JP5136141B2 - Information processing device - Google Patents

Description

  The present invention relates to an information processing apparatus.

  In recent years, Bluetooth (registered trademark) is known as a technology for transferring audio data using near field radio and performing streaming reproduction. Using Bluetooth, for example, audio data can be transferred from a mobile phone or a portable music player to a device such as a headset without using a cable.

  In the Bluetooth audio transfer service, a media packet is transmitted to the opposite device based on RTP (Real-time Transport Protocol). Specifically, after transmission of a media packet, the transmission timing of the next media packet is set according to the reproduction time of data included in the transmitted media packet. As a result, the media packets can be transmitted to the opposite device one after another without interruption of performance.

  However, since the timer value set as the transmission timing of the media packet does not completely match the reproduction time of the data included in the media packet, the transmission timing is determined while a plurality of media packets are transmitted. There is a possibility that the timer value set as is not an appropriate value.

  Therefore, the sum of the playback times included in the media packets already sent to the opposite device is compared with the elapsed time from the actual start of music transmission to the current time, and if an error occurs, the transmission timing Adjust.

At this time, information on the current time used for calculating the elapsed time is acquired from the system clock in the apparatus. Therefore, the time set in the system clock needs to be an accurate time. In order to keep the system clock in such a device accurate, for example, a wireless communication terminal that extracts time information from radio waves received from a base station of a mobile phone and corrects the time in the device has been proposed (for example, , See Patent Document 1).
JP 2002-142257 A

  In the invention described in Patent Document 1, the mobile phone terminal can correct the time in the terminal even when the radio wave cannot be received from the base station as in the out-of-service state. However, for example, a base station installed in a subway station may not be adjusted to the correct time. If incorrect time information is received from such a base station, the time in the terminal is also incorrect. It may happen that you adjust it.

  In such a state where the time in the terminal cannot be accurately maintained, the elapsed time cannot be accurately calculated. As a result, when the elapsed time is calculated to be shorter than the actual time and shorter than the reproduction time, it is determined that the data has been sent too much, and the data transmission is stopped for a predetermined time, resulting in sound interruption. If the elapsed time is calculated to be longer than the actual playback time and longer than the playback time, it is determined that the data has been delayed by transmitting data to the opposite device, and the data is returned at an interval shorter than usual to recover the delay. It will be sent.

  Therefore, an object of the present invention is to provide an information processing apparatus capable of realizing data transmission at an appropriate timing even when the system time fluctuates for some reason.

  In order to achieve the above object, an information processing apparatus according to the present invention is an information processing apparatus that transmits data in packets by short-range wireless communication, measures the current time, and adjusts the time setting at a predetermined timing. Time determination means, and determination means for determining whether or not the time setting of the time measurement means when the packet is transmitted varies from the time setting of the time measurement means when measuring the starting point of the elapsed time, When it is determined by the determination means that there is no change, the first elapsed time acquisition means for calculating the elapsed time from a predetermined time using the current time measured by the time measurement means, and the determination means If it is determined that the packet has been transmitted, the elapsed time from when the packet is transmitted to the time when the packet is transmitted is obtained from the current timing means when the packet is transmitted. A second elapsed time acquisition unit that calculates without using time, and a reproduction time of data included in the transmitted packet, the elapsed time, and the data included in the packet transmitted after the time at which the elapsed time is calculated Transmission timer means for setting the transmission timing of the next packet according to the total reproduction time.

  According to the present invention, even when the system time fluctuates for some reason, data transmission can be realized at an appropriate timing.

  Embodiments of the present invention will be described below with reference to the drawings. Here, a case where audio data is transmitted from a mobile phone capable of short-range wireless communication to the headset will be described as an example.

  FIG. 1 is a diagram illustrating a relationship between the mobile phone 1 according to the present embodiment and a device wirelessly connected thereto. The cellular phone 1 can transmit and receive data by short-range wireless communication such as Bluetooth, and can transfer audio data to the headset 2 that also supports short-range wireless communication. The headset 2 decodes the received audio data and reproduces it.

