JP2013090187A - Communication terminal device and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication terminal device and a communication terminal method in which a plurality of pieces of data can be synchronized and outputted without needing a buffer.SOLUTION: A communication terminal device 1A can transmit data to a front seat display 3 and a rear seat display 8. The communication terminal device 1A has a data reading part 10, and a delay time detecting part 11 for detecting delay time which is a difference between time taken for the data to be received by the front seat display 3 and time taken for the data to be received by the rear seat display 8. The data reading part 10, on the basis of the delay time, adjusts time when the data to be transmitted to the front seat display 3 is read and time when the data to be transmitted to the rear seat display 8 is read so that the time when the data is received by the front seat display 3 can be matched with the time when the data is received by the rear seat display 8.

Description

  The present invention relates to a communication terminal device and a communication method.

  In a communication terminal device and communication method, a plurality of data is output from different terminals, such as when video data is output from a plurality of terminals, or when corresponding video data and audio data are output from separate terminals. There is a case. In such a case, a technique for outputting a plurality of data in synchronization in consideration of a difference in time required for each terminal to receive data transmitted from a communication terminal device has been conventionally known.

  For example, in the lip sync control apparatus described in Japanese Patent Application Laid-Open No. 2003-46901, a digital broadcast is received by a set top box which is a receiving means, and audio is output using a decoder of an external device such as an AV amplifier. At this time, the set-top box separates the audio stream from the received digital broadcast, outputs the audio stream to the external device without decoding, and outputs the audio signal obtained by decoding the audio stream to the external device. . The set-top box separates the video stream from the received digital broadcast and outputs a video signal obtained by decoding the video stream to an external device. The audio signal and the video signal are lip-synced using time stamp information included in the audio stream and the video stream. The external device decodes the audio stream supplied from the set-top box into an audio signal by a decoder built in the external device. Then, the external device measures the delay amount between the audio signal from the set top box and the audio signal from the decoder by the delay amount measuring device, and based on this delay amount, the video signal and the audio from the decoder are measured. By delaying and outputting one of the signals, the video signal and the audio signal are output in synchronization. A communication terminal device such as this lip sync control device is relatively easy to operate, and is therefore suitable for a large-scale system such as CATV.

JP 2003-46901 A

  In the communication terminal device and the communication method as described above, in order to delay the output of data and match the output time, a buffer for temporarily storing data is required for each terminal. On the other hand, in recent years, with the advancement of ICT (Information Communication Technology), there is a case where a large amount of data such as high-definition data or Blu-ray data is transmitted by making full use of ultra-high-speed communication technology. In this case, a buffer having a larger capacity is required for each terminal, and there is a concern that the cost of a terminal that is desired to be inexpensive may increase.

  In addition, in recent years, when distributing contents etc. via a network, the codec for data compression / decompression and file format change, data protection, etc. for each terminal via data encoding / decoding May be sent to. Through the encoding and decoding, the time required until the data transmitted from the communication terminal apparatus is received by each terminal increases, and the data to be stored in the buffer increases accordingly. Therefore, the cost of the terminal may be further increased.

  The present invention has been made to solve such a problem, and provides a communication terminal device and a communication method capable of outputting a plurality of data in synchronization without requiring a buffer. With the goal.

  The communication terminal device according to the present invention is a communication terminal device capable of transmitting data to a plurality of terminals, a data reading means for reading data from a storage medium, and data read by the data reading means to the first terminal. A delay time detecting means for detecting a delay time that is a difference between a time required until the data is read and a time required for the data read by the data reading means to be received by the second terminal; The first terminal is based on the delay time detected by the delay time detection means so that the time when the data is received by the first terminal matches the time when the data is received by the second terminal. And adjusting the time for reading data for transmission to the time for reading data for transmission to the second terminal.

  In the communication terminal device according to the present invention, the delay time is detected by the delay time detection means, and based on the delay time, the time when the data is received by the first terminal and the time when the data is received by the second terminal Are adjusted so that the time for reading data for transmission to the first terminal and the time for reading data for transmission to the second terminal are adjusted. Therefore, even when data is not temporarily stored in the buffer, the time at which data is received by the first terminal matches the time at which data is received by the second terminal, and the first terminal and the second terminal Data can be output synchronously from the two terminals. Therefore, a plurality of data can be synchronized and output without requiring a buffer.

