JP2000278319A - Data broadcast multiplexing system for digital broadcast - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower a system price by using a low-speed transmission line for data transfer by sending a flow control message to a data server device when the number of TS packets in a buffer queue storing TS-packeted additional data becomes less than a prescribed threshold. SOLUTION: A sending-out multiplexing device(EM) 2 multiplexes data TSP by a TS multiplexing part 22 together with video and audio TSPs and sends them out as a transport stream by a sending transmission IF part 21. According to the flow control message from the EM 2, the data server device(DS) 3 generates data TSPs and connects the EM2 and DS3 by a transmission line. The EM2 sends the flow control message to the DS3 when the number of data TSPs in the buffer queue 27 storing the data TSPs decreases below the prescribed threshold. Consequently, the need for a high-speed transmission line between the DS3 and EM2 is eliminated to obtain a system which is inexpensive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a data broadcast multiplexing system for generating a transport stream in which additional data is multiplexed together with video / audio data compression-encoded by the MPEG system or the like, and more particularly, to an additional data The present invention relates to a data broadcast multiplexing system for digital broadcasting, which is performed between a data server device that generates multiplexing and a transmission multiplexing device that multiplexes additional data together with video / audio data.

[0002]

2. Description of the Related Art FIG.
levision Standard Committee)
The document "Proposed SMPTE RECOMMENDED P"
RACTICE: Opportunistic DataFlow Control Using Ethe
rnet as a Control Channel in an MPEG-2 TransportEm
issions Multiplex "(Issued November 10, 1998)
1 is a block diagram showing a conventional data broadcasting multiplexing system in digital broadcasting shown in FIG. 1, wherein 1 is a data broadcasting multiplexing system, and 2 is an EM (Emissio).
n Multiplexer), 3 is DS
(Data Server), the data server device 4 compresses and encodes the video data and divides it into TS packets (TSP
And a video encoder 5 which compresses and encodes the audio data, converts it to TSP, and transmits it.

[0003] A one-way transmission line 41 connects the video encoder 4 and the EM2, and a one-way transmission line 51 connects the audio encoder 5 and the EM2. 61
Is a one-way transmission line connecting DS3 and EM2, 62
Is a LAN (Local Area) connecting DS3 and EM2.
Network), which is a type of Ethernet (registered trademark). In the above-mentioned document, a DVB-ASI (Asynchr
onous Serial Interface) or transmission speed is 270M
bps SDTI (Serial Data Transport Interface)
Has been applied.

The EM2 is a device for multiplexing additional data together with video / audio data, and comprises the following parts.
21 is a transmission transmission IF unit, 22 is a TS multiplexing unit, 231 to
233 is a reception transmission IF unit, 24 is an Ethernet IF unit,
25 is a TCP / IP protocol processing unit, and 26 is a flow control processing unit. DS3 is a device for generating additional data, and includes the following parts. 31 is a data generator,
32 is a TS processing unit for dividing the data into TS packets, 33 is a transmission transmission IF unit, and 34 is an Ethernet IF
Unit, 35 is a TCP / IP protocol processing unit, and 36 is a flow control processing unit.

Next, the operation will be described. In recent years,
MPEG (Motion Picture)
Digitalization of television broadcasting is progressing using the Experts Group) method. Video / audio data compressed and encoded by the MPEG system is generally transmitted in the form of an MPEG2 TS (transport stream). It converts the data stream of each media such as video and audio into MP
It is divided into TS packets of a fixed length of 188 bytes defined by the EG2 Systems standard, and the T
It is generated by multiplexing S packets.

In digital television broadcasting, since video and audio can be compressed and transmitted, a corresponding transmission band becomes available. Utilizing this free band, additional data such as profile information of athletes related to the program content, or independent of the program content, for example,
There is a request to broadcast additional data such as stock price information to viewers. To realize this, these additional data are also divided into TS packets and multiplexed with the above-described MPEG2 TS.

FIG. 8 shows a configuration example of such a data broadcast multiplexing system. The operation of FIG. 8 will be described below. The video TSP transmitted by the video encoder 4 is
The data is transferred to EM2 via the one-way transmission line 41.
The reception transmission IF unit 232 passes the video TSP to the TS multiplexing unit 22 each time the video TSP arrives. The audio TSP transmitted by the audio encoder 5 is a one-way transmission line 5.
1 to EM2. Receive transmission IF unit 23
3 is a TS multiplexing unit 2 each time an audio TSP arrives.
Hand over to 2. Further, the data TSP transmitted by DS3 is
The data is transferred to EM2 via the one-way transmission line 61.
The reception transmission IF unit 231 converts the arrived data TSP into TS
It is passed to the multiplexing unit 22.

