JP5115120B2 - Video display device and audio output device - Google Patents

Description

  The present invention relates to a video display device and an audio output device, and more particularly to a synchronization process of video display and audio output when video and audio are output from different devices.

  2. Description of the Related Art In a video display device, for example, a small and portable device such as a mobile communication terminal device, an image of content obtained by receiving digital television broadcast is displayed. Here, this content includes, for example, video, audio, and characters, and the apparatus performs not only video display but also audio output and character display.

  Note that, in displaying and outputting content, the content is not limited to that obtained by receiving digital television broadcasts. For example, content received by a videophone may be used. Further, it may be content transmitted for streaming playback. Furthermore, the content stored in the storage medium may be used regardless of whether or not it can be removed.

  When displaying and outputting content, it may be desirable to prevent audio from being heard by people around the device. For example, when the voice is annoying to people, or when the user of the device does not want people to hear confidential information contained in the voice.

  Therefore, audio is output from an audio output device, for example, a headphone device. Furthermore, the video display device and the audio output device are connected by short-range wireless communication. For the short-range wireless communication, for example, Bluetooth (registered trademark) Bluetooth communication is used.

As described above, when video or the like is output from the video display device and audio is output from the audio output device wirelessly connected to the device, there is a delay until the audio is output. Therefore, it is known that the video display device performs processing for canceling the delay time, and synchronizes the output of the video and the like with the output of the audio (for example, see Patent Document 1).
Japanese Patent Laying-Open No. 2005-79614 (pages 2-3 and 11-13, FIG. 6)

  However, in the method disclosed in Patent Document 1 described above, in order to estimate the delay time, the audio output device refers to the time stamp and determines a time at which audio reproduction according to the audio reproduction capability is possible. It is necessary to have a function of taking synchronization, etc., and there has been a problem in that it is inevitable that the audio output device will be highly functional, eventually enlarged, and power consumption will be increased. This problem of increased power consumption is significant when the audio output device is portable and is driven by power stored in a battery.

  The present invention has been made to solve the above-described problems, and an audio output device that does not determine the audio output timing, and the audio output device is used to estimate the delay time, output video, etc. An object of the present invention is to provide a video display device that synchronizes with an output.

  In order to achieve the above object, a video display device according to the present invention stores video data of content including video data, a time at which the video data is displayed, audio data, and a time at which the audio data is output. A video display device for displaying and outputting audio data of the content to an audio output device, the display means for displaying the video data, and a short-distance wireless communication with the audio output device via a short-distance wireless line The short-distance wireless processing means sends a processing means, a time when the short-distance wireless processing means starts processing to transmit audio data to the audio output device, and a notification that the audio data is output from the audio output device. Audio delay time estimation means for estimating the audio delay time based on the difference with the received time, and the video data display time and video delay time added to the video data The process of causing the display means to display the audio data and transmitting the audio data to the audio output device at a time obtained by subtracting the audio delay time from the time when the audio data is output and adding the video delay time. Video and audio synchronization control means for starting the short-range wireless processing means.

  The audio output device of the present invention includes a short-range wireless processing unit that communicates with a video display device via a short-distance wireless line, and an audio output unit that outputs audio data received by the short-range wireless processing unit from a speaker. And when the audio output means outputs the audio data to which the predetermined identification information is added, the short distance wireless processing means is controlled to notify the video display device that the audio data has been output. And a control means.

  According to the present invention, it is possible to estimate the delay time by using an audio output device that does not determine the audio output timing, and to synchronize the output of video and the like with the audio output.

  Embodiments of a video display device and an audio output device according to the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 shows a connection between a mobile communication terminal device to which a video display device according to the first embodiment of the present invention is applied and a headphone device to which an audio output device according to the first embodiment of the present invention is applied. It is a block diagram which shows a structure. The mobile communication terminal device MS and the headphone device HP are connected by a short-range wireless communication line BT. Here, the short-range wireless communication line BT is a communication line based on the Bluetooth (R) method.

  FIG. 2 is a block diagram showing a configuration of the mobile communication terminal apparatus MS. This mobile communication terminal device MS includes a control unit 11 that controls the entire device, an antenna 12a that transmits and receives radio waves to and from a base station (not shown), a communication unit 12b, a transmission / reception unit 13, and an incoming call. Speaker 14a, microphone 14b for transmission, call unit 14c, display unit 15, and input device 16.

  The mobile communication terminal MS further includes a television processing unit 21, a video buffer 22, an STC (System Time Clock) unit 23 indicating time, an audio buffer 24, a video reproduction unit 31, and an audio data switching unit 41. And a voice reproduction unit 42, a voice reproduction speaker 42a, and a short-range wireless processing unit 43 that performs communication via the short-range wireless communication line BT. The video buffer 22 stores the video data decoded by the television processing unit 21. The audio buffer 24 stores the audio data decoded by the television processing unit 21. In FIG. 2, the flow of video data and audio data is indicated by thick solid arrows.

  FIG. 3 is a block diagram illustrating a detailed configuration of the television processing unit 21. This TV processing unit 21 includes an antenna 21a for receiving TV broadcast radio waves, a tuner unit 21b, a DEMUX unit 21c, a video decoding unit 21d connected to the video buffer 22, and an STC calibration connected to the STC unit 23. Unit 21e and an audio decoding unit 21f connected to the audio buffer 24.

  FIG. 4 is a block diagram illustrating a detailed configuration of the short-range wireless processing unit 43. The short-range wireless processing unit 43 is connected to the STC unit 23, and further connected to the voice buffer 24 via the voice data switching unit 41. The encoded voice buffer 43b is connected to the short-range wireless processing unit 43. A transmission / reception unit 43c, a short-range wireless communication unit 43d, and an antenna 43e that transmits and receives radio waves of the short-range wireless communication line BT are provided. The encoded audio buffer 43b stores the audio data encoded by the audio encoding unit 43a.

  FIG. 5 is a block diagram showing a configuration of the headphone device HP. The headphone device HP includes a control unit 51 that controls the entire device, a short-range wireless communication unit 52 that performs communication via the short-range wireless communication line BT, and an antenna 52a that transmits and receives radio waves on the short-range wireless communication line BT. , A short-range wireless transmission / reception unit 53, an encoded audio buffer 54, an audio decoding unit 55, an audio reproduction unit 56, an audio reproduction speaker 56a, a display unit 57, and an input device 58. The encoded audio buffer 54 stores encoded audio data received by the short-range wireless transmission / reception unit 53.

  The mobile communication terminal device MS and the headphone device HP described above may be composed of a computer and a program used by the computer. In particular, as will be described later, the operation of the control unit 11 and the operation of the control unit 51 (particularly the operation of the control unit 11) are not necessarily stylized, and therefore, from a computer and a program used by the computer. Preferably, it is configured.