  In addition, a storage unit capable of storing the data read by the data reading unit, and when the delay time is a predetermined time or less, the data is stored by the storage unit, and the time when the data is received by the first terminal, It is preferable to transmit the stored data to the first terminal or the second terminal so that the time when the data is received by the second terminal matches. In this way, when the delay time is shorter than the predetermined time, the data is temporarily stored by the storage means, so that the data is synchronously output from the first terminal and the second terminal, while the delay time is predetermined. For example, when the capacity of data to be stored is longer than the time and exceeds the capacity of the storage means, it is possible to shift to a method of adjusting the time to read data based on the delay time.

  In addition, at least one of the communication path between the data reading unit and the first terminal and the communication path between the data reading unit and the second terminal encodes the data read by the data reading unit. There is provided an encoding means and a decoding means for decoding the data encoded by the encoding means, and the delay time detecting means is configured so that the time required for the encoding means to encode the data and the encoding means It is preferable to detect the delay time in consideration of the time required for the decoding means to decode the encoded data. Through the encoding and decoding, the delay time becomes long and a large-capacity buffer is required. Therefore, the effect of the present invention is that a plurality of data can be synchronized and output without the need for a buffer. More preferably.

  The communication method according to the present invention is a communication method for transmitting data to a plurality of terminals. The time required for the data read from the storage medium to be received by the first terminal and the data read from the storage medium are A delay time that is a difference from a time required for reception by the second terminal is detected, and a time at which data is received by the first terminal coincides with a time at which data is received by the second terminal As described above, the time for reading data for transmission to the first terminal and the time for reading data for transmission to the second terminal are adjusted based on the delay time.

  In the communication method according to the present invention, the delay time is detected, and based on the delay time, the time when the data is received by the first terminal and the time when the data is received by the second terminal are matched. The time for reading data for transmission to the first terminal and the time for reading data for transmission to the second terminal are adjusted. Therefore, even when data is not temporarily stored in the buffer, the time at which data is received by the first terminal matches the time at which data is received by the second terminal, and the first terminal and the second terminal Data can be output synchronously from the two terminals. Therefore, a plurality of data can be synchronized and output without requiring a buffer.

  If the delay time is equal to or shorter than the predetermined time, the data read from the storage medium is stored, and the time when the data is received by the first terminal coincides with the time when the data is received by the second terminal. Thus, it is preferable to transmit the stored data to the first terminal or the second terminal. In this way, when the delay time is shorter than the predetermined time, the data read from the storage medium is temporarily stored, so that the data is synchronously output from the first terminal and the second terminal, while the delay time is Is longer than the predetermined time and the amount of data to be stored is large, it is possible to shift to a method of adjusting the time to read data based on the delay time.

  Further, the delay time is detected in consideration of the time required for encoding the data read from the storage medium and the time required for decoding the encoded data, and the first terminal and the second terminal It is preferable to transmit data to at least one of the data through encoding of the data read from the storage medium and decoding of the encoded data. Through the encoding and decoding, the delay time becomes long and a large-capacity buffer is required. Therefore, the effect of the present invention is that a plurality of data can be synchronized and output without the need for a buffer. More preferably.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the communication terminal device and communication method which can output several data synchronizing, without requiring a buffer.

It is a block diagram which shows the communication terminal device which concerns on 1st embodiment of this invention. It is a flowchart which shows operation | movement of the communication terminal device of FIG. It is a conceptual diagram which shows a time synchronous process. It is a key map showing in-vehicle network delay time measurement processing. It is a block diagram which shows the communication terminal device which concerns on 2nd embodiment of this invention. It is a flowchart which shows operation | movement of the communication terminal device of FIG.

  Hereinafter, preferred embodiments of a communication terminal device and a communication method according to the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent element, and the overlapping description is abbreviate | omitted.

[First embodiment]
FIG. 1 is a block diagram showing a communication terminal apparatus according to the first embodiment of the present invention. As illustrated in FIG. 1, the communication terminal device 1 </ b> A is applied to an in-car multimedia system 100 provided in a vehicle V, for example. The vehicle V is equipped with a head unit U1 and an RSE (Rear Seat Entertainment) unit U2. The head unit U1 includes a DVD 2, a front seat display (first terminal) 3, an encoder (encoding means) 4, and a first communication unit 5. The RSE unit U2 includes a second communication unit 6, a decoder (decoding means) 7, and a rear seat display (second terminal) 8.

  The DVD 2 reads data such as video data and audio data stored in a storage medium such as a DVD disk, a Blu-ray disk, and a built-in hard disk and transmits the data to a terminal and is connected to the front seat display 3 and the encoder 4. Has been. The DVD 2 transmits the read data to the front seat display 3 and the encoder 4.

