Music contents reproducing apparatus

A contents reproduction control portion uses feature quantity data about feature quantities of pieces of music and an interference degree table which defines degrees of interference among the feature quantities. In this manner, interference music to be output from between front-seat speakers and music to be output from rear-seat speakers is at least partially avoided.

TECHNICAL FIELD

The present invention relates to a music contents reproducing apparatus to be mounted in a vehicle or the like.

BACKGROUND ART

Some of music contents reproducing apparatuses to be mounted in vehicles such as cars are designed to be able to reproduce different music contents for front seats and rear seats. When different music contents for front seats and rear seats are reproduced in such an apparatus, headphones or earphones are used.

On the other hand, there has been proposed a technique called a sound image localization system, in which music can be listened to without use of headphones or the like (e.g. see Patent Document 1). According to this technique, parametric speakers are disposed in the back surface of a front seat so as to form a sound space with directivity in a head portion of a rear seat. This technique can limit a sound extent to some extent.

DISCLOSURE OF THE INVENTION

Problems that the Invention is to Solve

However, when different music contents are reproduced in the front seat and the rear seat by use of the sound image localization system, some kinds of music reproduced in the front seat and the rear seat respectively may give influence to each other or from one to the other. For example, when classical music is reproduced in the front seat and rock music is reproduced in the rear seat, interference occurs to make it difficult to listen to the music. When pieces of music belonging to one and the same category or violent pieces of music are reproduced, it may be difficult to listen to the pieces of music subjectively.

The present invention was developed in consideration of the foregoing situation. An object of the invention is to provide a music contents reproducing apparatus which can reproduce a plurality of pieces of music contents without causing interference with each other.

Means for Solving the Problems

According to the present invention, there is provided a control unit for controlling which piece of music contents to be output to one output portion in accordance with music contents to be output to another output portion using physical quantity data about physical quantities of respective pieces of music contents and a table which defines degrees of interference among the physical quantities. According to this configuration, music contents to be output to one output portion and music contents to be output to another output portion are selected using the interference table which defines degrees of interference among physical quantities of respective pieces of music contents. Thus, a plurality of pieces of music contents can be reproduced without causing interference with each other.

Effect of the Invention

According to the present invention, music contents to be output to one output portion and music contents to be output to another output portion are selected using an interference table which defines degrees of interference among physical quantities of respective pieces of music contents. Thus, a plurality of pieces of music contents can be reproduced without causing interference with each other.

DESCRIPTION OF REFERENCE NUMERALS

100,200music contents reproducing apparatus10,12input/output unit11,13speakers14headphones15audio output control portion16headphones connection detection portion17contents data storage portion18contents feature sort database19contents feature acquiring portion20,20B contents reproduction control portion21running state acquiring portion

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment

FIG. 1is a block diagram showing the schematic configuration of a music contents reproducing apparatus according to the first embodiment of the present invention. InFIG. 1, a music contents reproducing apparatus100according to this embodiment has a front-seat input/output unit10, front-seat speakers11, a rear-seat input/output unit12, rear-seat speakers13, rear-seat headphones14, an audio output control portion15, a headphones connection detection portion16, a contents data storage portion17, a contents feature sort database18, a contents feature acquiring portion19and a contents reproduction control portion20.

The front-seat input/output unit10has a display, a touch panel, etc. The front-seat input/output unit10inputs operation for activating each function of this apparatus100in a front seat, indication of the status of the input operation, indication of the status of execution of the function, etc. The front-seat speakers11perform sound output on the front seat side. The rear-seat input/output unit12has a display, a touch panel, etc. The rear-seat input/output unit12inputs operation for activating each function of this apparatus100in a rear seat, indication of the status of the input operation, indication of the status of execution of the function, etc. The rear-seat speakers13perform sound output on the front seat side. The rear-seat headphones14are used when music contents are listened to on the rear seat side.

The audio output control portion15controls supply of sound signals to the front-seat speakers11, the rear-seat speakers13and the headphones14. When a piece of music should be reproduced on the front seat side, the audio output control portion15supplies a sound signal of the piece of music to the front-seat speakers11. When a piece of music should be reproduced on the rear seat side, the audio output control portion15supplies a sound signal of the piece of music to the rear-seat speakers13or the headphones14. When the headphones14are not used, the sound signal of the piece of music to be reproduced on the rear seat side is supplied to the rear-seat speakers13. When the headphones14are used, the sound signal of the piece of music is supplied to the headphones14.

The headphones connection detection portion16detects the connection of the headphones14to an audio output terminal (not shown) of the apparatus body. The headphones connection detection portion16inputs a headphones detection signal to the contents reproduction control portion20when the headphones connection detection portion16detects the connection of the headphones14. The contents data storage portion17stores music contents ripped from recording media such as DVDs, CDs, etc. or music contents acquired by receiving TV broadcasts or radio broadcasts. The contents feature sort database18stores a sort table showing combinations of a plurality of pieces of music contents. The sort table is created when music contents are registered in the contents data storage portion17.