  The operation of each part of the apparatus according to the first embodiment of the present invention configured as described above will be described with reference to FIGS. First, the operation of each unit of the mobile communication terminal device MS will be described with reference to FIG. The communication unit 12b outputs the high-frequency signal received by the antenna 12a to the transmission / reception unit 13, and transmits the high-frequency signal output from the transmission / reception unit 13 from the antenna 12a.

  The transmission / reception unit 13 amplifies, frequency-converts, and demodulates the high-frequency signal from the communication unit 12b, thereby obtaining a digital signal, and sends the obtained call voice signal to the call unit 14c and sends a control signal to the control unit 11.

  Furthermore, the transmission / reception unit 13 modulates, frequency-converts and amplifies the digital signal, that is, the call voice signal output from the call unit 14c and the control signal output from the control unit 11, to obtain a high-frequency signal. The data is transmitted to the communication unit 12b.

  The calling unit 14c converts the digital audio signal output from the transmission / reception unit 13 into an analog audio signal, amplifies it, and sends the analog audio signal to the speaker 14a. The analog audio signal output from the microphone 14 b is amplified, converted into a digital audio signal, and transmitted to the transmission / reception unit 13.

  The display unit 15 is, for example, an LCD, and performs display operation of characters / numbers and video data under the control of the control unit 11. The displayed data is input operation or incoming signal from the input device 16. In response to an instruction from the control unit 11.

  The input device 16 includes a key including a numeric key for designating a telephone number of a communication partner and a plurality of function keys. When the key of the input device 16 is operated, the identifier of the key is notified to the control unit 11 and displayed on the display unit 15 as characters or controlled by the control unit 11.

  Next, the operation of each unit of the television processing unit 21 will be described with reference to FIG. The television processing unit 21 starts to operate according to an instruction from the control unit 11. Then, the tuner unit 21b selects a high frequency signal of a channel designated by a predetermined key operation of the input device 16 from the high frequency signals received by the antenna 21a.

  Then, the tuner unit 21b converts the selected high-frequency signal into an intermediate-frequency signal and demodulates the converted signal, thereby obtaining encoded television broadcast content. Here, the television broadcast content is a signal encoded by the MPEG system, but is not limited thereto.

  The DEMUX unit 21c separates the broadcast content obtained by the tuner unit 21b into an encoded video signal, an encoded audio signal, and PCR (Program Clock Reference). The encoded video signal is sent to the video decoding unit 21d, and the encoded audio signal is sent to the audio decoding unit 21f. Further, the PCR is sent to the STC calibration unit 21e. Here, the audio signal is a signal encoded by the AAC method, but is not limited thereto.

  The video decoding unit 21d decodes the encoded video signal separated by the DEMUX unit 21c for each video frame. Then, a time PTS (Presentation Time Stamp) at which the frame signal is displayed is added to the decoded video frame signal and stored in the video buffer 22. If the PTS is added to the encoded video frame signal, the added PTS is used.

  On the other hand, if not added, the video decoding unit 21d receives the encoded video frame signal and the encoded video frame signal received before the encoded video frame signal and displayed before the signal. The interval between the video frame signal and the video frame signal to which the PTS is added is counted by the number of encoded video frame signals. Then, a PTS is obtained and added by adding the time obtained by multiplying the added PTS to the time interval at which the video frame signal is created and the above number.

  FIG. 6 shows an example of the format of the decoded video signal stored in the video buffer 22. The decoded video signal 22a is information in which the PTS 22b and the video frame signal 22c displayed at the time indicated by the PTS 22b are associated with each other, and the information is sequentially arranged in the order of the PTS 22b included in each information. Yes.

  The audio decoding unit 21f decodes the encoded audio signal separated by the DEMUX unit 21c for each audio frame. Then, a time PTS at which the frame signal is output is added to the decoded audio frame signal and stored in the audio buffer 24. If the PTS is added to the encoded audio frame signal, the added PTS is used.

  On the other hand, if not added, the speech decoding unit 21f receives the encoded speech frame signal and the encoded speech frame signal received before the encoded speech frame signal and output before the signal. The interval between the audio frame signal and the audio frame signal to which the PTS is added is counted by the number of encoded audio frame signals. Then, a PTS is obtained and added by adding the time obtained by multiplying the added time interval by which the audio frame signal is generated and the above number to the added PTS.

  FIG. 7 shows an example of the format of the decoded audio signal stored in the audio buffer 24. The decoded audio signal 24a is information in which the PTS 24b and the audio frame signal 24c output at the time indicated by the PTS 24b are associated with each other, and the information is sequentially arranged in the order of the PTS 24b included in each information. Yes.

  The STC calibration unit 21e receives the PCR separated by the DEMUX unit 21c, and calibrates the STC unit 23 so that the STC unit 23 indicates the time indicated by the PCR.

  Returning to the description of the operation of each unit of the mobile communication terminal apparatus MS with reference to FIG. The video playback unit 31 starts to operate according to an instruction from the control unit 11. Then, a decoded video signal 22a in which the time indicated by the STC unit 23 is equal to the PTS 22b stored in the video buffer 22 is obtained. Next, the video frame signal 22c of the obtained decoded video signal 22a is displayed on the display unit 15. The video reproduction unit 31 repeats the operation of obtaining and displaying the decoded video signal 22a.

  When the time indicated by the STC unit 23 is equal to the PTS 22b stored in the video buffer 22, the video frame signal 22c must be displayed on the display unit 15. Therefore, the video reproduction unit 31 performs an operation of obtaining the decoded video signal 22a a predetermined time before the time indicated by the STC unit 23 becomes equal to the PTS 22b stored in the video buffer 22. Here, the predetermined time is a time required for the display processing of the video reproduction unit 31. In the above description, in order to simplify the description, the time required for the display process of the video reproduction unit 31 is assumed to be zero. In the following description, it is assumed that the value is also 0.

  The audio data switching unit 41 causes the audio reproduction unit 42 or the short-range wireless processing unit 43 to read the decoded audio signal 24 a stored in the audio buffer 24 in accordance with an instruction from the control unit 11.

  The sound reproducing unit 42 starts operation in response to an instruction from the control unit 11. Then, a decoded audio signal 24a in which the time indicated by the STC unit 23 is equal to the PTS 22b stored in the audio buffer 24 is obtained. Next, the audio frame signal 24c of the obtained decoded audio signal 24a is converted into an analog signal and output from the speaker 42a. The audio reproducing unit 42 repeats the operation of obtaining and outputting the decoded audio signal 24a.