  The front seat display 3 is a terminal for outputting data, and is provided at a position where a passenger sitting in the front seat can visually recognize. The front seat display 3 includes, for example, a liquid crystal display and a speaker.

  The encoder 4 encodes data. Examples of encoding include data compression / decompression, data file format change, and data encryption. The encoder 4 is connected to the first communication unit 5 and transmits the encoded data to the first communication unit 5.

  The first communication unit 5 transmits / receives data to / from the RSE unit U2, and is connected to the second communication unit 6 via the in-vehicle network N. The first communication unit 5 is connected to a clock (not shown) provided in the head unit U1.

  As the in-vehicle network N, Ethernet (registered trademark) AVB standardized by IEEE or a network capable of time synchronization between nodes can be adopted. Accordingly, the head unit U1 and the RSE unit U2 connected to the in-vehicle network N can have synchronized clocks (counter values).

  The second communication unit 6 transmits and receives data to and from the head unit U1. The second communication unit 6 is connected to a clock (not shown) provided in the RSE unit U2. The second communication unit 6 is connected to the decoder 7 and transmits the data received from the first communication unit 5 to the decoder 7.

  The decoder 7 decodes the data encoded by the encoder 4. The decoder 7 is connected to the rear seat display 8 and transmits the decoded data to the rear seat display 8.

  The rear seat display 8 is a terminal that outputs data, and is provided at a position where a passenger sitting in the rear seat can visually recognize. Similar to the front seat display 3, the rear seat display 8 includes, for example, a liquid crystal display and a speaker.

  Next, the communication terminal device 1A will be described in detail. The communication terminal device 1A can output data read from the DVD 2 in synchronization with the front seat display 3 and the rear seat display 8. The communication terminal device 1A includes a data reading unit (data reading unit) 10 and a delay time detection unit (delay time detection unit) 11.

  The data reading unit 10 reads data stored in a storage medium. The data reading unit 10 can perform so-called random access in which data is read independently and independently from the same storage medium.

  The delay time detection unit 11 is required until the data read by the data reading unit 10 is received by the front seat display 3 and until the data read by the data reading unit 10 is received by the rear seat display 8. A delay time that is a difference from the time is detected. The delay time detection unit 11 can be configured by, for example, an ECU (Electric Control Unit) provided in the head unit U1. The delay time detection unit 11 is provided in the DVD 2, for example. The delay time detection unit 11 may be provided in a part other than the DVD 2.

  The delay time detection unit 11 can store an encoder delay time Te required for the encoder 4 to encode the data read by the data reading unit 10. The encoder delay time Te is a fixed value unique to the encoder 4. In addition, the delay time detection unit 11 can store a decoder delay time Td required for the decoder 7 to decode the data encoded by the encoder 4. The decoder delay time Td is a fixed value unique to the decoder 7. Note that the encoder delay time Te and the decoder delay time Td may be stored in the delay time detection unit 11 in advance, or may be detected when the encoder 4 or the decoder 7 is connected to the in-vehicle multimedia system 100, for example. It may be transmitted to the unit 11 and stored.

  Next, the operation of the communication terminal device 1A according to the present embodiment will be described. FIG. 2 is a flowchart showing the operation of the communication terminal apparatus of FIG. 1, and shows a communication method according to this embodiment.

  As shown in FIG. 2, the operation of the communication terminal device 1A starts when the delay time detector 11 holds the encoder delay time Te and the decoder delay time Td (step S10). Next, the delay time detection unit 11 performs time synchronization processing for synchronizing the clocks of the head unit U1 and the RSE unit U2 (step S12).

  FIG. 3 is a conceptual diagram showing time synchronization processing. As shown in FIG. 3, in the time synchronization process, first, the first communication unit 5 that has received a command to start the time synchronization process from the delay time detection unit 11 determines the time T1 that is the current time from the clock of the head unit U1. The time T1 is acquired and transmitted to the second communication unit 6. At this time, it takes time t1 until the second communication unit 6 receives the time T1 after the first communication unit 5 transmits the time T1. The second communication unit 6 that has received the time T1 sets the clock time of the RSE unit U2 to T1. At this time, the clock time of the head unit U1 is time (T1 + t1).

