JP2003152736A - Transmission device and method, recording medium, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission device that attains retransmission in the unit of second data without losing the real timing performance of streaming against the occurrence of a communication error and minimizes the effect on the occurrence of missing data. SOLUTION: The transmission method of this invention includes: a step S11 of initializing a timer; and a step S13 of executing flash processing, that is, processing of clearing a packet waiting buffer and a transmission queue when it is discriminated in a step S12 that a flash time is reached. Further, a time until the flash time is selected to be a time being a multiple of N of an interval for wireless transmission of all base band packets corresponding to one data block at a prescribed communication speed. For example, in the case that the communication speed is 320 kbits/sec, the data length of a data block is 400 bytes, and N=4, the time until the flash time is 40 msec.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitting device and method, a recording medium, and a program, and for example, relates to a transmitting device and method, a recording medium, and a program suitable for use in streaming transfer of content data wirelessly. .

[0002]

2. Description of the Related Art Bluetooth (trademark) is known as a wireless communication technology applicable to home appliances and the like. Bluetoo
If wireless communication technology such as th is used, for example, CD (Compa
It is possible to wirelessly connect an audio reproducing device including a ct Disc) player or the like to a speaker device without using an audio cable to transmit audio data. As a result, it is possible to prevent the appearance of the audio cable from being impaired by the wiring of the audio cable, and the arrangement of the speakers to be limited due to the limitation of the length of the audio cable.

When audio data is transmitted from an audio reproducing device to a speaker device by Bluetooth, the audio data is transferred by streaming. That is, in the audio reproducing device on the transmission side,
The audio data shown in FIG. 1A is sequentially divided into predetermined data units called data blocks as shown in FIG. 1B, and the divided data blocks are divided into data blocks as shown in FIG. Information indicating the data length is added, and further converted into a baseband packet and transmitted.

In the speaker device on the receiving side, the received baseband packets are sequentially combined to restore the data block, and the restored data block is reproduced. When receiving a baseband packet, 1
The transmission side is notified of the presence or absence of a communication error for each packet.

The data length of the data block is 400
In the case of bytes, the data block to which the information indicating the data length is added is converted into baseband packet DH5 and baseband packet DH3 and transmitted, as shown in FIG. Here, the baseband packet DH5 is
The maximum data length is 339 bytes, and 3.
It takes 75 ms. The maximum data length of the baseband packet DH3 is 183 bytes, and 2.5 is used for the communication.
It takes m seconds. In FIG. 2 and subsequent figures, the numbers such as “1” in DH5-1 and “2” in DH3-2 indicate the transmission order.

Further, the data communication speed is 320 Kbit /
In case of seconds, as shown in FIG. 3, every 10 ms, 400
Baseband packets DH5 and DH3 obtained by dividing a byte data block are transmitted one packet at a time.

[0007] By the way, in Bluetooth, when an error occurs during communication of a baseband packet, it is usually prescribed that the communication of the same baseband packet is repeated until the baseband packet which could not be communicated is normally communicated. Has been done.

However, among the Bluetooth regulations,
The specification called Advance Audio Distribution Profile (hereinafter, abbreviated as A2DP) that defines the method of streaming transfer of audio data is more important than reliable transmission of all baseband packets when streaming transfer of audio signals. Emphasizes the real-time nature of data.

That is, in A2DP, when communication of a baseband packet fails, until a predetermined time (hereinafter referred to as flash time) provided for each communication of the baseband packet corresponding to one data block is reached. , Repeat the retransmission of the failed baseband packet, but when the flash time is reached, abandon the communication of the failed baseband packet and the data block to which the baseband packet belongs (in other words, Allow data loss of data block),
Communication of a baseband packet belonging to a data block next to a data block for which communication is abandoned is started.

For example, in the case of the example shown in FIG. 3, the baseband packet DH5-1 which requires 3.75 ms for communication.
And a baseband packet D that requires 2.5 ms for communication
Since H3-1 communicates for 10 msec, the retransmission time is
It is 3.75 (= 10-3.75-2.5) milliseconds. Therefore, when a communication error occurs, only one of the baseband packets DH5-1 and DH3-1 can be retransmitted only once. However, if the retransmission fails, the communication of the data block 1 will not be performed. You will have to give up.

The process of giving up the communication of the baseband packet which has failed in communication and the data block to which the baseband packet belongs is specifically performed by a memory (buffer, queue ( queue)
Etc.) (hereinafter referred to as flash processing).

[0012]

As a method for reducing the influence of communication error without changing the data communication speed (for example, 320 Kbit / sec), the data length of the data block is made larger or smaller. There is a way to do it.

