JP2012100104A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide "an electronic device" which prevents the generation of a soundless state as much as possible even if a communication condition deteriorates.SOLUTION: The electronic device of the present invention comprises: a data communication part 100 which can be used on a movable body and performs data communication with the outside; a receiving part 110 which receives stream data from a server 20 through the data communication part 100; a reproduction part 150 which reproduces the received stream data; a position detection part 162 which detects position information on the movable body; a communication condition determination part 164 which determines whether a communication condition is excellent or not based on the detected position information; an input part 140 which receives an instruction from a user; and a receiving control part 166 which suppresses the instruction so that the reproduction of the stream data being reproduced now can be continued when it is determined that the communication condition is not excellent, when an instruction to change the stream data being reproduced now is given through the input part.

Description

  The present invention relates to an electronic apparatus having a function of receiving and reproducing stream data distributed via a network or the like, and more particularly, to a reproduction control system for an electronic apparatus used on a mobile object.

  Internet radio typified by Pandora is a service that dynamically downloads and plays music content in an area that can be connected to the Internet via a mobile network. The in-vehicle device electronic device also has a function of connecting to the Internet using a wide-area or narrow-area network service, a public telephone line network, or the like, so that it is possible to view Internet radio while driving.

  In a mobile object typified by a vehicle, the position changes gradually and the communication situation is not always stable. Depending on the location, radio wave reception sensitivity or communication speed may decrease, or even in the worst case, communication may not be possible. Japanese Patent Laid-Open No. 2004-133867 solves such a problem. The in-vehicle device notifies the server of position information, and the server predicts the communication status of the in-vehicle device based on the received position information, and immediately matches the prediction result. Change the bit rate to the content and distribute the content to the in-vehicle device. For example, when the vehicle is approaching a tunnel, the server predicts deterioration of the communication status of the in-vehicle device and changes the content to be distributed to a lower bit rate.

JP 2006-197453 A

  When the conventional electronic device on the vehicle-mounted device cannot access the network due to the deterioration of the communication status, it cannot download the content data from the server and is forced to stop the reproduction. For this reason, in the electronic device on the vehicle-mounted device side, the cached data is reproduced while the content data is cached (buffered) in the memory. As a result, even if access to the server becomes intermittent or the bit rate for downloading content data becomes low, the content data can be reproduced continuously.

  However, for example, when playing music data distributed by Internet radio, when the user falls into a state where access to the temporary network is not possible, if the user operates skip to the next song, the cached data will not be It is necessary to play the music data of the song, but the music data of the next song cannot be downloaded, and the cached music data cannot be used effectively as playback data. There is a problem of becoming. Such a reproduction stop or silent state is unfavorable because it gives a user discomfort.

  An object of the present invention is to solve such a conventional problem and to provide an electronic device that prevents the occurrence of a silent state as much as possible even when the communication state deteriorates.

  An electronic apparatus according to the present invention is usable on a mobile body, and includes a communication unit that performs data communication with the outside, a reception unit that receives stream data from the outside via the communication unit, and the reception unit A buffer memory for storing a certain amount of stream data received in the above, a reproducing means for reproducing the stream data stored in the buffer memory, an output means for outputting the data reproduced by the reproducing means, and a communication means A determination unit that determines whether or not the data communication status is good, an input unit that receives an instruction from a user, and the determination unit when there is an instruction to change the stream data that is currently reproduced via the input unit If it is determined that the data communication status is not good, the process according to the instruction so that the output from the output means is continued. And a control means for controlling.

