KR20060128212A - Apparatus and method for playback speed altering with preservation of tone signal - Google Patents

Abstract

An apparatus and a method for varying a reproducing speed are provided to actively vary the reproducing speed of a meaning signal without deterioration of tone and sound quality by considering the density variation of sound. A file storage unit(110) stores a compressed sound file. A file buffer(120) buffers the compressed sound file. A reproducing speeder(160) stores the sound file and creates reproducing speed information according to a request of a user. A decoder(130) converts the sound file into PCM(Pulse Code Modulation) data. A data buffer(140) buffers the PCM data transmitted from the file buffer(120). A PCM data processor(170) searches for a meaningless voice section in the PCM data, and then controls the reproducing speed according to the reproducing speed information. A codec(150) converts the PCM data transmitted from the PCM data processor(170) into a voice analog signal.

Description

Apparatus and method for playback speed altering with preservation of tone signal}

1 is a block diagram of an MP3 player according to the prior art;

2 is a block diagram of a reproducing rate variable device for preserving a voice signal according to an embodiment of the present invention;

FIG. 3 is a detailed block diagram of a playback speed controller of the playback speed variable device for retaining the audio signal of FIG.

FIG. 4 is a detailed block diagram of a PCM data processor of the apparatus for variable playing speed storing the audio signal of FIG. 2; FIG.

5 is a flowchart illustrating a method of changing a reproduction speed for preserving a voice signal according to an embodiment of the present invention.

The present invention relates to a reproducing rate variable device and method for preserving a voice signal, and more particularly to a voice signal that actively varies the reproducing speed of a meaningful signal without deterioration of timbre and sound quality by using a change in density of the voice. The present invention relates to a variable speed regenerative apparatus and method.

In general, slowing the speed of speech can increase the interval between brain thinking after hearing recognition, thereby improving the ability of humans to recognize voice information. However, simply delaying the playback time to improve the speech information recognition deteriorates the speech and degrades the speech information recognition.

Conventionally, a method of increasing or decreasing a voice reproduction time mainly uses a method of compensating for degradation by using a voice nonlinear filter after changing the reproduction speed of a voice and changing the reproduction speed. 1 is a block diagram of an original sound reproduction block of an MP3 player according to the prior art.

The conventional method of increasing or decreasing the voice reproduction time has to use a voice nonlinear filter and has a problem of designing a voice nonlinear filter according to voice frequency characteristics.

The present invention was devised to solve the above-described problems, and the play speed variable for preserving the voice signal to adjust the voice play speed without degrading the meaningful voice by actively changing the speed in the voice section having a low meaning Its purpose is to provide an apparatus and method.

Other objects and advantages of the invention will be described below and will be appreciated by the embodiments of the invention. Furthermore, the objects and advantages of the present invention can be realized by means and combinations indicated in the claims.

According to an aspect of the present invention, a file storage unit for storing a compressed sound file, a file buffer for buffering a sound file of the file storage unit, a sound file information of the file buffer, and a playback speed of a user are stored. A reproduction speed adjusting unit for generating reproduction rate information on demand, a decoder for converting a sound file transmitted from the file buffer into PCM data, a data buffer for buffering PCM data transmitted from the decoder, and a PCM transmitted from the data buffer And a codec for converting PCM data transferred from the PCM data processor to a voice analog signal by finding a section in which data is absent from the data and adjusting a playback speed according to the reproduction speed information.

Here, the file storage unit stores at least one sound file of an MP3 file, a Windows Media Audio (WMA) file, and an OGG Vorbis (OGG) file, and the decoder stores the sound file stored in the file storage unit. Preferably, the decoder is at least one of an MP3 decoder, a Windows Media Audio decoder, and an Ogg Vorbis decoder.

