KR100483346B1 - System and Method for Ordering Goods Using Mobile Terminal - Google Patents

Abstract

The present invention relates to a method for generating an audio signal compressed file and a method for reproducing an audio signal compressed file, wherein the method for generating an audio signal compressed file according to the present invention comprises: (a) encoding a signal at a normal speed; (B) encoding the signal at the converted rate; And interleaving (c) the audio signal compressed data encoded at the normal speed of step (a) and the audio signal compressed data encoded at the converted speed of step (b). According to the present invention, it is possible to convert and reproduce the speed without changing the timbre, and there is an advantage that the normal speed reproduction and the speed conversion reproduction can be switched in real time because the data are interleaved for each frame.

Description

How to create an audio signal compressed file with speed conversion playback and file playback {System and Method for Ordering Goods Using Mobile Terminal}

The present invention relates to a method for generating an audio signal compressed file and a method for reproducing an MP3 file. The present invention relates to a frame data encoded at a normal speed and a frame data encoded at a converted speed. It is about how to play it.

1 is a flowchart illustrating a flow of a method of decoding a conventional MP3 file.

As shown in FIG. 1, first, an MP3 file stored in a memory is read (S100).

After reading the MP3 file, the frame synchronization information is retrieved (S102), and the header information of the frame is decoded (S104). The header information of the frame includes sampling frequency information, bit rate information and channel information.

If there is no error as a result of the header decoding, the frame is decoded (S108). If there is an error, the process returns to the step of searching for synchronization of the next frame (S102).

If there is no error as a result of the frame decoding, PCM data of the decoded frame is output (S112). If there is an error, the process returns to the step of searching for synchronization of the next frame (S102).

The above steps are repeated until the end of the MP3 file is reached.

The reproduction speed of the MP3 reproduced by the method as described above is determined by the transmission rate of data that sends digital sound source data to the D / A converter, and this rate is the same as the sampling frequency used when sampling the MP3 file.

Conventionally, in order to change the reproduction speed, the frequency at which sound source data is sent from the D / A converter is adjusted. In other words, if the frequency is higher than the frequency determined by the sampling frequency, the playback speed is faster, and if it is lower, the playback speed is slow.

In this case, the speed is variable and reproduced, but at the same time the frequency is also variable, causing the timbre to be severely changed. This is a phenomenon similar to the modulation of sound that appears when the tape is rotated quickly or slowly on the cassette tape.

Therefore, in order to prevent such a phenomenon, a method of slowing down the playback speed by calculating the natural frequency of the timbre and repeating the frequency to increase the data has been used, but this method has a large amount of calculation, which is not practically possible to process in real time. there was.

In order to solve the problems of the prior art as described above, an object of the present invention is to propose a method of generating an audio signal compressed file that can be reproduced by changing the speed without changing the timbre.

Another object of the present invention is to propose a method of generating an audio signal compression file including data encoded at a normal rate and data encoded at a converted rate.

Another object of the present invention is to propose a method for reproducing an audio signal compressed file that can reproduce an MP3 file including data encoded at a normal speed and data encoded at a converted speed, at a speed requested by a user.

In order to achieve the above object, the present invention provides a method for generating an audio signal compressed file that can be reproduced by varying the speed, comprising the steps of: (a) encoding a signal at a normal speed; (B) encoding the signal at the converted rate; And interleaving (c) the audio signal compressed data encoded at the normal speed of step (a) and the audio signal compressed data encoded at the converted speed of step (b).

The present invention may further include matching the audio signal compressed data encoded at the normal speed of the step (a) with the frame data bytes of the audio signal compressed data encoded at the converted speed of the step (b). .

When the speed converted in step (b) is a low speed, the interleaving step of (c) may include: determining a plurality of low-speed encoded frames corresponding to the frames encoded at the normal speed in step (a); And interleaving the corresponding plurality of low-speed encoded frames before or after the frame encoded at the normal speed.

When the speed converted in the step (b) is a high speed, the interleaving step of the step (c) is a step of determining a plurality of frames encoded at a normal speed corresponding to the frame encoded at a high speed in the step (b) ; And interleaving the frames encoded at the corresponding plurality of normal speeds before or after the frames encoded at the high speeds.