For example, as shown in FIG. 4, when the data length of the data block is increased to 800 bytes, the data block to which the information indicating the data length is added is divided into two baseband packets DH5 and one base band packet. Two baseband packets DH5 and one baseband packet DH3, which are converted into the band packet DH3 and converted into a data block of 800 bytes every 20 msec, are transmitted as shown in FIG.

In this case, the retransmission time is 10 (= 20-
Since it is 2 × 3.75-2.5) msec, for example, two baseband packets DH5 and one baseband packet DH3 can be retransmitted only once each. Therefore, the method of increasing the data length of the data block has an advantage that there is a high possibility that the communication error can be compensated by the retransmission.

However, if the communication error cannot be compensated by the retransmission and the data loss in the data block unit is tolerated, the amount of data is large, so that interpolation on the receiving side becomes difficult and the data loss becomes conspicuous. There are drawbacks. Even if there is no data loss, the receiving side processes data in data block units, that is, the processing is performed on the data block until all baseband packets belonging to the same data block are received. Since it does not exist, there is a drawback that the processing for the data block is delayed and the real-time property is impaired.

On the contrary, as shown in FIG. 6, for example, when the data length of the data block is reduced to 150 bytes, the data block to which the information indicating the data length is added is converted into one baseband packet DH3. , The baseband packet D every 3.75 msec as shown in FIG.
H3 will be transmitted one packet at a time.

In this case, the retransmission time is 1.25 (=
Although it is 3.75-2.5) msec, it takes 2.5 msec for the communication of the baseband packet DH3, and therefore it cannot be retransmitted even if a communication error occurs. Therefore, the communication error of one packet of the baseband packet DH3 is immediately
There is a drawback that data loss of one data block is tolerated. However, since the data length of the data block is small, interpolation on the receiving side is easy,
Data loss is not noticeable.

The present invention has been made in view of the above circumstances, and when a communication error occurs during streaming transfer of content data by radio, the base band is maintained without impairing the real timing property on the reproducing side. It is an object of the present invention to make it possible to retransmit a packet and to minimize the effect of data loss even if it occurs.

[0019]

The transmitting device of the present invention comprises a dividing means for dividing content data into a first data unit, and first and second holding means for temporarily holding the first data unit. A transfer unit for transferring the first data unit held by the first holding unit to the second holding unit, and the first data unit held by the second holding unit for reading the second data unit. A conversion unit that converts the data unit, a third holding unit that holds the second data unit converted by the conversion unit, and a second data unit that is held by the third holding unit are sequentially read and transmitted. The transmitting unit, the first data unit held by the second holding unit, and the second data unit held by the third holding unit.
Erasing means for erasing the second data unit corresponding to the first data unit at every integral multiple of the time provided for communicating at the predetermined communication speed. .

The transfer means may collectively transfer the plurality of first data units held by the first holding means to the second holding means.

The transfer means may transfer the plurality of first data units held by the first holding means to the second holding means at equal intervals.

The transmission method of the present invention includes a dividing step of dividing the content data into first data units, first and second holding steps of temporarily holding the first data unit, and first holding. The transfer step of transferring the first data unit held in the processing of the step to the processing of the second holding step and the first data unit held in the processing of the second holding step are read out to obtain the second data unit. A conversion step of converting into a data unit, a third holding step of holding the second data unit converted in the processing of the conversion step, and a second data unit held in the processing of the third holding step are sequentially performed. The transmission step of reading and transmitting, the first data unit held in the processing of the second holding step, and the second data unit held in the processing of the third holding step are set to the first data unit. Characterized in that it comprises an erasing step of erasing the second data units for each predetermined time integral multiples provided to communicate at a time corresponding to the unit.

A program for a recording medium according to the present invention includes a dividing step of dividing content data into first data units, first and second holding steps of temporarily holding the first data unit, and first In the holding step, the first data unit held in the holding step is transferred to the second holding step, and the first data unit held in the second holding step is read to read the first data unit. A conversion step of converting the data unit into the second data unit, a third holding step of holding the second data unit converted in the processing of the conversion step, and a second holding step of the third holding step.
Of the first data unit held in the process of the second holding step, and the second data unit held in the process of the third holding step, Second corresponding to one data unit
The erasing step of erasing the data unit at every integer multiple of the time provided for communicating at a predetermined communication speed.

