JP2002141944A - Data transmission system and data transmission method, and program storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system that can transfer data in response to the importance of transmitted/received data. SOLUTION: When the packet transmission of e.g. MPEG images is performed as data transferred via a network, whether any of I, P, B pictures is included in the packet is discriminated and a destination port number in response to the importance is set as UDP/TCP(User Datagram Protocol/Transmission Control Protocol) header information. Specifically, when the packet includes an I picture with high importance, a priority port number is set to a destination port number of the UDP (TCP) header, when data in the packet are only a B picture, a usual port number is set to the destination port number. The missing and delay possibility of the I picture with high priority is reduced in the network and reproduction at a receiver side can more accurately be carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a data transmission device,
And a data transmission method, and a program storage medium. More specifically, in a process of transferring mixed data of data having different degrees of importance, a data transmission device that can prevent a decrease in quality of transferred data by performing a transfer process according to the degree of importance, And a data transmission method, and a program storage medium.

[0002]

2. Description of the Related Art Currently, various data transfers are performed via various communication media such as Internet communication.
In recent years, transfer of image data, particularly moving image data, via a network has been actively performed. image data,
In particular, in general, moving image data is subjected to a process of reducing the data amount by encoding (compression) processing on the transmission side and executing decoding (decompression) processing on the reception side to reproduce the video data.

[0003] MPE is the most well-known method of image compression processing.
There is a G (Moving Pictures Experts Group) compression technique. It is anticipated that image data transfer in which an MPEG stream generated by the MPEG compression is stored in IP packets according to IP (Internet Protocol) and transferred on the Internet will rapidly become popular in the future.

[0004] A compressed image represented by MPEG or the like is represented by I
When transmitting using the P network, the RT which has information on the data encoding system and a time stamp as header information and enables real-time data transmission / reception
In many cases, packets are transmitted using the P (Real-time Transport Protocol) protocol. However, IP networks are generally unguaranteed networks, and it is not uncommon for packets to be damaged by errors in the transmission path or for packets to be dropped.

[0005] In a compressed image, a portion containing information that is particularly important in forming the image, for example, an MPE
In G, I-pictures and the like are scattered, and when a packet including this important portion is lost due to a network error or the like, very large damage is caused in terms of images. Specifically, for example, when an I picture in an MPEG compressed image is lost, several frames before and after the I picture cannot be restored.

On the other hand, recently, high-value-added networks that provide QoS (Quality of Service) or CoS (Class of Service) that guarantee the quality of data transfer on the network have also become a reality. However, these services are still generally expensive services,
Network users will be forced to make a trade-off between low-cost but low-reliability networks and high-cost but high-reliability networks.

[0007]

SUMMARY OF THE INVENTION The present invention relates to, for example, MP
In data transfer in which data of different importance, such as data subjected to EG compression, are mixed, data transfer processing is performed according to the importance, and even if an error such as packet loss occurs on the network, the data is received. It is an object of the present invention to provide a data transmission device and a data transmission method capable of minimizing data quality degradation.

[0008]

SUMMARY OF THE INVENTION A first aspect of the present invention is as follows.
The data transmitting apparatus has packet generating means for generating transfer data as a packet according to a communication protocol, wherein the packet generating means identifies the importance of the data stored in each packet and responds to the identification importance. The data transmission apparatus has a configuration in which a destination port number as priority information is set in header information to execute a packet generation process.

Further, in one embodiment of the data transmitting apparatus according to the present invention, the packet generating means sets the importance of the data as high priority data using data including reference information from other data as high importance data. A high priority destination port number is set, and data not including reference information from other data is set as low priority data and a low priority destination port number is set as low priority information. .

Further, in one embodiment of the data transmitting apparatus of the present invention, the data stored in the packet generated by the packet generating means is MPEG data, and the packet generating means stores the data stored in each data packet. I picture, P picture,
It has a configuration in which a destination port number as priority information according to which of the B pictures is included is set in the header information and a packet generation process is executed.

Further, in one embodiment of the data transmitting apparatus according to the present invention, the packet generation means includes a UDP (User
A configuration in which a different destination port number is set in a destination port number setting field in a UDP header according to Datagram Protocol according to the importance of data to be stored in each packet, and a UDP packet generation process is performed. It is characterized by.

Further, in one embodiment of the data transmitting apparatus according to the present invention, the packet generation means includes
A different destination port number is set in the destination port number setting field in the TCP header according to the mission control protocol according to the importance of the data stored in each packet, and the TCP packet generation process is executed. It is characterized by the following.