  Next, the second communication unit 6 transmits a return request to the first communication unit 5. At this time, it takes time t1 until the first communication unit 5 receives the request after the second communication unit 6 transmits the request. The first communication unit 5 that has received the request transmits a return packet to the second communication unit 6. At this time, it takes time t1 until the second communication unit 6 receives the return packet after the first communication unit 5 transmits the return packet. Therefore, the time from when the second communication unit 6 transmits the request until the second communication unit 6 receives the return packet is RTT = 2 × t1. Therefore, when the second communication unit 6 receives the return packet, the clock time of the RSE unit U2 is time (T1 + 2 × t1).

  From the above, the second communication unit 6 recognizes that the delay of the clock of the RSE unit U2 with respect to the clock of the head unit U1 is time t1. Then, the second communication unit 6 corrects the clock time of the RSE unit U2, and the time synchronization process is completed. As a result, the clock time of the head unit U1 and the clock time of the RSE unit U2 are both time T3. The first communication unit 5 transmits a notification of completion of time synchronization processing to the delay time detection unit 11.

  Returning to FIG. 2, next, the delay time detection unit 11 performs in-vehicle network delay time measurement processing for measuring the in-vehicle network delay time Tnet (step S14). The in-vehicle network delay time Tnet is a time required for data to pass through the in-vehicle network N.

  FIG. 4 is a conceptual diagram showing in-vehicle network delay time measurement processing. As shown in FIG. 4, in the in-vehicle network delay time measurement process, first, the first communication unit 5 that has received an instruction to start the in-vehicle network delay time measurement process from the delay time detection unit 11 starts from the clock of the head unit U1. Time T4 that is time is acquired, and time T4 is transmitted to the second communication unit 6. At this time, it takes time t2 until the second communication unit 6 receives the time T4 after the first communication unit 5 transmits the time T4. Therefore, when the second communication unit 6 receives time T4, the clock of the RSE unit U2 becomes time (T4 + t2). Accordingly, the second communication unit 6 recognizes that the in-vehicle network delay time Tnet = t2.

  Next, the second communication unit 6 transmits a notification that the in-vehicle network delay time Tnet = t2 to the first communication unit 5. Then, the first communication unit 5 sets the in-vehicle network delay time Tnet = t2, and the in-vehicle network delay time measurement process is completed. The first communication unit 5 transmits the in-vehicle network delay time Tnet to the delay time detecting unit 11 together with the notification of completion of the in-vehicle network delay time measurement process.

Returning to FIG. 2, the delay time detection unit 11 then calculates the time required for the data read by the data reading unit 10 to be received by the front seat display 3 and the data reading unit 10 according to the following equation (1). The delay time (Tf−Tr), which is the difference from the time required for the data read out in step 4 to be received by the rear seat display 8, is calculated (step S16).
(Tf−Tr) = (Te + Tnet + Td) (1)

  Next, the DVD 2 starts reproduction (step S18). The data reading unit 10 reads data to be transmitted to the rear seat display 8 from the storage medium, and transmits the data to the rear seat display 8 via the in-vehicle network N (step S20). At this time, the time at which the data reading unit 10 reads data to be transmitted to the rear seat display 8 is time Tr.

  Next, after the delay time (Tf−Tr) has elapsed from the time Tr, the data reading unit 10 reads data to be transmitted to the front seat display 3 from the storage medium and transmits the data to the front seat display 3. Then, the front seat display 3 and the rear seat display 8 output the received data (step S22).

  At this time, the time at which the data reading unit 10 reads data to be transmitted to the front seat display 3 is time Tf. In addition, the time at which data is output from the front seat display 3 and the time at which data is output from the rear seat display 8 are also the time Tf, and the data are output from the front seat display 3 and the rear seat display 8 synchronously. Is done. And a series of operation | movement is complete | finished.

  As described above, in the communication terminal device 1A and the communication method according to the present embodiment, the delay time (Tf-Tr) is detected by the delay time detection unit 11, and data is displayed on the front seat display 3 based on the delay time (Tf-Tr). The time Tf for reading data for transmission to the front seat display 3 and the time Tf for transmitting data to the rear seat display 8 are transmitted so that the time Tf for receiving the data and the time Tf for receiving data on the rear seat display 8 coincide with each other. The time Tr for reading the data for adjustment is adjusted. Therefore, even if the data is not temporarily stored in the buffer, the time Tf at which the data is received by the front seat display 3 and the time Tf at which the data is received by the rear seat display 8 coincide with each other. In addition, data can be output in synchronization with the rear seat display 8. Therefore, a plurality of data can be synchronized and output without requiring a buffer.