  Preferably, the control unit invalidates an instruction from the input unit. Preferably, the control means controls the receiving means so as not to receive stream data to be changed in response to an instruction from the input means. Preferably, the control means includes means for generating a warning sound when instructed from the input means. The electronic device further includes detection means for detecting position information of the moving body, and the determination means is configured to communicate based on communicable area information indicating an area where data communication is possible and position information detected by the detection means. It can be determined whether or not. Preferably, when the mobile unit is located within a certain distance from the boundary of the communicable area indicated by the communicable area information and the direction of the mobile unit exceeds the boundary, the communication status is not good. judge. Preferably, the determination unit refers to speed information of the moving body and varies the certain distance according to the speed of the moving body. Preferably, the determination unit refers to the route when the route to the destination is set, and determines that the communication status is not good when the route exceeds the boundary of the communicable area. Preferably, the determination unit determines that the communication state is not good when the reception rate of the stream data by the reception unit is smaller than the reproduction rate of the stream data by the reproduction unit. Preferably, the electronic device further includes storage means for storing audio data, and the control means switches to reproduction of the audio data stored in the storage means in response to an instruction from the input means, and the determination means When it is determined that the data communication status is good, the reproduction is switched to the reproduction of the stream data instructed from the input means. Preferably, the control means continues the output from the output means until the stream data stored in the buffer memory becomes empty when an instruction to change the stream data is given from the input means, and then stores it in the storage means. Switch to playback of stored audio data.

  A mobile data reproduction system according to the present invention includes an electronic device having the above characteristics and a stream data distribution device capable of wirelessly communicating with the electronic device. Preferably, the stream data distribution device is a server for distributing music data by Internet radio.

  According to the present invention, when the communication status deteriorates, control is performed so that the currently reproduced stream data is continued, so that it is possible to suppress the occurrence of reproduction stop or silence state as much as possible. Thereby, discomfort to the user can be reduced.

It is a figure explaining the outline of the data reproduction system of the mobile body which concerns on the Example of this invention. It is a block diagram which shows the typical structure of the electronic device shown in FIG. It is a figure explaining operation | movement of the receiving part shown in FIG. It is a figure explaining the function contained in the control part shown in FIG. It is a figure explaining the example of communicable area information. It is a flowchart explaining the reproduction | regeneration operation | movement of the electronic device which concerns on 1st Example of this invention. It is a flowchart explaining reproduction | regeneration operation | movement of the electronic device which concerns on 2nd Example of this invention. It is a figure explaining the judgment of a communication condition when the route to the destination is searched in the 2nd Example. It is a table which shows the relationship between the speed to the moving body by the 3rd Example of this invention, and the distance to a boundary. It is a figure explaining the internet reproduction | regeneration control by the 6th Example of this invention.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. In a preferred embodiment of the present invention, an electronic device having a function of receiving stream data wirelessly on a moving body such as an automobile and reproducing the data is illustrated. The electronic device may be a type that is fixed to an automobile, or may be a portable electronic device that can be brought into a moving body by a passenger, such as a smartphone, a mobile phone, or a portable information terminal. .

  FIG. 1 is a diagram for explaining the outline of a mobile data reproduction system according to an embodiment of the present invention. The reproduction system 10 includes a server (stream data distribution device) 20 capable of distributing stream data to an electronic device 30 on a mobile object, and an electronic device having a function of receiving stream data on the mobile object and reproducing it. The apparatus 30 includes a wireless communication network 40 that enables wireless communication between the server 20 and the electronic apparatus 30.

  The wireless communication network 40 includes a base station 42 that emits a radio signal with a constant intensity, and the Internet 44 connected to the base station 42, and is between the electronic device 30 and the server 20 existing in an area covered by the base station 42. Enable data communication. The communication between the electronic device 30 and the base station 42 can be a public wireless network or wireless network communication such as LAN, WAN, WiFi, or the like. The communication function of the electronic device 30 may be one that is mounted by itself, or may be one that connects another communication terminal. For example, the electronic device 30 can be a navigation device that itself has a communication function, a navigation device to which a communication terminal is externally connected, a smartphone, a mobile phone, or a portable information terminal. Moreover, a mobile body is not restricted to a motor vehicle but includes a two-wheeled vehicle, a motorcycle, and a pedestrian.

  FIG. 2 is a block diagram showing a typical internal configuration of the electronic device 30 of this embodiment. As shown in the figure, the electronic device 30 receives data from the server 20 via the data communication unit 100 that performs bidirectional data communication with the server 20 via the wireless communication network 40, and the data communication unit 100. Unit 110, audio output unit 120 that outputs sound from a speaker, display unit 130 that displays video on a display, input unit 140 that receives an instruction from a user, reproduction unit 150 that reproduces audio data and video data, and operations of each unit A control unit 160 for controlling, a memory 170 for storing data, programs, and the like, and a bus 180 for connecting each unit are provided.