Further, in one embodiment of the data transmitting apparatus of the present invention, the destination port number as priority information set by the packet generating means is a QoS (Quality of S).
ervice), which is information associated with the service quality.

Further, in one embodiment of the data transmitting apparatus of the present invention, the destination port number set as the priority information set by the packet generating means is a guarantee type data transfer for bandwidth guaranteed data transfer or a data transfer for non-guaranteed data transfer. The information is characterized by being associated as one of the best effort type selection criteria.

Further, a second aspect of the present invention, in the data transmission method, includes a packet generation step of generating transfer data as a packet according to a communication protocol,
The packet generating step identifies the importance of the data stored in each packet, and sets a destination port number as priority information according to the identification importance in the header information to execute the packet generation processing. There is a data transmission method which is a feature.

Further, in one embodiment of the data transmission method according to the present invention, in the packet generation step, the importance of the data is set as high priority information by using data including reference information from other data as high importance data. Is set as a high priority destination port number, and data without reference information from other data is set as low priority data and a low priority destination port number is set as low priority information.

Further, in one embodiment of the data transmission method of the present invention, the data stored in the packet generated in the packet generation step is MPEG data, and the packet generation step includes the step of converting the data stored in each data packet. It is characterized in that a destination port number as priority information according to which of the I picture, the P picture and the B picture constituting the MPEG data is included is set in the header information, and the packet generation processing is executed.

Further, in one embodiment of the data transmission method according to the present invention, the packet generation step may include a UDP
(DP) in the destination port number setting field in the UDP header in accordance with the (User Datagram Protocol) to set a different destination port number according to the importance of the data stored in each packet, and execute the UDP packet generation processing. Features.

Further, in one embodiment of the data transmission method according to the present invention, the packet generation step includes a TCP (T
A different destination port number is set in the destination port number setting field in the TCP header in accordance with the transmission control protocol according to the importance of the data stored in each packet, and the TCP packet generation process is performed. And

Further, in one embodiment of the data transmission method of the present invention, the destination port number as priority information set in the packet generation step is QoS (Quo).
quality of service) according to service quality.

Further, in one embodiment of the data transmission method according to the present invention, the destination port number as priority information set in the packet generation step is a guarantee type as bandwidth guaranteed data transfer, or a bandwidth non-guaranteed data transfer. The information is characterized by being associated as one of the best effort type selection criteria.

Further, a third aspect of the present invention is a program storage medium for providing a computer program for executing a data transmission process on a computer system, wherein the computer program converts transfer data into a communication protocol. A packet generation step of generating the packet as a packet according to the packet generation step, the packet generation step identifies the importance of data stored in each packet,
A program storage medium characterized by including a step of setting a destination port number as priority information according to the identification importance in header information and executing a packet generation process.

The program storage medium according to the third aspect of the present invention is a medium for providing a computer program in a computer-readable format to a general-purpose computer system capable of executing various program codes. It is.

Such a program storage medium defines a structural or functional cooperative relationship between the computer program and the storage medium for realizing the functions of a predetermined computer program on a computer system. Things. In other words, by installing the computer program into the computer system via the storage medium, a cooperative operation is exerted on the computer system, and the same operation and effect as the other aspects of the present invention can be obtained. You can do it.

Still other objects, features and advantages of the present invention are:
It will become apparent from the following more detailed description based on the embodiments of the present invention and the accompanying drawings.

[0026]

FIG. 1 is a block diagram illustrating an embodiment of a data transmitting apparatus according to the present invention. In the present embodiment, MPEG (Moving Pictures Experts Group), which is a general-purpose compression format, is used as data to be transmitted and received.
In the following description, an example in which MPEG2 is applied is described, but the present invention can be similarly applied to other compression methods such as MPEG4.

MPEG2 is a technology for realizing high-quality image compression processing. Most used MPE at present
The compression method of G2 is Discrete Cosine Transform (DC) which is compression using correlation in a screen.
T), a compression method combining motion compensation as compression based on correlation between screens and Huffman coding as compression based on correlation between code strings. In MPEG2, in order to perform predictive coding using motion compensation, a GOP (Group Of Pictures) structure including three elements called an I picture, a P picture, and a B picture as shown in FIG. 2 is employed.

An I picture (Intra coded image) is created by intra-field coding, and is image data that is not subjected to predictive coding from a previous image. If only images created using predictive coding are arranged, it is not possible to instantaneously display a screen in response to random access. Therefore, an access standard is created periodically so that random access can be supported. The I picture exists because it has GOP independence.