The program of the present invention includes a dividing step of dividing content data into first data units, first and second holding steps of temporarily holding the first data unit, and a first holding step. First retained in processing
A data step of transferring the data unit to the process of the second holding step, and a conversion step of reading the first data unit held in the process of the second holding step and converting the first data unit to the second data unit. A third holding step of holding the second data unit converted by the processing of the converting step;
Of the transmission step of sequentially reading and transmitting the second data unit held in the processing of the third holding step, the first data unit held in the processing of the second holding step, and the third holding step. An erasing step of erasing the second data unit held in the process at every integer multiple of the time provided for communicating the second data unit corresponding to the first data unit at a predetermined communication speed; Is executed by a computer.

In the transmitting apparatus and method and the program of the present invention, the content data is divided into the first data unit, converted into the second data unit and transmitted. Further, the held first data unit and second data unit are each an integer multiple of the time provided for communicating the second data unit corresponding to the first data unit at a predetermined communication speed. Erased to.

[0026]

FIG. 8 shows an example of the configuration of an audio data communication system to which the present invention is applied. The audio data communication system includes an audio reproducing device 1 and a speaker device 2 which are wirelessly connected by Bluetooth.

The audio reproducing apparatus 1 converts the audio data of the music read from a CD, for example, into baseband packets of streaming data, and transmits the baseband packets to the wirelessly connected speaker apparatus 2. Speaker device 2
Receives the baseband packet of the streaming data transmitted by the audio reproducing apparatus 1 and outputs the voice corresponding to the original audio data from the speaker 63 having a built-in voice.

The audio reproducing apparatus 1 reads the control program recorded on the recording medium 12 and executes the control program to obtain the control section 11 for controlling the data processing section 13 and the transmission processing section 14 and the audio data to be transmitted. Then, the data processing unit 13 divides the data block and supplies it to the transmission processing unit 14, and the transmission processing unit 14 that converts the data block supplied from the data processing unit 13 into a baseband packet and wirelessly transmits it. .

The data processing unit 13 includes a CD, a DVD (Digital
Versatile Disc), MD (Mini Disc), hard disk,
A data acquisition unit 22 that reads out audio data recorded on a recording medium 21 including a semiconductor memory and outputs the audio data to the blocking unit 23. Audio data input from the data acquisition unit 22 is a data block of a predetermined data length (L2CAP). Packetizing unit 23, a data block buffer 24 that buffers the data blocks generated by the blocker 23, and a data block buffered by the data block buffer 24. The data transfer unit 25 transfers data to the packetization waiting buffer 31.

The data acquisition unit 22 includes a microphone,
It is possible to obtain audio data input from another audio reproduction device (neither is shown) and input it to the blocking unit 23.

Further, the data acquisition unit 22 can appropriately perform encoding by a predetermined method according to the format of the acquired audio data and then divide the data block into data blocks.

A data block is an audio frame in which about 1000 samples of a predetermined sampling rate are grouped together, and several audio frames are grouped together. The data length of the data block is data loss or reception. In consideration of the reproduction delay on the side, the audio reproduction time is set to be within 50 msec at the maximum.

The transmission processing unit 14 reads the packetization waiting buffer 31 for buffering the data blocks transferred from the data transfer unit 25 of the data processing unit 13, and the data block buffered by the packetization waiting buffer 31. A packetization unit 32 that converts the packet into a predetermined baseband packet, a transmission queue 33 that temporarily holds the baseband packet generated by the packetization unit 32, and the baseband packets held in the transmission queue 33 are read one by one. The packet transmission unit 34 wirelessly transmits the packet.

The packetization waiting buffer 31 and the transmission queue 33 of the transmission processing unit 14 execute flush processing under the control of the control unit 11.

The speaker device 2 is the audio reproducing device 1.
Receives a baseband packet of streaming data wirelessly transmitted by the wireless communication unit, and sequentially combines the received data to restore a data block of audio data, and a reception processing unit 41 that decodes the restored data block and outputs a corresponding voice. An example of the configuration is the data processing unit 42.

The reception processing unit 41 receives the baseband packet of the streaming data, outputs it to the reception queue 52, and notifies the packet transmission unit 34 of the presence or absence of a communication error of the baseband packet. A reception queue 52 that temporarily holds the baseband packet received by the packet reception unit 51, a restoration unit 53 that restores a data block by sequentially reading and combining the baseband packets held by the reception queue 52, and restoration. It is composed of a restored data block buffer 54 for buffering the restored data block.

The data processing unit 42 sequentially reads the data blocks buffered by the restored data block buffer 54 and supplies the data blocks to the reproducing unit 62, decodes the supplied data blocks, and the like. Playback unit 6 for generating a corresponding audio signal
2 and a speaker 63 that emits a sound corresponding to the generated sound signal.

