KR100740373B1 - Music Service System, Control Server for Melody reproduction, Music Service Method, and Program for Music Service - Google Patents

Abstract

An object of the present invention is to provide music with low sound quality deterioration, especially for a mobile phone employing a narrow band codec, and in the solution for achieving the above object, the melody reproduction control server 1 has a MSC ( A melody reproduction instruction reception unit 11 for receiving a start instruction from the GS 53 through 54; a codec type detection unit 12 for detecting the codec type of the calling mobile phone U1; and a calling mobile phone U1. A sound source file transmitter 13 is constructed for transmitting a sound source file corresponding to the codec type of " The melody reproduction control server 1 determines the codec type of the calling party's mobile phone U1 according to the calling network type included in the start signal IAM, and the sound source file of the best sound quality according to the codec type. Select. In this way, since a sound source file dedicated to the codec for the narrow band is selected and played, it is possible to play the best sound quality in the range that can be reproduced by the codec of the cellular phone.

Music Provision System, Melody Playback Control Server, Music Provision Method, Music Provision Program

Description

Music delivery system, melody playback control server, music delivery method and program for music delivery {Music Service System, Control Server for Melody reproduction, Music Service Method, and Program for Music Service}

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the outline | summary of the whole system structure in 1st Embodiment.

Fig. 2 is a functional block diagram showing the configuration of the melody reproduction control server in the first embodiment.

Fig. 3 is a flowchart showing a method for creating each sound source file from the basic sound source in the first embodiment.

Fig. 4 is a flowchart showing the operation of the melody reproduction control server in the first embodiment.

Fig. 5 is a sequence diagram showing operations of the entire system according to the first embodiment.

Fig. 6 is a flowchart showing the operation of the melody reproduction control server in the second embodiment.

FIG. 7 is a sequence diagram showing operations of the entire system according to the second embodiment. FIG.

8 is a flowchart showing a flow of speech coding processing.

Fig. 9 is a schematic diagram showing the configuration of the entire system for realizing the outgoing melody service in the conventional example.

Fig. 10 is an explanatory diagram showing an aspect of a signal in a part of speech coding processing in the conventional example, i.

(Explanation of symbols for the main parts of the drawing)

1: Melody playback control server (music providing device)

2: sound source database (sound source file storage means)

3: subscriber service management server

4: subscriber database

11: melody playback instruction receiving means

12: codec type detection unit (codec type detection means)

13: sound source file transmitter (sound source file transmitter)

20: sound source file storage unit (sound source file storage means)

50: mobile phone network

51, 52: wireless base station

53 relay switch (GS)

54, 55: MSC

U1: calling party's mobile phone

U2: called party's mobile phone

Field of technology

The present invention relates to a music providing system for providing music to a mobile phone through a wireless base station.

Prior art

In recent years, with the spread of mobile telephones, techniques for improving the sound quality at the time of a call in the mobile telephones have been implemented. The codec for each main mobile phone system is shown below. Also, the method is shown in the order of codec type, transmission band kbit / sec, and voice band kbit / sec.

Codec Type Transmission Band Voice Band

PHS: ADPCM, 32, 32

PDC full rate: VSELP, 11.2, 6.7

PDC Half rate: PSI-CELP, 5.6, 3.45

GSM full rate: RPE-LTP, 22.8, 13

cdmaOne: EVRC, 9.6 8

WCDMA (FOMA): AMR, 38.6 12/23

Fixed Phone (Reference): PCM, 64, 64

In addition, the transmission band means the band of the entire radio section, the voice band means the band of the portion of the transmission band through which the voice signal flows.

For example, encoding processing by the EVRC codec used in the cdma network is performed in the order shown in FIG. First, when an audio analog signal is input (step S101), normalization of the audio analog input signal is performed (step S102). Subsequently, band filter processing (removal of low frequency components and high frequency components) in the analog signal (step S103) and analog / digital conversion processing (quantization: from analog to linear PCM) (step S104) are performed. Thereafter, the small amplitude portion of the audio waveform is deleted (step S105), and whether or not it is a human sound is discriminated and a noise removing process is performed (step S106). Then, the audio signal is encoded (step S107), and converted into a code for transmission (redundancy structure, error correction code added) (step S108).