The frequency of appearance of I-pictures is determined by the performance of random access required for each application.
2 per frame), that is, one per 15 images. The data amount of one I picture is 2 times that of one P picture.
３3 times, that is, 5 to 6 times of one B picture. GOP
Is a group of pictures from one I picture to the next I picture. Therefore, image prediction is performed between pictures in this group.

A P picture (Predictive coded image) is
An image created by performing predictive coding from the previous image,
Created based on I-pictures. A P picture is defined as an "inter-frame quasi-prediction coded image" for an I picture that is an "intra-coded image".

B picture (Bidirectionally predictive
The “encoded image” is “bidirectional predictive encoded image”. B
A picture is created by performing prediction from two preceding and succeeding I or P pictures.

G of I picture, P picture and B picture
FIG. 3 shows an example of the arrangement in the OP. I at the beginning of the GOP
The first-stage prediction from the picture is performed in the forward direction, that is, in the forward direction, and a P picture is created. At this time, the P pictures are arranged so as to skip a plurality of B pictures created later.

In the second-stage prediction, a plurality of B-pictures are created between two frames of the first I-picture and the P-picture coded in the first stage, that is, by bidirectional prediction. Can be Furthermore, the first P picture and the second P picture
Similarly, a plurality of B pictures are created between pictures. In decoding a B picture, motion compensation is performed using two motion vectors and two (previous and subsequent) reference images. The bidirectional prediction, which is a feature of MPEG, has a feature that high prediction efficiency can be obtained because two temporally past images and future images are used in prediction.

In this embodiment, data compressed by MPEG2 is transmitted as an IP packet (MPEG over IP) over a network. Therefore, the data transmitting side executes packet generation (packetizing processing), and the data receiving side executes packet expansion (depacketizing processing).

The data transmitting / receiving apparatus 100 of the present invention shown in FIG.
Is an MPEG processing PCI board 10 that executes MPEG compression and decompression and performs packet generation and expansion processing.
1. Ethernet (registered trademark) card 10 functioning as an interface with a LAN which is a communication network
2, an input / output interface 103 for input devices such as a mouse 15 and a keyboard 16;
Data processing on board 101, Ethernet card 10
Communication processing via I / O, input / output interface 10
Host CPU that controls processing of input data and the like via the CPU 3
104, storage of various programs controlled and executed by the host CPU 104, storage of data, host CPU 104
And a host memory 105 composed of a ROM and a ROM functioning as a work area of the computer. MPEG processing PCI board 101, Ethernet card 102, and host C
The PUs 104 are connected to the PCI bus 106, respectively.
It has a configuration that allows mutual data transmission and reception.

The MPEG processing PCI board 101 corresponds to FIG.
As shown in FIG. 1, for example, image data from the video camera 11 and audio data from the microphone 12 are input, and MPEG2
A compression process, an encoding multiplexing process, and a packet generation process (packetizing) are executed, and finally, an IP packet storing MPEG transport stream (TS) data is generated. The generated IP packet is output onto a PCI bus 106 and sent to the LAN via the Ethernet card 102.
And delivered to the destination address set in the header of the IP packet.

An IP packetized MPEG transport stream (TS) input via a LAN
The data is output to the PCI bus 106 via the Ethernet card 102 and is output to the MPEG processing PCI board 1.
01 is input. The MPEG processing PCI board 101 executes packet decompression processing (depacketizing) of input data, extracts MPEG compressed data, executes decoding processing, and reproduces and outputs the data on the display 13 and the speaker 14.

FIG. 4 shows the configuration of the MPEG processing PCI board 101. The moving image data input from the video camera 11 is input to the MPEG2 video encoder 201. The MPEG2 video encoder 201 generates an MPEG video stream based on input moving image data. The audio data input from the microphone 12 is M
It is input to the PEG2 audio encoder 202. M
The PEG2 audio encoder 202 generates an MPEG audio stream based on the input audio data.

MPEG2 video encoder 201, MP
EG2 audio encoder 202 These two streams are input to an MPEG multiplexer 203 and multiplexed as an MPEG2 transport stream. The transport stream (TS) is a packet stream each divided into a predetermined data amount, and L
A plurality of MPEG-TS packets (see FIG. 5) are included in an IP packet output from a network such as an AN.

