JPH1130986A - Music data acquiring system for vehicle and on-vehicle moving station applied to this system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the enhancement of communication efficiency by forming condition adaptation music data which is the music data curtailing the data quantity in accordance with reproduction condition data and transmitting this condition adaptation music data to an on-vehicle moving station. SOLUTION: A music data processing section 20 executes data communicate with a vehicle by using a signal transmission and reception circuit 22. This music data processing section 20 reads the music data of the musical piece having a request out of a first memory section 24. The music data processing section 20 subjects the read out music data to the processing meeting the information sent from the vehicle and forms the data for signal transmission. At this time, the min. reproduction threshold data of this vehicle is read out of a second memory section 26 and the compression encoding of the music data is executed in accordance with the min. reproduction threshold data. The data meeting the reproduction ability (monaural, etc.), of the audio apparatus is formed here. Namely, the music data adapted to the music reproduction conditions on the vehicle side is formed for the signal transmission to the vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle music data acquisition system in which an in-vehicle mobile station acquires music data from a radio base station, which system can improve the communication efficiency by reducing the amount of music data. About.

[0002]

2. Description of the Related Art Audio equipment for vehicles has become widespread, and users can enjoy their driving comfortably by playing favorite music using the audio equipment. Conventionally, a music recording medium such as a cassette tape or a CD is mounted on an audio device, and music data read from the medium is output from a speaker. The user has to prepare a medium on which his favorite music is recorded before driving, and bring the medium into the vehicle.

On the other hand, in recent years, it has been proposed to mount a communication device on a vehicle and send various kinds of information from the information center to the vehicle. For example, VICS (Vehicle Information and Communication System), which is a system for providing traffic information to vehicles, has been realized. It has been attempted to further develop such a communication system to send various information to a vehicle. This is expected to improve the functions of the vehicle and provide new services.

[0004]

Under such a background, it is conceivable to send music data to a vehicle using a communication system. For example, when the vehicle user sends a request for a certain song to the information center, the information center returns music data in response to the request. The user can listen to favorite music at any time without preparing a music recording medium in advance, and can enjoy driving more comfortably.

[0005] Here, the communication state between the vehicle and the information center is not always kept in a good condition, and the vehicle may enter a non-communicable area such as a tunnel during data communication. Therefore, it is necessary to transmit music data in as short a time as possible. For that purpose, it is desired to increase communication efficiency as much as possible, that is, to transmit music data that can obtain a sufficiently high sound quality with a data amount as small as possible. However, there is no conventional communication technique for improving communication efficiency in consideration of transmitting music data for listening in a vehicle.

[0006] For example, the wireless telephone device described in Japanese Patent Laid-Open No. 5-7181 receives a voice signal transmitted from a base station, performs variable length coding, and stores the coded voice signal in a semiconductor memory. In this device, data compression is performed after reception, but communication efficiency from the base station to the wireless telephone is not improved.

Conventionally, various compression techniques (MPEG
Audio etc.), and the communication efficiency is improved by applying a compression technique. However, as seen in the communication karaoke system, in the conventional communication system, the same data amount and the same music data are transmitted to any receiving station. This is because the specifications of the audio equipment on the receiving side and the quietness (shielding / soundproof performance) of the music playback place are determined.

On the other hand, when a receiving station is mounted on a vehicle, different vehicles are equipped with different audio equipment. For example, assume that stereo music data is sent to a vehicle equipped with a monaural audio device. For a vehicle, it means that unnecessary data is sent together with necessary music data (for monaural).

In communication of music data, it is common to cut a signal having a standard background noise or less from the music data. However, the degree of silence differs for each type of vehicle, and in many vehicles, a sound having a volume higher than the standard background noise cannot be heard. From the viewpoint of the vehicle, useless data that is inaudible to the user even when reproduced is sent together with the music data.

As described above, when music to be reproduced by a vehicle is communicated, there is room for improving communication efficiency by eliminating useless data in addition to the conventional compression method. The type of data that is wasted differs for each vehicle, and further improvement in communication efficiency can be expected by sending the minimum necessary data to each vehicle.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to acquire music data for a vehicle capable of improving the communication efficiency as compared with the related art from the viewpoint of transmitting music data to the vehicle. It is an object of the present invention to provide a system and a vehicle-mounted mobile station suitable for the system.