  When the time indicated by the STC unit 23 is equal to the PTS 22b stored in the audio buffer 24, audio based on the audio frame signal 24c must be output from the speaker 42a. Therefore, the audio reproduction unit 42 performs an operation of obtaining the decoded audio signal 24a a predetermined time before the time indicated by the STC unit 23 becomes equal to the PTS 22b stored in the audio buffer 24.

  Here, the predetermined time is a time required for the sound output processing of the sound reproducing unit 42. In the above description, in order to simplify the description, the time required for the audio output process of the audio reproduction unit 42 is assumed to be zero. In the following description, it is assumed that the value is also 0. This is the same as described in the explanation of the operation of the video reproduction unit 31.

  Next, the operation of each unit of the short-range wireless processing unit 43 will be described with reference to FIG. The short-range wireless processing unit 43 starts to operate according to an instruction from the control unit 11. Then, the speech encoding unit 43a obtains from the speech buffer 24 a decoded speech signal 24a in which the time indicated by the STC unit 23 is equal to the PTS 22b.

  The audio encoding unit 43a encodes the audio frame signal 24c of the obtained decoded audio signal 24a, and stores the encoded audio signal in the encoded audio buffer 43b. Encoding is performed in units of a predetermined frame (hereinafter, this frame is referred to as an SBC frame) by, for example, the SBC (Sub Band Codec) method, but is not limited thereto. The voice encoding unit 43a repeats the operation of obtaining, encoding, and storing the decoded voice signal 24a.

  The short-range wireless transmission / reception unit 43c reads out the encoded audio signal stored in the encoded audio buffer 43b in units of SBC frames in the order stored in the encoded audio buffer 43b, and reads the encoded audio signal. The voice signal and the control signal output from the control unit 11 are modulated, frequency-converted and amplified to obtain a high-frequency signal, which is sent to the short-range wireless communication unit 43d for transmission. Further, the short-range wireless transmission / reception unit 43 c sends the control signal received by the short-range wireless communication unit 43 d to the control unit 11.

  The short-range wireless communication unit 43d transmits the high-frequency signal transmitted from the short-range wireless transmission / reception unit 43c from the antenna 43e. In addition, the high-frequency signal received by the antenna 43e is sent to the short-range wireless transceiver 43c.

  Next, the operation of each part of the headphone device HP will be described with reference to FIG. The short-range wireless communication unit 52 sends the high-frequency signal received by the antenna 52 a to the short-range wireless transmission / reception unit 53. Moreover, the high frequency signal output from the short-range wireless transmission / reception unit 53 is transmitted from the antenna 52a.

  The short-range wireless transmission / reception unit 53 amplifies, frequency-converts and demodulates the high-frequency signal from the short-range wireless communication unit 52, thereby obtaining a digital signal, and the obtained audio signal in SBC frame unit is encoded as the audio buffer 54. And a control signal is sent to the control unit 51.

  Further, the short-range wireless transmission / reception unit 53 modulates, frequency-converts and amplifies the digital signal, that is, the control signal output from the control unit 51, obtains a high-frequency signal, and sends it to the short-range wireless communication unit 52. Send it.

  The audio decoding unit 55 reads out the audio signal stored in the encoded audio buffer 54 in units of SBC frames in the order stored in the encoded audio buffer 54, and decodes the read audio signal. Then, the decoded audio signal is sent to the audio reproduction unit 56. The audio reproduction unit 56 converts the audio signal decoded by the audio decoding unit 55 into an analog signal, and outputs the converted audio signal from the speaker 56a.

  The display unit 57 is, for example, an LCD and is controlled by the control unit 51 to display characters / numbers and video data. The displayed data responds to an input operation from the input device 58. In response to an instruction from the control unit 51, switching is performed. The display unit 57 may be a lamp such as an LED.

  The input device 58 includes a key including a plurality of function keys. When a key of the input device 58 is operated, the identifier of the key is notified to the control unit 51 and displayed on the display unit 57 or controlled by the control unit 51.

  Hereinafter, a process of synchronizing the video output in the mobile communication terminal apparatus MS and the audio output in the headphone apparatus HP according to the first embodiment of the present invention will be described.

  First, the reason why the audio output in the headphone device HP is delayed will be described. According to the above-described operation, there is no delay in audio output when audio is output from the speaker 42a of the mobile communication terminal device MS in reproducing broadcast content including video and audio received by the television processing unit 21.

  That is, when the time indicated by the STC unit 23 is equal to the PTS 22b stored in the video buffer 22, the video frame signal 22c is displayed on the display unit 15. However, when audio is output from the speaker 56a of the headphone device HP, the audio output is not output at the time indicated by the PTS 24b, and a delay occurs due to the following reason.

  First, there is a delay that occurs when the voice signal is in the mobile communication terminal device MS. The delay time is the time required for encoding by the voice encoding unit 43a and the encoded voice signal is encoded. This is the sum of the time from when it is stored in the audio buffer 43b until it is read out.

  Second, there is a delay for the voice signal to be transmitted through the short-range wireless communication line BT. Third, there is a delay that occurs when the audio signal is in the headphone device HP, and the delay time is the time from when the encoded audio signal is stored in the encoded audio buffer 54 until it is read out, and the audio This is the sum of the time required for decoding by the decoding unit 55.

  Of these delay times, the longest time is the time from when the audio signal is in the mobile communication terminal apparatus MS and the encoded audio signal is stored in the encoded audio buffer 43b until it is read out. There are many cases. The next largest time is often the time from when the audio signal is in the headphone device HP and the encoded audio signal is stored in the encoded audio buffer 54 until it is read out.

  Therefore, the control unit 11 estimates a delay time generated by the first to third delays as described below. Then, the display of the video frame signal 22c by the video playback unit 31 is delayed for a first predetermined time, and / or the audio frame signal 24c is encoded or transmitted by the short-range wireless processing unit 43 by a second predetermined time. Start ahead over time. Here, the delay is canceled by controlling the sum of the first predetermined time and the second predetermined time to be equal to the delay time when the sound is output from the speaker 56a.

  In order to delay the display of the video frame signal 22c by the video playback unit 31 for a first predetermined time, the control unit 11 instructs the video playback unit 31 to perform the first predetermined time at the time indicated by the STC unit 23. The video frame signal 22c associated with the PTS 22b equal to the sum of the times added is obtained and displayed.

  In order to start the encoding or transmission of the audio frame signal 24c by the short-range wireless processing unit 43 in advance for the second predetermined time, the control unit 11 includes the audio encoding unit 43a of the short-range wireless processing unit 43. The voice frame signal 24c associated with the PTS 24b equal to the difference time obtained by subtracting the second predetermined time from the time indicated by the STC unit 23 is obtained and encoded.

  In addition, according to the process that precedes the encoding of the audio frame signal 24c, the video is output when the audio is output from the speaker 42a of the mobile communication terminal device MS and when the audio is output from the speaker 56a of the headphone device HP. There is little difference in time displayed on the display unit 15.