The MPEG-2 transport stream generated by the MPEG multiplexer 203 further includes an RT
In the P packet generating means 204, an RTP packet is generated by adding an RTP header to the MPEG2 transport stream, and a UDP (User Datagram Pr
otocol) A packet generating means 205 adds a UDP header to the RTP packet to generate a UDP packet, and an IP packet generating means 206
An IP packet is generated by adding an IP header to the DP packet, output to the PCI bus 106 via the PCI interface 207, and output from the Ethernet card 102 shown in FIG.

The I output on the network as described above
The P packet is input to the MPEG processing PCI card via the Ethernet card 102 and the PCI bus 106,
The input from the PCI interface 207 to the IP packet expanding means 208 expands the IP packet,
The packet is expanded according to the header information and UDP
In the packet expanding means 209, UDP packet expanding processing is executed, and finally, the RTP packet expanding means 210
MPE by the expansion process according to the RTP header
The G2 transport stream is extracted. RTP
The packet has a time stamp as described later, and the delay fluctuation in network transfer, the order of arrival, and the like are corrected and absorbed based on the time stamp.

The extracted MPEG2 transport stream is separated into an MPEG video stream and an MPEG audio stream by an MPEG demultiplexer 211, and a decoding process is executed by an MPEG video decoder 212 and an MPEG audio decoder 213, respectively. , Speaker 1
4 is played.

In data transfer such as video conferencing and video on demand (VOD) over an IP network, continuous supply of data is emphasized.
A protocol that performs retransmission processing such as a transmission control protocol is rarely used, and UDP that does not perform retransmission processing is used. However, it is also possible to transmit and receive using TCP.

UDP is designed so that an application process can transfer data to a process of another application on a remote machine with minimum overhead. Therefore, the information included in the UDP header is only the source port number, the destination port number, the data length, and the checksum.
There is no data field for identifying the packet order, such as a protocol (ntrol protocol).

Therefore, as a protocol for transmitting and receiving real-time image and audio data in an IP network, a real-time transport protocol: RTP (Re
al-time Transport Protocol) is used. RTP is located in the transport layer and is generally used over UDP.

FIG. 5 shows the details of the RTP header in the structure of the IP packet obtained by packetizing the MPEG transport stream by RTP, UDP, and IP. The RTP header includes a version number (v), padding (P), presence or absence of an extension header (X), and the number of transmission sources (CRSC: Contributor).
ting Source), marker information (M), payload type, sequence number, RTP time stamp, synchronous source identifier, and contributing source (CSRC) identifier. The processing time is controlled when the RTP packet is expanded by the time stamp added to the RTP header, and the real-time image or audio reproduction control can be performed. As shown in FIG. 5, the MPEG transport stream as compressed data is
A plurality is stored in the IP packet.

FIG. 6 shows details of a UDP (User Datagram Protocol) header in an IP packet obtained by packetizing an MPEG transport stream by RTP, UDP, and IP. UDP is a protocol that provides a connectionless service, and has a simple header configuration. As shown in the figure, the UDP header has a source port number, a destination port number, a header indicating the data length, and a length indicating the total number of bytes of the data length. It has a checksum as a reliability guarantee value of the UDP packet. Since the UDP has such a simple configuration, control is simplified.

In the present invention, it is also possible to use a TCP (Transmission Control Protocol) format instead of the UDP format. FIG. 7 shows the configuration of an MPEG transport stream packet using TCP. The TCP header contains a source port number, a destination port number, and a sequence number indicating the number of bytes indicating the number of bytes from the beginning of the data packet at the beginning of the data packet. Acknowledgment number indicating the transmission sequence number of the next data sent from the other party. Header information consisting of code bits such as a header length and a TCP segment processing method. Window size indicating the remaining number of bytes that can be received. Checksum as reliability guarantee value of TCP packet. It has an urgent pointer that indicates data that needs urgent processing.

Next, FIG. 8 shows details of an IP header in the structure of an IP packet obtained by packetizing an MPEG transport stream by RTP, UDP (TCP), and IP. TOS that stores a version indicating a version of IPv4, IPv6, etc., a header length, and priority information
(Type of Service) field, packet length, packet identifier, flag as control information on data division (fragment) in the IP layer, fragment offset indicating the location of division (fragment) saler data, data until discarding data TTL (Time to Liv) indicating time information
e), protocol used in upper layer (4: IP, TC
P: 7, UDP: 17...) Header checksum, source IP address, and destination IP address.