[0008] The TS multiplexing unit 22 includes a reception transmission IF unit 23
Video TSP and audio TS passed from 1 to 233
P and data TSP are multiplexed to form an MPEG2 TS
Is generated and the MPEG2 TS is transmitted to the transmission / transmission IF unit 21.
Send to At this time, the TS multiplexing unit 22 multiplexes the data TSP with the lowest priority. That is, only when there is no video TSP and audio TSP to be received, the data TSP is received from the reception transmission IF unit 231 and sent to the transmission transmission IF unit 21. The transmission transmission IF unit 21
The G2 TS is transmitted in the form of a transmission line. still,
The transmission transmission path referred to here is, for example, a broadcast radio wave based on the 8VSB modulation method in the case of U.S. terrestrial broadcasting, and the transmission speed in that case is 19.39 Mbps.

[0009] The video TSP and the audio TSP are generated at the pace of the video encoder 4 and the audio encoder 5, sent to the EM2, and broadcast using a certain portion of the band of the transmission path. The data TSP is broadcast using the remaining bandwidth of the transmission transmission line that has not been used in the video TSP or the audio TSP. Therefore, the data TSP must be generated in accordance with the situation on the EM2 side, not generated at the pace of DS3. Therefore, flow control is performed between DS3 and EM2 as follows.

The TS multiplexing unit 22 notifies the flow control processing unit 26 of the presence or absence of a TSP to be transmitted as a control signal 221. The flow control processing unit 26 transmits the T
When notified that there is no SP, a flow control message is issued to DS3. This flow control message is sent to the TCP / IP protocol processing unit 25, Ethernet IF unit 24, Ethernet 62, Ethernet IF
Through the unit 34 and the TCP / IP protocol processing unit 35,
The flow control processing unit 36 in S3 is notified. The flow control processing unit 36 that has received the flow control message gives the data generation unit 31 permission to generate data, and in response, the data generation unit 31 passes the data to the TS conversion processing unit 32. The data is TS-packetized by the TS conversion processing unit 32 and reaches the TS multiplexing unit 22 via the transmission / transmission IF unit 33, the one-way transmission line 61, and the reception / transmission IF unit 231.

[0011]

Since the conventional data broadcast multiplexing system for digital broadcasting is configured as described above, in order to fill the remaining bandwidth of the transmission line with the data TSP, the TS multiplexing unit 22 is required. Is the transmission transmission IF unit 2
When a transmission control IF unit 21 determines that there is no next TSP when the TSP is passed, a flow control message is sent from the EM2 to the DS3 until the transmission transmission IF unit 21 completes transmission of one TSP. , DS3 in response
Needs to reach the EM2 from the data TSP. For that purpose, a transmission line much faster than the transmission line must be applied as the one-way transmission line 61. Therefore, a high-speed transmission IF is provided to both DS3 and EM2.
And the cost of the entire system increases.

When the 8VSB modulation method is assumed as the transmission line, the above time is about 78 μs (188 bytes).
e ÷ 19.39 Mbps). In the above-mentioned document, as the one-way transmission line 61, for example, 216 Mb
ps DVB-ASI is applied, and the transfer time of one TSP from DS3 to EM2 is approximately 7 μsec (188 bytes).
(÷ 216 Mbps). As a result, the transfer time of the flow control message and other processing time are secured.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and eliminates the need for a high-speed transmission line between a data server device and a transmission multiplexing device. The purpose is to:

[0014]

According to the present invention, there is provided a data broadcast multiplexing system for digital broadcasting, wherein a transmission multiplexing apparatus includes a buffer queue for storing TS packetized additional data, and a TS queue in the buffer queue. When the number of packets falls below a specified threshold, a flow control message is transmitted to the data server device.

A data broadcast multiplexing system for digital broadcasting according to the present invention is an RTT measurement processing section for measuring an RTT time from transmission of a flow control message to a transmission multiplexing device until arrival of additional data as a response. And calculates a prescribed threshold value based on the measured RTT.