By encoding the speech according to the above procedure, in the small amplitude section compression process in step S105, in the case of the silent section or the noise section, only the signal called noise is transmitted to lower the transmission rate, and the power required for transmission and the power of the cellular phone are reduced. Can reduce consumption In addition, the process of step S106 removes the background noise to improve the sound quality (clarity) of the call voice.

On the other hand, in recent years, the case of listening to music on a mobile phone is increasing. In particular, as a service through which music flows through a cellular phone network, there are the following services.

(1) Watching music: Call a music viewer and watch music by specifying the song you want to listen to. (2) Outgoing melody service: While A calls B and makes a call, A listens to music designated by B instead of Ring Back Tone (Ring Back Melody Service: `` Bello Melo Service '') . (3) Self-outgoing melody service: A calls B and listens to music A designated by A instead of Ring Back Tone.

When using a service as described above, when listening to music on a mobile phone, the data of the sound source file provided by the music supplier is transferred to the mobile phone of the person who listens to the music through the mobile phone network. Then, in the case where the person A who listens to music is a narrow band mobile phone (PDC (Personal Digital Cellular), GSM (Global System for Mobile Communications, GSM), cdmaOne), the mobile phone is transferred between the mobile phone and the wireless base station. There is a problem that the sound quality deteriorates due to the voice codec characteristics of the telephone network. 9, the outgoing melody service described above will be briefly described, and the flow of sound source files and the state of sound quality degradation in the case of the cdmaOne network will be described.

As shown in Fig. 9, first, when the calling party's mobile phone U101 calls the called party's mobile phone U102 that subscribes to the Valmelo service, the mobile phone network 110 that has received the call request is made. The receiving party's mobile phone (U102), which is the subscriber, via the wireless base station 101, 104, MSC (Mobile Switching Center) 102, 103, GS (Gateway Switch: relay base station) 105, and the like. Is checked (arrows L1, L2, L3, L4, L5). The balmello service is a ring back tone to a telephone, and refers to a service for supplying music to a calling telephone with music designated by the user of the called telephone. In the Valmelo service, the MSC 102 with the calling mobile phone U101 accesses the subscriber service management server 106 through the GS 105, and the called mobile phone U102 subscribes to the Balmelo service. It is checked based on the subscriber database 107 whether there is any (arrow L6). When the destination mobile phone U102 subscribes to the Valmelo service, an activation request is made from the MSC 102 to the melody reproduction control server 108, and the subscriber reproduces the sound source file designated by the subscriber. The sound source data is requested to be sent to the calling party's mobile phone U101 instead of the ringing tone (arrow L7).

Then, the melody reproduction control server 108 reads the sound source file F3 in WAV format from the sound source database 109 (arrow M1), and the GS 105 and the MSC under the voice mode of PCM 64 kbit / sec. It transmits to the wireless base station 101 via 102 (arrows M2, M3, M4). When information is transmitted in this voice mode, since the transmission band is wideband, sound quality deterioration does not occur during the transmission from the melody reproduction control server 108 to the radio base station 101. Then, the wireless base station 101 performs encoding in accordance with the codec of the calling mobile phone U101. For example, encoding for an EVRC (Enhanced Variable Rate Codec) codec of 8 kbit / sec is performed. Therefore, in this section (arrow M5), since the transmission band becomes a narrow band, there is a situation that the sound quality of music is large. That is, in the wireless base station 101, the EVRC codec, which is an audio encoding process by the algorithm shown in FIG. 8 described above, is performed, and the sound quality of the sound source data reproduced from the sound source file is degraded.

Here, the above-mentioned deterioration of music will be described in detail. This deterioration is caused by the process of clarifying the voice which is a characteristic of the above-described EVRC codec. Specifically, in the processing of step S105, the small amplitude portion is deleted after the normalization of the analog signal and the band filter processing. In other words, with respect to the sound source file, a portion having a large dynamic range and a large volume and a small portion are continuously changed. For example, a section indicated by the symbol X for the sound source file (waveform) as shown in Fig. 10A. Since the noise amount portion of the audio signal is removed (see FIG. 10 (b)), the music is partially cut away, and a problem occurs that the sound quality provided is deteriorated.