  The mobile phone 1 is connected to a network via the base station 3 and the exchange 4 and can perform voice communication and data communication. In addition, the mobile phone 1 can receive information on the current time from the base station 3 at a predetermined timing and adjust the system clock in the mobile phone 1. Note that the base station 3 has a GPS antenna, and receives a GPS signal generated based on a time set by the atomic clock from a GPS (not shown) having an atomic clock. The current time can be set with high accuracy by this GPS signal.

  FIG. 2 is a block diagram showing a configuration of the mobile phone according to the present embodiment. The cellular phone 1 includes a control unit 51, an operation unit 52, a display unit 53, a voice input / output unit 54, a radio telephone communication unit 55, a system clock 56, a storage unit 57, a media player unit 58, a content processing unit 59, a short-range wireless communication. The communication unit 60 is configured.

  The control unit 51 includes a CPU, a ROM, a RAM, and the like, and controls the entire mobile phone 1.

  The operation unit 52 includes operation keys, a touch panel, a touch sensor, and the like, and inputs a signal corresponding to a user operation to the control unit 51.

  The display unit 53 is configured by a liquid crystal display, an organic EL display, or the like, and displays characters and images according to the operation of the application.

  The voice input / output unit 54 includes a speaker and a microphone, and performs input / output of call voice of a voice call by the wireless telephone communication unit 55 and output of voice / music of music content and moving image content.

  The radio telephone communication unit 55 performs voice communication and packet communication via the base station 3. For example, when voice is transmitted by voice communication, data obtained by performing signal processing such as encoding or error control on voice data obtained by collecting voice from the microphone of the voice input / output unit 54 is converted into radio waves. The data is converted and transmitted to the base station 3. The received voice receives radio waves from the base station 3, converts the radio waves into electric signals, performs signal processing such as decoding and error correction, and outputs the voice from the speaker of the voice input / output unit 54.

  The radio telephone communication unit 55 has a correction time acquisition unit 55a, receives time information from the base station 3 at a predetermined timing, and calculates the current time measured by the system clock 56 based on the time information. adjust.

  The storage unit 57 stores various application software, music content, moving image content, and the like. The music player and the moving image content stored in the storage unit 57 are instructed to be reproduced by the media player unit 58.

  The media player unit 58 reads the content stored in the storage unit 57, and instructs playback, stop, pause, or the like. In addition to the content stored in the storage unit 57, for example, when the mobile phone is provided with a function for receiving digital television broadcasting such as One Seg or radio broadcasting, as a player of television broadcasting or radio broadcasting. It can also be used.

  The content processing unit 59 encodes and decodes content. For example, when reproduction of music content is instructed by the media player unit 58 and output from the speaker of the audio input / output unit 54, the content processing unit 59 decodes corresponding music content encoded by an encoding method such as AAC or MP3. The data is decoded by the method and output from the speaker of the audio input / output unit 54.

  The short-range wireless communication unit 60 includes a wireless communication module such as Bluetooth that uses a radio wave having a wireless transmission power smaller than that of the wireless telephone communication unit 55, and performs wireless communication with the opposite device.

  The short-range wireless communication unit 60 includes a capability acquisition unit 60a, a configuration unit 60b, a frame cutout unit 60c, a packet generation unit 60d, a packet transmission unit 60e, and a transmission time calculation unit 60f.

  The capability acquisition unit 60a acquires information on the type of codec supported by the opposite device and the parameter for each codec type.

  The configuration unit 60b negotiates the codec type and the parameter for each codec type using the information acquired by the capability acquisition unit 60a when starting data transfer to the opposite device.

