32 holds 1 when the pause instruction signal is H, and holds 0 when the pause instruction signal is L. Register 33
Holds 1 when the audio encoding instruction signal is H,
When it is L, it holds 0.

Referring to FIGS. 2 and 3, each unit of audio processing device 30 operates as follows. When the processor 35 is interrupted by an audio frame pulse generated by the audio frame pulse generator 36, the processor 35 changes the audio encoding instruction signal stored in the register 33 to L (audio encoding instruction is issued. Is determined) (S2). If the audio encoding instruction has not been issued (NO in S2), the process ends. If an audio encoding instruction has been issued (YES in S2), the processor 35 increments the audio frame counter stored in the memory 37 by one (S4). It is assumed that the audio frame counter is set to -1 in the initial state.

The processor 35 determines whether the audio frame counter is 2 or more (S6). If the audio frame counter is 0 or 1 (N in S6)
O), since the audio encoding process has not been performed yet,
The process ends.

When the audio frame counter becomes 2 or more (YES in S6), the processor 35 reads one frame of audio data from the two-port memory 31 (S8). When the audio frame counter is 0 or 1, no audio data reading processing is performed, and the audio data during that time is held in the two-port memory 31. Therefore, in the process of S8, the audio data two frames before is always read, and in the subsequent audio encoding process, the audio data two frames before the currently input audio data is read. An audio encoding process is performed.

Referring to FIG. 4, processor 35 substitutes the value of pause instruction flag 1 representing the state of the pause instruction signal one frame before into the pause instruction flag 2 representing the state of the pause instruction signal two frames before. . Further, the value of the pause instruction flag 0 representing the current state of the pause instruction flag is substituted for the pause instruction flag 1. Further, the value of the pause instruction signal stored in the register 32 is substituted for the pause instruction flag 0 (S10). Pause instruction flag 0-2
Are stored in the memory 37.

The processor 35 performs the processing of S10
It is determined whether the pause instruction flag 1 has changed from 1 to 0 (S12). The frame to be subjected to the audio encoding process is delayed by two frames from the currently input frame. Therefore, the fact that the pause instruction flag 1 has changed from 1 to 0 indicates that the pause instruction signal becomes L after the frame currently being subjected to audio encoding processing, and the audio encoding processing is temporarily stopped. That is, referring to FIG. 5, when the frame currently undergoing audio encoding processing is frame A2, for example, the pause instruction signal is L in frame A3 immediately after frame A2.
Therefore, the pause instruction flag 1 changes from 1 to 0.

When the pause instruction flag 1 changes from 1 to 0 (YES in S12), the pause is performed immediately after the frame for which audio encoding is to be performed as described above. A process of gently decreasing the gain of the audio level of the frame until it reaches a reference value (for example, 0) (hereinafter, referred to as “fade-out process”) is performed (S14).

After the fade-out processing, or when the pause instruction flag 1 has not changed from 0 to 1 (NO in S12), the processor 35 determines whether or not the pause instruction flag 2 has changed from 0 to 1. (S16). The fact that the pause instruction flag 2 has changed from 0 to 1 means that the pause instruction signal corresponding to the frame immediately before the frame currently being processed is H, and the audio encoding process has been paused. The pause instruction signal corresponding to the frame to be processed becomes L, indicating that the audio encoding process is restarted from the current frame. That is, referring to FIG. 5, as an example, when the frame to be subjected to the audio encoding process is currently A5, the pause instruction signal becomes H from frame A5, and the pause is released. Therefore, the pause instruction flag 2
Changes from 0 to 1.

When the pause instruction flag 2 changes from 0 to 1 (YES in S16), the process of gradually increasing the gain of the audio level of the frame to be audio-encoded from the reference value (for example, 0) ( Hereinafter, “fade-in processing”) is performed (S18).

After the fade-in processing, or when the pause instruction flag 2 has not changed from 0 to 1 (N in S16)
O), the processor 35 determines whether or not the pause instruction flag 2 is 1 (S20).

When the pause instruction flag 2 is 1 (S2
Since the pause instruction signal for the frame currently being processed is H and the pause of the audio encoding process has been released, the audio encoding process is performed (S22). The processor 35 writes the audio-encoded data into the FIFO memory 34 (S
24). Thus, the processing for the frame currently being processed is completed. Note that the audio encoding processing is processing such as MPEG1 audio compression processing as in the related art.