In the data broadcasting multiplexing system for digital broadcasting according to the present invention, the RTT measurement processing unit continues to measure the RTT time even during the operation of the apparatus, and recalculates the specified threshold value each time the measured RTT is updated. It is something to do.

In the data broadcasting multiplexing system for digital broadcasting according to the present invention, the transmission multiplexing apparatus includes a remaining band measurement processing unit for measuring an effective transmission time of the data TS packet, and based on the measured TSP transmission time. In this case, a prescribed threshold value is calculated.

In a data broadcasting multiplex system for digital broadcasting according to the present invention, a transmission multiplexing device and a data server device are connected by a LAN which is a bidirectional network,
The data transfer from the data server device to the transmission multiplexing device and the flow control message transfer in the opposite direction are both performed by this L.
This is performed via an AN.

A data broadcast multiplexing system in digital broadcasting according to the present invention transfers data from a data server device to a transmission multiplexing device by a TCP / IP protocol and performs flow control by the TCP protocol. is there.

In the data broadcasting multiplexing system for digital broadcasting according to the present invention, the transmission multiplexing apparatus is provided with a TS conversion processing section for additional data, and the data from the data server apparatus to the transmission multiplexing apparatus is not converted into TS packets. Is to be forwarded.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a block diagram showing a data broadcast multiplexing system in digital broadcasting according to a first embodiment of the present invention. In the figure, reference numeral 1 denotes a data broadcast multiplexing system, and 2 denotes transmission, which is abbreviated as EM (Emission Multiplexer). A multiplexing device, 3 is a data server device, which is abbreviated as DS (Data Server), 4 is a video encoder, which compresses and encodes video data, divides it into TS packets (TSP), and sends it out; It is an audio encoder that converts it to TSP and sends it out.

Reference numeral 41 denotes a one-way transmission line connecting the video encoder 4 and EM2, and reference numeral 51 denotes a one-way transmission line connecting the audio encoder 5 and EM2. 61
Is a one-way transmission line connecting DS3 and EM2, 62
Is a LAN (Local Area) connecting DS3 and EM2.
Network) is a type of Ethernet.

EM2 is a device for multiplexing the additional data together with the video / audio data, and comprises the following parts.
21 is a transmission transmission IF unit, 22 is a TS multiplexing unit, 231 to
233 is a reception transmission IF unit, 24 is an Ethernet IF unit,
25 is a TCP / IP protocol processing unit, and 26 is a flow control processing unit. Reference numeral 27 denotes a buffer queue for storing data TSP in a stage preceding the TS multiplexing unit 22;
1 is queue length information for notifying the flow control processing unit 26 of the number of remaining TSPs in the buffer queue 27. DS3 is a device for generating additional data, and includes the following parts. 31 is a data generating unit, 32 is a TS processing unit for dividing the data into TS packets, 33 is a transmission transmission IF unit,
34 is an Ethernet IF unit, 35 is a TCP / IP protocol processing unit, and 36 is a flow control processing unit.

Next, the operation will be described. The video TSP transmitted by the video encoder 4 is a one-way transmission line 4
1 to EM2. Receive transmission IF unit 23
2 is transferred to the TS multiplexing unit 22 each time the video TSP arrives. The audio TSP transmitted by the audio encoder 5 is transmitted to the EM2 via the one-way transmission line 51.
Is forwarded to The reception transmission IF unit 233 includes an audio T
Each time the SP arrives, it is passed to the TS multiplexing unit 22. further,
The data TSP transmitted by the DS3 is a one-way transmission line 6
1 to EM2. Receive transmission IF unit 23
1 stores the arrived data TSP at the end of the buffer queue 27. The TS multiplexing unit 22 stores the buffer queue 2
7, the data TSP is taken out from the beginning.

The TS multiplexing unit 22 includes a reception transmission IF unit 23
2 and 233, the data TSP stored at the end of the buffer queue 27 by the reception / transmission IF unit 231 and fetched from the head of the buffer queue 27 to be multiplexed.
A TS is generated and the MPEG2 TS is transmitted and transmitted.
Send to section 21. At this time, the TS multiplexing unit 22 outputs the data T
The SP is multiplexed with the lowest priority. That is, the data TSP is taken out from the head of the buffer queue 27 and sent to the transmission transmission IF unit 21 only when there is no video TSP and audio TSP to be received. Transmission transmission IF unit 21
Sends an MPEG2 TS in the form of a transmission line. Note that the transmission transmission path here is, for example, a broadcast wave by the 8VSB modulation method in the case of U.S. terrestrial broadcasting, and the transmission speed in that case is 19.39 Mbps.