[0012]

SUMMARY OF THE INVENTION A vehicle music data acquisition system according to the present invention is a system in which a vehicle-mounted mobile station acquires music data from a radio base station. The on-vehicle mobile station includes a transmitting unit that transmits reproduction condition data relating to a music reproduction condition of the vehicle to the wireless base station, and a receiving unit that receives music data transmitted from the wireless base station. The wireless base station includes: a condition adaptive music data generating unit that generates condition adaptive music data that is music data with a reduced data amount based on the reproduction condition data; and a transmission that transmits the condition adaptive music data to a vehicle-mounted mobile station. Means.

[0013] Further, the on-vehicle mobile station according to one aspect of the present invention acquires music data from a radio base station, and transmits transmission condition data relating to music reproduction conditions of the own vehicle to the radio base station. Receiving means for receiving, from a wireless base station, condition-adaptive music data, which is music data whose data amount has been reduced based on the reproduction condition data, wherein the received condition-adaptive music data corresponds to the music reproduction condition. By performing the processing, the music is reproduced and output.

According to the present invention, the on-vehicle mobile station transmits reproduction condition data indicating the music reproduction conditions of the own vehicle to the radio base station. The vehicle-mounted mobile station that has received the reproduction condition data generates condition-adaptive music data, which is music data with a reduced data amount based on the reproduction condition data.

For example, the reproduction condition data is data relating to the specifications of audio equipment provided in the vehicle-mounted mobile station. The data relating to the audio equipment specification may be the audio equipment specification itself, or may be information that indicates the audio equipment specification, such as “car type”. In this case, the wireless base station stores audio device specifications for each “vehicle type”.

There are various types of audio equipment, such as monaural, stereo, and multi-channel. In the wireless base station, music data is generated according to the type of the audio device on the vehicle side. No data for stereo reproduction is sent to a vehicle equipped with a monaural type device. Therefore, from the viewpoint of the vehicle, only the monaural reproduction data required by the own vehicle can be obtained.

For example, the reproduction condition data is data relating to the quietness of the vehicle. The degree of silence of a vehicle is determined by equipment such as soundproofing members in the vehicle compartment, body rigidity, engine specifications and the like. In a vehicle with a high degree of silence, a relatively low volume sound can be heard by the user. For vehicles with low silence,
A low volume sound cannot be heard by the user. The data relating to the quietness may be the quietness itself (for example, the minimum volume that can be heard in the vehicle). Further, the data regarding the quietness may be “vehicle type” or the like. In this case, the wireless base station is provided with a degree of silence for each “vehicle type”.

In the wireless base station, the amount of music data is reduced based on the quietness of the vehicle. For example, when music data is compressed, data representing a sound having a volume that cannot be heard by a vehicle is deleted. Data with a volume that is higher than the background noise of the normal compression technique will also be cut. Since the silence differs for each vehicle, the amount of data reduction also differs for each vehicle. Due to the above data reduction, music data is transmitted to the vehicle without unnecessary data that cannot be heard by the user even when reproduced. Regardless of a vehicle with a high degree of silence or a vehicle with a low degree of silence, sound data in a range audible by the vehicle can be sufficiently reproduced, and music data with a data amount as small as possible is transmitted.

As described above, according to the present invention, condition-adaptive music data, which is music data whose data amount has been reduced based on the reproduction condition data, is transmitted from the radio base station to the vehicle-mounted mobile station. In the on-vehicle mobile station, the condition-adaptive music data is subjected to processing corresponding to the music reproduction conditions of the own vehicle, and the music is reproduced and output. Therefore, the amount of data during communication can be effectively reduced to the extent that sufficient sound quality can be obtained under the music playback conditions of the vehicle. In particular, in response to different music playback conditions for each vehicle, data communication without waste is performed for each vehicle. Thereby, communication efficiency is improved, and the vehicle can acquire music data in a short time.