Next, the operation of the audio data communication system will be described. First, the operation of the audio reproducing apparatus 1 will be described with reference to FIGS. 9 to 15.

FIG. 9 is a flowchart illustrating a first operation example of the data processing unit 13 of the audio reproducing device 1.

In step S1, the data acquisition unit 22
Reads the audio data recorded on the recording medium 21 and outputs it to the blocking unit 23. The blocking unit 23 sets the audio data sequentially input from the data acquisition unit 22 to a predetermined data length (for example, 150 bytes,
It is divided into data blocks of 400 bytes or 800 bytes) and output to the data block buffer 24. The data block buffer 24 buffers the data block input from the blocking unit 23.

In step S2, the data transfer unit 25
Determines whether or not a predetermined number N (for example, N = 4) of data blocks have been buffered in the data block buffer 24. If it is determined that the N data blocks are not buffered, the process returns to step S1 and the subsequent processes are repeated. Then, step S2
In, when it is determined that N data blocks have been buffered, the process proceeds to step S3.

In step S3, the data transfer unit 25
Reads the N data blocks buffered in the data block buffer 24, and as shown in FIG.
Then, N data blocks are collectively transferred. Also,
The data transfer unit 25 clears the data block buffer 24. After that, the process returns to step S1 until the data block of the audio data for one song is transferred to the transmission processing unit 14, and the subsequent processes are repeated.

FIG. 11 is a flow chart for explaining flash control processing by the control unit 11 of the audio reproducing apparatus 1. The flash control process is started in synchronization with the transfer of N data blocks (the process of step S3) by the data transfer unit 25 of the data processing unit 13 described above.

In step S11, the control section 11
A timer (which is built in the control unit 11) that measures the time until the flash time is initialized. In step S12, the control unit 11 determines whether or not the time measured by the timer has reached the flash time, and waits until it is determined that the flash time has been reached.

Here, the time until the flash time is
The time is N times the interval at which all baseband packets corresponding to one data block are wirelessly transmitted at a predetermined communication speed.

For example, the communication speed is 320 Kbit / sec,
When the data length of the data block is 400 bytes and N = 4, the intervals for wirelessly communicating one baseband packet DH5 and one baseband packet DH3 corresponding to the 400-byte data block are shown in FIG. As described above, since it is 10 msec, the time until the flash time is 40 (= 4 × 10) msec.

Further, for example, the communication speed is 320 Kbit / sec, the data length of the data block is 800 bytes, and N =
In the case of 4, the interval for wirelessly communicating two baseband packets DH5 and one baseband packet DH3 corresponding to a data block of 800 bytes is 20 msec as shown in FIG. The time until is 80 (= 4 × 20) milliseconds.

Further, for example, the communication speed is 320 Kbit / sec, the data length of the data block is 150 bytes, and N =
In the case of 4, the interval for wirelessly communicating one baseband packet DH3 corresponding to a data block of 150 bytes is 3.75 msec as shown in FIG. 7, so the time until the flash time is 15 (= 4 x 3.75)
m seconds.

If it is determined in step S12 that the flash time has been reached, the process proceeds to step S13. In step S13, the control unit 11 causes a flush process, that is, a process of clearing the packetization waiting buffer 31 and the transmission queue 33 of the transmission processing unit 14. After that, the process returns to step S11, and the subsequent processes are repeated.

Next, FIG. 12 shows the data processing unit 1 described above.
7 is a flowchart illustrating a process of a packetization unit 32 that converts a data block buffered in a packetization waiting buffer 31 by a data transfer unit 25 of No. 3 into a baseband packet. Note that this processing is executed in parallel with the above-mentioned flash control processing.

In step S21, the packetizing unit 3
2 sequentially reads the data blocks buffered in the packetization waiting buffer 31 one by one, as shown in FIG.
As shown in (C), information indicating the data length is added. In step S22, the packetizing unit 32
The data block to which the information indicating the data length is added is converted into one or more baseband packets as described above according to the data length of the data block. Step S23
At, the packetization unit 32 stores the converted baseband packet in the transmission queue 33. After that, the process returns to step S21, and the subsequent processes are repeated.

Next, FIG. 13 shows the packetizing unit 3 described above.
6 is a flowchart illustrating a process of a packet transmission unit 34 that wirelessly transmits a baseband packet temporarily stored in a transmission queue 33 according to step 2. Note that this processing is also executed in parallel with the flash control processing described above.