  Therefore, there is little discomfort given to the user of the device viewing the display unit 15 when the speaker that outputs the sound is switched. However, for the preceding processing, it is necessary that the audio frame signal 24c having a data amount output over the second predetermined time is stored in the audio buffer 24.

  On the other hand, the process of delaying the display of the video frame signal 22c is performed regardless of the amount of the video frame signal 22c stored in the video buffer 22 and the amount of the audio frame signal 24c stored in the audio buffer 24. There is no need to refer to these quantities.

  Next, a process for estimating the delay time that occurs when the control unit 11 outputs sound from the speaker 56a of the headphone device HP will be described. FIG. 8 shows a flowchart of an operation in which the control unit 11 estimates the delay time.

  The control unit 11 starts an operation of estimating the delay time at a predetermined time interval (step S11a). Here, since the delay time is not always constant, it is desirable to estimate at a predetermined time interval. Note that it is not appropriate that the predetermined time interval is equal to or less than the estimated or expected delay time. This is because, as will be described later, the delay time is estimated by transmitting an SBC frame to the headphone device HP and receiving an answer regarding the transmitted SBC frame from the headphone device HP.

  Therefore, if it is performed at a time interval equal to or less than the delay time, the control unit 11 may be confused in determining which of the SBC frames is the received response. In addition, the delay time estimation processing load may be excessive. On the other hand, since the delay time is not always constant, it is appropriate to repeat the estimation of the delay time at a predetermined interval. This interval may be repeatedly estimated by delay time estimation, and may be larger when the estimated delay time variance is small, and may be smaller when the variance is large.

  Next, the control unit 11 instructs the speech encoding unit 43a of the short-range wireless transmission / reception unit 43c to add a playback response request to the SBC frame and store it in the encoded speech buffer 43b, and the speech related to the frame. The time when the frame signal 24c is read from the audio buffer 24 via the audio data switching unit 41 is reported (step S11b).

  This reproduction response request is added, for example, by changing one bit of the header in the frame. Then, the control unit 11 sets the time reported by the speech encoding unit 43a as T11. Here, the speech encoding unit 43a may obtain the time based on the time indicated by a clock (not shown) included in the control unit 11 or may be obtained based on the time indicated by the STC unit 23. As a result, the time used in the operation in which the control unit 11 estimates the delay time thereafter is one of these two times.

  Note that the time indicated by the STC unit 23 may change greatly from the change of the actual time due to a change in the program of the broadcasted content. Therefore, when the time indicated by the STC unit 23 is used during the operation for estimating the delay time, the above operation may estimate a delay time outside the expected range, for example, a negative delay time. . The control unit 11 discards the delay time outside the expected range.

  In the above description, it is assumed that whether or not the SBC frame is a frame to which a playback response request used for estimating the delay time is added is indicated by identification information that is one bit of the header in the frame. Whether or not the frame is a frame to which a reproduction response request is added is not limited according to identification information that is one bit of the header.

  For example, when an SBC frame is assigned a frame number that is an integer and the frame number is divisible by an integer, the SBC frame may be identified as being used for estimating the delay time. Alternatively, the SBC frame with a predetermined frame number may be identified as being used for estimating the delay time.

  According to these, a frame number divisible by a certain integer or a predetermined frame number is identification information for identifying that the SBC frame is used for estimating the delay time.

  According to these processes, it is not necessary to transmit a bit indicating whether or not it is a reproduction response request, and a reduction in the number of bits of the header can be obtained. The integer that divides the frame number or the predetermined frame number may be determined in advance or may be determined by an instruction from the control unit 11. Further, the change may be possible by an instruction from the control unit 11.

  The control unit 11 instructs the short-range wireless transmission / reception unit 43c to report the time when the SBC frame to which the reproduction response request is added is transmitted to the short-range wireless communication line BT by the short-range wireless communication unit 43d (Step S11). S11c). Let the reported time be T12. Subsequently, the short-range wireless transmission / reception unit 43c is instructed to report the time when the reply that the SBC frame to which the reproduction response request is added is received by the headphone device HP is obtained (step S11d). Let the reported time be T13.

  Further, the control unit 11 instructs the short-range wireless transmission / reception unit 43c to report the time when the response indicating that the SBC frame to which the reproduction response request is added is output by the headphone device HP is obtained (step S11e). Let the reported time be T14.

Based on the reported times T11 to T14, the control unit 11 estimates the delay time (step S11f) and ends the delay time estimation operation (step S11g). Here, the delay time is
(T14-T11)-(T13-T12) / 2
And calculate and estimate. The first term (T14-T11) indicates the time from when the audio frame signal 24c related to the SBC frame is read from the audio buffer 24 until the audio included in the SBC frame is output.

  However, at this time, there is a delay for transmitting a response that the sound related to the SBC frame is output by the headphone device HP via the short-range wireless communication line BT. Therefore, the second term (T13-T12) / 2 is a term for subtracting and correcting the added delay.

  That is, (T13-T12) is a delay for transmitting the SBC frame via the short-range wireless communication line BT when the SBC frame is transmitted from the short-range wireless transmission / reception unit 43c to the headphone device HP, and the headphone device HP This is a sum of delay times due to two delays, a delay for transmission via the short-range wireless communication line BT when transmitting a reply that a frame has been received. Therefore, in the second term, (T13-T12) is divided by 2.

  When the delay time estimated as described above is a value outside the expected range, the control unit 11 may regard the value as a temporary change and discard it. Further, the control unit 11 may obtain the delay time by calculating an average value of a predetermined number of delay times estimated in the latest past.

  Furthermore, when the estimated delay time is considered to be monotonically increasing or decreasing monotonously with respect to time, the control unit 11 assumes that the delay time is a linear function with respect to time. good. The parameter of the function can be obtained by, for example, the least square method.

  When the estimated delay time repeatedly increases and decreases with respect to time, the control unit 11 may assume that the delay time is a function of the sum of a fixed number and a sine function. The parameters of the function, that is, the constant number and the amplitude, frequency, and initial phase of the sine function can be obtained by, for example, the least square method.

  Next, a process of synchronizing the output of video in the mobile communication terminal apparatus MS and the output of sound in the headphone apparatus HP, which will be described in each part of the headphone apparatus HP. When the short-range wireless transmission / reception unit 53 of the headphone device HP receives the SBC frame to which the request is added, the short-range wireless transmission / reception unit 53 immediately transmits to the mobile communication terminal device MS that the frame has been received. Then, with the request added, the audio signal in SBC frame units is stored in the encoded audio buffer 54.