The playback speed controller may further include a header data analyzer configured to store sound file information of the file buffer, a playback speed generator configured to set playback speed information of a sound file of the file buffer currently driven according to a playback speed request of the user, and the playback A PCM data controller controlling the PCM data processing unit to play the sound file according to the speed information, and an operation state controller controlling the playback speed generator to set the playback speed information according to the detected playback speed request of the user. .

The reproduction speed controller may further include an operation state indicator for displaying operation state information of the sound file of the file buffer.

The PCM data processor may also set a voice filter for attenuating sound signals excluding voices from the PCM data transmitted from the data buffer, a criterion for finding a sounded section and a silent section from the PCM data, and setting silent section information according to the set criteria. And a PCM data enhancer for adding silent data to the silent section according to the playback speed information, and a PCM data reducer to remove silent data according to the playback speed information to the silent section.

In another aspect, the present invention provides a method for adjusting a reproduction speed using sound reproduction information separated from a sound file, the threshold sound pressure setting step of setting a reference sound pressure for determining a variable speed range of the sound file, the reference sound pressure A variable region setting step of setting a predetermined range section from the variable region to a playback speed setting step of setting playback speed control information at a section ratio outside the variable region and the variable region; receiving a playback rate ratio from a user; Playing a sound file according to the play speed ratio using the speed control information.

Here, in the threshold reproducing sound pressure setting step, the reference sound pressure may be set after reproducing a portion of the sound file to attenuate signals other than voice.

The threshold reproducing sound pressure setting step may be a reference sound pressure value of a sample sound pressure obtained by sampling a portion of the sound file four or more times in a time interval of 24/1000 seconds or more.

In the variable region setting step, the predetermined range may be a sound pressure section of 170% or less and a sound pressure section of + 40% or more with respect to the reference sound pressure.

In the sound file reproducing step, the sound file may be reproduced at the speed ratio input by the user according to the following equation in the variable region.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

2 is a block diagram of a reproducing speed variable device for preserving a voice signal according to an embodiment of the present invention. As shown, the apparatus for varying playback speed according to an embodiment of the present invention includes a file storage unit 110, a file buffer 120, a decoder 130, a data buffer 140, a codec 150, and a playback speed controller. 160 and the PCM data processing unit 170.

The variable playback speed apparatus according to an embodiment of the present invention may be used as a part for performing a variable playback speed function of an original sound playback apparatus, for example, an MP3 player, and may be implemented by a combination of hardware and software.

The file storage unit 110 stores a sound file. The sound file is preferably a compressed sound file such as an MP3 (MPEG Audio Layer 3) file, a WMA (Windows Media Audio) file, an OGG (Ogg Vorbis) file, and the like.

The decoder 130 converts the sound file stored in the file storage unit 120 into PCM data. Decoder 130 may be one or more, it is preferably provided for each type of sound file. For example, the decoder 130 may be an MP3 decoder, a WMA decoder or an OGG decoder.

The codec 150 receives the PCM data decoded by the decoder 130 through the PCM data processor 170 and converts the PCM data into a voice analog signal. The codec 150 may be connected to an earphone 180 for converting a voice analog signal into a sound.

The file buffer 120 is inserted between the file storage unit 110 and the decoder 130, and the data buffer 140 is inserted between the decoder 130 and the codec 150.

The playback speed controller 160 stores information of a file to be driven, provides an operation state of a file currently being driven, and generates playback speed information according to a user's playback speed adjustment request. In addition, the playback speed controller 160 controls and drives the PCM data processor 170.

The PCM data processor 170 is driven by the control of the playback speed controller 160 and attenuates a sound signal except for voice by searching for a section without voice in the PCM data received from the data buffer 140. The reproduction speed of the section in which there is no voice is varied according to the reproduction speed information.

In the playback speed adjusting apparatus for preserving the voice signal according to an embodiment of the present invention, the playback speed adjusting unit 160 uses the sound file information of the file buffer 120, but does not modify the sound file, thereby compressing the compressed file. It has no effect on restoration.