In step S31, the packet transmission unit 34 determines whether or not there is an untransmitted baseband packet (including a baseband packet for which communication has failed) in the transmission queue 33, and the untransmitted baseband packet is detected. Wait until it is determined that there is. If it is determined that there is an untransmitted baseband packet, the process proceeds to step S32. In step S32, the packet transmission unit 32 reads one baseband packet in the earliest order of transmission among the untransmitted baseband packets stored in the transmission queue 33. Step S
At 33, the packet transmission unit 32 wirelessly transmits one read baseband packet.

The transmitted baseband packet is received by the packet reception unit 51 of the reception processing unit 41 of the speaker device 1 and stored in the reception queue 52. It should be noted that the packet receiving unit 51 notifies the packet transmitting unit 34 every time a baseband packet is transmitted, whether or not there is a communication error in the baseband packet.

In step S34, the packet transmitter 32 determines whether or not the communication of the baseband packet is successful, based on the notification from the packet receiver 51 of the speaker device 2. If it is determined that the transmission of the baseband packet has succeeded, the process proceeds to step S35.
Proceed to. In step S35, the control unit 11 deletes the baseband packet read in step S32 from the transmission queue 33. After this, the processing is step S3.
The procedure returns to 1 and the subsequent processing is repeated.

If it is determined in step S34 that the transmission of the baseband packet has not succeeded, the process returns to step S31, and the subsequent processes are repeated.

That is, while the communication-failed baseband packet remains in the transmission queue 33, the baseband packet is retransmitted. However, when the transmission queue 33 is cleared by the flush process, retransmission is impossible and the transmission of the baseband packet newly stored in the transmission queue 3 is started.

In FIG. 14, the communication speed is 320 Kbit /
Seconds, data length of data block is 150 bytes, N = 4
, The packet transmitting unit 34 of the audio reproducing apparatus 1 to the packet receiving unit 51 of the speaker apparatus 2
Shows the timing at which baseband packets are transmitted without error. In this case, as described above, since the time until the flash time is set to 15 msec, the retransmission time is 5 (= 15-4 × 2.5) msec. Therefore, even if a communication error occurs, the baseband packet DH3 can be retransmitted up to twice.

It can be said that this is higher in noise resistance than that in the conventional case where the communication speed and the data length of the data block are the same condition (FIG. 7), the retransmission is impossible.

However, the communication speed is 320 Kbit / sec,
When the data length of the data block is 150 bytes and N = 4, for example, as shown in FIG. 15, when three or more communication errors occur within 15 ms until the flash time, the baseband packet DH3-1, DH3
-2, the communication is successful by retransmission, and even if the communication of the baseband packet DH3 is successful once, the transmission queue 33 storing the untransmitted baseband packet DH3-4 is cleared by the flash control process. I will end up.

Therefore, the baseband packet DH3
-4 results in data loss without being transmitted even once. However, since the baseband packet DH3-4 corresponds to the data block 4 shown in FIG. 10 on a one-to-one basis, the baseband packet DH3- on the speaker device 2 side.
Baseband packet DH where data loss of 4 is mixed up
3-2, DH3-5, etc. are not affected.

Next, FIG. 16 is a flow chart for explaining the processing of the restoration section 53 of the reception processing section 41 of the speaker device 2. In step S41, the restoration unit 53 determines whether or not there is an unread baseband packet in the reception queue 52, and waits until it is determined that there is an unread baseband packet. If it is determined that there is a baseband packet that has not been read, the process proceeds to step S42.

In step S42, the restoration section 53
Among the unread baseband packets stored in the reception queue 52, the earliest received baseband packet is read. In step S43, the restoration unit 53 determines whether the read baseband packet belongs to a new data block different from the data block to which the read baseband packet has belonged, based on the information included in the baseband packet. To judge.

If it is determined that the packet is a baseband packet belonging to a new data block, the process goes to step S
Proceed to 44. For example, the communication speed is 320 Kbit / sec,
If the data length of the data block is 150 bytes,
Baseband packet DH3 and data block are 1: 1
Therefore, the process always proceeds to step S44.

In step S44, the restoration section 53
The baseband packet read in step S42 is set as the head of a new data block to be restored.

In step S45, the restoration unit 53
By this time, it is determined whether there is a restored data block in the processing of step S46 (described later) or the like.
If it is determined that there is no restored data block by this time, the process returns to step S41, and the subsequent processes are repeated.

It is to be noted that, in step S45, it is determined that there is no restored data block by this time only when the baseband packet obtained by converting the head data block obtained by dividing the audio data is read. Is.

When it is determined in step S43 that the packet is not a baseband packet belonging to a new data block, the process proceeds to step S46. For example, in FIG.
As shown in FIG. 5, when the communication speed is 320 Kbit / sec and the data length of the data block is 400 bytes, the baseband packets DH5-1 and DH3 are continuously communicated.
Since -2 belongs to the same data block, when the baseband packet DH3-2 is read, the process proceeds to step S46.