The present invention may further include inserting header information indicating whether each frame is encoded at a normal speed or a frame encoded at a converted speed when encoding in the above steps (a) and (b). Can be.

Encoding the signal at the converted speed of step (b) comprises: analyzing the pattern of the normal speed signal in the frequency domain when the converted speed is low; Converting the signal to repeat the analyzed pattern by a slow rate; The method may include encoding the converted signal.

Encoding the signal at the converted speed of step (b) comprises: analyzing the pattern of the normal speed signal in the frequency domain when the converted speed is low; Converting the signal to reduce the number of repetitions of the analyzed pattern by a high rate; The method may include encoding the converted signal.

On the other hand, the present invention provides a method for reproducing an audio signal compressed file having a frame encoded at a normal speed and a frame encoded with a converted speed, the method comprising: reading an audio signal compressed file (a); (B) setting a frame skip number to match the playback speed selected by the user; (C) skipping the frame according to the frame skip number set in the step (b), and decoding the frame corresponding to the playback speed selected by the user; Resetting the frame skip number to match the playback speed selected by the user (d); And repeating steps (a) to (d) to the end of the audio signal compressed file.

On the other hand, the present invention provides a method for reproducing an audio signal compressed file having a frame encoded at a normal speed and a frame encoded with a converted speed, the method comprising: reading an audio signal compressed file (a); Analyzing the header information of the frame and decoding the frame if the frame is a frame suitable for the playback rate requested by the user, and skipping the frame if the frame is not suitable for the frame rate requested by the user. .

In addition, the present invention provides an apparatus for reproducing an audio signal compressed file in which a frame encoded at a normal rate and a frame at which a rate is converted and encoded are present, comprising: a memory in which the audio signal compressed file is stored; A file reading unit for reading an audio signal compressed file from the memory; A decoder for receiving and decoding frame data of an audio signal compression file from the file reading unit; A rate conversion control unit providing a frame transmission control signal to the file reading unit to decode a frame corresponding to a playback rate requested by a user when transmitting the frame from the file reading unit to the decoder; And a D / A converter for converting an output signal of the decoder into an analog signal.

The rate conversion control unit may provide a frame transmission control signal including frame skip number information to the frame reading unit.

The rate conversion controller may provide a frame transmission control signal for analyzing the header information of the frame data read from the file reading unit to transmit only the frame corresponding to the playback speed selected by the user to the decoder lock.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the audio signal compression file generation method and audio signal compression file reproduction method capable of speed conversion reproduction according to the present invention.

The present invention can be applied to all files that compress and store an audio signal, but for the convenience of description, an MP3 file will be described as an example.

2 is a diagram illustrating an MP3 data format structure for low speed playback at 1/2 times according to an embodiment of the present invention.

As shown in FIG. 2, the MP3 data according to the preferred embodiment of the present invention has a form in which the frame 200 encoded at a constant speed and the frames 202 and 204 encoded at a half speed are interleaved. It is a repeating structure. The above data structure can be created by preliminarily converting the data converted at the normal speed and the data converted at the 1 / 2x speed into the MP3 format, and then interleaving them at the ratio of the frame rates of the two files.

In FIG. 2, only the data structure in the case of reproduction at 1 / 2x speed is shown, but the present invention is not limited to the MP3 data structure in reproduction at 1 / 2x speed. It will be apparent to those skilled in the art that they belong to the category of categories.

In FIG. 2, the MP3 data included in one constant speed frame 202 is the same as the MP3 data included in two 1 / 2x frames 202 and 204. That is, the attributes of the signal output when the fixed frame 200 is reproduced and the signal output when the two 1 / 2x frames 202 and 204 are reproduced are the same, and the reproduction time is twice that of the constant frame. It is growing.

Since the two 1 / 2x frames 202 and 204 corresponding to the constant frame 200 are encoded data so that the playback time is doubled while maintaining the frequency property of the original signal, the tone is not changed even when the playback is performed.

Therefore, when the MP3 data is formed as shown in FIG. 2, the amount of data is increased, but the tone can be reproduced at low speed without changing the tone, which can be effectively utilized for language learning requiring low speed reproduction.