If the PCM data processor 170 does not adjust the playback speed, the PCM data processor 170 may transfer the compressed file to the codec 150 without processing the PCM data in the data buffer 140, thereby operating the compressed file in a conventional MP3 player method. Will be.

FIG. 3 is a detailed block diagram of a playback speed controller of the playback speed variable device for storing the audio signal of FIG. As shown, the playback speed controller 160 includes a header data analyzer 162, an operation status indicator 164, a playback speed generator 166, a PCM data controller 168, and an operation status controller 167. .

The header data analyzer 162 stores file information to be currently driven. The file information includes file type, version, sample rate, samples per channel, packed information, required bits, and free format. (free format), etc. The file information may store additional information according to the file type.

The operation status indicator 164 holds information on the operation status of the file currently being driven and displays progress time, error status, etc. in the form of text and icons.

Here, the error state may be used as detailed information according to the state in the operation state controller 167. Error conditions include broken frames, data overflow, unsupported layers, forbidden bit rates, and wrong MPEG builds in MP3. WMA includes a bad asf header, a bad packet header, a bad weighting mode, a bad packet, and the like.

The playback speed generator 166 determines a playback speed of a file currently being operated according to a playback speed adjustment request of the user. In other words, if the voice rate is high in the currently running file, the playback speed is controlled by a variable playback speed that preserves the voice signal.If the current file has few voice signals, the playback speed is increased by increasing the playback speed itself. Set an adjustment ratio.

The PCM data controller 168 controls the PCM data processor 170. That is, the setting of the voice filter 172 and the driving of the volume meter 174 are controlled. In addition, the PCM data controller 168 controls the PCM data processor 170 to add or reduce silent data necessary to adjust the playback speed while preserving the voice signal according to the playback rate ratio generated by the playback speed generator 166. Can be.

The reproduction speed variable method of preserving the audio signal refers to a method of adding silence to a portion in which there is no audio signal. In this case, since the length of each word constituting the sentence of the sound file is different and the silent section between the words is not constant, portions without the voice signal appear irregularly. Therefore, it is preferable to add or reduce the silence according to the shape of the voice signal. .

The operation state controller 167 drives the components of the reproduction speed controller 160, that is, the header data analyzer 162, the operation state indicator 164, the reproduction speed generator 166, and the PCM data regulator 168. To perform the function.

The operation state controller 167 is driven when a timer interrupt of a preset original sound reproduction device is generated or when a management program of the original sound reproduction device reads a new file. Here, the management program may be a program that performs music playback, a function of displaying MP3 information on the LCD, a menu function, a keyboard input function, and the like in an original sound reproducing apparatus such as an MP3 player.

When the timer interrupt occurs, the operation state controller 167 checks whether there is a change in the operation state indicator 164, and if there is a change, notifies the operation state indicator 164 according to the change.

In addition, the operation state controller 164 controls the playback speed generator 166 to generate a new playback speed according to the changed playback speed if the changed content changes the playback speed. Then, the changed contents are notified to the PCM data controller 170 to drive the PCM data controller 170.

On the other hand, if there is no change in the operation state indicator 164, the operation state controller 167 ends the operation and returns control to the process performed just before the interrupt is generated.

FIG. 4 is a detailed block diagram of the PCM data processing unit of the reproduction speed variable device for storing the audio signal shown in FIG. As illustrated, the PCM data processor 170 includes a voice filter 172, a volume meter 174, a PCM data enhancer 176, and a PCM data reducer 177.

The voice filter 172 receives PCM data from the data buffer 120 and attenuates sound signals except voice. This is because if there is a sound signal other than voice in the PCM buffer 178, the section without voice cannot be found.

Two or more voice filters 172 may be provided, and it is preferable to use a male and a female separately. The reason why the male and the female can be distinguished by the voice alone is that the tone of the male and the female is different. When the voice filter 172 is applied by dividing the male and female, the attenuation precision for the sound other than the voice can be improved. .