The video TSP and the audio TSP are generated at the pace of the video encoder 4 and the audio encoder 5, are sent to the EM 2, and are broadcast using a certain portion of the band of the transmission line. The data TSP is broadcast using the remaining bandwidth of the transmission transmission line that has not been used in the video TSP or the audio TSP. Therefore, the data TSP must be generated in accordance with the situation on the EM2 side, not generated at the pace of DS3. Therefore, flow control is performed between DS3 and EM2 as follows.

The buffer queue 27 always notifies the flow control processing unit 26 of queue length information 271.
When the number of remaining TSPs notified by the queue length information 271 falls below a prescribed threshold, the flow control processing unit 26 generates a flow control message to the DS3. This flow control message is sent to the TCP / IP protocol processing unit 2
5, Ethernet IF unit 24, Ethernet 62, Ethernet IF unit 34, TCP / IP protocol processing unit 3
After that, the flow control processing unit 36 of the DS 3 is notified. The flow control processing unit 36 that has received the flow control message gives the data generation unit 31 permission to generate data, and in response, the data generation unit 31 passes the data to the TS conversion processing unit 32. The data is converted to a T
The packet is converted into an S packet, and transmitted to the buffer queue 27 via the transmission / transmission IF unit 33, the one-way transmission line 61, and the reception / transmission IF unit 231.

As described above, according to the first embodiment, the flow control message arrives from EM2 to DS3 by the time the transmission transmission IF unit 21 completes the transmission of the TSP of the specified threshold value. When the data TSP arrives from the DS 3 to the EM 2 as a response, the remaining band of the transmission path can be filled with the data TSP. As described above, since a margin of the processing time can be secured as compared with the conventional example, an effect that a transmission line lower in speed than the conventional example can be applied as the one-way transmission line 61 can be obtained.

Embodiment 2 FIG. 2 is a block diagram showing a data broadcast multiplexing system in digital broadcasting according to a second embodiment of the present invention.
Is an RTT measurement processing unit, 261 is a flow control message generation notification that notifies the timing when the flow control processing unit 26 generates the flow control message, and 272 is the data TSP arrival that notifies the timing when new data TSP arrives in the buffer queue 27. The notification 281 is RTT information measured by the RTT measurement processing unit 28. Others are the same as FIG.

Next, the operation will be described. After EM2 generates a flow control message, it responds with DS
RTT is the time from 3 to EM2 until data TSP arrives
(Round Trip Time). The transmission transmission IF unit 2
The time when 1 completes transmitting one TSP is referred to as “TSP transmission time”. If the specified threshold is (RTT ÷
If it is too small for (TSP transmission time), the buffer queue 27 may underflow, and the remaining band of the transmission path cannot be filled with the data TSP. That is, the utilization efficiency of the transmission transmission path band is reduced. vice versa,
If the specified threshold is too large for (RTT ÷ TSP transmission time), the data TSP is stored in the buffer queue 2
7, the transmission delay of the data TSP increases insignificantly. In the second embodiment, RT
By measuring T and setting the specified threshold based on RTT, the accuracy of flow control is improved.

In FIG. 2, the RTT measurement processing unit 28
The time from receiving the flow control message occurrence notification 261 to receiving the next data TSP arrival notification 272 is measured, and the measured time is notified to the flow control processing unit 26 as RTT information 281. The flow control processing unit 26 operates at a provisional prescribed threshold value (for example, 1 TSP) at the time of device startup, and when the RTT information 281 is first notified,
A specified threshold value is calculated using the T value, and thereafter, the operation is performed at the specified threshold value.

As described above, according to the second embodiment, the RTT varies depending on the transmission distance of the one-way transmission line 61, the transmission speed, and the processing performance of the DS3. By executing the control, it is possible to flexibly cope with various system configurations and obtain an effect that the system can be easily constructed.

Embodiment 3 FIG. 3 is a block diagram showing details of an RTT measurement processing section of a data broadcast multiplexing system in digital broadcasting according to a third embodiment of the present invention. In the figure, reference numeral 282 indicates time measurement by self-running at a constant speed. This is a timer queue storing a plurality of timers. Flow control message occurrence notification 261, data T
The SP arrival notification 272 and the RTT information 281 are the same as in the second embodiment.