More preferably, both the audio equipment specifications and the quietness are used as the reproduction condition data. For each audio device, speaker performance etc.
Various performance values are different, and the frequency-volume range that can be reproduced from the speaker is also different. Further, there is a frequency-volume region that can be heard by the user according to the quietness of the vehicle. In consideration of the two areas, music data in an area worth sending to the vehicle (that is, sound that can be reproduced and output and that can be heard by the user) is transmitted as condition-adaptive music data. Further, as described above, the data amount is appropriately reduced according to the type such as monaural or stereo. Thereby, the communication efficiency is further improved.

It is preferable to employ the data reduction of the present invention in addition to the conventional compression technique. Thereby, both data reduction effects are combined, and communication efficiency is further improved. For example, as shown in an embodiment described later, M
The above-mentioned compression based on vehicle quietness can be incorporated into PEG audio compression.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention (hereinafter, referred to as embodiments) will be described below with reference to the drawings.
In the present embodiment, the information center corresponds to the wireless base station of the present invention. The requested song title is sent from the vehicle to the information center. Music data is sent from the information center to the vehicle in response to the request.

[Data Reduction Method] First, the principle of the data amount reduction method during communication in this embodiment will be described. From the vehicle to the information center, playback condition data relating to the music playback conditions of the own vehicle is sent together with the requested music title. The reproduction condition data includes a vehicle type, a vehicle model, audio device specifications, and the like. The audio device specifications include various hardware and software information on the audio output device and the data communication related device as necessary. The information center, based on the information sent from the vehicle,
The music data with the least data amount is returned as much as possible within the range suitable for the vehicle that sent the request. In the present embodiment, the data amount of music data is reduced by using the following methods (1) and (2) together.

(1) "Data reduction based on audio equipment specifications (number of channels, etc.)" Audio equipment specifications include audio reproduction capability (reproducible level) such as monaural, stereo, and multi-channel (for example, 5.1 channels). Is included. The information center
Returns music data that matches the playback ability. For example, if the vehicle has monaural audio equipment,
Returns monaural music data. For the stereo type and the multi-channel type, stereo music data and multi-channel music data are returned, respectively. There is no transmission of stereo music data or multi-channel music data to vehicles equipped with monaural type audio equipment. Therefore, useless data is omitted, and the amount of data during communication is reduced. In a specific configuration example described later, a case where either monaural data or stereo data is transmitted will be described.

(2) "Psychoacoustic coding based on vehicle characteristics" An international standard, MPEG, is used as a compression method for music data.
There are audio standards. In the MPEG audio standard,
As described below, sound data that cannot be heard by humans is deleted. This is so-called psychoacoustic coding.

(A) Cut of data having a volume lower than the minimum audible limit during silence. (B) frequency mask area cut. Human ears do not hear sounds that are close in frequency. Therefore, the small sound whose frequency is close to the loud sound is cut. (C) Cut of the time mask area. Since a small sound immediately after a loud sound cannot be heard by a human ear, this small sound is cut.

FIG. 1 shows an MPEG compression method. In FIG. 1, the horizontal axis is frequency and the vertical axis is volume.
The solid line in the figure shows the waveform of the music data before compression at a certain point in time. An alternate long and short dash line X is a line indicating the minimum audible limit of (A). A dotted line Y is called a masking threshold, and is a line indicating the mask region in the above (B) and (C). In MPEG, by cutting data with a volume below the two lines X and Y,
Data volume is reduced.

In this embodiment, a "minimum reproduction limit characteristic" indicated by a thick dotted line Z in FIG. 1 is further set. As described below, the line of the minimum reproduction limit characteristic is a line for cutting data that is not worth sending to the vehicle and improving communication efficiency, and is set based on the following two conditions.

(A) Quietness (Noise State) As described above, the quietness is determined by equipping a vehicle with soundproofing members and the like.
Determined by body composition, engine specifications, etc. In the present embodiment, the quietness of the vehicle is specified based on the vehicle type information. Quietness determines the actual minimum audible limit in a vehicle. The actual minimum audible limit in a car is usually higher than the minimum audible limit in quietness specified by MPEG. The minimum reproduction limit characteristic line Z is set so that data below the actual minimum audible limit is cut.