  When transmitting music content or the like to the opposite device, the frame cutout unit 60c cuts out a frame from the content data to be transmitted in accordance with the type of codec determined by negotiation with the opposite device. If the codec type of the audio data read from the storage unit 57 by the media player unit 58 is different from the codec type determined by the configuration unit 60b, the audio data is once decoded by the content processing unit 59 and configured. The audio data encoded by the type of codec determined by the unit 60b is supplied to the frame cutout unit 60c.

  The packet generation unit 60d generates a packet for data transfer to the opposite device for each frame extracted by the frame extraction unit 60c. The generated packet is temporarily stored in a packet transmission buffer.

  The packet transmission unit 60e reads an appropriate amount of packets stored in the packet transmission buffer and transmits the packets to the opposite device. The transmission timing of this packet is determined by the transmission time calculation unit 60f.

  The transmission time calculation unit 60f sets an appropriate timing for transmitting the next packet in the transmission timer, and urges the packet transmission unit 60e to transmit the packet when the transmission timer expires.

  A case will be described in which the mobile phone 1 having the above configuration performs streaming transfer of audio data to the headset that is the opposite device using the short-range wireless communication unit 60.

  In the case of streaming transfer of audio data, it is necessary to set an appropriate timing by the transmission time calculation unit 60f so that the audio data reproduced by the headset is not cut off.

  Therefore, the transmission time calculation unit 60f acquires the time (reproduction time) required when reproducing from the beginning to the end of the audio data included in the packet transmitted by the packet transmission unit 60e, and based on this reproduction time, the packet The transmission timing of the next packet is set by the transmission unit 60e. However, the time until the next packet transmission set by the transmission timer is not completely the same as the playback time of the audio data of the transmitted packet, so the transmission timing may be shifted while multiple packets are being transmitted. is there.

  Therefore, the transmission time calculation unit 60f calculates the total reproduction time of the audio data transmitted by the packet transmission unit 60e, and calculates the elapsed time from the actual transmission of the audio data to the current time. Then, the total reproduction time and the elapsed time are compared, and if an error occurs, the transmission timing of the next packet is adjusted.

  Here, the current time used by the transmission time calculation unit 60 f to calculate the elapsed time is a time acquired from the system clock 56. The system time is adjusted to the correct time using the current time information obtained from the base station, but is not accurate when the current time information is obtained from a base station installed in the basement. There is a case.

  As described above, since the time adjusted in the system clock 56 is different depending on the synchronized base station, when the user moves the mobile phone 1 that is transferring audio data to the headset using the short-range wireless communication unit 60, The elapsed time may not be accurately calculated.

  Therefore, the transmission time calculation unit 60f determines whether or not the current time acquired from the system clock 56 is an appropriate time for calculating the elapsed time, and if it is an appropriate time, the elapsed time is determined according to the current time. If the time is not appropriate, the elapsed time is calculated without using the acquired current time.

  FIG. 3 is a flowchart showing a process of transferring the packet stored in the packet transmission buffer to the headset. In order to store the packet in the packet transmission buffer, the audio data is read from the storage unit 57 by the media player unit 58, decoded and re-encoded as appropriate by the content processing unit 59, and then frame extraction is performed. The frame is cut out by the unit 60c, and the transmission packet is generated by the packet generation unit 60d.

  The packet transmitter 60e reads the packet to be transmitted first from the packet transmission buffer and transmits it to the headset 2 (S101). If the packet transmitted at this time is the last packet of the audio data (Yes in S102), the audio data transfer process is completed.

  If it is not the last packet (No in S102), since there is a packet to be transmitted next, processing for determining the transmission timing of the packet to be transmitted next is performed. First, the current time information is acquired from the system clock 56 (S103). Then, it is determined whether or not the system time is an appropriate time (S104). This determination method will be described later.

  If the system time is an appropriate time for calculating the elapsed time (Yes in S104), the elapsed time is calculated using the system time (S105). The elapsed time at this time is calculated by adding the elapsed time since the transmission of the previous packet to the elapsed time when the previous packet was transmitted, for example, as in equation (1). .