Hereinafter, the audio frame pulse generator 3
Each time an audio frame pulse is generated from FIG.
And the processing shown in FIG. 3 is performed.

With reference to a specific example shown in FIG. 5, the audio level of the encoded data obtained by the audio processing device 30 will be described.

In the example of FIG. 5, at the timing when the frames A3 and A4 are input to the two-port memory 31, the pause instruction signal becomes L, and the recording is temporarily stopped. According to the above processing, frames A0, A1, A6 and A
In the process of 7, since the values of the pause instruction flags 1 and 2 have not changed and the value of the pause instruction flag 2 is 1, the audio encoding process is executed according to the normal process (S22).

In the processing of the frame A2, as described above, the pause instruction flag 1 has changed from 1 to 0 (YES in S12 of FIG. 3) and the pause instruction flag 2 is 1 (S20). YES), after performing the fade-out processing, the audio encoding processing is performed (S14, S22).

Also in the processing of frame A5, as described above, pause instruction flag 2 has changed from 0 to 1 (YES in S16 of FIG. 3), and pause instruction flag 2 is 1 (YES in S20). ), After the fade-in process is performed, the audio encoding process is performed (S
18, S22).

For this reason, the gain of the audio level in each frame is as shown in FIG. 5, for example, and the fade-out processing is performed in the frame immediately before the pause instruction is issued.
Fade-in processing is performed in the frame at the time when the pause instruction is released, and audio encoding processing is performed.
The audio encoded data thus completed is stored in the order of frames A0, A1, A2, A5, A6, and A7, and is reproduced in this order during audio reproduction. At the time of reproduction, the image fades out at the frame A2 and fades in at the frame A5. Therefore, the audio level does not change abruptly before and after the recording is temporarily stopped, and the audio can be reproduced without generating noise.

The audio processing device 30 described above
It can be realized by a computer. With reference to FIG. 6, the audio processing device 30
1, a keyboard 45 and a mouse 46 for giving instructions to the computer 41, a display 42 for displaying the results calculated by the computer 41, etc.
A magnetic tape device 43 for reading programs executed by the computer 41, a CD-ROM (Compact
Disc-Read Only Memory) Device 47 and Communication Modem 4
9 is included.

The program for the audio encoding process described with reference to FIGS. 2 and 3 includes a magnetic tape 44 or a CD-R, which is a recording medium readable by the computer 41.
Recorded on the OM 48, the magnetic tape device 43 and the CD-
Each is read by the ROM device 47. Alternatively, it is read by the communication modem 49 via the communication line.

Referring to FIG. 7, computer 41 includes a CPU (Central Processing Unit) 50 for executing a program read via magnetic tape device 43, CD-ROM device 47 or communication modem 49, and a computer. ROM (Read Only Memory) 51 for storing other programs and data necessary for the operation of 41
And a RAM (Random Access Memo) for storing the program, parameters for executing the program, calculation results, and the like.
ry) 52 and a magnetic disk 53 for storing programs, data, and the like.

The RAM 52 plays the role of a two-port memory 31, a register 32, a register 33, a FIFO memory 34, and a memory 37.
5 and an audio frame pulse generator 36.

Magnetic tape device 43, CD-ROM device 4
7 or the program read by the communication modem 49 is executed by the CPU 50 to perform audio encoding processing.

As described above, according to the audio processing apparatus 30 of the present embodiment, even when the recording is paused, the audio processing is performed by performing the fade-out process and the fade-in process before and after the pause. An encoding process can be performed. For this reason, audio reproduction can be performed without generating noise due to a rapid change in audio level during reproduction.

[Second Embodiment] The audio encoding apparatus according to the present embodiment has the same hardware configuration as the audio processing apparatus 30 according to the first embodiment described with reference to FIG. Therefore, the detailed description will not be repeated here. In the processor 35 of the present embodiment, the timing of performing the fade-out process is advanced as compared with the processor 35 of the first embodiment.

Referring to FIGS. 8 and 9, each section of audio processing apparatus 30 according to the present embodiment operates as follows. The processing from S32 to S40 shown in FIG.
Are the same as the processing from S2 to S10. Therefore, detailed description thereof will not be repeated here.