(B) Audio equipment specifications Audio equipment has superiority in performance such as speaker performance. Therefore, the reproducible frequency-volume range differs for each audio device. Therefore, the minimum reproduction limit characteristic line Z is set based on the specifications of the audio equipment so that data in an unreproducible area is cut.

The above-mentioned minimum reproduction limit characteristics are as follows for each vehicle type.
Also, it differs for each audio device. Data indicating the characteristic line Z of the vehicle that sent the request is used in the information center. Music data is compression-encoded using the characteristic line Z and the signal cut lines X and Y of MPEG. At this time, data having a volume lower than any of the lines X, Y, and Z is deleted, and data having a volume higher than all the lines are encoded.

In the configuration example described later, the information center
A table in which the vehicle type, the audio device, and the characteristic line Z are associated with each other is prepared. Based on the information sent from the vehicle, a characteristic line Z of the vehicle that sent the request is selected from the table.

As described above, by using the "minimum reproduction limit characteristic", unnecessary data which cannot be heard by the user even when reproduced is deleted according to the quietness of the vehicle (a). Further, data that cannot be reproduced by the vehicle is deleted based on the audio equipment specifications of the vehicle (b). Therefore, data worth sending to the vehicle (that is, data that is actually reproducible on the vehicle side and can be heard by the user) is transmitted. Since unnecessary data is omitted, communication efficiency is improved.

"Example of Configuration of Vehicle Music Data Acquisition System" FIG. 2 is a block diagram showing the configuration of the vehicle music data acquisition system of the present embodiment. In the left half of the figure, the control unit 1 controls the entire system on the vehicle side. A vehicle storage unit 3 is connected to the control unit 1, and a song title list is stored in the vehicle storage unit 3. The song title list is used when receiving a request from a user. Further, the vehicle storage unit 3 stores a vehicle type (including a model year), a CPU type of the control unit 1, and audio equipment specifications as vehicle additional information. Further, the vehicle storage unit 3 stores music data obtained from an information center using the present system. Whether to write the music data to the vehicle storage unit 3 when acquiring the music data is determined according to a user's instruction.

A joystick switch 7 and a voice recognition device 9 are connected to the control unit 1 via an input interface unit 5. The user can input various instructions to the control unit 1 by operating the joystick switch 7. The instruction includes an instruction to start or stop the reproduction of music and a request music. The user can also input the same instruction by voice via the voice recognition device 9.

An audio speaker 13 and a display 15 are connected to the control unit 1 via an output interface unit 11. The control unit 1 decodes the music data obtained from the information center, and sends it to the audio speaker 13 via the output interface unit 11. Music data is output from the audio speaker 13 after amplification. The display 15 displays the title of the music being played back. In addition, a list of song names that can be requested is displayed on the display 15 in order to accept a request from the user. The user can display 1
5, the user operates the joystick switch 7 or inputs the requested song title by voice. In addition, the display 15 may be used also as a display device for another device such as a vehicle-mounted navigation device.

Further, a transmission / reception circuit 17 is connected to the control unit 1, and the control unit 1 performs data communication with the information center using the transmission / reception circuit 17.

Next, the configuration of the information center will be described. The music data processing unit 20 functions as a control unit that controls the entire system on the information center side. A transmission / reception circuit 22 is connected to the music data processing unit 20, and the music data processing unit 20 performs data communication with the vehicle using the transmission / reception circuit 22.

The music data processing section 20 is connected to a first storage section 24 and a second storage section 26. First
The storage unit 24 stores music data of a large number of songs for responding to requests. The “minimum limit characteristic data” described above with reference to FIG. 1 is stored in the second storage unit 26 in the form of a characteristic table. In the characteristic table, combinations of vehicle types and audio equipment specifications are associated with minimum limit characteristic data corresponding to the combinations.