The processing of step S106 is a function unique to the speech codec that removes the background noise to increase the intelligibility of the speech. This function has a reference value for discriminating speech and noise internally, compares the reference value with a prediction gain of the input signal, and discriminates between speech and noise. Is identified. The voice codec encodes 20 msec (160 Sample) as one frame. However, when the correlation between signal frames is small, the prediction gain becomes small. At this time, the voice has a large interframe correlation and a large prediction gain in the case of 20msec unit, but the prediction gain is small because the noise is a random signal. If the sound changes abruptly in orchestra, rock music, or the like, the correlation between the frames is small, and the prediction gain is small, so that the noise is likely to be regarded as noise. In the case of orchestra and rock music, there are some that are widely distributed in a wide frequency band when viewed in the frequency space, and have a frequency characteristic close to noise. Therefore, in the case of such a song, sound quality deterioration is severe. If it is regarded as noise, only the signal called noise is transmitted without speech encoding, and in the frame (every 20 ms) when the noise identification signal is received, a low level pseudo noise (white noise) is reproduced by the receiving terminal. There is a problem that the sound quality deteriorates without being reproduced according to the original music.

Summarizing the above, the cause of sound quality deterioration is as follows. The sound source file F3 is transmitted from the melody reproduction control server 108 by the voice mode of 64 kbit / sec μLawPCM. Since the GS 105 and the MSC 102 are transmitted in the voice mode of 64 kbit / sec, there is no degradation of sound quality. On the other hand, the wireless base station 101 converts the wireless section signal into a voice codec unique to the mobile phone system. At this time, since the band between the radio base station 101 and the mobile telephone U101 is narrow, encoding specialized for speech is performed. Therefore, normal music tends to be regarded as noise, and therefore sound quality deteriorates.

In addition, if the above function is removed from the existing codec provided in the cellular phone or the wireless base station, the sound quality deterioration can be prevented, but the noise canceling function does not work, and thus the normal voice call quality deteriorates. The specifications of the voice codec cannot be changed. Moreover, even if the noise canceling function is eliminated, the construction of a codec device of such an algorithm is enormously troublesome, and there is also a problem in that it is expensive to exchange with what is already provided in a cellular phone or a wireless base station.

And the technique of suppressing sound quality deterioration is disclosed by patent document 1. As shown in FIG. In Patent Document 1, in a voice call between mobile phones, when the mobile phones use the same codec in the same mobile phone network, the base station and the mobile phone are not converted into PCM in the mobile phone network. A codec through system for directly exchanging coded signals used between mobile phones is disclosed. This reduces the number of times of encoding by the codec and prevents degradation of speech quality. However, the technique described in Patent Literature 1 is a codec through technique relating to voice data at the time of a call and cannot improve sound quality with respect to music data. That is, even if the sound source file is transmitted using codec through, for example, the sound quality deteriorates in the first stage of the encoding process for speech as described above.

[Patent Document 1] Japanese Patent Laid-Open No. 11-55716

As described above, in the conventional music providing system, since the band between the wireless base station and the cellular phone is narrow and a codec specialized in voice is used, there is a problem that the sound quality of the music cannot be maintained.

When the music is requested to be played, the prepared sound source file is connected to the cellular phone network in the voice mode (64 kbit / sec PCM) and played. Since one sound source file is provided for one content, music is provided using the same sound source file for all reproduction request subscribers for the same content. Therefore, in particular, in a mobile phone having a narrow bandwidth for transmitting data, sound quality deterioration due to codec characteristics of a wireless section occurs, so that music with good sound quality could not be provided.

The degree of sound quality deterioration varies greatly depending on the codec type of the cellular phone. When listening to music using W-CDMA or PHS, you can listen to the same sound quality as you would on a fixed phone. In the case of cdma, GSM, and PDC, the sound quality deteriorates greatly depending on the song due to the coding characteristics of the respective codecs. That is, in cdma, GSM, and PDC, when a song with a large number of frequency components is heard, the voice codec cannot be followed, resulting in theft and unclearness, and the sound quality is greatly deteriorated. On the other hand, in the case of a music having a small number of frequency components, the sound quality deteriorates little.

SUMMARY OF THE INVENTION An object of the present invention is to provide a function of playing music with low sound quality deterioration by reproducing a sound source processed for a narrow band codec. In other words, the present invention automatically creates a sound source file for a narrow band from a basic sound source file, and selects and connects a sound source file of the best sound quality according to the type of cellular phone at the time of reproduction request, thereby connecting the sound quality of music. The present invention provides a music providing system that can prevent deterioration.