  Then, when the voice related to the SBC frame to which the request is added is output from the voice playback unit 56 to the speaker 56a, the voice decoding unit 55 sends a response indicating that the voice included in the SBC frame has been played back. 51, the mobile communication terminal device MS is made to transmit via the short-range wireless transmission / reception unit 53.

  Note that the estimation of the delay time for transmitting the response that the SBC frame is output by the headphone device HP via the short-range wireless communication line BT is performed together with the transmission / reception of the SBC frame to which the request is added. It is not limited.

  After arbitrary data is transmitted from the short-range wireless transmission / reception unit 43c to the headphone device HP, when the data is received by the short-range wireless transmission / reception unit 53 of the headphone device HP, the short-range wireless transmission / reception unit 53 is immediately received. It may be performed by transmitting a message to the mobile communication terminal device MS.

  Also, a predetermined protocol used by the short-range wireless transmission / reception unit 43c for communication over the short-range wireless communication line BT without transmitting the fact that the short-range wireless transmission / reception unit 53 of the headphone device HP has been received to the mobile communication terminal device MS. It may be estimated by calculation from the time when the above step is performed. The delay time may be determined in advance according to the specifications of the short-range wireless communication unit 43d.

(Second Embodiment)
The second embodiment is different from the first embodiment in the mobile communication terminal device MS. Therefore, the configuration and operation of the mobile communication terminal device MS according to the second embodiment will be described. Note that the same parts as those of the mobile communication terminal apparatus MS according to the first embodiment are denoted by the same reference numerals and description thereof is omitted. Although the control unit 11 is denoted by the same reference numeral, there is a difference in the delay time estimation operation, and the operation will be described.

  FIG. 9 is a block diagram showing a configuration of the mobile communication terminal apparatus MS according to the second embodiment. This mobile communication terminal device MS includes a short-range wireless processing unit 43-2 instead of the short-range wireless processing unit 43, as compared with the mobile communication terminal device MS according to the first embodiment whose configuration is shown in FIG. In addition, a microphone 44 for delay time estimation is provided.

  FIG. 10 is a block diagram illustrating a detailed configuration of the short-range wireless processing unit 43-2. The short-range wireless processing unit 43-2 includes a speech encoding unit 43a2 instead of the speech encoding unit 43a, as compared with the short-range wireless processing unit 43 according to the first embodiment.

  The operation of the speech encoding unit 43a2 will be described. The speech encoding unit 43a2 obtains the decoded speech signal 24a of the speech encoding unit 43a according to the first embodiment, encodes the obtained speech frame signal 24c, and encodes the encoded speech signal. In addition to the operation stored in the audio buffer 43b, the following operation is performed.

  The voice encoding unit 43a2 encodes a predetermined delay time estimation speech signal based on an instruction from the control unit 11, and stores the encoded delay time estimation speech signal in the encoded speech buffer 43b. Here, the predetermined delay time estimation audio signal is an artificial audio signal not included in the audio frame signal 24c stored in the audio buffer 24, and one or a plurality of audio signals having a predetermined frequency are included. These audio signals are added at a predetermined volume and do not adversely affect the user's auditory organ.

  The predetermined delay time estimation audio signal can be encoded by the audio encoding unit 43a2, can be output by the headphone device HP, and the audio output by the headphone device HP can be input by the microphone 44. It is. And when output by the headphone device HP, it is desirable that the user of the device is incapable of listening or difficult to hear. That is, it is desirable that the audio signal has a frequency that is impossible or difficult to hear depending on human hearing.

  Next, an operation in which the control unit 11 according to the second embodiment estimates the delay time will be described. FIG. 11 shows a flowchart of an operation in which the control unit 11 estimates the delay time. The control unit 11 starts an operation for estimating the delay time (step S11i), instructs the speech encoding unit 43a2 to encode a predetermined delay time estimation speech signal, and stores it in the encoded speech buffer 43b. . And the time which started the encoding is reported (step S11j). Reported time and T21.

  Next, the control part 11 takes the waiting time of predetermined time (step S11k). This time is shorter than the expected delay time and is a sound other than the sound from which the predetermined delay time estimation sound signal is output, and is the same sound as that from which the delay time estimation sound signal was output. This is to avoid an erroneous estimation of the delay time due to the fact that is input by the microphone 44.

  Subsequently, the control unit 11 determines whether or not the voice input by the microphone 44 matches the output of the predetermined delay time estimation voice signal (step S11m). The time input by the microphone 44 is obtained (step S11n). Let the obtained time be T22.

And the control part 11 estimates delay time (step S11o), and complete | finishes the estimation operation of delay time (step S11p). Here, the delay time is
T22-T21
And calculate and estimate.

  If they do not match in step S11m, the control unit 11 repeats the operation of step S11m to determine whether or not they match. On the other hand, if they do not match for a long time, the control unit 11 ends the estimation operation without estimating the delay time (step S11p). Here, the long time is a time exceeding the maximum expected delay time.

  If they do not match for a long time, the sound output from the headphone device HP cannot be input by the microphone 44. That is, the sound is not limited to the headphone device HP not operating, for example, output from the headphone device HP. This is because the control unit 11 determines that the delay time cannot be estimated, for example, because the volume of the sound is low or the distance between the headphone device HP and the microphone 44 is long.

  The audio signal for estimating the delay time cannot be heard by the user of the device or is difficult to hear, and it is not always impossible to input the sound output from the headphone device HP by the microphone 44. In this case, the control unit 11 performs an operation for estimating the delay time at a predetermined time interval. Here, the predetermined time interval is as described in the description of the operation for estimating the delay time in the first embodiment.

  Normally, the mobile communication terminal device MS and the headphone device HP are used at a distance of about several tens of centimeters to 1 meter. The speaker 56a of the headphone device HP outputs sound in the direction of the ear of the user of the headphone device HP. However, the sound output from the speaker 56a of the headphone device HP may be designed to leak around the headphone device HP.

  The microphone 44 is for receiving a predetermined delay time estimation audio signal, and the frequency characteristics and the amplification factor of the input audio are designed exclusively for reception of the signal. Therefore, it is not always impossible to input the sound output from the headphone device HP through the microphone 44. Therefore, it is effective for the control unit 11 to perform an operation for estimating the delay time at predetermined time intervals. Here, estimation may not always be possible.

  In addition, when the speech encoding unit 43a2 encodes a predetermined delay time estimation speech signal, it is appropriate to select a time zone in which the speech frame signal 24c to be encoded stored in the speech buffer 24 is silent. is there. This is to avoid affecting the encoding of the audio frame signal 24c by encoding the predetermined delay time estimation audio signal.

  The delay time estimation audio signal is not limited to an audio signal having a frequency that cannot be heard or is difficult to hear depending on human hearing. Even a voice that can be heard by human hearing may be a voice signal that cannot be heard by a user of the apparatus due to a masking effect or that is difficult to hear.