In step S46, the restoration section 53
The baseband packet read this time is combined with the rear part of the baseband packet read last time and stored. The process returns to step S41, and the subsequent processes are repeated.

If it is determined in step S45 that there is a data block restored by this time,
The process proceeds to step S47. In step S47, the restoration unit 53 compares the actual data length of the data block restored up to this point with the information indicating the data length included in the head baseband packet used for the restoration.

In step S48, step S45
It is determined whether or not the two data lengths compared in step 2 match. If it is determined that the two data lengths match, the process proceeds to step S49.

For example, the communication speed is 320 Kbit / sec,
If the data length of the data block is 150 bytes,
Since one data block is restored using one baseband packet DH3, the two data lengths always match. Therefore, the process proceeds to step S49.

In step S49, the restoration unit 53
The restored data block is buffered in the restored data block buffer 54. The data blocks buffered in the restored data block buffer 54 are read one by one by the data block reading unit 61 of the data processing unit 42 and supplied to the subsequent stage.

In step S48, step S45
If it is determined that the two data lengths compared with each other do not match, or if it is determined that the first baseband packet used for restoration does not include information indicating the data length and the comparison cannot be performed, Advances to step S50.

For example, as shown in FIG. 4, the communication speed is 3
20 Kbit / sec, data length of data block is 800
Baseband packet DH if byte
5-1 DH5-2, DH3-3, DH5-4, DH5
-5, DH5-7 are sequentially received, and when the baseband packet DH5-7 is read in step S42, the data block restored up to this time is a combination of the baseband packets DH5-4 and DH5-5. However, since the data of the baseband packet DH3-6 is dropped, the actual data length of the restored data block is shorter than 800 bytes by that much. In this case, the process proceeds to step S50.

Further, for example, when the communication speed is 320 Kbit / sec and the data length of the data block is 400 bytes, the baseband packets DH5-1 and DH are used.
3-2, DH3-4, DH5-5 are sequentially received, and when the baseband packet DH5-5 is read in step S42, the data blocks restored by this time are
The baseband packet DH3-4 is used and includes the information indicating the data length.
H5-3 is missing data. Therefore, since it is impossible to compare the data lengths, the processing in this case is step S5.
Go to 0.

In step S50, the restoration unit 53
Discard the restored data block. The process is step S
Returning to step 41, the subsequent processing is repeated.

In the first operation example of the data processing unit 13 described above, N data blocks are collectively transferred from the data transfer unit 25 to the packetization waiting buffer 31, but FIG. As shown, each data block may be sequentially transferred at equal intervals. Hereinafter, this is referred to as a second operation example of the data processing unit 13. Even when the data processing unit 13 operates in the second operation example, the time until the flash time is
As described above, the time is N times the interval at which all baseband packets in which one data block is converted at a predetermined communication speed are wirelessly transmitted.

FIG. 18 shows that when the data processing unit 13 operates in the second operation example, the communication speed is 320 Kbit / sec, the data length of the data block is 150 bytes, and N = 4, the audio reproducing apparatus 1 The timing at which baseband packets are communicated from the packet transmitter 34 to the packet receiver 51 of the speaker device 2 without error is shown. In this case, as described above, the time until the flash time is set to 15 msec, but since the data blocks are transferred to the packetization waiting buffer 31 of the transmission processing unit 14 one by one at equal intervals, a communication error occurs. If no occurrence occurs, the baseband packets will be transmitted to the speaker device 2 at equal intervals as shown in the figure.

FIG. 19 shows the communication in the case where an error occurs in the communication of the baseband packet from the packet transmitting unit 34 of the audio reproducing apparatus 1 to the packet receiving unit 51 of the speaker apparatus 2 under the same conditions as in FIG. An example of timing is shown.

For example, as shown in FIG. 19, when three or more communication errors occur within 15 msec until the flash time, the baseband packets DH3-1 and DH3-2 are sent.
Communication succeeded due to retransmission, and baseband packet D
Even if H3 succeeds in communication once, the transmission queue 33 in which the untransmitted baseband packet DH3-4 is stored is cleared by the flash control process.

Therefore, the baseband packet DH3
-4 results in data loss without being transmitted even once. However, since the baseband packet DH3-4 corresponds to the data block 4 shown in FIG. 17 on a one-to-one basis, the baseband packet DH3- on the speaker device 2 side.
Baseband packet DH where data loss of 4 is mixed up
3-2, DH3-5, etc. are not affected.