FIG. 2is a table showing an example of the sort table. InFIG. 2, music (music contents) and features of the music are registered in the form of normalized values ranging from 0 to 1. In Music1, for example, a parameter indicating violence is “1.0”, a parameter indicating rhythmicity is “0.5”, a parameter indicating freshness is “0.1”, a parameter indicating simplicity is “0.2”, and a parameter indicating softness is “0.0”. In Music2, a parameter indicating violence is “0.0”, a parameter indicating rhythmicity is “0.2”, a parameter indicating freshness is “0.5”, a parameter indicating simplicity is “0.7”, and a parameter indicating softness is “1.0”.

The sort table is created by use of CDDB (CD DataBase) or contents feature extraction technology. The sort table shows a plurality of features of music contents. CDDB is a database for providing users with information about music recorded on music CDs or music/video DVDs. For use of CDDB, the music contents reproducing apparatus100is designed to have a function of gaining access to the Internet.

The contents feature extraction technology, for example, includes the technique disclosed in JP-A-2002-278547. According to JP-A-2002-278547, eight physical feature quantities shown inFIG. 3are extracted from an input sound signal, and the extracted feature quantities are converted into impression values, that is, numerical quantities expressing subjective impressions of each piece of music by Expression (1).

In Expression (1), Ii designates an impression value with respect to an impression factor i, Pj designates a value of a feature quantity j, and Wij designates a weighting factor indicating the relation between the feature quantity j and the impression factor i. The impression value Ii is a numerical quantity indicating the subjective impression of a piece of music. The impression value Ii is used as a numerical quantity integrating degrees (referred to as Ej) of impressions which can be expressed by specific adjectives. When, for example, the impression of a piece of music is expressed by degrees from five aspects “violence (E1)”, “rhythmicity (E2)”, “freshness (E3)”, “simplicity (E4)” and “softness (E5)”, Ii can be obtained from Ej by Expression (2).

Return toFIG. 1again. The contents feature acquiring portion19acquires the features (violence, rhythmicity, freshness, simplicity, softness, etc.) of music contents registered in the contents data storage portion17. The features of the music contents acquired by the contents feature acquiring portion19are registered in the aforementioned sort table.

The contents reproduction control portion20has a function to output Music N, which will hardly interfere with Music1to be output to the front speakers, to the rear-seat speakers using feature quantity data about the feature quantities of Music1and an interference degree table which defines the degree of interference among feature quantities. The contents reproduction control portion20is constituted by a not-shown CPU (Central Processing Unit), a ROM storing programs for controlling the CPU, a RAM to be used in the operation of the CPU, etc.

When an operation to reproduce music contents is performed by the front-seat input/output unit10in the state where the music contents have been stored in the contents data storage portion17, the contents reproduction control portion20reads the music contents from the contents data storage portion17and inputs the music contents into the audio output control portion15together with a selection signal for selecting the front-seat speakers11. When an operation to reproduce music contents is performed by the rear-seat input/output unit12in the state where no music contents are being reproduced on the front-seat side, the contents reproduction control portion20reads the music contents from the contents data storage portion17and inputs the music contents into the audio output control portion15together with a selection signal for selecting rear-seat speakers13. In this event, when a headphones detection signal has been beforehand input from the headphones connection detection portion16, the contents reproduction control portion20inputs a selection signal for selecting the headphones14to the audio output control portion15. When a headphones detection signal is input in the middle of selection of the rear-seat speakers13, the contents reproduction control portion20changes the devices from the speakers13to the headphones14.

The contents reproduction control portion20uses the headphones connection detection portion16to determine whether the headphones14are connected or not. When the headphones14are connected, the contents reproduction control portion20cancels the selection of the music contents to be output to the front seat or the rear seat. When the headphones14are not connected, the contents reproduction control portion20carries out the selection. The contents reproduction control portion20refers to the sort database to obtain the degree of interference of music contents selected on the front seat side with other music contents stored in the contents data storage portion17. After obtaining the degree of interference with any other music contents, the contents reproduction control portion20will cancel the selection of the music contents if the degree of interference of the music contents exceeds a predetermined threshold value.

The degree of interference is obtained by Expression (3) in this embodiment.

In Expression (3), m and n designate pieces of music, F(i,j) designates an influence ratio of a feature quantity, α(i,m) designates a feature quantity of the piece of music m, and α(j,n) designates a feature quantity of the piece of music n. The influence ratio F(i,j) of the feature quantity is obtained from the interference degree table shown inFIG. 4. The interference degree table expresses the influence ratio F(i,j) of the feature quantity between the two pieces of music. In the case ofFIG. 4, the influence ratio between “violence” and “violence” is “1.0” indicating 100%, the influence ratio between “violence” and “rhythmicity” is “0.5” indicating 50%, the influence ratio between “violence” and “freshness” is “0.1” indicating 10%, the influence ratio between “violence” and “simplicity” is “0.2” indicating 20%, and the influence ratio between “violence” and “softness” is “0.0” indicating 0%. The interference degree table may be stored in the contents reproduction control portion20, or may be stored in the contents data storage portion17or the contents feature sort database18.