Next, the operation will be described. Embodiment 2
Then, the RTT was measured immediately after the device was started,
It may fluctuate due to factors such as the processing load of S3. In the third embodiment, the RTT measurement processing unit 28 is configured so that the RTT measurement can be continued even during the operation of the apparatus. In FIG. 3, upon receiving the flow control message occurrence notification 261, the RTT measurement processing unit 28 newly generates a timer, resets the measured time to 0, and packs it at the end of the timer queue 282. This timer is hereinafter called a timer queue 28
Until it is taken out of 2, it will run and keep time. Further, the RTT measurement processing unit 28 transmits the data TSP arrival notification 2
72, the timer is extracted from the head of the timer queue 282, and the time indicated by the timer, that is, the time the timer has been in the timer queue 282, is stored in the RTT information 28.
The flow control processing unit 26 is notified as “1”. When the RTT information 281 is updated, the flow control processing unit 26 recalculates the specified threshold using the RTT value.

As described above, according to the third embodiment, the flow control is executed by using the specified threshold value that follows the actual RTT fluctuation. The effect that the precision of control can be ensured is obtained.

Embodiment 4 FIG. FIG. 4 is a block diagram showing a data broadcasting multiplexing system in digital broadcasting according to a fourth embodiment of the present invention.
Is the remaining band measurement processing unit that measures the effective “TSP transmission time”, 291 is TSP type information indicating the type of TSP being processed by the TS multiplexing unit 22, and 292 is the remaining band measurement processing unit 2.
Reference numeral 9 denotes the measured TSP transmission time information. Others are shown in Figure 1
Is the same as

Next, the operation will be described. "TS
The “P transmission time” is (188 bytes ÷ transmission transmission line speed) at the shortest. However, the speed at which the data TSP is extracted from the buffer queue 27 is a speed corresponding to the remaining bandwidth obtained by subtracting the bandwidth consumed in transmitting the video TSP and the audio TSP from the transmission channel speed. That is, the effective “TSP transmission time” of the data TSP is (188 bytes ÷ the remaining band). Embodiment 4
Measures the effective "TSP transmission time" and sets a specified threshold based on the measured "TSP transmission time", thereby improving the accuracy of flow control.

In FIG. 4, the remaining band measurement processing unit 29
TSP type information 29 during the fixed sampling time
1 is monitored and counted for each TSP type. Data TS
The effective “TSP transmission time” of P is calculated as the sample time ÷
(The number of data TSPs + the number of null TSPs), which is used as the TSP transmission time information 292.
Notify. Here, the null TSP is a TS packet inserted as a dummy when there is no significant TSP to be transmitted. The flow control processing unit 26 includes the TSP transmission time information 2
When 92 is updated, the specified threshold is recalculated using the TSP transmission time.

As described above, according to the fourth embodiment, by measuring the effective TSP transmission time and executing the flow control based on the measured time, it is possible to prevent the extra queue in the buffer queue 27 and prevent the data TSP The effect that the transmission delay of this can be suppressed is acquired.

Embodiment 5 FIG. 5 is a block diagram showing a data broadcasting multiplexing system in digital broadcasting according to a fifth embodiment of the present invention. In the drawing, the difference from FIG. 1 shown in the first embodiment is that DS3 and EM2 are bidirectionally connected. LAN, which is a network, for example, 10 Mbps
Or, connect with 100Mbps Ethernet, DS
The point is that the data TSP from 3 to EM2 is also transferred via this LAN. Others are the same as FIG. For this reason,
The one-way transmission line 61 becomes unnecessary, and the transmission transmission IF unit 3
3 and the reception transmission IF unit 231 are deleted, and the transmission IF function performed by them is replaced by each Ethernet IF unit 24,
34 takes over. The reason for the above configuration is that the provision of the buffer queue 27 eliminates the need to connect the DS3 and the EM2 with a high-speed one-way transmission line as in the conventional example.

As described above, according to the fifth embodiment, the commonly used LAN 63 such as Ethernet is shared as the transmission / reception transmission path between the DS3 and the EM2.
The effect that the system can be constructed at lower cost can be obtained.

Embodiment 6 FIG. FIG. 6 is a block diagram showing a data broadcast multiplexing system in digital broadcasting according to a sixth embodiment of the present invention.
0 is a TSP reception processing unit. The flow control processing units 26 and 36 are deleted from FIG.