The volume measurer 174 sets a criterion for finding a section with speech and a section without speech in the PCM buffer 178, and generates information about a section without speech according to the set criterion.

The PCM data enhancer 176 slows down the playback speed while preserving the audio signal. Using the section information without speech provided by the acoustic analyzer 174, silent data is added to the section without speech at a time interval determined by the reproduction speed generator 166.

The PCM data reducer 177 functions to speed up the playback speed while preserving the audio signal. The silent data is removed at a time interval determined by the reproduction speed generator 166 in a section in which there is no voice provided by the acoustic analyzer 174.

5 is a flowchart illustrating a method of changing a reproduction speed for preserving a voice signal according to an embodiment of the present invention. As shown, the regeneration speed adjusting method according to an embodiment of the present invention includes the step of setting the critical reproducing sound pressure step (S100), the variable region setting step (S200), the reproducing speed setting step (S300), and the speed ratio (S400). And the regeneration step (S500) according to the speed ratio.

According to an embodiment of the present invention, a method of changing a reproduction speed for preserving a voice signal may separately store and store digitally sampled and compressed sounds into sound and sound reproduction information, and reproduce the sound using the sound reproduction information.

First, the threshold reproducing sound pressure setting step S100 sets a threshold reproducing sound pressure Tp which is a reference for determining a sound source reproducing speed adjusting section.

In this step, the reproduction speed generator 166 reproduces the sound recorded for a short time or a sound that the user cannot detect and passes the voice filter 172. A voice signal in which a signal other than voice is attenuated is extracted through the voice filter 172, and the extracted voice signal sets a threshold reproducing sound pressure Tp to distinguish between silent and sound using the volume meter 174.

For example, the threshold reproducing sound pressure may set the threshold sound pressure as an adjacent sample value by inspecting the recorded sound four times in a time interval of 24/1000 sec or more.

In the variable region setting step (S200), the reproduction speed generator 166 sets a range of a predetermined range as the active variable region based on the critical reproduction sound pressure.

Here, the predetermined range may be, for example, a sound pressure of -70% or less and a sound pressure section of + 40% or more with respect to the set threshold reproducing sound pressure. This is represented by Equation 1 below.

(Tp-0.7Tp)> Variable Area> (Tp + 0.4Tp))

In the regeneration speed setting step S300, the reproducing speed generator 166 sets the variable area set in the variable area setting step S200 as a reproducing speed control section, and regenerates at a period outside the variable area and at an interval ratio within the variable area. Set the adjustment information. Here, the playback speed control information is information that can be adjusted by the user according to the playback speed to be changed.

In step S400 of receiving the speed ratio, the operation state controller 167 receives a speed ratio to increase or decrease the sound from the user.

In the reproducing step (S500) according to the speed ratio, the PCM data controller 168 reproduces the sound using the sound reproduction information, the reproduction speed adjustment information, and the speed ratio input by the user.

In this step, if the playback speed is slowed down, the PCM data enhancer 176 is controlled according to the playback speed adjustment information to add silence to a section lower than the threshold value, and if the playback speed is increased, the PCM is controlled according to the playback speed adjustment information. The data reducer 177 is controlled to reduce the period lower than the threshold value and transmit the reduced data to the codec 150.

For example, in the variable region, that is, the region out of the range of the critical reproduction sound pressure, sound may be reproduced according to the speed ratio input by the user as shown in Equation 2 below.

In Equation 2, X is a silent ratio added or deleted in the silent section to adjust the playback speed. Equation (2) indicates that when a silent section is found in reproducing sound, only a section having less meaning in the voice can be actively changed by adding or deleting a silent section multiplied by X to the silent section.

Therefore, the reproduction speed adjusting method for preserving the voice signal of the present invention enables the user to reproduce the original sound at a desired speed without degrading the meaningful voice.