In order to achieve the above object, the music providing system according to the present invention is a music providing system for providing music to a cellular phone, which accumulates a plurality of sound source files created based on a basic sound source file in correspondence with the codec characteristics of the cellular phone. A sound source file storage means, codec type detection means for detecting the codec type of the mobile phone based on a music reproduction request output from the mobile phone, and a sound source file corresponding to the codec type detected by the codec type detection means. And sound source file transmission means for reading from the sound source file storage means, reproducing the read sound source file, and outputting sound source data. In this case, it is preferable that the plurality of sound source files are created based on the basic sound source file with different simultaneous transmission frequencies.

In a narrow-band codec, when a song with a large number of simultaneous transmission frequencies (harmonic number) is played back, it becomes a very bad sound quality deterioration with theft and ambiguity. For this reason, in the present invention, a song having a small number of simultaneous transmission frequencies (hereinafter, referred to as "tone number") is created in advance, and this sound source file is connected in accordance with the codec characteristics at the time of the reproduction request. Since the number of chords that can be transmitted differs for each codec, among the plurality of sound source files, a sound source file having the maximum harmonic number is selected and connected below the number of chords that can be transmitted. The more chords you have, the deeper the music. On the other hand, music with a low number of chords becomes simple music with a low depth of the main melody, but the sound quality does not deteriorate even when played with a narrow band codec.

The codec type detecting means detects the codec type of the cellular phone based on the type of the calling network included in the input start signal or based on negotiation with the wireless base station. Also good. The sound source file transmitting means may reproduce the sound source file as a ringback tone of the cellular phone to output sound source data.

A music providing apparatus according to the present invention is used in a music providing system for providing music to a cellular phone via a wireless base station, and includes the sound source file storing means. The music providing apparatus may further comprise the codec type detecting means and the sound source file transmitting means. The music providing method according to the present invention is a method for providing music to a cellular phone via a wireless base station. That is, a plurality of sound source files according to codec characteristics are accumulated in advance for the music, the codec types of the mobile phone are detected, and a sound source file corresponding to the detected codec type is acquired from the accumulated sound source files, The acquired sound source file is transmitted from the wireless base station to the mobile phone. The music providing program according to the present invention is for realizing each of the above means in a music providing computer for providing music to a cellular phone via a wireless base station.

As described above, according to the present invention, in a service for listening to music on a mobile phone, a plurality of sound source files in accordance with the codec characteristics of the mobile phone are created and stored in advance, and an optimum sound source file according to the codec type is requested upon reproduction. By selecting and playing, you can play music of the best quality. In other words, since a sound source file that is optimal for a narrow-band codec is selected and connected, it is possible to listen to a song with less sound quality deterioration.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing. The sound source file used for the cellular phone network includes a sound source file flowing in place of the ringing tone, and music corresponding to the ringing tone is provided to the cellular phone from the music providing device through the cellular phone network using the sound source file. In the following embodiment, the case where the above-mentioned Valmelo service is provided in a cdma network is demonstrated. However, the sound source file transmitted to the cellular phone network is not limited to the file of the sound source data flowing instead of the ring tone by the Valmelo service.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the outline | summary of the whole system structure in 1st Embodiment. Hereinafter, it demonstrates based on this drawing.

As shown in Fig. 1, the system for realizing the Valmelo service is a wireless base station installed in the calling mobile phone U1, the called mobile phone U2, the mobile phone network 50, and the mobile phone network 50. Melody for providing music connected to the MSC 54 and the GS 53, in addition to the basic configuration enabling communication by mobile phones such as 51, 52, GS 53, MSC 54, 55, etc. A reproduction control server 1 (music providing device) and a subscriber service management server 3 that registers and manages users who subscribe to the Valmelo service are provided. The melody reproduction control server 1 has a sound source database 2 in which sound source files are provided, and the subscriber service management server 3 has a subscriber database 4. The mobile phones U1 and U2 also have a codec function (characteristic) for converting an analog signal into digital data or vice versa. Therefore, the cellular phone decodes the data of the sound source file encoded by the melody reproduction control server 1 based on the codec function, converts the decoded and decoded sound source data into an analog signal, and converts the analog signal from the speaker. Run the function to print. This function may be a streaming function for simultaneously receiving data and performing playback.

In addition, since the specific configuration of the Valmelo service is as described in the background art, the detailed description thereof is omitted. Here, in Fig. 1, the calling party's mobile phone is indicated by code U1, and the called party's mobile phone is indicated by code U2. In addition, the installation situation of the radio base stations 51 and 52, the MSCs 54 and 55, and the GS 53 is not limited to the situation shown in this figure. For example, the melody reproduction control server 1 may be started from the MSC 55 located at the called party's mobile phone U2 side.