TOS (Type of Servic) in the IP header
e) The field is a field for defining the priority of data and determining what type of data transfer is to be performed. FIG. 9A shows details of the TOS field. The TOS field has an 8-bit configuration, and the first 3
Priority information is stored in bits. [000] has no priority and [100] has the highest priority. The next 4 bits are a field for designating what kind of transfer is to be performed according to the upper layer protocol, and the handling is determined by setting bits such as speed priority and reliability priority.

FIG. 9 (b) shows a DS (Di) that is configured to store priority information by using the TOS field in a different manner.
fferentiated Service) field configuration. The DS field has an 8-bit configuration, and sets priority information in the first 6 bits. [Xxxxxx0] has a configuration in which detailed priority information can be defined, such as standard use (standard), and [xxxx11] for experiment or local use. The DS field is stored in the above-described TOS field in IPv4, but is stored in the traffic field in IPv6.

In the data transfer of the MPEG transport stream (MPEG-TS) of the present invention, apart from the priority information of the data transfer such as the above-mentioned TOS field or DS field, UDP (or TCP)
An MPEG transport stream (MPEG-T) in which the destination port number in the header is stored in an IP packet
The setting is made different depending on the picture included in S), and the priority processing of the data transfer is executed according to the set destination port number.

It should be noted that the IP header described in FIG.
4 is a header configuration. The IPv6 header also has a priority information storage field, and the IPv6 priority information includes a congestion control type (congestion-controlled) and a congestion non-control type (Non-congestion-controlled). The congestion-controlled type is a priority for controlling reliable data transfer, and a priority from 0 to 7 is set. For example, a high priority is set for network management or remote login, and e-mail is set. It is possible to use such as setting a low priority to the like. The non-congestion-controlled type is used in services that require real-time properties, is set with a priority of 8 to 15, and is narrow for low priority (ex. Priority 8). A band is set, a wide band is set for a high one (ex. Priority 15), and when the band is not sufficiently secured, a low priority (ex. Priority 8) is discarded and only a high one is discarded. A process for sending the message is executed.

In the packetization processing (packet generation processing) at the time of the encoding processing in the MPEG processing PCI port 101 in FIG. 1, any one of an I picture, a P picture, and a B picture is included in the MPEG transport stream (MPEG-TS). Is set depending on whether or not is included.

FIG. 10 is a block diagram showing a processing configuration of the UDP packet generating means 205 for setting priority information according to the type of picture stored in the packet. The UDP packet generation means 205 is provided with the RTP packet generation means 20.
4 receives an RTP packet. RTP packets are
It is configured as a packet having an RTP header, and stores an MPEG transport stream packet in the data portion.

As for the RTP packet, the RTP packet storage data identification means 701 of the UDP packet generation means 205 identifies the MPEG transport stream (MPEG-TS) packet stored in the RTP packet. The identification is performed as a determination as to whether or not the stored MPEG-TS includes an I picture. As described above, the I picture is a picture including reference information of other P pictures and B pictures, and is a picture of high importance.

RTP packet storage data identification means 701
The result of the determination as to whether or not an I picture is included in the packet is output to the UDP header information generating means 702, and if the packet is an RTP packet including an I picture, the destination port number in the UDP header Set the high priority port number in the setting field. If the packet does not include an I-picture, a low-priority port number is set in the destination port number setting field in the UDP header.

The UDP header information generating means 702 generates other header information including a destination port number according to the priority according to the picture type in the packet, and generates the UDP header information.
The packetizing processing means 703 generates a UDP packet having a UDP header, and the IP packet generating means 2
At 06, a packet is generated and sent to the destination address via the network interface. In FIG. 10, each processing block is functionally separated for the sake of explanation, but a series of processing can be executed by CPU control as a sequence processing.

Although the configuration of FIG. 10 shows an example of the UDP packet generating means, when generating a packet in accordance with TCP, that is, in the case of the packet configuration shown in FIG. 7, the I-picture is generated by the TCP packet generating means. If the packet is an included RTP packet, a high priority port number is set in the destination port number setting field in the TCP header. If the packet does not include an I-picture, a low-priority port number is set in the destination port number setting field in the TCP header.

Further, in the above example, two types of priorities are set as two different destination port numbers as priority information based on the determination as to whether or not an RTP packet contains an I picture. As explained, such 2
The configuration is not limited to the example in which two types of priorities are set, such that a packet including an I picture has the highest priority, a packet including a P picture has a medium priority, and a packet including only a B picture has a low priority. I picture contained in P
A configuration may be adopted in which three or more types of destination port numbers corresponding to more detailed priority information are set based on the number and ratio of pictures and B pictures.