  The electronic device 30 has a function of receiving and reproducing the stream data distributed from the server 20, but here, the function when the electronic device 30 receives and reproduces the music data distributed by the Internet radio. Will be explained.

  The control unit 160 executes an operation in accordance with a user instruction from the input unit 140. When an instruction for playing Internet radio is given from the input unit 140, the control unit 160 accesses the server 20 having the selected URL via the data communication unit 100. For example, the server 20 transmits information on a music list that can be distributed by Internet radio to the electronic device 30, and the reproducible music list is displayed on the display unit 130. Next, when the user selects a desired music piece, the signal is transmitted to the server 20, the music stream data is distributed from the server 20 to the electronic device 30, and the stream data is received by the receiving unit 110. .

  As shown in FIG. 3, the reception unit 110 includes a buffer memory 112 that stores received stream data. Preferably, the buffer memory 112 reads the stream data written first from DATA IN first from DATA OUT. FIFO (First In First Out) memory is used. The buffer memory 112 is used for reproducing stream data while fetching a predetermined amount of stream data distributed from the server 20 first. When the communication status becomes unstable (for example, the signal reception strength from the base station is low, or there is a noise source nearby), the download of the stream data temporarily stops or becomes intermittent However, since the stream data stored in the buffer memory 112 is reproduced, it is possible to prevent the sound from being interrupted or being silent. When the communication state is good, the reception bit rate by the data communication unit 100 is larger than the reproduction bit rate by the reproduction unit 150, and a certain amount of stream data 112A is stored in the buffer memory 112. As it worsens, the rate can be reversed.

  FIG. 4 shows a functional block diagram of the control unit 160 of the present embodiment, but only the components related to the present embodiment are shown here. Based on the determination results of the position detection unit 162 that detects the position of the moving object, the communication status determination unit 164 that determines or predicts whether the data communication status is good, and the communication status determination unit 164 A reproduction control unit 166 for controlling reproduction of the video data.

  The position detection unit 162 detects the position of the moving body on which the electronic device 30 is mounted. If the electronic device 30 has a positioning function using a GPS satellite, the position detection unit 162 uses position information measured by the function, or a speed sensor and an orientation sensor are mounted on the moving body. In some cases, the relative position information obtained from these is used. In addition, the position detection unit 162 may acquire position information measured by the positioning function mounted on the moving body when the electronic device 30 does not have the positioning function. If the position of the moving body can be acquired from the outside, it may be used.

  Preferably, the position detection unit 162 detects the absolute coordinates of the latitude and longitude of the moving body and the moving direction (vector) of the moving body. Since positioning by a typical GPS satellite measures the latitude and longitude of a moving body at regular time intervals (for example, every 1 second), it is possible to detect the absolute position and vector of the moving body from the results. is there. Of course, it is also possible to use the output of other speed sensors and direction sensors. Moreover, the position detection part 162 has a function which detects the speed of a moving body in another Example.

  In a preferred embodiment, the communication status determination unit 164 determines whether or not the communication status is good in response to the input of a skip operation instructing the change of the music being played from the input unit 140. The communication status determination unit 164 determines whether or not the communication status is good based on the position information detected by the position detection unit 162 and the communicable area information. The communicable area information is position information indicating a communicable area with reference to the base station. The communicable area information can be conceptually expressed as shown in FIG. For example, the communicable area information shown in FIG. 5A is a circular area defined by a radius r from the position of the base station P, and its boundary B is a range where radio waves reach from the base station P, that is, It is a receivable range, and when it exceeds the boundary B, it means out of range. Further, the communicable area information illustrated in FIG. 5B is a rectangular area defined by four corner coordinates C1, C2, C3, and C4 based on the position of the base station P. Of course, an area in which communication is possible with other shapes may be specified. For example, a communicable closed area may be defined by a road (link).