The music data processing unit 20 reads the music data of the requested music from the first storage unit 24. Then, the music data processing unit 20 performs processing according to the information sent from the vehicle on the read music data,
Generate data for transmission. At this time, the minimum reproduction limit data of the corresponding vehicle is read from the second storage unit 26, and the music data is compression-encoded based on the minimum reproduction limit data. As described above with reference to FIG. 1, data compression is performed using the minimum reproduction limit data and effectively utilizing the characteristics of the vehicle while complying with MPEG. Here, data suitable for the reproduction capability (monaural etc.) of the audio device is generated. In this way, music data adapted to the music reproduction conditions on the vehicle side is generated for transmission to the vehicle.

The music data processing unit 20 is connected to the Internet 28. The song requested by the vehicle may not be stored in the first storage unit 24. At this time, the music data processing unit 20 obtains unowned music data via the Internet 28. The obtained music data is used to generate music data for transmission in the music data processing unit 20 and is written to the first storage unit 24.

Next, the processing from the request of the user to the reproduction of the requested music will be described with reference to the flowchart of FIG. First, a request music is selected by the user on the vehicle side (S10). At this time, the control unit 1
Reads out the song title list stored in the vehicle storage unit 3 and causes the display 15 to display it. The user looks at the display 15 and inputs the requested music title by operating the joystick switch 7 or by voice input. When the requested music title is input, the control unit 1 reads out the vehicle additional information from the vehicle storage unit 3. As described above, the vehicle additional information includes the vehicle type, the type of the CPU, and the audio equipment specification. The control unit 1 adds vehicle information to the title of the requested music (S12). Then, the request to which the vehicle information is added is transmitted to the information center using the transmission / reception circuit 17.

In the information center, the music data processing unit 2
0, upon receiving the request (S16), determines whether the requested music is stored in the first storage unit 24 (S18). If so, the music data processing unit 20 reads the data from the first storage unit 24 (S22). If not, the music data processing unit 20 searches for data using the Internet (S
20), the data of the requested music is read via the Internet (S22).

Next, the music data processing unit 20 reads the minimum reproduction limit data of the vehicle that has sent the request from the second storage unit 26 (S24). Here, the vehicle additional information attached to the request sent from the vehicle is referred to. Then, the minimum reproduction limit data corresponding to the vehicle type and the audio equipment specification is read.

Further, the music data processing section 20 checks the reproduction capability (reproducible level) of the audio device on the vehicle side, and determines whether or not the audio device is a monaural type (S26). This determination is also made based on the vehicle additional information sent from the vehicle. In the case of NO (stereo) in S26, the music data read in S22 is compression-encoded,
Music data for stereo is generated as data for transmission (S28). Here, as described with reference to FIG. 1, compression using the minimum reproduction limit data read in S24 is performed in compliance with MPEG. On the other hand, if YES (monaural) in S26, monaural music data for transmission is generated (S30). MPEG in S30
Compression encoding using the minimum reproduction limit is performed. The music data (condition-adaptive music data) compressed and encoded in S28 or S30 is transmitted from the music data processing unit 20 to the vehicle via the transmission / reception circuit 22 (S3).
2). When information indicating the type of monaural or stereo is not sent from the vehicle side, stereo music data is generated as a default.

When the vehicle receives the music data (S34), the control section 1 decodes the compressed data.
Decoding is performed in a procedure reverse to the compression (S28, S30) on the information center side. The vehicle storage unit 3 stores its own minimum reproduction limit data, and this data is used for decoding processing as appropriate. The control unit 1 converts the decrypted data into
The signal is sent to the audio speaker 13 via the output interface 11. Music data converted into an analog signal by a D / A converter (not shown) and amplified by an amplifier (not shown) is output from the audio speaker 13 (S
36). At this time, the control unit 1 causes the display 15 to appropriately display the title of the song being reproduced.