  When this masking effect is used, the speech encoding unit 43a2 has a frequency close to the frequency of the delay time estimation speech signal and only before and after the time when the speech signal with a large volume is generated. Is added to the audio frame signal 24c and encoded.

  For this reason, even if the delay time estimation speech signal is not always the same frequency and one of a plurality of frequencies is appropriately used, the delay time estimation speech signal cannot be encoded at a predetermined time interval. However, even if it is not a predetermined time interval, there is an effect by repeatedly estimating the delay time.

  On the other hand, it is possible for the user of the apparatus to always listen to a predetermined delay time estimation audio signal, and the user uses the headphone apparatus HP when the sound output from the headphone apparatus HP is input by the microphone 44. In the case where it is not always impossible, the speech encoding unit 43a2 is a speech signal included in the speech frame signal 24c stored in the speech buffer 24, and the featured speech signal is converted into a delay time estimation speech. Signal.

  The delay time estimation audio signal used in this way is, for example, an audio signal having a characteristic frequency distribution, that is, a sound of a predetermined instrument, and an audio signal having a large volume after a predetermined silence. Even when this delay time estimation audio signal is used, there is an effect that the delay time can be repeatedly estimated even if it is not a predetermined time interval.

  In addition, when it is impossible for the user to always input the sound output from the headphone device HP by the microphone 44 when the user is using the headphone device HP, the control unit 11 displays the short-range wireless processing unit. 43-2 is controlled to send the audio signal to the headphone device HP, and after estimating the delay time, the audio data switching unit 41 is controlled, and the short-range wireless processing unit 43-2 is connected to the audio buffer 24. The stored audio frame signal 24c may be read out.

  Prior to the estimation of the delay time, it is preferable that the control unit 11 notifies the user to bring the speaker 56a of the headphone device HP closer to the microphone 44. This notification is based on display on the display unit 15, sound output from the speaker 42a, sound output from the speaker 56a, and the like.

  Each unit of the mobile communication terminal device MS and the headphone device HP according to the second embodiment has a function of creating an SBC frame to which a reproduction response request according to the first embodiment is added, Does not require the function to report the time of transmission / reception.

  In the above description, the mobile communication terminal device MS according to the second embodiment is provided with the microphone 44 different from the microphone 14b, but is not limited thereto. The microphone 44b may not be provided and the transmission microphone 14b may be used for delay time estimation.

  The headphone device HP in the second embodiment does not require any operation other than the essential function of the headphone device HP, that is, the function of outputting the sound received via the short-range wireless communication line BT from the speaker 56a. In other words, the second embodiment can be applied to any headphone device HP.

(Third embodiment)
The third embodiment is different from the first embodiment in the headphone device HP. Therefore, the configuration and operation of the headphone device HP according to the second embodiment will be described. Note that the same portions as those of the headphone device HP according to the first embodiment are denoted by the same reference numerals and description thereof is omitted. In addition, although the same code | symbol is attached | subjected to the control part 11 of mobile communication terminal device MS, since there exists a difference in the estimation operation | movement of delay time, the operation | movement is demonstrated.

  FIG. 12 is a block diagram showing a configuration of a headphone device HP according to the second embodiment. Compared with the headphone device HP according to the first embodiment whose configuration is shown in FIG. 5, the headphone device HP is replaced with a control unit 51-3 instead of the control unit 51 and a near-field wireless transmission / reception unit 53. The distance wireless transmission / reception unit 53-3 is provided, and a voice decoding unit 55-3 is provided instead of the voice decoding unit 55.

  The difference between the operation of the short-range wireless transmission / reception unit 53-3 and the operation of the short-range wireless transmission / reception unit 53 according to the first embodiment is as follows. That is, when the short-range wireless transmission / reception unit 53-3 receives the SBC frame to which the predetermined identification information is added, the short-range wireless transmission / reception unit 53-3 immediately notifies the control unit 51-3 of that fact. On the other hand, the short-range wireless transmission / reception unit 53 according to the first embodiment transmits a message to that effect to the mobile communication terminal device MS.

  The difference between the operation of the speech decoding unit 55-3 and the operation of the speech decoding unit 55 according to the first embodiment is as follows. That is, when the audio signal for each SBC frame to which the predetermined identification information is added is output from the audio reproduction unit 56 to the speaker 56a, the audio decoding unit 55-3 immediately notifies the control unit 51-3. To do. On the other hand, the speech decoding unit 55 according to the first embodiment transmits a message to that effect to the mobile communication terminal device MS.

  In addition to the operation of the control unit 51 according to the first embodiment, the control unit 51-3 receives the time when the notification sent from the short-range wireless transmission / reception unit 53-3 is received, and the speech decoding unit 55- The time of the difference from the time when the notification sent from 3 is received is measured. Then, the time (T31) is transmitted to the mobile communication terminal device MS via the short-range wireless transmission / reception unit 53-3. This T31 is a delay time that occurs when the audio signal is in the headphone device HP.

  Note that the above-described processing for measuring the delay time generated when the audio signal is in the headphone device HP is performed by receiving an SBC frame to which predetermined identification information is added from the mobile communication terminal device MS. However, it is not limited to this. It may be performed with respect to a predetermined SBC frame defined in the headphone device HP. In addition, the transmission of the measured time (T31) is performed every time it is measured, but the present invention is not limited to this. Each time a request is received from the mobile communication terminal device MS, the latest measured time (T31) or the time (T31) calculated from the average of the times measured in the near past may be transmitted.

  As described above, the control unit 51-3 only needs to obtain the time difference between the times when the two notifications are received, and does not need to obtain the time. In other words, since it is not necessary to provide a clock, there is no need for a complicated and expensive configuration.

  Next, an operation in which the control unit 11 according to the third embodiment estimates the delay time will be described. FIG. 13 shows a flowchart of the operation in which the control unit 11 estimates the delay time. In addition, about the operation | movement step included in the operation | movement which the control part 11 concerning 1st Embodiment estimates delay time, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  First, the control unit 11 starts the operation of estimating the delay time in steps S11a to S11c, and reads the time T11 when the audio frame signal 24c related to the SBC frame to which the predetermined identification information is added is read from the audio buffer 24. An operation of obtaining from the short-range wireless transmission / reception unit 43c the time T12 obtained from the speech encoding unit 43a and further transmitting the SBC frame to which the predetermined identification information is added to the short-range wireless communication line BT is performed.

  Subsequently, the control unit 11 receives the delay time T31 transmitted from the headphone device HP when the audio signal is in the headphone device HP via the short-range wireless transmission / reception unit 43c (step S11r).