To form MP3 data to be reproduced at 1 / 3x speed, the MP3 data will be configured in such a way that three 1 / 3x frames are interleaved after one constant frame.

3 is a diagram illustrating an MP3 data format structure for accelerated reproduction at double speed according to an embodiment of the present invention.

As shown in FIG. 3, MP3 data for double speed playback according to an exemplary embodiment of the present invention repeats a form in which one double speed frame 304 is interleaved in two normal speed frames 300 and 302. It is a structure. As in the case of FIG. 2, the above data structure may be made by pre-creating the data converted at the normal speed and the data converted at the double speed, making the MP3 format, and interleaving at the ratio of the frame rates of the two files. .

Although FIG. 3 illustrates the MP3 data format accelerated and reproduced at 2X speed, it will be apparent to those skilled in the art that the MP3 data format accelerated and reproduced at 3X or 4X speed, not 2X, also belongs to the scope of the present invention.

Since the double speed frame 304 corresponding to the two constant frames 300 and 302 is data obtained by reducing the playback time to 1/2 while maintaining the property of the normal speed signal, the speed is variable but the tone is not changed.

4 is a flowchart illustrating a flow of a method of generating MP3 data for speed conversion reproduction according to a preferred embodiment of the present invention.

As shown in FIG. 4, first, rate rate information for conversion and reproduction is received from a person who wants to generate MP3 data (S400). Since the present invention uses a method of interleaving a frame having a variable speed to a constant speed frame, the converted speed ratio is preferably an integer multiple of the normal speed.

After receiving the rate ratio information, an MP3 file encoding the signal at a normal speed is generated (S402). The method of generating the normal speed MP3 data will be described later.

After the MP3 file is generated at the normal speed, the MP3 file encoded at the converted speed is generated (S404). The method of MP3 encoding to reproduce at low speed or acceleration will be described later.

When the MP3 file encoded at the normal speed and the MP3 file encoded at the converted speed are generated, the number of frame bytes of the file encoded at the normal speed and the file encoded at the converted speed are matched (S506).

The amount of PCM (Pulse Code Modulation) data that an MP3 file can generate in one frame is determined. In addition, since the file data is encoded in units of BPS, it is possible to accurately search for a specific time of the file.

However, since the padding bit is defined to fit the BPS of the whole file, it decides whether to add one byte to the frame after encoding, depending on whether the entire BPS is correct. Is determined. Therefore, if the average BPS is met, one frame may have 1 byte more data than another frame.

The above MP3 data structure is not a problem at all when playing a general MP3 file consisting of frames of normal speed only. However, as in the present invention, there may be a problem in a data structure in which a frame having a normal speed and a frame whose speed is converted are interleaved together. In the present invention, when a user requests playback at a normal speed, only the frame encoded at the normal speed is played. When a user requests playback at the converted speed, only the frame encoded at the converted speed should be played. If the data amounts of are not the same, the position of the frame corresponding to the requested rate cannot be calculated accurately.

Therefore, in the present invention, the padding bits are added to the frame encoded at the normal speed and the frame encoded at the converted speed so that the byte counts of all the frames are matched.

After matching the byte counts of all the frames, the file encoded at the speed converted according to the speed ratio received in step S400 is interleaved with the file encoded at the normal speed (S408).

For example, in the case of requesting MP3 data that can reproduce 3 times deceleration at one speed, a structure in which three triple deceleration frames are interleaved after one normal speed frame will be repeated. In addition, in the case of requesting MP3 data capable of reproducing 4x acceleration at one speed, a structure in which one 4x acceleration frame is interleaved after 4 normal speed frames will be repeated.

5 is a flowchart illustrating a flow of a method of generating an MP3 file to be decelerated and reproduced according to a preferred embodiment of the present invention.

In order to generate the file to be slowed down and reproduced, first, the frequency domain of the original signal, that is, the normal speed signal is analyzed (S500). As mentioned above, the frequency domain may be identified by a device that applies a Fourier transform to the signal or analyzes other frequency components.

After determining the frequency components of the signal, it is analyzed what pattern the normal speed signal has in the frequency domain (S502). The general audio signal has a specific period and the pattern is repeated. In this step, the pattern information that is repeated with this period is analyzed.