Next, the operation will be described. The sixth embodiment is different from the fifth embodiment in that data TSP from DS3 to EM2 is transferred by the TCP / IP protocol,
This achieves flow control as a data broadcast multiplexing system using the flow control function of the CP / IP protocol itself.

In FIG. 6, the flow control between DS3 and EM2 is executed as follows. Buffer queue 27
Is the queue length information 271 to the TSP reception processing unit 260.
Is always informed. When the number of remaining TSPs notified by the queue length information 271 falls below a specified threshold, the TSP reception processing unit 260 extracts the data TSP received and held by the TCP / IP protocol processing unit 25, and Add to When the TSP reception processing unit 260 extracts the data TSP, an empty space is generated in the buffer inside the TCP / IP protocol processing unit 25. An ACK message specified by the TCP protocol is sent to the TCP / IP protocol processing unit 35 to notify that the buffer has become empty. TCP / I receiving this
The P protocol processing unit 35 transmits the data TSP held in the internal buffer to the EM2 as TCP protocol data. This data TSP is TCP / IP
It arrives at the protocol processing unit 25, is stored in an internal buffer thereof, and waits for being taken out by the TSP reception processing unit 260. On the other hand, when the TCP / IP protocol processing unit 35 has a free space in the internal buffer, the TCP / IP protocol processing unit 35 again accepts the data transmission request from the TS conversion processing unit 32 that had been blocked until then. This gives T
The S-processing unit 32 and the data generation unit 31 restart the operation.

As described above, according to the sixth embodiment, the interconnect control between the DS3 and the EM2 is ensured by realizing the flow control as a data broadcast multiplexing system by the TCP protocol which is widely used. Is obtained.

Embodiment 7 FIG. FIG. 7 is a block diagram showing a data broadcasting multiplexing system in digital broadcasting according to a seventh embodiment of the present invention.
Is the T provided at the stage preceding the buffer queue 27 in EM2.
It is an S processing section. In addition, with respect to FIG.
The S processing unit 32 has been deleted. Also, T in EM2
The SP reception processing unit 260 is shown as being integrated with the TS conversion processing unit 32.

Next, the operation will be described. The seventh embodiment differs from the sixth embodiment in that a TS conversion unit 32 for the data TSP is provided on the EM side. In FIG. 7, the flow control between DS3 and EM2 is executed as follows. The TS processing unit 32 stores the queue length information 27
When the number of remaining TSPs notified by 1 falls below a prescribed threshold value, the TCP / IP protocol processing unit 25 extracts the received / held data, converts it to TSP, and adds it to the buffer queue 27. The flow control of the TCP protocol due to the fact that the TS conversion processing unit 32 extracts the data is the same as in FIG. However, DS3 is different in that the generated data is transmitted to EM2 as data of the TCP protocol without being divided into TS packets.

As described above, according to the seventh embodiment, the TS conversion processing is generally a high-speed processing on the order of μ seconds and cannot be realized without dedicated hardware.
Since the conversion processing unit is provided on the EM2 side, special hardware is not required on the DS3 side, and an effect is obtained that it can be configured with general PC hardware.

[0049]

As described above, according to the present invention, the transmission multiplexing apparatus is provided with the buffer queue for storing the TS packetized additional data.
Since the flow control message is transmitted to the data server device when the number of S packets falls below the prescribed threshold value, a low-speed transmission path can be applied to data transfer from the data server device to the transmission multiplexing device. Therefore, an effect that the system can be configured at low cost can be obtained.

According to the present invention, there is provided the RTT measurement processing section for measuring the RTT time from when the flow control message is transmitted to the transmission multiplexing apparatus until the additional data arrives as a response thereto, and based on the measured RTT. Since the configuration is such that the specified threshold value is calculated by the above-described method, an effect is obtained that it is easy to ensure the accuracy of the flow control for various system configurations.

According to the present invention, the RTT measurement processing unit
Continue to measure the RTT time while the device is operating, and
Since the prescribed threshold value is recalculated every time T is updated, the effect of ensuring the accuracy of the flow control even if the RTT fluctuates during the operation of the apparatus can be obtained.

According to the present invention, the transmission multiplexing apparatus includes the remaining band measurement processing unit for measuring the effective transmission time of the data TS packet, and calculates the specified threshold based on the measured TSP transmission time. Data T
The effect that the transmission delay of SP can be suppressed can be obtained.