Referring to FIG. 9, the processor 35 executes the processing in S4
It is determined whether the pause instruction flag 0 has changed from 1 to 0 during the process of 0 (S42). The frame for which audio processing is to be performed is delayed by two frames from the currently input frame. Therefore, the fact that the pause instruction flag 0 has changed from 1 to 0 indicates that the pause instruction signal becomes L two frames after the frame currently being audio-encoded and the audio encoding process is temporarily stopped. That is, FIG.
, When the current frame to be subjected to the audio encoding process is A1, the pause is performed at frame A3 two frames later, and the pause instruction flag 0 changes from 1 to 0.

When the pause instruction flag 0 changes from 1 to 0 (YES in S42), the pause is started two frames after the frame currently being audio-encoded as described above. A fade-out process is performed on the frame to be tried (S4
4). This means that the fade-out processing has been performed on the frame two frames before the pause instruction signal becomes L.

After the fade-out process, or when the pause instruction flag 0 has not changed from 1 to 0 (NO in S42), the processor 35 determines whether or not the pause instruction flag 1 is 0 (S46). The fact that the pause instruction flag 1 is 0 indicates that the pause instruction signal for the frame immediately after the frame currently being processed is L. That is, referring to FIG. 10, the frame currently being subjected to audio encoding processing is frame A2.
Or in the case of A3, the pause instruction flag 1 becomes 0 because the pause processing is performed in the frame A3 or A4 immediately after each frame.

When the pause instruction flag 1 is 0 (S4
(YES in 6), a process of maintaining the gain of the audio level of the frame currently being subjected to the audio encoding process at a reference value (for example, 0) (hereinafter referred to as “mute process”) is performed (S48).

After the mute processing, or when the pause instruction flag 1 is 1 (NO in S46), S50 to S58
Are performed. The processing of S50 to S58 is the same as the processing of S16 to S24 described with reference to FIG. Therefore, the detailed description will not be repeated here.

Hereinafter, the audio frame pulse generator 3
Each time an audio frame pulse is generated from FIG.
And the processing shown in FIG. 9 is performed.

Referring to a specific example shown in FIG. 10, the audio level of the encoded data obtained by the audio processing device 30 will be described.

In the example of FIG. 10, frames A3 and A4
Is input to the two-port memory 31, the pause instruction signal becomes L, and the recording is temporarily stopped. According to the processing described above, in the processing of frames A0, A6 and A7, pause instruction flags 0 and 2 are set.
And the value of the pause instruction flag 1 is 1
And the value of the pause instruction flag 2 is 1, the audio encoding process is executed according to the normal process (S5).
6).

In the processing of the frame A1, as described above, the pause instruction flag 0 has changed from 1 to 0 (YES in S42 of FIG. 9), and the value of the pause instruction flag 2 is 1 ( After YES in S54, the fade-out process is performed, and then the audio encoding process is performed (S44, S56).

In the processing of frames A2 and A3, as described above, the value of pause instruction flag 1 is 0 (YES in S446), and the value of pause instruction flag 2 is 1 (YES in S54). After the mute processing is performed, the audio encoding processing is performed (S4).
8, S56).

Also in the processing of frame A5, the pause instruction flag 2 has changed from 0 to 1 as described above (YES in S50 of FIG. 9), and the pause instruction flag 2 is 1 (YES in S54). ), After the fade-in process is performed, the audio encoding process is performed (S
52, S58).

Therefore, the gain of the audio level in each frame is as shown in FIG. 10, for example. The fade-out process is performed in the frame two frames before the pause instruction is performed, and the frame at the time when the pause instruction is released is set. A fade-in process is performed, and a mute process is performed in a frame during the fade-in process. After that, an audio encoding process is performed. The audio encoded data thus completed includes frames A0, A1, A2,
A5, A6, and A7 are stored in this order, and are reproduced in this order during audio reproduction. At the time of reproduction, the image fades out at the frame A1, the audio level becomes 0 at the frame A2, and then fades at the frame A5. For this reason,
A sudden change in the sound level does not occur before and after the pause during recording, and the sound can be reproduced without generating noise.