  Preferably, memory 170 stores a plurality of base stations and communicable area information associated therewith. For example, as shown in FIG. 9A, base station, location information (prefecture, city, latitude, longitude) of the base station, and address information in which communicable area information corresponding to the base station is stored. Is stored in the memory 170, and the base station and communicable area information can be retrieved from the reference table. Alternatively, in addition to storing the reference table and the communicable area information in the memory 170, the electronic device 30 may acquire the communicable area information from the server 20 and other external devices.

  In a preferred embodiment, the communication status determination unit 164 determines that the communication status deteriorates when the position of the mobile body is within a certain distance from the boundary B of the communicable area and the direction of the mobile body goes outside the boundary B. judge. That is, in the vicinity of the boundary, the radio wave reception sensitivity decreases and the communication status becomes unstable, and if the boundary B is exceeded, communication is not possible. For example, in FIG. 5A, it is determined whether or not the linear distance L between the position Q1 of the moving body and the boundary B is equal to or less than a threshold value. The straight line distance L can be obtained from the intersection of the straight line (radius) passing through the base station (center) P and the position Q1 and the boundary B. Further, if the vector V is detected from the difference between the positions Q0 detected before the position Q1 and extends a certain length from the position Q1 in the direction of the vector V, the moving body is moved to the boundary B. It is determined to go outside. The direction of the moving object may be calculated from at least two positions detected immediately before, or may be a weighted average of vectors calculated between the two positions when more detection positions are used. In addition to calculating the vector from the detected position, an azimuth sensor mounted on the moving body may be used.

  When the communication status determining unit 164 determines that the communication status is not good, that is, the communication status is deteriorated, the playback control unit 166 controls the playback so that the skip operation is suppressed. In the preferred embodiment, the playback control unit 166 issues a warning for the input skip operation and notifies that the current song cannot be immediately changed to the next song. As the warning, for example, a beep sound can be generated from the audio output unit 120 or a warning message can be displayed on the display unit 130. Furthermore, the playback control unit 166 treats the skip operation as invalid and continues playback of the current stream data.

  Next, the operation of the mobile data reproduction system of this embodiment will be described with reference to the flowchart of FIG. First, when an instruction for playing Internet radio is input through the input unit 140, the control unit 160 searches the server 20 connected to the Internet 44 through the data communication unit 100. This search is performed using a URL unique to the server 20. In this way, the electronic device 30 accesses the server 20 that provides the Internet radio service (step S101).

  For example, a music list is displayed on the display unit 130 of the electronic apparatus 30, and when the user selects a desired music A, the server 20 distributes stream data of the music A to the electronic apparatus 30. The receiving unit 110 accumulates the stream data in the buffer memory 112, and the reproducing unit 150 reproduces the stream data read from the buffer memory 112 at the same time. The reproduced sound is output from the sound output unit 120. In this way, music data by Internet radio is reproduced (step S102).

  During reproduction of the Internet radio, the control unit 160 monitors whether or not the next song skip button is pressed from the input unit 140 (step S103). The skip operation is not limited to pressing a button, but may be a selection using a touch panel or the like. When the skip operation is executed, the position detection unit 162 detects the position of the moving body (step S104). The position detection of the moving object may be performed in response to the input of the skip operation, but in addition to that, the position of the moving object is always detected and the value is held in a register for a certain period. If the electronic device includes a navigation function, position information used in the navigation function may be acquired.

  Next, the communication status determination unit 164 searches for a base station that covers the position of the detected mobile object, and extracts communicable area information corresponding to the base station (step S105). For example, the base station and the communicable area information corresponding thereto are searched using a reference table as shown in FIG. Next, the communication status determination unit 164 determines whether or not the position of the moving body is within 1 km from the boundary B indicated by the communicable area information (step S106). If the distance is more than 1 km, the communication status is predicted to continue to be stable, so the playback control unit 166 performs a process for skipping to the next song in accordance with the skip operation (step S107). Thus, the control unit 160 makes a request to the server 20 to stop transmission of the current music A data stream and a request to transmit the next music B data stream.