The preferred embodiment of the present invention has been described above. According to the present embodiment, the data amount of music data for communication is reduced based on the audio equipment specification (monaural, stereo, etc.) of the vehicle receiving the music data. Also, as shown in FIG. 1, compression processing is performed based on the minimum reproduction limit characteristic of the vehicle that has sent the request, and data that cannot be reproduced on the vehicle side or data that cannot be heard by the user even after reproduction is deleted. Is done. In this manner, the amount of data during communication can be effectively and significantly reduced within a range where sufficient sound quality can be obtained under the music playback conditions of the vehicle. In particular, in response to different music reproduction conditions for each vehicle, lean data communication suitable for the other vehicle is performed. Thereby, communication efficiency is improved, and the vehicle can acquire music data in a short time. The probability of occurrence of a situation where a vehicle enters a communication disabled area during communication is also reduced.

In this embodiment, the minimum reproduction limit data is stored in the second storage unit 26 on the information center side. On the other hand, the minimum reproduction limit data may be added to the request and transmitted from the vehicle to the information center when transmitting the request.

On the information center side, music data which has been compressed and encoded in advance may be prepared and stored in a storage medium. In this case, a plurality of music data are prepared for one song. Each data is compressed so as to conform to different music reproduction conditions (vehicle type and audio equipment specification). A request for a song and vehicle additional information are sent to the information center. The music data processing unit 20 reads out the data of the requested music corresponding to the vehicle additional information from the storage medium. The read data is sent to the vehicle. According to this configuration, data transmission to the vehicle can be started in a short time as compared with starting the compression encoding process in response to the request.

As a modification of the present embodiment, it is preferable that the vehicle additional information added to the request include the current operating rate of the CPU of the control unit 1. For example, assume that the vehicle-side system in FIG. 2 is integrated with a navigation device. For the route guidance processing, the CP of the control unit 1
It is assumed that the operation rate of U has reached 30%. The control unit 1
The operation rate of the CPU is included in the vehicle additional information and transmitted to the information center. In the information center, the music data processing unit 20
Generates transmission music data corresponding to the CPU operation rate. This avoids communication of music data that cannot be processed by the CPU on the vehicle side. The control unit 1 can quickly process the sent music data.

In addition, in the present embodiment, the user
In S10, a plurality of requests can be input collectively. Also, a request can be input during the reproduction of another song. Processing and data communication on the information center side take some time, and it may not be possible to respond to requests in real time. Even in this case, the user can enjoy a plurality of songs continuously without a break, by a batch request for a plurality of songs or a request during reproduction of another song.

[Brief description of the drawings]

FIG. 1 is a diagram showing a data amount reduction method of music data according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a vehicle music data acquisition system according to an embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the system of FIG. 2;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 control unit, 3 vehicle storage unit, 5 input interface, 7 joystick switch, 9 voice recognition device, 11 output interface, 13 audio speaker, 15 display, 17 transmission / reception circuit, 20
Music data processing unit, 22 transmission / reception circuit, 24 first storage unit, 26 second storage unit.

Claims (4)

[Claims] 1. A vehicle music data acquisition system in which an in-vehicle mobile station acquires music data from a wireless base station, wherein the in-vehicle mobile station transmits reproduction condition data relating to music reproduction conditions of the vehicle to the radio base station. Transmitting means, and receiving means for receiving music data transmitted from the wireless base station, wherein the wireless base station is condition-adaptive music that is music data whose data amount is reduced based on the reproduction condition data. A music data acquisition system for vehicles, comprising: condition-adaptive music data generating means for generating data; and transmitting means for transmitting the condition-adaptive music data to a vehicle-mounted mobile station. 2. The vehicle music data acquisition system according to claim 1, wherein the reproduction condition data includes data relating to an audio equipment specification of an on-vehicle mobile station. 3. The vehicle music data acquisition system according to claim 1, wherein the reproduction condition data includes data relating to quietness of the vehicle. 4. An in-vehicle mobile station for acquiring music data from a radio base station, comprising: transmitting means for transmitting reproduction condition data relating to music reproduction conditions of the own vehicle to the radio base station; and data based on the reproduction condition data. Receiving means for receiving, from the radio base station, condition-adaptive music data, which is music data of a reduced amount, and performing a process corresponding to the music reproduction condition on the received condition-adaptive music data, thereby reproducing music. An in-vehicle mobile station for reproducing and outputting.