In the embodiment of the present invention, since the melody reproduction control server 1 is characterized, the configuration and operation of the melody reproduction control server 1 are mainly described in detail. In other words, when the call is made to the called party's mobile phone U2 subscribing to the Valmelo service from the calling party's mobile phone U1, the following is shown after the melody reproduction control server 1 is activated in the MSC 54. To explain.

FIG. 2 is a functional block diagram showing the configuration of the melody reproduction control server in FIG. Hereinafter, it demonstrates based on FIG. 1 and FIG.

First, as shown in FIG. 2, the melody reproduction control server 1 receives a melody reproduction instruction reception unit 11 that receives a start instruction from the MSC 54 through the GS 53, and the calling party's mobile phone U1. The codec type detection section 12 (codec type detection means) for detecting the codec type of the mobile station; and the sound source file corresponding to the codec type of the calling mobile phone U1 with respect to the calling mobile phone U1. And a sound source file transmitter 13 (sound source file transmitter) for transmitting from the terminal.

The melody reproduction control server 1 shown in FIG. 2 is constituted by a general server computer. And the melody reproduction control server 1 which consists of a server computer memorize | stores the program for driving a computer in the memory, The CPU 10 of the server 1 reads the program stored in the said memory in order, The function of the melody reproduction instruction reception unit 11 which receives the start instruction from the MSC 54 via the GS 53, and the codec type detection unit 12 (codec type) for detecting the codec type of the calling mobile phone U1. Sound source file transmitter 13 (sound source file transmission) for transmitting the sound source file corresponding to the function of the detection means) and the codec type of the calling mobile phone U1 from the radio base station 51 to the calling mobile phone U1. Means).

Therefore, the function of the melody reproduction instruction reception unit 11 that receives the start instruction from the MSC 54 through the GS 53 to the CPU 10 of the computer in the memory of the computer constituting the melody reproduction control server 1. And a function of the codec type detection unit 12 (codec type detection means) for detecting the codec type of the calling mobile phone U1 and the sound source file corresponding to the codec type of the calling mobile phone U1. The program for executing the function of the sound source file transmitter 13 (sound source file transmission means) transmitted from the radio base station 51 to the cellular phone U1 is stored in advance.

The sound source database 2 stored in the memory of the server computer functions as a sound source file storage unit 20 (sound source file storage means) for storing sound source files provided to the calling party's cellular phone U1. For each of the music (songs) 20a, 20b, and 20c, a plurality of voice files F1, F2, and F3 of voice data having the best sound quality according to the codec characteristics of the cellular phone are stored.

The sound files F1, F2, F3 are previously created from the basic sound source as sound source files having the configurable number (a1, a2 or a3) according to the codec type, and are stored in the sound source file storage unit 20. The sound source file F1 shown in FIG. 2 has the constituent chord number a1 as 3, the sound source file F2 as the constituent chord number a2 as 8, and the sound source file F3 as the constituent chord number a3. It is set to 40 each. The sound source files F1, F2, F3 are provided with a file ID for identifying a file name and a codec ID for identifying codec characteristics, and are stored in the sound source file storage unit 20. Therefore, the sound source file storage unit 20 identifies the file ID based on the codec ID for each music (song) 20a, 20b, 20c received from the sound source file transmitter 13, and the sound source file F1 according to the codec characteristics. , F2 or F3). Note that the constituent harmonics of the sound source file are not limited to those shown in FIG.

Next, a method in which the melody reproduction control server 1 creates a plurality of sound source files in accordance with the codec characteristics of the cellular phone based on the basic sound source data will be described with reference to FIG.

The sound source file of the basic sound source data is input to the melody reproduction control server 1 (step S11). When the sound source file of the basic sound source data is input, the melody reproduction control server 1 divides the basic sound source data into frames every 20 msec (step S12), and converts the frame into a frequency space (step S13).

Next, the melody reproduction control server 1 extracts M components of the pitch frequency (Formant frequency) from the sound source data converted into the frequency space (step S14), and extracts the harmonic components of the extracted pitch frequency. It adds to a fundamental frequency component (step S15).