  On the other hand, when the position of the moving body is within 1 km from the boundary B, the communication status determination unit 164 further determines whether or not the direction of the moving body is outside the boundary B (step S108). Preferably, the direction of the moving body (vector) calculated from the position of the latest moving body and the position of the immediately preceding moving body is used, and the moving body is positioned outside the boundary B by moving in that direction by a predetermined distance. It is determined whether or not to do. If it is determined that the moving body does not face the boundary B, the playback control unit 166 skips the next song (step S107). On the other hand, when it is determined that the direction of the moving body is outside the boundary, the reproduction control unit 166 generates a warning (step S109). As described above, the warning is an error display or a beep sound. Further, the playback control unit 166 invalidates the input skip operation, continues to receive the data stream of the music piece A, and continues this playback.

  The biggest frustration when playing a music source in the car is that the sound is interrupted. On the Internet radio, due to its characteristics, downloading of sound data is interrupted outside the network service area, so it cannot be played. . By performing the reproduction control as in the present embodiment, especially when moving in the vicinity of the boundary B area, the reachability (radio wave reception sensitivity) of the network becomes unstable, so this is not known. Unnecessary frustration such as silence caused by the user skipping the next song can be prevented. Although the network itself becomes unstable on the area boundary, the function of preventing a silent state due to network down is secured by the cache function using the buffer memory 112 of the receiving unit 110. The present embodiment is useful for preventing an operation that invalidates the function by a user operation (next music skip) even though an unnecessary silent state is previously prevented on the electronic device side.

  Next, a second embodiment of the present invention will be described. In the second embodiment, when a route to the destination is set, the electronic device 30 refers to this route to determine the communication status. When the electronic device 30 has a navigation function, or when the electronic device 30 can acquire information about a route from the server 20, the traveling direction of the moving body is known, so that the communication status can be easily predicted.

  FIG. 7 is a flowchart for explaining the operation of the second embodiment, and is the same as that of the first embodiment except for the determination in step S120. When a skip operation is input from the user during the reproduction of music by the Internet radio (step S103), the communication status determination unit 164 causes the position of the mobile body to be within 1 km from the boundary B of the communicable area in response to this. It is determined whether or not there is. When the distance is within 1 km, the communication status determination unit 164 determines whether the route to the destination exceeds the boundary B. If the route exceeds the boundary B, the communication status determination unit 164 determines that the communication status is not good.

  FIG. 8 is a diagram for explaining the determination of the communication status when the route to the destination is set. In the figure, the broken line indicates the boundary B of the communicable area, the thick solid line indicates the route R to the destination, and M indicates the vehicle position. When the position of the moving body is within 1 km from the boundary B and the route R exceeds the boundary B, it is determined that the communication status is deteriorated. However, when the travel distance of the route R until the boundary B is exceeded is larger than the threshold value, it may be determined that the communication state is good because the time until the boundary B is exceeded is long.

  In this way, in the second embodiment, the communication status can be predicted more easily and accurately by referring to the route to the destination. In the second embodiment, the determination based on the route (step S120) is performed instead of the determination based on the direction (vector) of the moving body in the first embodiment (step S108). If the time to reach can be predicted from the route, the determination of the position of the moving body and the distance to the boundary B (step S106) may not be performed. Furthermore, it is possible to perform both determination based on the direction (vector) of the moving body (step S108) and determination based on the route (step S120).

  Next, a third embodiment of the present invention will be described. In the third embodiment, the communication status is determined in consideration of the speed of the moving object. The moving body has different moving speeds depending on automobiles, bicycles, pedestrians, and the like. Since the time for the moving body to reach the boundary B differs depending on the speed of the moving body, it is desirable to change the threshold value for determining the distance between the moving body and the boundary B according to the speed of the moving body.

  In the third embodiment, the communication status determination unit 164 acquires speed information of the moving body when determining the communication status. The speed information may be acquired in any form. For example, the speed information is acquired from a vehicle speed sensor mounted on the vehicle, or the change in the position of the moving body is known, so the speed information is calculated therefrom. It is possible. The communication status determination unit 164 preferably refers to a table in which the relationship between the speed of the moving object and the threshold value for determining the distance L to the boundary B as shown in FIG. To decide. Then, the communication status determination unit 164 compares the determined threshold value with the distance L from the moving body to the boundary B, and performs the determination in step S106. In addition to the table shown in FIG. 9B, the threshold value may be determined by a linear function equation that defines the relationship between the speed of the moving object and the threshold value.