  And the control part 11 estimates the delay time for an audio | voice signal to be transmitted via short-distance radio | wireless communication line BT (step S11s). The delay time for transmission is estimated by one or more of the following methods as described in the explanation of the operation of the control unit 11 according to the first embodiment.

  First, after arbitrary data is transmitted from the short-range wireless transmission / reception unit 43c to the headphone device HP, the short-range wireless transmission / reception unit 53-3 of the headphone device HP immediately transmits reception to the mobile communication terminal device MS. To be estimated. Second, it is estimated based on the time at which the short-range wireless transmission / reception unit 43c performs a step of a predetermined protocol used in the communication of the short-range wireless communication line BT. Thirdly, it is estimated according to a predetermined specification of the short-range wireless communication unit 43d.

  Then, the control unit 11 estimates the delay time (step S11t), and ends the delay time estimation operation (step S11u). Here, the delay time includes an estimated value of the delay time that occurs when the audio signal is in the mobile communication terminal device MS, an estimated value of the delay time that occurs when the audio signal is in the headphone device HP, and the audio signal. It is estimated as the total time with the estimated value of the delay time for transmission via the short-range wireless communication line BT.

The delay time that occurs when the audio signal is in the mobile communication terminal device MS uses the time obtained by the operations of Step S11b and Step S11c. T12-T11
It is estimated that. The delay time generated when the audio signal is in the headphone device HP is received in step S11r T31.
It is estimated that. Further, the delay time for transmitting the audio signal via the short-range wireless communication line BT is a value estimated by the operation in step S11s.

  Note that the three operations of the operations of Step S11b and Step S11c, the operation of Step S11r, and the operation of Step S11s are not necessarily performed in the order shown in the flowchart of FIG. It may be done in a different order. Moreover, the time interval at which the three operations are performed may be determined independently. In that case, every time any operation is performed, the delay time in step S11t is estimated.

  In the above description, the delay time is estimated using the SBC frame to which the predetermined identification information is added. As already described in the description of the first embodiment, an SBC frame to which predetermined identification information is added is, for example, an SBC frame that is divisible by a certain integer, or an SBC frame that is assigned to an SBC frame. The SBC frame may be an integer with a certain frame number.

  As described above, the largest delay time is a delay time that occurs when the audio signal is in the mobile communication terminal device MS, and the next largest delay time is a delay that occurs when the audio signal is in the headphone device HP. Often time. Therefore, it is desirable that the control unit 11 correctly estimates the delay time that occurs when the voice signal is in the mobile communication terminal apparatus MS by more frequently executing the operations of step S11b and step S11c. These operations have no effect on the operation of the headphone device HP, and no communication occurs via the short-range wireless communication line BT. Therefore, even if executed frequently, the sound output by the headphone device HP can be affected. Sex is very small.

  On the other hand, the estimation of the delay time that occurs when the audio signal is in the headphone device HP requires the operation of the headphone device HP, and communication occurs via the short-range wireless communication line BT. Therefore, the error included in the estimated value of the delay time that occurs when the audio signal is in the headphone device HP is made smaller than the error that is included in the estimated value of the delay time that occurs when the audio signal is in the headphone device HP. There is little need.

  That is, the control unit 11 may rarely execute the operation of step S11r. Since the operation of estimating the delay time that occurs when the audio signal is present in the headphone device HP is accompanied by the operation of the headphone device HP, rarely executing this operation avoids an influence on the audio output by the headphone device HP. Desirable for.

  As an example of rare execution, it may be performed once immediately before the sound output by the headphone device HP is started. Further, when the delay time generated when the audio signal is in the headphone device HP is obtained or expected in advance, the obtained or expected value may be used. Further, the control unit 11 may inquire of the headphone device HP about the delay time at a predetermined time interval without controlling the interval for measuring the delay time generated when the audio signal is in the headphone device HP.

  As another example that is rarely executed, the control unit 11 may estimate the delay time when the channel received by the television processing unit 21 is changed. Since the change of the channel is performed by a predetermined key operation of the input device 16, the controller 11 can grasp it. Further, the delay time may be estimated when the broadcast program received by the television processing unit 21 is changed. The change of the program is grasped when the PCR separated by the DEMUX unit 21c changes discontinuously different from the change in real time.

(Other embodiments)
The above first to third embodiments are not necessarily exclusive. Appropriate combinations can be made.

  Although the above description has been made taking video data and audio data broadcast on television as examples, the present invention is not limited to this. For example, when video data and audio data are received according to the RTP protocol, a time stamp indicating the time at which the video data is displayed and a time stamp indicating the time at which the audio data is output have different media clocks. Depending on the time shown. However, referring to the RTCP packet, a process for associating the time indicated by these media clocks with the time indicated by the common reference clock is well known. Therefore, the present invention can be applied by regarding the common reference clock as the STC unit 23.

  In the above description, the broadcast received by the television processing unit 21 is composed of video and audio. However, the present invention is not limited to this. For example, characters displayed on the display unit 15 may be further included. The display of this character may be delayed by the same process as the process of delaying the playback of the video frame signal 22c described above by the video playback unit 31, and the description thereof is omitted.

  In the above description, the voice data switching unit 41 of the mobile communication terminal apparatus MS causes either the voice reproduction unit 42 or the short-range wireless processing unit 43 to read data from the voice buffer 24. This is not a limitation. Both of them may be made to read data.

  In order to make both read the data, the control unit 11 controls the audio reproduction unit 42 to delay the output of the audio frame signal 24c from the speaker 42a. Here, the delay time is the same as the time when the video playback unit 31 is instructed to delay the playback of the video frame signal 22c. The process in which the audio reproduction unit 42 delays the output of the audio frame signal 24c is the same as the process in which the video reproduction unit 31 delays the reproduction of the video frame signal 22c, and the description thereof is omitted.

  According to such processing, the present invention is generated from the display of the display unit 15 of the mobile communication terminal device MS, the sound generated from the speaker 42a of the mobile communication terminal device MS, and the speaker 56a of the headphone device HP. This is effective for synchronizing with audio. Furthermore, the present invention is effective in synchronizing the sounds generated from the two speakers regardless of whether or not the display is performed on the display unit 15 of the mobile communication terminal device MS.

  In the above description, the present invention has been described by taking as an example the case where there is one headphone device HP. However, the present invention can naturally be applied to a system having a plurality of headphone devices HP. In that case, the control unit 11 of the mobile communication terminal apparatus MS estimates the delay time for each headphone apparatus HP.

  The difference in the delay time for each headphone device HP is that the control unit 11 encodes and transmits the audio signal in advance for each headphone device HP, and sets the preceding time to be different for each headphone device HP. To cancel. Alternatively, when transmitting the audio signal stored in the encoded audio buffer 43b to each headphone device HP, the time to transmit to the short-range wireless transmission / reception unit 43c is canceled by setting the time different for each headphone device HP.