In addition, the melody reproduction control server 1 performs a smoothing process on the sound source data obtained by adding the extracted harmonic component of the pitch frequency to the fundamental frequency component (step S16). The smoothing process will be described in detail. If the fundamental frequency is greatly changed for each frame of 20 msec, the sound quality of the sound source data deteriorates, and smoothing processing is performed to prevent this. That is, the base frequency of the preceding and following frames is added by adding the frequency component of the sound source data contained in the preceding frame to the frequency component of the sound source data contained in the subsequent frame among the continuous frames divided in 20 msec units. This change is suppressed by the smoothing process.

By the smoothing process, the continuity of the music can be maintained, and the rate at which the sound quality of the sound source data changes can be reduced. For example, the sound source data contained in the Kth frame divided into a plurality of Kth frames, and the frequency component of the sound source data included in the Kth frame before smoothing is F (K, ω) and the Kth frame after smoothing. If the frequency component of G (K, ω) and the frequency is ω, the frequency component G after smoothing (K, ω) is

G (K, ω) = F (K, ω) * ((1-α) + αG (K-1, ω))

Obtained by

Subsequently, the melody reproduction control server 1 extracts N basic frequency components from the frequency components of the sound source data included in each frame after the smoothing process (step S17). The number N of extracted fundamental frequency components depends on the codec characteristics of the cellular phone. In the example shown in Fig. 2, the number N of the extracted fundamental frequencies corresponds to the number of harmonics that can be transmitted by the codec characteristic of the cellular phone. Frequency component is extracted.

In addition, the melody reproduction control server 1 keeps the sound source data of the harmonic components of the N fundamental frequency components as it is, and compresses the other sound source data with a comb filter (step S18). Next, the melody reproduction control server 1 performs inverse Fourier transform processing on the compressed sound source data, returns to sound source data in time space (step S19), and creates a sound source file for a narrow band (step S20). ). In the example shown in Fig. 2, three kinds of sound source files F1. F2, F3 including sound source data of constituent chord a1 = 3, a2 = 4, a3 = 8 are the same songs 20a, 20b or 20c. Each is written.

Next, the operation of the music supply system shown in FIG. 1 will be described based on FIGS. 4 and 5. This operation is performed by the user of the mobile phone U2 of the calling party, when the call is made to the called mobile phone U2 subscribing to the Balmelo service from the calling mobile phone U1. The case of providing to the cellular phone U1 of the source as a ring back tone is described.

First, in step S31 of FIG. 5, when the user outputs the outgoing signal for the receiving side mobile phone U2 to the wireless base station 51 using the calling party's mobile phone U1, the wireless base station 51 sends the outgoing signal. The signal is output to the MSC 54. Upon receiving the outgoing signal, the MSC 54 inquires of the subscriber service management server 3 as to whether or not the destination mobile phone U2 subscribes to the Valmelo service and obtains a response (not shown). ). And when it joins, the MSC 54 outputs the starting signal IAM to GS53. When the GS 53 receives the start signal IAM from the MSC 54, it transmits it to the melody reproduction instruction accepting unit 11 of the melody reproduction control server 1 (step S32 in Fig. 5). Thereby, preparations for providing the sound source data designated by the called party's mobile phone U2 as ringback tones to the calling party's mobile phone U1 are arranged.

When the melody reproduction instruction reception unit 11 of the melody reproduction control server 1 receives the activation signal IAM (step S21 in Fig. 4), the melody reproduction instruction reception unit 11 transmits this activation signal to the codec type detection unit 12. The start signal IAM output from the calling mobile phone U1 includes a carrier code and type information of the telephone network. Here, the communication service provider code is information for identifying a mobile telephone or a service provider that provides communication by high power failure. The type information of the telephone network is information for distinguishing the communication circuit network of the cellular phone or the communication circuit network of the cellular phone. The codec type detection unit 12 of the melody reproduction control server 1 extracts the carrier code included in the activation signal IAM and the type information of the telephone network, and determines the codec characteristics of the calling terminal. That is, the codec type detection unit 12 of the melody reproduction control server 1 determines the codec characteristic of the calling terminal as a codec characteristic suitable for the communication network of the fixed telephone, if the calling terminal is a fixed telephone, and the calling terminal is a mobile telephone. If so, the codec characteristics suitable for the communication network of this cellular phone are determined. Since the operation of the music supply system shown in FIG. 1 will be described with respect to a cellular phone, the codec type detection unit 12 of the melody reproduction control server 1 uses the cellular phone to display the codec characteristics of the calling terminal. Is determined by the codec characteristic (step S22 of FIG. 4, step S33 of FIG. 5).