  Further, in the communication terminal device 1A and the communication method according to the present embodiment, as described above, the data read by the data reading unit 10 is encoded in the communication path between the data reading unit 10 and the rear seat display 8. An encoder 4 and a decoder 7 for decoding the data encoded by the encoder 4 are provided. The delay time detection unit 11 includes an encoder delay time Te required for the encoder 4 to encode data, and the encoder 4 The delay time (Tf−Tr) is detected in consideration of the decoder delay time Td required for the decoder 7 to decode the encoded data. Data is transmitted to the rear seat display 8 through encoding of data read from the storage medium and decoding of the encoded data. Here, since the delay time is increased and a large-capacity buffer is required through encoding and decoding, the present invention can synchronize and output a plurality of data without the need for a buffer. The effect of is exhibited more suitably.

[Second Embodiment]
FIG. 5 is a block diagram showing a communication terminal apparatus according to the second embodiment of the present invention. As shown in FIG. 2, the communication terminal device 1B applied to the in-vehicle multimedia system 200 according to this embodiment differs from the communication terminal device 1A according to the first embodiment (see FIG. 1) in that a buffer (memory) Means) 12 and a selector 13 are provided.

  The buffer 12 is connected to the data reading unit 10 and can temporarily store data for a predetermined time read by the data reading unit 10. The predetermined time is a buffer temporary storage time Tbuf, and is stored in the delay time detection unit 11. The buffer temporary storable time Tbuf may be stored in the delay time detection unit 11 in advance, or transmitted and stored in the delay time detection unit 11 when the buffer 12 is connected to the in-vehicle multimedia system 200 or the like. May be.

  The selector 13 is connected to the DVD 2, the buffer 12, and the front seat display 3, and transmits any one of data transmitted from the DVD 2 and data transmitted from the buffer 12 to the front seat display 3.

  Next, the operation of the communication terminal device 1B according to the present embodiment will be described. FIG. 6 is a flowchart showing the operation of the communication terminal apparatus of FIG. 5, and shows a communication method according to the present embodiment.

  As shown in FIG. 6, the operation of the communication terminal device 1B starts when the delay time detection unit 11 holds the encoder delay time Te, the decoder delay time Td, and the buffer temporary storage time Tbuf (step S30). Next, the delay time detection unit 11 performs time synchronization processing (step S32). This step S32 is executed in the same manner as step S12 of FIG.

  Next, the delay time detector 11 performs an in-vehicle network delay time measurement procedure (step S34). This step S34 is executed in the same manner as step S14 in FIG.

  Next, the delay time detector 11 calculates a delay time (Tf−Tr) (step S36). This step S36 is executed in the same manner as step S16 in FIG.

  Next, the delay time detector 11 determines whether or not the delay time (Tf−Tr) is larger than the buffer temporary storage possible time Tbuf (step S38).

  If it is determined in step S38 that the delay time (Tf−Tr) is longer than the buffer temporary storage possible time Tbuf, the DVD 2 starts reproduction (step S40). The data reading unit 10 reads data to be transmitted to the rear seat display 8 from the storage medium at time Tr and transmits the data to the rear seat display 8 via the in-vehicle network N (step S42).

  Next, the data reading unit 10 reads data to be transmitted to the front seat display 3 from the storage medium at time Tf and transmits the data to the front seat display 3. Then, the front seat display 3 and the rear seat display 8 output data at time Tf (step S44). Steps S40, S42, and S44 are executed in the same manner as steps S18, S20, and S22 of FIG. And a series of operation | movement is complete | finished.

  On the other hand, when it is determined in step S38 that the delay time (Tf−Tr) is not longer than the buffer temporary storage possible time Tbuf, the DVD 2 starts reproduction (step S46). Next, the data reading unit 10 reads data from the storage medium and transmits the data to the buffer 12 and the encoder 4 (step S48). At this time, the time at which the data reading unit 10 reads data is time Tr.

  Next, after the delay time (Tf−Tr) has elapsed from the time Tr, the buffer 12 transmits data for the temporarily stored delay time (Tf−Tr) to the front seat display 3. The front seat display 3 outputs the data received from the buffer 12. The rear seat display 8 outputs data received via the in-vehicle network N (step S50). At this time, the time when the data is output from the front seat display 3 and the time when the data is output from the rear seat display 8 are time Tf, respectively, and the data is synchronized from the front seat display 3 and the rear seat display 8. Is output. And a series of operation | movement is complete | finished.