The data transmitting side that executes data encoding and packet generation processing executes the above-described processing to transmit an IP packet to the network. An IP packet transmitted to a network is transferred to a destination address via a router arranged in the network. FIG. 11 shows a conceptual diagram of the network.

The image transmission apparatus 801 on the data transmission side has the configuration shown in FIG.
Performs encoding and packetizing. The IP packet generated in the image transmission device 801 is transmitted to a network 80 such as the Internet via a router 802.
3 is sent. In the header information of the UDP packet (or TCP packet) included in the IP packet, different destination port numbers according to the priorities according to the above-described picture types are set. The IP packet arrives at the router 808 corresponding to the destination address via the plurality of routers 804, 805, 806, 807 on the network,
The packet is expanded, decoded (decoded), and reproduced by the image transmission device 809 on the receiving side.

As shown in FIG. 11, a plurality of routers are connected on the network, and each router 801 performs data transfer according to the priority determined according to the destination port number of the UDP (or TCP) header described above. Processing is performed.

FIG. 12 is a diagram for explaining processing according to the priority determined according to the destination port number in each router.
Shown in An IP packet arriving at a router via a network reads header information of a UDP (or TCP) packet and performs processing according to the header.

According to the destination port number stored in the header of the UDP (or TCP) packet, each packet is assigned to a different queue (queue). In the example of FIG. 12, the router has queues divided into four priorities.

Here, for example, the destination port number of the UDP (or TCP) header set in the image transmitting apparatus is a packet having an I picture: [8000] A packet having a P picture: [8001] A B picture It is assumed that the setting is made such that the packet has: [8002] Other packets: [8003]

In the router, the destination port number for the destination port number [8001], the destination port number [8002], the destination port number for the destination port number [8002], the destination port number for the destination port number [8001], A process of sorting the packets of [8003] is performed.

The processing of each queue in the router is as follows:
In B: C: D, packet output is executed at a processing ratio of 4: 3: 2: 1. Therefore, the packet stored in the queue A is subjected to the transfer processing with the highest priority, and the next is the queue B,
Queue C and queue D are in order.

As a result, the destination port number is set to [800
0] is processed with the highest priority, and a packet having a P picture with the destination port number set to [8001] is processed with the next priority. A packet having a B picture set to [8002] is processed at the next priority, and a packet having no I, P, B picture set to [8003] as the destination port number is processed at the next priority. Is processed. Image transmission device 809 on the data receiving side (see FIG. 11)
Then, it becomes possible to more reliably receive the highest priority packet.

The processing example using the queue according to the priority in the router shown in FIG. 12 is one processing example, and various other processings related to data transfer such as a processing speed and a transfer certainty confirmation processing are performed. It is possible to vary according to the priority.

QoS (Quality of Service), CoS (Clas
s of Service). These parameters are set as parameters such as delay, fluctuation (variation in transmission), minimum guaranteed speed, and peak speed in data transfer via a network. By changing these processing modes according to the destination port number in the above-mentioned UDP (or TCP) header, the processing modes in the router, other data transfer, and the relay unit are changed so that a high-priority packet is transmitted with a higher probability. It is possible to transmit to the destination without delay. In this case, the destination port number information in the UDP (or TCP) header has a function as information associated with service quality according to QoS (Quality of Service).

As data transfer processing, there are guarantee type transfer processing that guarantees a bandwidth, and best effort type transfer processing that does not guarantee a bandwidth during network congestion.
By changing these processing modes according to the value (priority information) set for the destination port number in the above-mentioned UDP (or TCP) header, a packet with a high priority is reliably delayed to the destination with a higher probability. It is possible to send without. In this case, the destination port number in the UDP (or TCP) header is information associated with either a guarantee type as bandwidth guaranteed data transfer or a best effort type as bandwidth non-guaranteed data transfer. As a function.

FIG. 13 shows a processing flow on the data transmitting side which performs data encoding and packetizing. The processing flow of FIG. 13 will be described.

First, an MPEG transport stream encoded (encoded) by the MPEG video encoder 201 and the MPEG audio encoder 202 shown in FIG. 4 and generated by the MPEG multiplexer 203 is input to the RTP packet generating means 204 (S10).
1) The RTP packet generation means 204
The sequence number and other header information are written in the TP header (S102), and an RTP packet is generated (S103).