After the determination of the codec characteristic is finished, the codec type detection unit 12 of the melody reproduction control server 1 outputs the determined codec characteristic information to the sound source file transmitter 13. The sound source file transmitter 13 is adapted to the codec characteristic determined from the sound source files F1, F2, F3 stored in the sound source file storage unit 20 of the sound source database 2 based on the received codec characteristic information. The sound source file is searched and the corresponding sound source file is read (step S23 in FIG. 4, steps S34 and S35 in FIG. 5). For example, as shown in FIG. 2, there are three kinds of sound source files F1, F2, and F3 for the same song, and the constituent harmonics are a1 = 3, a2 = 8, and a3 = 40, respectively. The maximum number of chords that can be transmitted through the cellular network is 3 for half rate PDC, 6 for full rate PDC, 10 for cdma, 40 for PHS, 40 for fixed telephone. It shall be none. The premise of the operation description is for a cdma type mobile phone. Therefore, when transmitting to a cdma mobile phone, a sound source file having a maximum number of chords contained in the sound source file is 10 or less. In the example shown in Fig. 2, the sound source file F2 having a harmonic number a2 = 8 is prepared, so that the sound source file F2 having the harmony number 8 is selected.

As shown in Fig. 2, three kinds of sound source files F1, F2, and F3 are created for each of the same pieces 20a, 20b, or 20c. In the example of FIG. 2, as described above, the sound source file F2 is read. The sound source file transmitter 13 of the melody reproduction control server 1 reproduces the read sound source file F1, and stores the GS 53 in the audio mode of PCM 64 Kbit / sec in the sound mode data included in the sound source file F1. (Step S24 of FIG. 4, step S36 of FIG. 5).

The GS 53 transmits the sound source data transmitted in the voice mode to the MSC 54 in order, and the MSC 54 carries the sound source data transmitted from the GS 53 from the wireless base station 51. It is transmitted by radio to the telephone U1. The source cellular phone U1 decodes the data of the sound source file encoded by the melody reproduction control server 1, converts the decoded and decoded sound source data into an analog signal, and outputs the analog signal from the speaker.

Thereafter, the sound source file is transmitted to the calling party's cellular phone U1 (step S24 in FIG. 4 and step S36 in FIG. 5). Thereby, the sound source file is transmitted to the calling party's cellular phone U1 (arrows M1 to M5 in Fig. 1). Therefore, since the sound source file with less deterioration is transmitted to the calling party's cellular phone U1, such a sound source file is reproduced, so that the user can listen to high quality music while waiting to call (step S37 in Fig. 5).

Thereafter, when the called party's mobile phone U2 responds (positive judgment in step S25 of FIG. 4, step S38 of FIG. 5), that is, when the called user comes to the phone, the melody reproduction control server ( A cutting instruction is made in 1) (step S39 in Fig. 5), and the melody reproduction control server 1 stops transmitting the sound source file (step S26 in Fig. 4). Then, the call is possible between the calling party's mobile phone U1 and the called party's mobile phone U2 (steps S40, S41 in Fig. 5).

Although the case of the cdma network has been described herein, the present invention can similarly generate a sound source file corresponding to each codec type with respect to other codec types. Therefore, by storing sound source files suitable for each codec type in advance in the sound source database 2, it is possible to provide music without deterioration of sound quality to all users.

In addition, the melody reproduction control server 1 determines the codec type of the calling mobile phone U1 according to the calling network type included in the start signal IAM, and selects the sound source file of the best sound quality according to the codec type. . In this way, the music supply system of the present embodiment selects and plays a sound source file dedicated to a codec for narrow bands, so that music of the best sound quality can be played in the range that can be reproduced by the codec of the cellular phone.

6 is a flowchart illustrating the operation of the melody reproduction control server in the second embodiment. FIG. 7 is a sequence diagram showing an operation of the entire system according to the second embodiment. FIG. Hereinafter, it demonstrates based on FIG. 1, FIG. 6, and FIG. However, one part same as 1st Embodiment abbreviate | omits description.

In this embodiment, it has basically the same structure as 1st embodiment, and devises further about the determination of the codec type of a mobile telephone. That is, the melody reproduction control server 1 obtains the codec type of the calling party's mobile phone U1 by negotiation. Then, by selecting and playing the best sound source file corresponding to the codec type obtained by the negotiation, it is possible to play music with little sound quality deterioration.