For 15 msec until the next flush time, after the baseband packet DH3-5 is transmitted,
Since there is a time until the baseband packets DH3-6 are stored in the transmission queue 33, the baseband packets DH3-6 are transmitted at intervals. If the transmission of this baseband packet DH3-6 fails, immediately
The baseband packets DH3-6 already stored in the transmission queue 33 are retransmitted. When the baseband packet DH3-6 is successfully retransmitted, the baseband packet DH3-7 is already stored in the transmission queue 33, and thus the baseband packet DH3-7 is immediately transmitted.

The first operation example of the data processing unit 13 (transferring N data blocks in a lump) allows the N data blocks of audio data to be quickly generated, that is, the data acquisition unit 22. It is suitable for reading audio data from the recording medium 21.

On the other hand, in the second operation example (transferring N data blocks at equal intervals), when N data blocks of audio data cannot be quickly generated, that is, the data acquisition unit 22. It is suitable for obtaining audio data input from a microphone. As in the second operation example, if the generated data blocks are sequentially transferred one by one, converted into baseband packets and transmitted, it is possible to suppress the delay of the audio output on the receiving side.

In this embodiment, only the case where the audio data is wirelessly communicated is mentioned, but naturally the present invention can be applied to the case of streaming transfer of the video data.

Further, although Bluetooth is used for wireless communication in this embodiment, the present invention is not limited to Bluetooth.
wireless communication technologies other than th (for example, IEEE (Institute of El
electrical and Electronics Engineers) 802.11b
(Wireless LAN) and the like). In that case, the data block (L2CAP packet) in Bluetooth described above can be read as an IP packet.

The series of processes described above can be executed by hardware, but can also be executed by software. When a series of processes is executed by software, a program that constitutes the software can execute various functions by installing a computer in which dedicated hardware is installed or various programs. It is installed from a recording medium into a possible personal computer such as a general-purpose computer.

This recording medium is, for example, a recording medium 12 shown in FIG. , Optical disc (CD-ROM (Compact Disc-Read Only Me
mory), DVD (including Digital Versatile Disc)), magneto-optical disc (including MD (Mini Disc)), or semiconductor memory, etc. ROM that stores the program that is provided to the user
And hard disk.

In this specification, the steps for describing the program recorded on the recording medium are not limited to the processing performed in time series according to the order described, but may be performed in parallel even if the processing is not necessarily performed in time series. Alternatively, it also includes processes that are individually executed.

In this specification, the system means
It represents the entire apparatus composed of a plurality of devices.

[0092]

As described above, according to the transmitting apparatus and method and the program of the present invention, the content data is divided into the first data unit, converted into the second data unit, transmitted, and held. The first data unit and the second data unit are erased at every integer multiple of the time provided for communicating the second data unit corresponding to the first data unit at a predetermined communication speed. Therefore, in response to the occurrence of a communication error, the second data unit can be retransmitted without impairing the real timing property on the receiving side, and further, even if data loss occurs, its influence is minimized. It becomes possible.

[Brief description of drawings]

FIG. 1 is a diagram for explaining generation of a baseband packet in Bluetooth.

FIG. 2 is a diagram showing an example of baseband packet generation in Bluetooth.

FIG. 3 is a diagram showing a communication timing of a baseband packet corresponding to FIG.

FIG. 4 is a diagram showing an example of baseband packet generation in Bluetooth.

5 is a diagram showing communication timing of baseband packets corresponding to FIG.

FIG. 6 is a diagram showing an example of baseband packet generation in Bluetooth.

FIG. 7 is a diagram showing a timing of communication of a baseband packet corresponding to FIG.

FIG. 8 is a block diagram showing a configuration example of an audio data communication system to which the present invention has been applied.

9 is a flowchart illustrating a first operation example of the data processing unit 13 in FIG.

FIG. 10 is a diagram for explaining a first operation example of the data processing unit 13.

11 is a flowchart illustrating a flash control process by a control unit 11 of FIG.

12 is a flowchart illustrating a process of the packetizing unit 32 in FIG.

FIG. 13 is a flowchart illustrating a process of a packet transmission unit 34.

FIG. 14 is a diagram showing a timing of streaming transfer of a baseband packet corresponding to the first operation example of the data processing unit 13.

FIG. 15 is a diagram showing a timing of streaming transfer of a baseband packet corresponding to a first operation example of the data processing unit 13.

16 is a flowchart illustrating a process of the restoration unit 53 in FIG.

FIG. 17 is a diagram for explaining a second operation example of the data processing unit 13.