Elapsed time = elapsed time when the previous packet was transmitted + (current system time-1 system time when the previous packet was transmitted) (1)
On the other hand, if the system time is not an appropriate time (No in S104), the elapsed time is calculated without using the acquired system time (S106). A method for calculating the elapsed time without using the acquired time will be described later.

  Then, the elapsed time is compared with the total playback time of the song included in the previously transmitted packet (S107), and if there is no error, the next transmission is performed based on the playback time of the song included in the last transmitted packet. The transmission time of the packet to be transmitted is set in the transmission timer, and if there is an error, the transmission time of the packet to be transmitted next is set in the transmission timer based on the time of this error and the playback time of the song included in the last transmitted packet. Set (S108).

  When the transmission timer set in step S108 expires (Yes in S109), the packet transmission unit 60e reads the next packet to be transmitted from the buffer and transmits it to the headset.

  Through the processing as described above, the transmission packet is sequentially transmitted from the mobile phone 1 to the headset every time set in the transmission timer, so that the packet can be transmitted at an appropriate timing.

  Next, a method for determining whether or not the system time performed in step S104 of FIG. 3 is appropriate will be described in detail. Here, the determination process when the system time is determined to be appropriate up to the previous packet and the elapsed time is calculated using the time will be described.

  The state in which the system time is inappropriate for calculating the elapsed time is a case where the system time 56 fluctuates from the adjustment of the system clock 56 that has timed the time from which the elapsed time is calculated. Therefore, if the system time is appropriate up to the previous packet, the time acquired from the current system clock 56 when the packet was transmitted and the system clock 56 acquired when the previous packet was transmitted. It is possible to detect that the system time is inappropriate when a predetermined error occurs by comparing the current time calculated based on the determined time.

  In order to calculate the current time using the system time when the previous packet was transmitted, the system time acquired in step S103 when the previous packet was transmitted is included in the previous packet. What is necessary is just to add the reproduction time of audio data.

  The current time using the system time when the previous packet is transmitted may be calculated by adding the time set in the transmission timer to the system time when the previous packet was transmitted. .

  Thus, an error between the current time calculated using the system time one packet before and the current time acquired from the system clock 56 is calculated as shown in, for example, Expression (2).

Error = (system time at transmission of the previous packet + 1 reproduction time of audio data contained in the previous packet) −current system time (2)
Then, when the current system time is in the past from the current time calculated using the time at the previous packet transmission (when error <0), or the current system time is one before When the current time calculated using the time at the time of packet transmission is a time that is a predetermined time or more in the future (error> predetermined time), the system clock 56 is adjusted when the previous packet is transmitted. It can be judged that it fluctuated. Therefore, it is determined that the current time acquired from the system clock 56 is not appropriate for calculating the elapsed time.

  Note that the predetermined time, which is a threshold used for determination when the system clock 56 is at a future time, is a system time shift that can normally occur. For example, the occurrence of an interrupt when the operation key of the mobile phone 1 is continuously pressed prevents media data transmission for audio streaming reproduction, and the time when data should be originally transmitted and the time when data is actually transmitted Time difference may occur. Therefore, an allowable time difference (for example, 100 ms) between the time at which data is originally transmitted and the time at which data is actually transmitted is used as a threshold, and it is determined that the system clock 56 has fluctuated due to the time difference between the current times due to such factors. Make it harder.

  On the other hand, if the current time acquired from the system clock 56 is a time that is later than the time calculated using the time at the time of previous packet transmission and the error is within a predetermined time, the previous packet was transmitted. There is no significant fluctuation from the adjustment of the system clock 56 at the time. Therefore, it is determined that the current time acquired from the system clock 56 is appropriate for calculating the elapsed time.

  If it is determined that the system clock 56 is not appropriate by the above method, the transmission time calculation unit 60f calculates the elapsed time without using the system time information acquired from the system clock 56 in step S106.