In particular, in a television program, commercials (Commercial
Message) or the like, switching from stereo sound to monaural sound is performed. Then, it is possible to perform recording pause and pause release by using the voice switching as a trigger. However, video signals and audio signals do not always correspond exactly. For this reason, if a pause operation is performed with audio switching as a trigger, in a normal audio encoding process, due to a shift between the video signal and the audio signal, the audio corresponding to the video after the pause is reproduced when the video is reproduced before the pause. In some cases, a signal is reproduced, and vice versa. In audio processing apparatus 30 according to the present embodiment, fade-out processing is performed two frames before the frame in which the pause instruction signal is L, and mute processing is performed one frame before. Therefore, an audio signal corresponding to the video after the pause is not generated at the time of reproducing the video before the pause, and it is possible to avoid a mismatch in the reproduction timing when a plurality of devices are used.

The audio processing device 30 described above
It can be realized by a computer. The method of realizing the audio processing device 30 by the computer is the same as the method of realizing the first embodiment described with reference to FIGS. Therefore, the detailed description will not be repeated here.

In the audio processing apparatus 30, the fade-out processing is performed in the frame two frames before the frame in which the pause instruction signal is L. However, the fade-out processing is performed in the frame three or more frames before, and the mute processing is performed in the subsequent frame. May be performed.

As described above, according to the audio processing apparatus 30 according to the present embodiment, audio can be reproduced without generating noise due to a sudden change in the audio level when reproducing the audio signal. . Further, even when a plurality of devices are synchronized to perform the audio encoding process, it is possible to avoid a mismatch in reproduction timing between the plurality of devices.

The embodiments disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0074]

According to the invention described in claims 1 to 12,
Audio reproduction can be performed without a sudden change in audio level at the time of reproduction and without accompanying noise.

According to the fourth, eighth and twelfth aspects of the present invention, it is possible to avoid a mismatch in reproduction timing when a plurality of devices are used.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an audio processing device according to Embodiments 1 and 2 of the present invention.

FIG. 2 is a flowchart of an audio encoding process according to Embodiment 1.

FIG. 3 is a flowchart of an audio encoding process according to Embodiment 1.

FIG. 4 is a diagram for explaining a process of updating the value of a pause instruction flag.

FIG. 5 is a diagram for describing an audio level after audio encoding processing according to Embodiment 1.

FIG. 6 is an external view of a computer that realizes the audio processing device.

FIG. 7 is an internal block diagram of a computer that realizes the audio processing device.

FIG. 8 is a flowchart of an audio encoding process according to Embodiment 2.

FIG. 9 is a flowchart of an audio encoding process according to Embodiment 2.

FIG. 10 is a diagram for describing an audio level after audio encoding processing according to Embodiment 2.

FIG. 11 is a diagram illustrating a conventional audio encoding process.

[Explanation of symbols]

30 audio processing unit, 31 two-port memory, 3
2, 33 registers, 34 FIFO memory, 35 processor, 36 audio frame pulse generator, 3
7 Memory.

Claims (12)