  According to the third embodiment, it is possible to predict the communication status according to the speed of the moving object. Further, the third embodiment may be used in combination with the first and second embodiments.

  Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, the storage bit rate of the data stream stored in the buffer memory 112 of the reception unit 110 (storage amount per unit time) and the reproduction bit rate of the data stream reproduced by the reproduction unit 150 (unit time) The communication status is predicted in consideration of the amount of playback per unit).

  The high radio wave reception sensitivity in the data communication unit 100 of the electronic device 30 does not necessarily mean that the storage bit rate is high. This is because if a large number of electronic devices 30 performing data communication exist in the same communicable area, the storage bit rate of the electronic device 30 decreases accordingly. Since the playback bit rate is constant, if the storage bit rate is higher than the playback bit rate, a certain amount of stream data is accumulated in the buffer memory 112, but conversely the storage bit rate can be lower than the playback bit rate. For example, the stream data stored in the buffer memory decreases and eventually becomes zero.

  In the fourth embodiment, the communication status determination unit 164 compares the storage bit rate and the reproduction bit rate, and determines that the communication status is not good if the storage bit rate is low. The determination of the fourth embodiment can be combined with the determination of the first to third embodiments, and the communication status can be predicted to deteriorate when the logical product of these determinations, so that the determination accuracy can be increased. Further, the determination of the fourth embodiment may be combined with any one of the determinations of the first to third embodiments, and it may be determined that the communication status deteriorates when the logical product of these determinations.

  Next, a fifth embodiment of the present invention will be described. In the first embodiment, when it is determined that the communication status is not good, the user's skip operation is invalidated or canceled. However, in the fifth embodiment, while the skip operation is enabled, The receiving unit 110 is controlled so that reception of the stream data continues.

  If the communication status determination unit 164 determines that the communication status is not good, the playback control unit 166 validates the skip operation and sends the stream data of the current song A to the server 20 via the data communication unit 100. Requests stop of transmission and requests transmission of stream data of the next music piece B. In response to these requests, the server 20 stops the transmission of the music piece A and transmits the stream data of the music piece B to the electronic device 30. Here, the playback control unit 166 controls the receiving unit 110 so that the receiving unit 110 does not receive the stream data of the music B, and plays back the stream data stored in the buffer memory 112 of the receiving unit 110 in the playing unit 150. I will let you.

  Next, a sixth embodiment of the present invention will be described. FIG. 10 is a diagram for explaining the outline of the sixth embodiment. In the sixth embodiment, as shown in FIG. 10A, when a skip operation is performed in a situation where the communication situation determination unit 164 determines that the communication situation is not good or the communication situation is deteriorated, the reproduction control unit 166 stores that there was a skip operation and switches to music playback of another audio source that can be used in the electronic device 30 at time P1. The example shown in the figure is the reproduction of audio data stored in the hard disk, but the audio source may be a disk such as a CD.

  Next, the communication status determination unit 164 constantly monitors the communication status, and when it is determined that the communication status becomes favorable at time P2, that is, when the mobile body returns to the communicable area, the determination result is displayed as a reproduction control unit. Tell 166. In response to this, the playback control unit 166 starts distribution of the audio data of the next music from the Internet radio according to the skip operation, and at time P3 after the audio data of the next music is cached in the buffer memory 112 by a certain amount, Switch from playing audio data on the hard disk to playing the next song on the Internet radio. Note that the timing P3 for starting the reproduction of the next music may be performed after the music on the hard disk is finished in order to prevent the music from being finished in the middle of the music.

  Also preferably, when the playback control unit 166 can obtain information such as the title, artist, or genre of the currently played music from the stream data distributed from the Internet radio, the playback control unit 166 outputs it to another audio source. Whether music of the same title is stored, if there is no music of the same title, whether music of the same artist is stored, if no music of the same artist exists, music of the same genre Is stored, and an alternative music piece is reproduced during the incommunicable area in such a priority order. Thereby, the silent section in the communication impossible area can be eliminated or shortened.