  One method of calculating the elapsed time without using the system time is a method of resetting the elapsed time and restarting the calculation of the elapsed time from the initial value when it is determined that the system time is not appropriate. That is, the difference from the beginning of the song to the current time is calculated as the elapsed time, but if it is determined that the system time is not appropriate, it is changed to calculate the elapsed time from the time when this packet was transmitted.

  Therefore, the total reproduction time of the audio data included in the transmitted packet used for comparison with the elapsed time in step S107 is also calculated as the total reproduction time of the audio data from the packet transmitted at the time when the elapsed time is reset. It is compared with the elapsed time reset as follows.

  When the elapsed time is reset in this way, the determination of “appropriate system time” performed in step S104 when a packet subsequent to that packet is transmitted is the same as that before the elapsed time is reset. This is performed by comparing the time calculated by adding the reproduction time of the audio data contained in the previous packet to the system time when the time is transmitted and the time acquired from the system clock 56.

  That is, it is determined whether or not it is “appropriate system time” with reference to the system clock 56 when the elapsed time is reset. Therefore, after the elapsed time was reset, when the system clock 56 was adjusted again using the time information from the base station, it was adjusted to return to the adjustment of the system clock 56 when the first packet was transmitted. However, the elapsed time is reset again in the same manner as when the system clock 56 deviates from the time when the first packet is transmitted.

  Another method for calculating the elapsed time that does not use the system time is to add the elapsed time calculated when the previous packet was transmitted and the reproduction time of the audio data included in the packet transmitted this time. Is calculated as the elapsed time from the start of data transmission to the time when the packet transmitted this time is transmitted.

  When the elapsed time is calculated by this method, since the starting point of the elapsed time calculation is the time when the first packet is transmitted, the time counted by the system clock 56 of the same adjustment as when the first packet was transmitted is “appropriate. It ’s a good time. Therefore, unlike the case of resetting the elapsed time described above, it is first determined whether or not the time of the system clock 56 acquired when the packet is transmitted is “appropriate time” even after the elapsed time is corrected. This is performed with reference to the system clock 56 when the packet is transmitted.

  Therefore, if the elapsed time is corrected in order to determine whether or not the system time when the packet is transmitted after correcting the elapsed time is “appropriate time”, the expression (2) used for the determination in step S104 is used. ) Is stored as a difference from “appropriate time”. Thereafter, when a packet is transmitted, an error from the current time calculated from the system time at the previous packet transmission is calculated using the system time at that time, as shown in Expression (2). Add the value stored as the difference from “appropriate time”. When this result is 0 (when the system clock 56 is adjusted so as to cancel the difference from the “appropriate time”), it is determined that the current time of the system clock 56 is “appropriate time”. The elapsed time is calculated using the system time.

  On the other hand, if the sum is not zero (if the difference from “appropriate time” is not canceled), this total value is newly stored as the difference from “appropriate time”. . By updating the difference value in this way, it is possible to detect that the system clock 56 has returned to the “appropriate time” even when the system time moves around several times.

  As described above, when the system time is detected and the system time fluctuates, the elapsed time from the start of the first data transmission is calculated without using the system time information. The transmission timing can be set appropriately, and the audio data can be reproduced without causing a sound interruption or the like in the opposite device.

  In addition, it is not limited to the said embodiment, You may change suitably in the range which does not deviate from the summary of this invention.