FIG. 18 is a diagram showing the timing of streaming transfer of baseband packets corresponding to the second operation example of the data processing unit 13;

FIG. 19 is a diagram showing the timing of streaming transfer of baseband packets corresponding to the second operation example of the data processing unit 13.

[Explanation of symbols]

1 audio reproducing device, 2 speaker device, 11
Control unit, 12 recording media, 13 data processing unit,
14 transmission processing unit, 21 recording medium, 22 data acquisition unit, 23 blocking unit, 24 data block buffer, 25 data transfer unit, 31 packetization waiting buffer, 32 packetization unit, 33 transmission queue, 34 packet transmission unit

Continued front page    F term (reference) 5K033 BA01 BA14 CC01 DA17 DB12                 5K034 AA03 AA07 CC05 DD01 EE03                       EE11 FF01 FF02 HH01 HH02                       HH11 HH12 MM03 MM25                 5K067 AA23 BB21 CC04 CC08 CC10                       DD52 DD54 EE02 EE12 HH21                       HH22 HH23 KK15

Claims (9)

[Claims] 1. A transmission device for streaming-transferring content data according to a predetermined wireless communication standard, and a dividing means for dividing the content data into first data units, and a first holding unit for temporarily holding the first data units. 1 and 2 holding means, transfer means for transferring the first data unit held by the first holding means to the second holding means, and held by the second holding means A conversion unit that reads the first data unit and converts it into a second data unit, a third holding unit that holds the second data unit converted by the conversion unit, and a third holding unit. Transmitting means for sequentially reading and transmitting the second data unit held by the second data unit, the first data unit held by the second holding means, and The second data unit held by the third holding unit has an integral multiple of the time provided for communicating the second data unit corresponding to the first data unit at a predetermined communication speed. A transmitting device comprising: an erasing unit for erasing at every time. 2. The transfer means collectively transfers the plurality of first data units held by the first holding means to the second holding means. The transmission device according to 1. 3. The transfer unit transfers the plurality of first data units held by the first holding unit to the second holding unit at equal intervals. The transmission device according to 1. 4. The predetermined wireless communication standard is Bluetooth.
The transmission device according to claim 1, wherein the first data unit is an L2CAP packet, and the second data unit is a baseband packet. 5. The transmission device according to claim 1, wherein the content data is audio data. 6. The transmission device according to claim 1, wherein the content data is video data. 7. A transmission method of a transmission device for streaming-transferring content data according to a predetermined wireless communication standard, the method comprising: dividing the content data into first data units; and temporarily dividing the first data units. A first and a second holding step of holding, a transfer step of transferring the first data unit held in the processing of the first holding step to the processing of the second holding step, and the second A conversion step of reading the first data unit held by the processing of the holding step and converting it into a second data unit; and a third step of holding the second data unit converted by the processing of the converting step. And a transmitting step of sequentially reading and transmitting the second data unit retained in the process of the third retaining step, The first data unit held in the process of the second holding step and the second data unit held in the process of the third holding step are the first data unit corresponding to the first data unit. And an erasing step of erasing the two data units at an integer multiple of the time provided for communicating at a predetermined communication speed. 8. A program for streaming transfer of content data according to a predetermined wireless communication standard, comprising a dividing step of dividing the content data into a first data unit, and temporarily dividing the first data unit. A first and a second holding step of holding, a transfer step of transferring the first data unit held in the processing of the first holding step to the processing of the second holding step, and the second A conversion step of reading the first data unit held by the processing of the holding step and converting it into a second data unit; and a third step of holding the second data unit converted by the processing of the converting step. And a transmitting step of sequentially reading and transmitting the second data unit retained in the process of the third retaining step, The first data unit held in the process of the second holding step and the second data unit held in the process of the third holding step are the second data units corresponding to the first data unit. And an erasing step of erasing the data unit at every integer multiple of the time provided for communicating at a predetermined communication speed. 9. A dividing step of dividing the content data into a first data unit to a computer for streaming transfer of the content data according to a predetermined wireless communication standard, and a first step of temporarily holding the first data unit. And a second holding step, a transfer step of transferring the first data unit held in the processing of the first holding step to the processing of the second holding step, and a transfer step of the second holding step. A conversion step of reading the first data unit held in the process and converting it into a second data unit; and a third holding step of holding the second data unit converted in the process of the conversion step. A transmission step of sequentially reading and transmitting the second data unit held in the processing of the third holding step, and the second holding The first data unit held in the processing of step and the second data unit held in the processing of the third holding step are the second data unit corresponding to the first data unit. And a erasing step for erasing the data at a predetermined communication speed for each integral multiple of the time provided.