After analyzing the pattern information of the normal speed signal, the audio signal is converted so that the analyzed pattern is repeated by a low speed ratio (S504). For example, if the analyzed pattern is repeated two times at a normal speed at a predetermined time, the audio signal is converted so that the same pattern is repeated four times in case of deceleration by 1/2 times. In this way, if the signal is converted so that the same pattern is repeated further by the low speed ratio, the tone of the original signal is maintained so that the timbre does not change and only the reproduction time is increased by the low speed ratio.

When the audio signal is converted according to the low speed ratio, the converted signal is encoded (S606).

In FIG. 5, only the case of generating MP3 data reproduced at low speed is illustrated, but MP3 data reproduced at high speed may be generated by applying a principle similar to that of FIG. 5.

Specifically, MP3 data reproduced at high speed may be generated by modifying step S504 shown in FIG. 5. In the case of high speed reproduction, the audio signal is converted so that the number of repetitions of the pattern is reduced by the high speed ratio. For example, when a high speed reproduction is to be performed at twice the rate, when a pattern analyzed at a predetermined time is repeated twice in a normal speed signal, the audio signal is modified so that the pattern is repeated only once. The procedure after converting the signal is the same as that shown in FIG.

6 is a flowchart showing the flow of the MP3 data rate conversion reproduction method according to an embodiment of the present invention.

As shown in FIG. 6, first, an MP3 file having a structure as shown in FIG. 2 or 3 is read (S600).

After the MP3 data is read, a frame skip number is set according to the playback mode (S602). Here, the frame skip number refers to information on the number of skip frames. According to an embodiment of the present invention, when the normal speed frame and the 1 / 2x frame are interleaved as shown in FIG. 2 and the user selects the normal speed playback, only the frames encoded at the normal speed while skipping by two frames are played. do. In the data structure as shown in FIG. 2, in contrast, when the user selects 1 / 2x playback, the process of skipping a frame is repeated after the first frame is played and the frame is skipped after the next frame is played. It will be possible to play only the frames encoded with.

As described above, if the MP3 file is decoded while skipping frames according to the playback speed, a module for setting a frame skip number is required, but a frame encoded at a normal speed or a frame encoded at a converted speed in the header of each frame The advantage is that no overhead for identifying cognition is required.

In the MP3 data structure as shown in Fig. 2, if the user selects normal speed playback, the first frame skip number will be set to 0, and if the user selects 1 / 2x playback, the frame skip number will be set to 1. .

If the frame skip number is set, the frame to be decoded is skipped by the set number (S604).

After skipping the frame by the set number, the header information of the frame to be decoded is decoded (S606). The header information of the frame includes sampling frequency information, bit rate information and channel information. As described above, the frame header of the MP3 data reproduced in the same manner as in FIG. 7 may not need to include information regarding an encoding speed.

As a result of decoding the header information, if there is no error in the header information (S608), the corresponding frame is decoded (S610). However, if there is an error in the header information, the process proceeds to the next step without decoding the corresponding frame.

After decoding one frame, the frame skip number is set again according to the reproduction mode (S612). For example, in the frame structure shown in FIG. 2, when the user selects normal speed playback, the frame skip number is set to 2, and when the user selects 1 / 2x playback, the frame skip number is set to 0. FIG.

After the frame skip number is set again, pulse code modulation (PCM) data, which is decoded data, is output (S614).

If it is not the end of the file (S616), the process returns to the step (S604) to skip the frame by the frame skip number. In the frame structure as shown in FIG. 2, since the frame skip number is set back to 2 as described above, the frame skipped is decoded for two frames without decoding the next frame.

7 is a flow chart showing the flow of a method of MP3 data rate conversion reproduction according to another embodiment of the present invention.

As shown in FIG. 7, first, an MP3 file having the structure as shown in FIG. 2 or 3 is read (S700).

After reading the file, the header information of the frame is decoded (S702). As described above, the header information includes sampling frequency information, bit rate information, channel information, and the like, and the header information of the MP3 file reproduced in the same manner as in FIG. 7 further includes information about an encoding speed.