Next, the RTP packet is input to the UDP packet generation means, and it is determined whether or not the RTP packet contains an I picture (S104). Here, an example in which two types of packet discrimination as to whether or not an I picture is included in a packet is shown.

If the packet contains an I picture, the process proceeds to step S106, where a port number of a higher priority type (priority port number) is set in the destination port number field of the UDP header. If the packet does not include an I-picture, the process advances to step S105 to set a low-priority type port number (normal port number) in the destination port number field of the UDP header. As the destination port number, a number of port numbers (at least two different destination port numbers) according to the type of the priority to be set is acquired in advance.

When the UDP header information in which the destination port number is set according to the priority is generated, a UDP packet is generated in step S107 (S107). Thereafter, the UDP packet is input to the IP packet generating means 206. By adding the IP header, an IP packet is generated (S108). These processes are sequentially performed on the MPEG transport stream read from the encoder, the generated IP packet is written to the network interface (S109), and then output to the network (S110).

FIG. 14 shows a processing flow in the receiving apparatus for receiving these IP packets. The processing flow will be described with reference to FIG. The IP packet received from the network interface 207 is read, and the processing of expanding the read IP packet is performed by the IP packet expanding unit 20.
8 to extract a UDP packet (S20).
1).

Next, it is determined whether the destination port number included in the UDP header of the UDP packet is a setting of a priority port number or a normal port number, or whether any other port number is set (S202).

If the priority port number or the normal port number is not set, the packet is a packet other than the processing target of the MPEG data, and the following processing is not executed. If the priority port number or the normal port number is set, step S203 The UDP packet expansion processing unit 209 executes the UDP packet expansion processing, extracts the RTP packet (S203), and in the RTP packet expansion processing unit, determines the arrival packet according to the sequence number stored as the header information of the RTP packet. Are rearranged (S204). Further, the MPEG transport stream data as the actual data, which is the payload of the RTP packet, is written in the order of the rearranged RTP packet to the MPE.
The signal is input to the G demultiplexer 211 (S205), and MP
The EG video decoder 212 and the MPEG audio decoder 213 execute decoding (decoding) processing and reproduce the data on the display 13 and the speaker 14.

In this way, it is possible to reproduce the image (audio) data by following the sequence number of the RTP packet. Although the packet processing using UDP has been described in the processing flows shown in FIGS. 13 and 14, the same processing can be performed with a packet configuration using TCP. In the case of TCP, if the packet includes an I picture, the priority port number is set to the destination port number of the TCP header. If the packet does not include the I picture, the normal port is set to the destination port number of the TCP header. Set the number.

Further, the above-described data transfer processing example uses
The EG compressed data has been described as an example, but not limited to MPEG data, but when a series of data composed of data having different degrees of importance is packetized and transferred, data transfer with the same priority assignment as described above is performed. Is possible.

As a data importance setting method, MPE
Similar to the I picture, P picture, and B picture in G, there is a method in which an I picture having reference information of another picture is given the highest priority, and data having no reference information to another picture such as a B picture is given a low priority. is there. Further, as described above, 3 according to the data structure in the packet.
You may make it set the priority more than a kind.

As described above, important information (ex. Reference information) is transferred by setting the destination port number as a different port number as priority information according to the data type and transferring the data to be transferred via the network. The stored data is processed preferentially, and in the processing on the data receiving side, it is possible to reduce the possibility of occurrence of an error such as reproduction failure.

The present invention has been described in detail with reference to the specific embodiments. However, it is obvious that those skilled in the art can modify or substitute the embodiment without departing from the spirit of the present invention. That is, the present invention has been disclosed by way of example, and should not be construed as limiting. In order to determine the gist of the present invention, the claims described at the beginning should be considered.

[0086]

As described above, the data transmitting apparatus, the data receiving apparatus, the data transmitting method, and the data transmitting apparatus according to the present invention,
According to the program storage medium, on the data transmission side, the header information of the data packet in which the data is stored contains information indicating the priority according to the type of data stored in the packet, and a port different from the destination port number of the UDP or TCP header. Because the number is set and transmitted to the network, packets containing important information are identified by the destination port number, processed preferentially, and are discarded in the middle of the network or a transfer delay occurs. , And reproduction on the data receiving side can be realized as an error-free process.

Further, according to the data transmitting apparatus, the data receiving apparatus, the data transmitting method, and the program storage medium of the present invention, in the MPEG compressed data transfer processing, the header information of the data packet storing the data includes I picture, P picture,
Since the priorities are set according to whether or not B pictures are included and transmitted to the network, for example, I pictures including important information are preferentially processed, and are discarded in the middle of the network or transfer delay occurs. Such a situation is reduced, and the reproduction on the data receiving side can be realized as an error-free process.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an outline of a system configuration according to the present invention.