In FIG. 6 and FIG. 7, only parts different from the first embodiment will be described. After receiving the start instruction, the melody reproduction control server 1 (step S2 1 in FIG. 6) then transmits the codec type of the calling party's mobile phone U1 to the MSC 54 at the calling party through the GS 53. FIG. Inquire (step S22 'of FIG. 6, step S331 of FIG. 7). In response to this, a response is obtained (step S332 in Fig. 7), and the codec type is determined.

As described above, in the present embodiment, since the melody reproduction control server 1 voluntarily determines the codec type, not only the case where the melody reproduction control server 1 is activated but also when the cell phone is activated by the melody reproduction control server 1 side. It can be applied to.

The present invention can be widely used in the overall service of listening to music with a mobile phone. For example, the present invention can be used for an outgoing melody service in which music flows in place of a ring tone to a mobile phone, or a service for viewing music by designating a song to be heard by calling a music viewer. In this way, it is possible to provide music without deterioration in sound quality, and has industrial applicability.

As described above, according to the present invention, in a service for listening to music on a mobile phone, a plurality of sound source files in accordance with the codec characteristics of the mobile phone are created and stored in advance, and an optimum sound source file according to the codec type is requested upon reproduction. By selecting and playing, you can play music of the best quality. In other words, since a sound source file that is optimal for a narrow-band codec is selected and connected, it is possible to listen to a song with less sound quality deterioration.

Claims (10)

In the music providing system for providing music to the mobile phone, Sound source file storage means for accumulating a plurality of sound source files created based on the basic sound source file in correspondence with the codec characteristics of the cellular phone; Codec type detection means for detecting a codec characteristic of the mobile phone based on a music reproduction request output from the mobile phone; And a sound source file transmitting means for reading a sound source file corresponding to the codec characteristic detected by the codec type detecting means from the sound source file storing means, reproducing the read sound source file, and outputting music data. Provide system. The method of claim 1, And the plurality of sound source files are created based on the basic sound source file with different simultaneous transmission frequencies. The method of claim 1, And the codec type detecting means detects the codec type of the cellular phone based on the calling network type included in the input start signal. The method of claim 1, And the codec type detecting means detects the codec type of the cellular phone on the basis of negotiation with the radio base station of the caller. The method of claim 1, And the sound source file transmitting means reproduces the sound source file as a ring back tone of the cellular phone and outputs sound source data. A melody reproduction control server used in a music providing system for providing music to a mobile phone through a communication network, And the melody reproduction control server has a function of providing sound source data by reproducing a sound source file corresponding to the codec characteristic of the cellular phone when a reproduction request is made. The method of claim 6, The melody play control server Sound source file storage means for accumulating a plurality of sound source files created based on the basic sound source file in correspondence with the codec characteristics of the cellular phone; Codec type detection means for detecting a codec characteristic of the mobile phone based on a music reproduction request output from the mobile phone; And a sound source file transmitting means for reading a sound source file corresponding to the codec characteristic detected by the codec type detecting means from the sound source file storage means, reproducing the read sound source file, and outputting music data. Replay Control Server. The method of claim 7, wherein And the melody reproduction control server has a function of creating the plurality of sound source files based on a basic sound source file with different simultaneous transmission frequencies. In a method for providing music to a mobile phone through a communication network, Creating a plurality of sound source files according to the codec characteristics of the mobile phone based on the basic sound source file, and pre-scaling these sound source files; Detecting a codec characteristic of the cellular phone based on a music reproduction request output from the cellular phone; Acquiring a sound source file corresponding to the detected codec characteristic from the accumulated sound source files; And a step of reproducing the acquired sound source file to output music data. In the computer of the melody reproduction control server used in the music providing system for providing music to the mobile phone through a communication network, A function of the sound source file storage means for accumulating a plurality of sound source files according to the codec characteristics of the mobile phone based on the basic sound source file; A function of codec type detection means for detecting a codec characteristic of the mobile phone based on a music reproduction request output from the mobile phone; For providing music for executing a function of a sound source file transmission means for acquiring a sound source file corresponding to codec characteristics detected by the codec type detection means from the sound source file storage means, and reproducing the sound source file to output music data The recording medium on which the program is recorded.

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