As a result of decoding the header information, it is detected whether there is an error (S704). If there is an error, the frame is skipped without decoding the frame (S706), and the header information of the next frame is decoded.

After detecting whether there is an error in the header information, the header information is analyzed to determine whether the frame to be decoded is a frame corresponding to the playback rate requested by the user (S708).

For example, in the frame structure as shown in FIG. 2, when the user selects normal speed play and decodes the first frame, the header information of the first frame stores information as a frame encoded at normal speed. It is determined that the frame corresponds to the playback speed requested by the user. However, if the user selects 1 / 2x playback, it is determined that the frame does not match the playback speed requested by the user through the header information of the first frame.

If it is determined that the frame does not match the playback mode, the frame is skipped (S706), and the header information of the next frame is decoded (S708).

If it is determined that the frame matches the playback mode, the frame is decoded (S710). When the frame is decoded, PCM data which is the result data of decoding is output (S712). If it is the end of the file (S714), and if it is not the end of the file, the process of decoding the header information of the next frame (S702) proceeds to the end of the file.

 8 is a block diagram showing the configuration of an MP3 playback apparatus capable of speed conversion according to a preferred embodiment of the present invention.

As shown in FIG. 8, the MP3 player according to the preferred embodiment of the present invention includes a memory 800, a file reading unit 802, a decoder 804, a speed conversion control unit 806, and a D / A converter 808. ) May be included.

In FIG. 8, the memory 800 functions to store MP3 file data. The memory may be implemented as a hard disk, a RAM, or the like, and one of ordinary skill in the art will readily understand that the memory storing the file may be implemented in various forms.

The file reading unit 802 reads the MP3 file requested by the user from the memory 800 and transmits the MP3 file to the decoder 804. The file reading unit 802 analyzes frame header information and the like of the read MP3 file, provides frame data to the decoder 804, and detects whether or not the file has no error. This file reading will generally be accomplished via either module of the CPU.

The speed conversion control unit 806 functions to provide a control signal to the file reading unit 802 to decode a frame corresponding to a playback speed selected by the user (S804).

According to an embodiment of the present invention, the speed conversion control unit 806 provides the frame skip number described with reference to FIG. 7 each time each frame is played. The file reading unit 802 provides the frame data skipped according to the frame skip number to the decoder so that the MP3 file is decoded according to the playback speed selected by the user.

According to another embodiment of the present invention, the speed conversion control unit 806 analyzes the header information of the MP3 file frame read by the file reading unit, and determines whether to decode the corresponding frame by determining whether the frame corresponds to the playback speed requested by the user. A signal indicating whether or not is generated and provided to the file reading unit 802. The file reading unit 802 provides the frame to the decoder only for the frame in which the speed conversion control unit 806 generates the decoding instruction signal.

The decoder 804 functions to decode the MP3 frame data provided from the file reading unit 802. As described above, various MP3 decoding schemes may be used, and a detailed description thereof will be omitted since the decoding operation is not a feature of the present invention.

The D / A converter 808 converts the PCM data output from the decoder 804 into an analog signal so that the original signal can be reproduced.

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art will be able to make various modifications, changes, and additions within the spirit and scope of the present invention. Additions should be considered to be within the scope of the following claims.

As described above, the audio signal compression file generation method and the audio signal compression file reproduction method capable of speed-converting reproduction according to the present invention have the advantage that the tone can be changed and reproduced without changing the tone.

In addition, since the data is interleaved frame by frame, normal speed playback and speed conversion playback can be switched in real time, especially when reading and playing back data from a CD disc such as an MP3 CD player. There is a simple advantage to playback because you do not need to search again.

In addition, all frames are equally sized so that they can be precisely located at a specific location within the file, enabling fast search, a key feature for language use.

1 is a flow chart showing the flow of a method of decoding a conventional MP3 file.

2 is a diagram showing an MP3 data format structure for low speed playback at 1/2 times according to an embodiment of the present invention.

3 is a diagram illustrating an MP3 data format structure for accelerated reproduction at double speed according to an embodiment of the present invention.

4 is a flow chart showing the flow of a method of generating MP3 data for speed conversion reproduction according to a preferred embodiment of the present invention.