As mentioned above, although this invention was demonstrated by the limited embodiment and drawing, this invention is not limited by this, The person of ordinary skill in the art to which this invention belongs, Of course, various modifications and variations are possible within the scope of equivalent claims.

As described above, the apparatus and method for changing a playback speed for preserving a voice signal of the present invention do not use a voice nonlinear filter for compensating for voice degradation by actively changing the speed of a voice section having a low meaning to adjust the voice playback speed. It is possible to adjust the voice playback speed without degrading the meaningful voice even without it.

Claims (10)

A file storage unit for storing the compressed sound file; A file buffer for buffering a sound file of the file storage unit; A reproduction speed adjusting unit which stores sound file information of the file buffer and generates reproduction rate information according to a reproduction rate request of a user; A decoder for converting a sound file transferred from the file buffer into PCM data; A data buffer for buffering the PCM data delivered from the decoder; A PCM data processor for finding a section in which the voice is absent from the PCM data transferred from the data buffer and adjusting a playback speed according to the playback speed information; And Codec for converting PCM data transmitted from the PCM data processing unit into a voice analog signal A playback speed variable device for preserving a voice signal comprising a. The method of claim 1, The file storage unit stores at least one sound file of an MP3 (MP3) file, a Windows Media Audio (WMA) file, and an OGG Vorbis (OGG) file, The decoder is an decoder of at least one of an MP3 decoder, a Windows Media Audio decoder, an Ogg Vorbis decoder, which decodes a sound file stored in the file storage unit. Variable playback speed to preserve the audio signal. The method of claim 1, The playback speed adjusting unit A header data analyzer for storing sound file information of the file buffer; A reproduction speed generator for setting reproduction rate information of a sound file of the file buffer currently being driven according to a reproduction rate request of a user; A PCM data controller controlling the PCM data processor to play the sound file according to the play speed information; An operation state controller for controlling the playback speed generator to set playback speed information according to a detected playback speed request of the user; Variable playback speed to preserve the audio signal. The method of claim 1, The playback speed adjusting unit An operation state indicator for displaying operation state information of the sound file of the file buffer; Variable playback speed to preserve the audio signal. The method of claim 1, The PCM data processing unit A voice filter for attenuating sound signals excluding voices from the PCM data transferred from the data buffer; A volume meter configured to set a criterion for finding a sounded section and a silent section from the PCM data and to generate silent section information according to the set criteria; A PCM data enhancer for adding silent data to the silent section according to the reproduction speed information; And A PCM data reducer for removing silent data in the silent section according to the reproduction speed information; Variable playback speed to preserve the audio signal. In the playback speed adjustment method of playing a sound using sound playback information separated from a sound file, A threshold reproducing sound pressure setting step of setting a reference sound pressure defining a reproducing speed variable region of the sound file; A variable region setting step of setting a predetermined range section to the variable region from the reference sound pressure; A playback speed setting step of setting playback speed control information at intervals outside the variable area and the variable area; Receiving a play rate ratio from a user; Playing a sound file according to the play speed ratio using the play speed control information; A reproduction speed variable method for preserving an audio signal comprising a. The method of claim 6, The threshold regeneration sound pressure setting step Reproducing a portion of the sound file to attenuate signals other than speech and setting the reference sound pressure Playback speed variable method to preserve the audio signal. The method of claim 7, wherein The threshold regeneration sound pressure setting step The reference sound pressure value is a sample sound pressure value obtained by sampling a portion of the sound file at least four times in a time interval of 24/1000 seconds or more. Variable playback speed for preserving audio signals. The method of claim 8, The variable region setting step The predetermined range section is a sound pressure section of less than 170% and a sound pressure section of more than + 40% with respect to the reference sound pressure Variable playback speed for preserving audio signals. The method of claim 6, The sound file playback step Playing the sound file at the speed ratio input by the user according to the following equation in the variable region:

Variable playback speed for preserving audio signals.

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