[Claims] 1. A first signal for instructing an encoding process of audio data that selectively takes one of a first value and a second value, and one of a third value and a fourth value. An audio processing apparatus for encoding audio data on a frame basis based on a second signal for instructing a temporary stop of encoding processing of audio data to be selectively taken. A memory having a first port and a second port from which audio data is output; connected to the memory, and when audio data is input to the memory, the audio data is read from the memory with a delay, Based on the histories of the first and second signals, selectively execute either a process of encoding audio data or a process of not encoding audio data. Audio data encoding means, coupled to the audio data encoding means, and based on the history of the second signal, the audio data encoding means performs audio encoding in frames before and after a period during which the audio data encoding means does not encode audio data. An audio level control means for controlling a gain of audio data encoded by the audio data encoding means so as to eliminate an audio level difference of data. 2. The audio level control means is coupled to the audio data encoding means,
First fade-out means for reducing the gain of the audio level of the audio data to a reference value in a first predetermined frame period before the frame at which the audio data encoding means stops encoding, based on the signal history of The audio data encoding means, and the second
Fade-in means for increasing the gain of the audio level of the audio data from the reference value in a second predetermined frame period after the frame in which the audio data encoding means resumes encoding based on the signal history of The audio processing device according to claim 1. 3. The first fade-out means is coupled to the audio data encoding means, and one frame immediately before the audio data encoding means stops encoding based on a history of the second signal. 3. The audio processing apparatus according to claim 2, further comprising a second fade-out means for reducing the gain of the audio level of the audio data to a reference value. 4. The first fade-out means is coupled to the audio data encoding means, and the second fade-out means is
The gain of the audio level of the audio data is determined for a predetermined frame two or more frames before the frame at which the audio data encoding unit stops encoding based on the signal history of A second fade-out means for reducing to the reference value in accordance with
Based on the signal history, the gain of the audio level of the audio data of the frame after the predetermined frame and before the audio data encoding unit stops encoding is set to the reference value. 3. The audio processing device according to claim 2, further comprising: a mute means for maintaining the audio processing value. 5. A first signal for instructing an encoding process of audio data that selectively takes one of a first value and a second value, and one of a third value and a fourth value. An audio processing method for encoding audio data on a frame basis based on a second signal for instructing a temporary stop of encoding processing of audio data to be selectively taken, wherein the input audio data is delayed. And a gain of the audio data that is encoded based on the delayed audio data and the history of the second signal so as to eliminate an audio level difference of the audio data in frames before and after a period in which the audio data is not encoded. Controlling the audio data based on the delayed audio data and the history of the first and second signals. Selectively performing either a process of encoding data or a process of not encoding data. 6. The method according to claim 6, wherein the step of controlling the gain includes, based on the delayed audio data and the history of the second signal, in a first predetermined frame period before a frame in which encoding of the audio data is stopped. Reducing the gain of the audio level of the audio data to a reference value; and a second predetermined frame after a frame in which encoding of the audio data is restarted based on the delayed audio data and the history of the second signal. The audio processing method according to claim 5, further comprising: increasing a gain of the audio level of the audio data from the reference value during a period. 7. The step of reducing the gain to a reference value includes, based on the delayed audio data and the history of the second signal, the audio data of the audio data in one frame immediately before the stop of the encoding of the audio data. 7. The audio processing method according to claim 6, comprising reducing a level gain to a reference value. 8. The step of reducing the gain to a reference value, comprising the step of: performing, on the basis of the delayed audio data and the history of the second signal, at least two frames before a frame at which encoding of the audio data is stopped. Reducing the gain of the audio level of the audio data to the reference value in accordance with a predetermined method for a predetermined frame; based on the delayed audio data and the history of the second signal, Maintaining the audio level gain of the audio data of the frame after the predetermined frame and before the encoding of the audio data is stopped at the reference value.
An audio processing method according to claim 1. 9. A first signal for instructing audio data encoding processing to selectively take one of the first and second values, and one of the third and fourth values. A program for causing a computer to execute an audio processing method for encoding audio data on a frame basis based on a second signal for instructing a temporary stop of encoding processing of audio data to be selectively taken is recorded. A computer-readable recording medium, comprising: a step of delaying input audio data; and wherein audio data is not encoded based on the delayed audio data and the history of the second signal. Gain of audio data that is encoded to eliminate the difference in audio level of audio data in frames before and after the period And selectively performing either a process of encoding the audio data or a process of not encoding based on the delayed audio data and the history of the first and second signals. And a computer-readable recording medium. 10. The step of controlling a gain, the step of: controlling a gain in a first predetermined frame period before a frame in which encoding of audio data is stopped based on a history of delayed audio data and a history of the second signal. Reducing the gain of the audio level of the audio data to a reference value; and a second predetermined frame after a frame in which encoding of the audio data is restarted based on the delayed audio data and the history of the second signal. Increasing the gain of the audio level of the audio data from the reference value during a period. 11. The step of reducing a gain to a reference value comprises the steps of:
Reducing the gain of the audio level of the audio data to a reference value in one frame immediately before the encoding of the audio data is stopped based on the signal history of
A computer-readable recording medium according to claim 10. 12. The step of reducing the gain to a reference value includes the step of, based on the delayed audio data and the history of the second signal, setting a gain at least two frames before a frame at which encoding of audio data is stopped. Reducing the gain of the audio level of the audio data to the reference value in accordance with a predetermined method for a predetermined frame; based on the delayed audio data and the history of the second signal, Maintaining the gain of the audio level of the audio data of the frame after the predetermined frame and before the encoding of the audio data is stopped at the reference value.
0. The computer-readable recording medium according to 0.