In the sort table shown inFIG. 2, each feature parameter of one piece of music is multiplied by all of feature parameters of the other piece of music. Each multiplication result is multiplied by the influence ratio FF(i,j) of the corresponding feature quantity in the interference degree table. Thus, the degree of interference between the two pieces of music is obtained. For example, in the case of Music1and Music2in the sort table ofFIG. 2, the degree of interference is obtained as follows.

In such a manner, the degree of interference between two pieces of music is obtained.

FIG. 5is a flow chart showing a process for removing pieces of music causing interference. When there is a music list display request from the rear seat (Step S10), the feature quantities of a piece of music reproduced in the front seat are acquired (Step S11). Next, whether the headphones14are connected or not is determined based on whether there is a headphones detection signal from the headphones connection detection portion16(Step S12). When the headphones14are connected, a music list is displayed without being edited (Step S13). On the contrary, when the headphones14are not connected, searching the music list is started (Step S14). First, the degree of interference between Music1included in the music list and the piece of music reproduced in the front seat is calculated (Step S15).

Next, it is determined whether the calculated degree of interference is a value exceeding a predetermined threshold value Th or not (Step S16). When the calculated degree of interference is not larger than the threshold value Th, the routine of processing returns to Step S14. When the calculated degree of interference is not smaller than the threshold value Th, Music1is removed from the music list (Step S17). Thus, the aforementioned process of Steps S14to S17is repeated on each selected piece of music. Pieces of music whose degree of interference exceeds the threshold value Th are removed from the music list. Thus, an edited music list is created. The created music list is output to the rear-seat input/output unit12and displayed on a display (Step S13).

According to the music contents reproducing apparatus in this embodiment, when a plurality of pieces of music contents to be reproduced simultaneously in the front seat and the rear seat are selected, music contents causing no interference with each other can be selected with reference to the interference degree table.

In the aforementioned embodiment, when a piece of music which is being reproduced is changed to another piece of music in the middle without listening to the end in either the front seat or the rear seat, interference may be caused by the changed piece of music. When such a state is detected with reference to the degrees of interference among respective pieces of music contents, the interference can be reduced by narrowing only the volume for reproduction of the changed piece of music contents or both the volumes for reproduction of the two pieces of music contents.

Second Embodiment

FIG. 6is a block diagram showing the schematic configuration of a music contents reproducing apparatus according to the second embodiment of the present invention. InFIG. 6, a music contents reproducing apparatus200according to this embodiment is the same as the aforementioned music contents reproducing apparatus according to the first embodiment, except that the music contents reproducing apparatus200includes a running state acquiring portion21for acquiring the running state of a vehicle mounted with this apparatus.

For example, the running state acquiring portion21regards the vehicle as parked when the vehicle velocity is not higher than 8 km/h and the parking brake of the vehicle is applied. The running state acquiring portion21regards the vehicle as running when the vehicle velocity is higher than 8 km/h. The running state of the vehicle is acquired thus, and the acquired running state is input to the contents reproduction control portion20B. The contents reproduction control portion20B calculates the degree of interference between two pieces of music contents based on parameters decided in accordance with the reproduction environment of the music contents taking the current running state of the vehicle into consideration. The peripheral noise increases when the vehicle is running at a high speed, for example, when the vehicle is running on an expressway or the like. Accordingly, the feature parameters are changed in accordance with the vehicle velocity so as to relax the limitation of the degree of interference.

The feature parameters are changed, for example, by use of a vehicle velocity influence degree table shown inFIG. 7. In this vehicle velocity influence degree table, for example, the feature parameter indicating “violence” is set at “1.0” when the vehicle is parked, “0.8” when the vehicle velocity is not higher than 8 km/h, “0.6” when the vehicle velocity is higher than 8 km/h and not higher than 50 km/h, “0.4” when the vehicle velocity is higher than 50 km/h and not higher than 90 km/h, “0.2” when the vehicle velocity is higher than 90 km/h and not higher than 110 km/h, and “0.0” when the vehicle velocity is higher than 110 km/h.

The degree of interference in consideration of the influence of the vehicle velocity can be obtained by Expression (4).

Thus, according to the music contents reproducing apparatus200in this embodiment, the degree of interference is calculated based on feature parameters decided in accordance with the vehicle velocity so that a music list suitable to the reproduction environment of the music contents reproducing apparatus200can be created.

Although the present invention has been described in detail and with reference to its specific embodiments, it is obvious to those skilled in the art that various changes or modifications can be made on the present invention without departing from its spirit and scope.

This application is based on a Japanese patent application (Japanese Patent Application No. 2004-287927) filed on Sep. 30, 2004, contents of which are incorporated herein by reference.

INDUSTRIAL APPLICABILITY

In the music contents reproducing apparatus according to the present invention, music contents to be output to one output portion and music contents to be output to another output portion are selected by use of an interference table which defines the degrees of interference among physical quantities of respective pieces of music contents. Accordingly, the music contents reproducing apparatus has an effect that a plurality of pieces of music contents can be reproduced without causing interference with each other, and is useful as a music contents reproducing apparatus or the like mounted in a car or the like.