  In the above example, the playback control unit 166 switches to playback of a music piece of another audio source at time P1 in response to the skip operation. However, as shown in FIG. 10B, there is a skip operation. In this case, the reproduction is continued until the time P1 ′ when the data in the buffer memory 112 becomes empty by the reproduction, and then the audio data of the next music is stored in the buffer memory 112 according to the skip operation after returning to the communicable area. You may make it start reproduction | regeneration of a music. Thereby, generation | occurrence | production of a silence state can be suppressed more. Also in this case, a music piece of another audio source may be played between times P1 'and P2.

  The preferred embodiment of the present invention has been described in detail above, but the present invention is not limited to the specific embodiment, and various modifications can be made within the scope of the present invention described in the claims. Deformation / change is possible.

10: Mobile data reproduction system 20: Server 30: Electronic device 40: Wireless communication network 42: Base station 44: Internet 100: Data communication unit 110: Reception unit 120: Audio output unit 130: Display unit 140: Input unit 150 : Playback unit 160: Control unit 162: Position detection unit 164: Communication status determination unit 166: Playback control unit 170: Memory 180: Bus P: Base station B: Boundary Q0, Q1: Position of moving object

Claims (13)

An electronic device that can be used on a mobile body,
A communication means for data communication with the outside;
Receiving means for receiving stream data from outside via the communication means;
A buffer memory for storing a certain amount of stream data received by the receiving means;
Reproducing means for reproducing the stream data stored in the buffer memory;
Output means for outputting data reproduced by the reproducing means;
Determining means for determining whether the data communication status of the communication means is good;
Input means for receiving instructions from the user;
When there is an instruction to change the stream data currently being played back through the input unit, if the determination unit determines that the data communication status is not good, the output from the output unit is continued. Control means for controlling the processing according to the instruction,
An electronic device. The electronic device according to claim 1, wherein the control unit invalidates an instruction from the input unit. The electronic device according to claim 1, wherein the control unit controls the receiving unit so as not to receive stream data to be changed in response to an instruction from the input unit. The electronic device according to claim 1, wherein the control unit includes a unit that generates a warning sound when an instruction is given from the input unit. The electronic device further includes detection means for detecting position information of the moving body, and the determination means is configured to communicate based on communicable area information indicating an area where data communication is possible and position information detected by the detection means. The electronic device according to claim 1, wherein it is determined whether or not the battery is good. The determination means determines that the communication status is not good when the mobile body is located within a certain distance from the boundary of the communicable area indicated by the communicable area information and the direction of the mobile body exceeds the boundary. The electronic device according to claim 5. The electronic device according to claim 6, wherein the determination unit refers to speed information of the moving body and varies the fixed distance according to the speed of the moving body. The determination means refers to the route when the route to the destination is set, and determines that the communication status is not good when the route exceeds the boundary of the communicable area. The electronic device according to one. 5. The determination unit according to claim 1, wherein the determination unit determines that the communication state is not good when a reception rate of the stream data by the reception unit is smaller than a reproduction rate of the stream data by the reproduction unit. Electronic equipment. The electronic device further includes storage means for storing audio data, and the control means switches to reproduction of the audio data stored in the storage means in response to an instruction from the input means, and data communication is performed by the determination means. The electronic apparatus according to claim 1, wherein the electronic apparatus switches to reproduction of stream data instructed from the input unit when it is determined that the situation is good. When the stream data is instructed from the input unit, the control unit continues the output from the output unit until the stream data stored in the buffer memory becomes empty, and then stored in the storage unit. The electronic device according to claim 10, wherein the electronic device is switched to reproduction of audio data. An electronic device according to any one of claims 1 to 11,
A stream data distribution device capable of wireless communication with the electronic device;
A mobile data reproduction system having The data reproduction system according to claim 12, wherein the stream data distribution device is a server for distributing music data by Internet radio.

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