According to the present invention, the transmission multiplexing device and the data server device are connected by the LAN which is a bidirectional network, and the data transfer from the data server device to the transmission multiplexing device and the flow control message transfer in the reverse direction are performed. , Both are configured to be performed via this LAN, so that a dedicated one-way transmission line is not required for data transfer from the data server device to the transmission multiplexing device, and the effect of being able to configure the system at lower cost is obtained.

According to the present invention, data is transferred from the data server device to the transmission multiplexing device according to the TCP / IP protocol, and flow control is performed according to the TCP protocol. Is obtained.

According to the present invention, the transmission multiplexing apparatus is provided with the TS processing section for the additional data, so that the data from the data server apparatus to the transmission multiplexing apparatus is transferred without being formed into TS packets. This has the effect that the data server device can be configured without special hardware.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a data broadcast multiplexing system in digital broadcasting according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a data broadcast multiplexing system in digital broadcasting according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing details of an RTT measurement processing unit of a data broadcast multiplexing system in digital broadcasting according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing a data broadcast multiplexing system in digital broadcasting according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing a data broadcast multiplexing system in digital broadcasting according to a fifth embodiment of the present invention.

FIG. 6 is a block diagram showing a data broadcast multiplexing system in digital broadcasting according to a sixth embodiment of the present invention.

FIG. 7 is a block diagram showing a data broadcast multiplexing system in digital broadcasting according to a seventh embodiment of the present invention.

FIG. 8 is a block diagram showing a conventional data broadcast multiplexing system in digital broadcasting.

[Explanation of symbols]

1 data broadcasting multiplexing system, 2 transmission multiplexing device,
3 data server device, 27 buffer queue, 28
RTT measurement processing unit, 29 remaining band measurement processing unit, 32 T
S processing section, 63 LAN.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04L 13/08 H04L 13/00 309Z F-term (Reference) 5K028 AA06 EE03 KK01 KK23 KK32 MM12 PP11 SS24 5K030 GA05 HA08 HB01 HB02 HB13 HB29 HC14 HD06 JA01 KA03 LA07 LA08 LC01 MB06 5K034 AA03 AA10 CC01 CC03 CC05 DD01 EE07 FF13 HH01 MM11 QQ04

Claims (7)

[Claims] 1. A transmission multiplexing apparatus for multiplexing additional data together with video / audio data in TS packets and transmitting the multiplexed data as a transport stream, and generating additional data based on a flow control message from the transmission multiplexing apparatus. In a data broadcast multiplexing system for digital broadcasting comprising a data server device and a transmission line connecting the transmission multiplexing device and the data server device, the transmission multiplexing device transmits the TS packetized additional data. A data broadcast multiplexing system for digital broadcasting, comprising a buffer queue for storing, and transmitting a flow control message to the data server device when the number of TS packets in the buffer queue falls below a prescribed threshold value. . 2. The transmission multiplexing device includes an RTT measurement processing unit that measures an RTT time from when a flow control message is transmitted to when additional data arrives as a response to the flow control message, and defines a threshold based on the measured RTT. 2. The data broadcast multiplexing system according to claim 1, wherein the value is calculated. 3. The RTT measurement processing unit is capable of executing the RTT measurement while the apparatus is operating.
3. The data broadcast multiplexing system according to claim 2, wherein the measurement of the TT time is continued, and the specified threshold is recalculated every time the measured RTT is updated. 4. The transmission multiplexing apparatus includes a remaining band measurement processing unit that measures an effective transmission time of a data TS packet, and calculates a specified threshold based on the measured TSP transmission time. 2. A data broadcast multiplexing system in digital broadcasting according to claim 1. 5. A transmission multiplexing device and a data server device are connected by a LAN which is a two-way network, and both data transfer from the data server device to the transmission multiplexing device and flow control message transfer in the opposite direction are performed on this LAN. 2. The data broadcast multiplexing system for digital broadcasting according to claim 1, wherein the data broadcasting is performed via a network. 6. Transferring data from a data server device to a transmission multiplexing device by a TCP / IP protocol,
6. The data broadcast multiplexing system in digital broadcasting according to claim 5, wherein flow control is performed by a protocol. 7. The transmission multiplexing apparatus according to claim 6, further comprising a TS conversion section for additional data, wherein the transmission multiplexing apparatus transfers data from the data server device to the transmission multiplexing apparatus without forming a TS packet. Data broadcasting multiplexing system for digital broadcasting.