  Such a communication terminal device 1B and communication method according to the present embodiment have substantially the same effects as the communication terminal device 1A according to the first embodiment. In addition, the communication terminal device 1B and the communication method according to the present embodiment include the buffer 12 that can store the data read by the data reading unit 10, and the delay time (Tf−Tr) is equal to or less than the buffer temporary storage time Tbuf. In such a case, the data is stored in the buffer 12, and the stored data is stored in the front so that the time when the data is received by the front seat display 3 and the time when the data is received by the rear seat display 8 coincide with each other. When the delay time (Tf−Tr) is shorter than the buffer temporary storage time Tbuf for transmission to the seat display 3, the front seat display 3 and the rear seat display 8 are temporarily stored by the buffer 12. On the other hand, the delay time (Tf−Tr) is longer than the buffer temporary storage time Tbuf, Capacity should do data the like when exceeding the capacity of the buffer 12, it is possible to shift the system to adjust the time of reading the data based on the delay time (Tf-Tr). As a result, the communication terminal device 1B and the communication method according to the present embodiment allow the network delay time Tnet of the in-vehicle network system 200 when the new device is added in the in-vehicle multimedia system 200 or the configuration of the in-vehicle multimedia system 200 changes. It is possible to cope with a case where the value becomes large.

  As mentioned above, although embodiment which concerns on the communication terminal device and communication method of this invention was described in detail, this invention is not limited to the said embodiment. For example, in the above embodiment, the terminals connected to the communication terminal devices 1A and 1B are the front seat display 3 and the rear seat display 8, but other terminals may be further connected.

  In addition, for example, the communication terminal devices 1A and 1B and the communication method according to the above-described embodiment are applied to the in-car multimedia systems 100 and 200, respectively, but the DVD, the display, the speaker, and the like are connected to each other via a network. The present invention can also be applied to multimedia systems such as CATV, CATV, and the like. In short, the present invention can be applied to a system that transmits data to a plurality of terminals.

  DESCRIPTION OF SYMBOLS 1A, 1B ... Communication terminal device, 3 ... Front seat display (first terminal), 4 ... Encoder (encoding means), 7 ... Decoder (decoding means), 8 ... Rear seat display (second terminal), 10 Data read unit (data read unit) 11 Delay time detection unit (delay time detection unit) 12 Buffer (storage unit)

Claims (6)

In a communication terminal device capable of transmitting data to a plurality of terminals,
Data reading means for reading data from the storage medium;
Delay that is the difference between the time required for the data read by the data reading means to be received by the first terminal and the time required for the data read by the data reading means to be received by the second terminal A delay time detecting means for detecting time,
The data reading means is configured to detect the delay time detected by the delay time detection means so that a time when the data is received by the first terminal and a time when the data is received by the second terminal are the same. Adjusting the time for reading data for transmission to the first terminal and the time for reading data for transmission to the second terminal,
A communication terminal device. A storage unit capable of storing the data read by the data reading unit;
If the delay time is less than or equal to a predetermined time, the data is stored by the storage means, and the time when the data is received by the first terminal coincides with the time when the data is received by the second terminal The communication terminal apparatus according to claim 1, wherein the stored data is transmitted to the first terminal or the second terminal. In at least one of the communication path between the data reading unit and the first terminal and the communication path between the data reading unit and the second terminal, the data read by the data reading unit is stored. An encoding means for encoding and a decoding means for decoding the data encoded by the encoding means;
The delay time detecting means takes into account the time required for the encoding means to encode data and the time required for the decoding means to decode the data encoded by the encoding means. The communication terminal device according to claim 1, which detects time. In a communication method for transmitting data to a plurality of terminals,
Detects a delay time that is the difference between the time required for the data read from the storage medium to be received by the first terminal and the time required for the data read from the storage medium to be received by the second terminal. ,
Data to be transmitted to the first terminal based on the delay time so that the time when the data is received by the first terminal and the time when the data is received by the second terminal coincide with each other. Adjusting the time to read and the time to read data for transmission to the second terminal;
A communication method characterized by the above.   When the delay time is equal to or shorter than a predetermined time, the data read from the storage medium is stored, the time when the data is received by the first terminal, and the time when the data is received by the second terminal. The communication method according to claim 4, wherein the stored data is transmitted to the first terminal or the second terminal so as to match. In consideration of the time required for encoding the data read from the storage medium and the time required for decoding the encoded data, the delay time is detected,
5. The data is transmitted to at least one of the first terminal and the second terminal through encoding of data read from a storage medium and decoding of the encoded data. Or the communication method of 5.

Images