The figure which showed the relationship between the mobile telephone which concerns on embodiment of this invention, and the apparatus wirelessly connected to it. The block diagram which showed the structure of the mobile telephone which concerns on embodiment of this invention. The flowchart which showed the process in which the mobile telephone which concerns on embodiment of this invention transfers the packet stored in the buffer for packet transmission to a headset.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cellular phone, 2 Headset, 3 Base station, 4 Exchange, 51 Control part, 52 Operation part, 53 Display part, 54 Voice input / output part, 55 Radio telephone communication part, 55a Correction time acquisition part, 56 System clock, 57 Storage unit, 58 media player unit, 59 content processing unit, 60 short-range wireless communication unit, 60a capability acquisition unit, 60b configuration unit, 60c frame cutout unit, 60d packet generation unit, 60e packet transmission unit, 60f transmission time calculation unit

Claims (6)

An information processing apparatus that transmits data in packets by short-range wireless communication,
A time measuring means for measuring the current time and adjusting the time setting at a predetermined timing;
A determination unit for determining whether or not the time setting of the time measuring unit when the packet is transmitted varies from the time setting of the time measuring unit when the starting point of the elapsed time is measured;
A first elapsed time acquisition unit that calculates an elapsed time from a predetermined time using the current time measured by the time measuring unit when the determination unit determines that there is no variation; and a variation by the determination unit A second process of calculating an elapsed time from a predetermined time to when the packet is transmitted without using the current time acquired from the time measuring unit when the packet is transmitted. Time acquisition means;
The transmission timing of the next packet is set according to the total playback time of the data included in the packet transmitted after the playback time of the data included in the transmitted packet, the elapsed time, and the elapsed time calculation start time. A transmission timer means,
An information processing apparatus comprising: An information processing apparatus that transmits data in packets by short-range wireless communication,
A time measuring means for measuring the current time and adjusting the time setting at a predetermined timing;
Time information acquisition means for acquiring the current time measured by the time measurement means;
The current time is acquired by the time information acquisition unit when a packet is transmitted, and the current time is set to a current time calculated based on the time acquired by the time information acquisition unit at the time of transmission. Determining means for determining whether or not there is an error,
A first elapsed time acquisition unit that calculates an elapsed time from a predetermined time using the time acquired by the time information acquisition unit when the determination unit determines that there is no predetermined error;
A second elapsed time acquisition unit that sets an elapsed time without using the current time acquired by the time information acquisition unit when the determination unit determines that there is a predetermined error;
The transmission timing of the next packet is set according to the total playback time of the data included in the packet transmitted after the playback time of the data included in the transmitted packet, the elapsed time, and the elapsed time calculation start time. A transmission timer means,
An information processing apparatus comprising:   The second elapsed time acquisition unit acquires the current time by the time information acquisition unit when a packet is transmitted, and the current time is set to the time acquired by the time information acquisition unit at the time of transmission of the previous packet. If the time is past the current time calculated based on this, the elapsed time is calculated by adding the reproduction time of the data included in the transmitted packet to the elapsed time at the time of transmission of the previous packet. The information processing apparatus according to claim 2.   The second elapsed time acquisition unit acquires the current time by the time information acquisition unit when a packet is transmitted, and the current time is set to the time acquired by the time information acquisition unit at the time of transmission of the previous packet. Elapsed by adding the reproduction time of the data contained in the transmitted packet to the elapsed time at the previous packet transmission if it is a time that is a predetermined time or more ahead of the current time calculated based on The information processing apparatus according to claim 2, wherein time is calculated.   The second elapsed time acquisition unit acquires the current time by the time information acquisition unit when a packet is transmitted, and the current time is set to the time acquired by the time information acquisition unit at the time of transmission of the previous packet. If it is a time that is past the current time calculated based on this, the elapsed time is set to an initial value, and the starting point of the elapsed time is the current time acquired by the time information acquisition means at the time of packet transmission The information processing apparatus according to claim 2.   The second elapsed time acquisition unit acquires the current time by the time information acquisition unit when a packet is transmitted, and the current time is set to the time acquired by the time information acquisition unit at the time of transmission of the previous packet. If the current time calculated based on the current time is a predetermined time or more in the future, the elapsed time is set to an initial value, and the starting point of the elapsed time is the current time acquired by the time information acquisition means at the time of packet transmission The information processing apparatus according to claim 2.

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