  The above description uses an example in which the present invention is applied to the mobile communication terminal device MS and the headphone device HP. However, the application of the present invention is not limited to these apparatuses. For example, instead of the mobile communication terminal apparatus MS, the present invention may be applied to a fixed or portable television receiver. Thereby, without outputting the sound from the television receiver or outputting the sound with a small volume, the sound can be output with an appropriate volume from the headphone device HP placed near the TV viewer. it can. Thus, a person other than the television viewer is not broken by the sound broadcast on the television.

  Further, the present invention can naturally be applied to an audio output device that is driven by a commercial power supply and outputs a sound with a large volume instead of the headphone device HP.

  In the above description, the audio signal is a monaural signal, but the present invention is not limited to this. Even a stereo signal may be processed in exactly the same way. Further, one sound of the stereo signal may be output from the speaker 42a of the mobile communication terminal device MS and may be output from the speaker 56a of the other sound headphone device HP. Furthermore, the sound of each stereo signal may be output from different headphone devices HP. The present invention is not limited to the above configuration, and various modifications are possible.

1 is a block diagram showing a configuration in which a mobile communication terminal device according to a first embodiment of the present invention and a headphone device are connected. The block diagram which shows the structure of the mobile communication terminal device which concerns on the 1st Embodiment of this invention. The figure which shows the detailed structure of the television processing part which concerns on the 1st Embodiment of this invention. The figure which shows the detailed structure of the short distance radio | wireless process part which concerns on the 1st Embodiment of this invention. 1 is a block diagram showing a configuration of a headphone device according to a first embodiment of the present invention. The figure which shows an example of the format of the decoded video signal memorize | stored in the video buffer which concerns on the 1st Embodiment of this invention. The figure which shows an example of the format of the decoded audio | voice signal memorize | stored in the audio | voice buffer which concerns on the 1st Embodiment of this invention. The flowchart of the operation | movement which the control part which concerns on the 1st Embodiment of this invention estimates delay time. The block diagram which shows the structure of the mobile communication terminal device which concerns on the 2nd Embodiment of this invention. The figure which shows the detailed structure of the short distance radio | wireless process part which concerns on the 2nd Embodiment of this invention. The flowchart of the operation | movement which the control part which concerns on the 2nd Embodiment of this invention estimates delay time. The block diagram which shows the structure of the headphone apparatus which concerns on the 3rd Embodiment of this invention. The flowchart of the operation | movement which the control part which concerns on the 3rd Embodiment of this invention estimates delay time.

Explanation of symbols

MS Mobile communication terminal device HP Headphone device BT Short-range wireless communication line 11, 51, 51-3 Control unit 15 Display unit 21 TV processing unit 22 Video buffer 22a Decoded video signal 22b, 24b PTS
22c Video frame signal 23 STC unit 24 Audio buffer 24a Decoded audio signal 24c Audio frame signal 31 Video playback unit 41 Audio data switching unit 42, 56 Audio playback unit 42a, 56a Speaker 43, 43-2 Short-range wireless processing unit 43a 43a2 Speech encoding unit 43b, 54 Encoded speech buffer 43c, 53, 53-3 Short-range wireless transmission / reception unit 43d, 52 Short-range wireless communication unit 44 Microphone 55, 55-3 Speech decoding unit

Claims (7)

Displays video data of content consisting of video data, time when the video data is displayed, audio data, and time when the audio data is output, and outputs the audio data of the content to the audio output device A video display device,
Display means for displaying video data;
Short-range wireless processing means for communicating with the voice output device via a short-range wireless line;
A time at which the short-range wireless processing means has started processing to transmit voice data to the voice output device; and a time at which the short-range wireless processing means has received notification that the voice data has been output from the voice output device; Voice delay time estimation means for estimating the voice delay time based on the difference between
Displaying the video data on the display means at the time when the video data is displayed and the video delay time, and transmitting the audio data to the audio output device, the audio data is output. And a video / audio synchronization control unit which causes the short-range wireless processing unit to start at a time obtained by subtracting the audio delay time from the time and adding the video delay time. The voice delay time estimating means corrects the voice delay time by reducing a time during which the short-range wireless processing means receives the notification from the voice output device via the short-range wireless line. The video display device according to claim 1. Short-range wireless processing means for communicating with the video display device via a short-range wireless line;
Audio output means for outputting audio data received by the short-range wireless processing means from a speaker;
When the audio output means outputs audio data to which predetermined identification information is added, video / audio synchronization control means for controlling the short-range wireless processing means to notify the video display device that the audio data has been output. And an audio output device. Displays video data of content consisting of video data, time when the video data is displayed, audio data, and time when the audio data is output, and outputs the audio data of the content to the audio output device A video display device,
Display means for displaying video data;
Short-range wireless processing means for communicating with the voice output device via a short-range wireless line;
A microphone,
A voice that estimates a voice delay time based on a difference between a time when the short-range wireless processing means starts a process of sending voice data to the voice output device and a time when the microphone inputs a voice when the voice data is output. A delay time estimating means;
Displaying the video data on the display means at the time when the video data is displayed and the video delay time, and transmitting the audio data to the audio output device, the audio data is output. And a video / audio synchronization control unit which causes the short-range wireless processing unit to start at a time obtained by subtracting the audio delay time from the time and adding the video delay time. Displays video data of content consisting of video data, time when the video data is displayed, audio data, and time when the audio data is output, and outputs the audio data of the content to the audio output device A video display device,
Display means for displaying video data;
Short-range wireless processing means for communicating with the voice output device via a short-range wireless line;
The time from when the short-range wireless processing means starts processing to transmit the audio data to the voice output device to the end thereof, and the voice output device received by the short-range wireless processing means from the voice output device Voice delay time estimating means for estimating the voice delay time by the sum of the measured time from the reception of the data to the output of the voice data;
Displaying the video data on the display means at the time when the video data is displayed and the video delay time, and transmitting the audio data to the audio output device, the audio data is output. And a video / audio synchronization control unit which causes the short-range wireless processing unit to start at a time obtained by subtracting the audio delay time from the time and adding the video delay time. The voice delay time estimating means corrects the voice delay time by adding a time for the short-range wireless processing means to transmit the voice data to the voice output device via the short-range radio line. The video display device according to claim 5. Short-range wireless processing means for communicating with the video display device via a short-range wireless line;
Audio output means for outputting audio data received by the short-range wireless processing means from a speaker;
The audio output means measures the time until the audio data is output after the short distance wireless processing means receives the audio data, and notifies the video display device of the time by controlling the short distance radio processing means. And an audio / video synchronization control means.

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