Figure 5 is a flow chart showing the flow of a method for generating a slow playback MP3 file according to a preferred embodiment of the present invention.

6 is a flow chart showing the flow of the MP3 data rate conversion reproduction method according to an embodiment of the present invention.

7 is a flow chart showing the flow of the MP3 data rate conversion reproduction method according to another embodiment of the present invention.

8 is a block diagram showing the configuration of an MP3 playback apparatus capable of speed conversion according to a preferred embodiment of the present invention.

Claims (12)

In a method for generating an audio signal compressed file that can be played at varying speeds, Encoding a signal at a normal speed (a); (B) encoding the signal at the converted rate; The conversion of the encoded low-speed encoded data into the compressed data encoded at high speed among the audio signal compressed data encoded at the normal speed of step (a) and the encoded audio signal compressed data at the converted speed of step (b) (C) interleaving according to the ratio of the speeds. The method of claim 1, And matching the frame data bytes of the audio signal compressed data encoded at the normal speed of step (a) with the audio signal compressed data encoded at the converted speed of step (b). How to create a compressed file. The method of claim 1, If the speed converted in step (b) is a low speed, The interleaving step of step (c), Determining a plurality of low-speed encoded frames corresponding to the frames encoded at the normal speed in the step (a); And interleaving the corresponding plurality of low speed encoded frames before or after the frames encoded at the normal speed. The method of claim 1, If the speed converted in the step (b) is a high speed, The interleaving step of step (c), Determining a plurality of frames encoded at a normal speed corresponding to the frame encoded at a high speed in the step (b); And interleaving the frames encoded at the corresponding plurality of normal speeds before or after the frames encoded at the high speeds. The method of claim 1, When encoding in the steps (a) and (b), the audio information further comprises the step of inserting header information indicating whether each frame is a frame encoded at a normal speed or a frame encoded at a converted speed How to create a signal archive. The method of claim 1, Encoding the signal at the converted speed of step (b), if the converted speed is a low speed, Analyzing a pattern of steady speed signals in the frequency domain; Converting the signal to repeat the analyzed pattern by a slow rate; And encoding the converted signal. The method of claim 1, Encoding the signal at the converted speed of step (b), if the converted speed is a high speed, Analyzing a pattern of steady speed signals in the frequency domain; Converting the signal to reduce the number of repetitions of the analyzed pattern by a high rate; And encoding the converted signal. In a method of playing an audio signal compressed file in which a frame encoded at a normal rate and a frame at which the rate is converted and existed together exist, (A) reading an audio signal compressed file; (B) setting a frame skip number to match the playback speed selected by the user; (C) skipping the frame according to the frame skip number set in the step (b), and decoding the frame corresponding to the playback speed selected by the user; Resetting the frame skip number to match the playback speed selected by the user (d); And Repeating steps (a) to (d) to the end of the audio signal compressed file. In a method of playing an audio signal compressed file in which a frame encoded at a normal rate and a frame at which the rate is converted and existed together exist, (A) reading an audio signal compressed file; Analyzing the header information of the frame to decode the frame if the frame is a frame suitable for the playback rate requested by the user, and skipping the frame if the frame is not suitable for the frame rate requested by the user; And And (c) playing the decoded data of the corresponding frame by digital analog conversion. In an apparatus for playing an audio signal compressed file in which a frame encoded at a normal speed and a frame encoded with a converted speed exist together, A memory in which an audio signal compressed file is stored; A file reading unit for reading an audio signal compressed file from the memory; A decoder for receiving and decoding frame data of an audio signal compression file from the file reading unit; A rate conversion control unit providing a frame transmission control signal to the file reading unit to decode a frame corresponding to a playback rate requested by a user when transmitting the frame from the file reading unit to the decoder; And And a D / A converter for converting the output signal of the decoder into an analog signal. The method of claim 10, And the rate conversion control unit provides a frame transmission control signal including frame skip number information to the frame reading unit. The method of claim 10, The rate converting control unit analyzes the header information of the frame data read from the file reading unit and provides a frame transmission control signal for transmitting only the frame corresponding to the playback speed selected by the user to the decoder lock. Playback device.