FIG. 2 is a diagram illustrating a configuration of MPEG image data.

FIG. 3 is a diagram illustrating a reference configuration of MPEG image data.

FIG. 4 is a block diagram showing a configuration of an MPEG processing PCI board of the present invention.

FIG. 5 is a diagram illustrating an RTP header configuration in an IP packet transferred in the system of the present invention.

FIG. 6 is a diagram illustrating a UDP header configuration in an IP packet transferred in the system of the present invention.

FIG. 7 is a diagram illustrating a TCP header configuration in an IP packet transferred in the system of the present invention.

FIG. 8 is a diagram illustrating an IP header configuration in an IP packet transferred in the system of the present invention.

FIG. 9 is a diagram illustrating a configuration of a priority information field of an IP header in an IP packet transferred in the system of the present invention.

FIG. 10 is a diagram illustrating a configuration of priority information setting processing for a packet transferred in the system of the present invention.

FIG. 11 is a diagram illustrating a transfer network configuration of an IP packet transferred in the system of the present invention.

FIG. 12 is a diagram illustrating a processing example in a router based on the priority of an IP packet transferred in the system of the present invention.

FIG. 13 is a flowchart illustrating a packet generation process involving priority setting on the transmission side of an IP packet transferred in the system of the present invention.

FIG. 14 is a flowchart illustrating processing on the receiving side of an IP packet transferred in the system of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Video camera 12 Microphone 13 Display 14 Speaker 15 Mouse 16 Keyboard 101 MPEG processing PCI board 102 Ethernet card 103 Input / output interface 104 Host CPU 105 Hoist memory 106 PCI bus 201 MPEG video encoder 202 MPEG audio encoder 203 MPEG multiplexer 204 RTP packet generation means 205 UDP packet generating means 206 IP packet generating means 207 PCI interface 208 IP packet expanding means 209 UDP packet expanding means 210 RTP packet expanding means 211 MPEG demultiplexer 212 MPEG video decoder 213 MPEG audio decoder 701 RTP packet storage data identifying means 702 U P header information generating unit 703 UDP packetizer means

Claims (15)

[Claims] 1. A data transmitting apparatus, comprising: packet generating means for generating transfer data as a packet according to a communication protocol, wherein said packet generating means identifies importance of data stored in each packet, and A data transmission device having a configuration in which a destination port number as priority information according to identification importance is set in header information to execute a packet generation process. 2. The packet generation means sets the importance of the data, sets a high priority destination port number as high priority information with data including reference information from other data as high priority data, 2. The data transmitting apparatus according to claim 1, wherein the data transmitting apparatus has a configuration in which data not including reference information from data is set as low priority data and a low priority destination port number is set as low priority information. 3. The data stored in the packet generated by the packet generating means is MPEG data, and the data stored in each data packet includes an I picture, a P picture, and a B picture constituting the MPEG data. 2. The data transmitting apparatus according to claim 1, wherein a destination port number as priority information according to which of the pictures is included is set in the header information to execute a packet generation process. 4. The packet generation means according to claim 1, wherein the destination port number setting field in the UDP header conforming to a UDP (User Datagram Protocol) stores a different destination port number according to the importance of the data stored in each packet. 2. The data transmitting apparatus according to claim 1, wherein the data transmitting apparatus has a configuration for performing a UDP packet generation process by setting. 5. The packet generating means according to claim 1, wherein said packet generating means is a TCP (Transmission Control Protocol).
10. A TCP packet generation process, wherein a different destination port number is set in a destination port number setting field in a P header according to importance of data stored in each packet, and a TCP packet generation process is executed. 2. The data transmission device according to 1. 6. The destination port number as priority information set by the packet generation means is QoS (Quality of Service).
2. The data transmission apparatus according to claim 1, wherein the information is information associated with a service quality according to vice). 7. The destination port number as priority information set by the packet generating means is used as a selection criterion of either a guarantee type for bandwidth guaranteed data transfer or a best effort type for non-guaranteed data transfer. 2. The data transmitting apparatus according to claim 1, wherein the information is associated information. 8. A data transmission method, comprising a packet generation step of generating transfer data as a packet according to a communication protocol, wherein the packet generation step identifies the importance of data stored in each packet, and A data transmission method characterized by setting a destination port number as priority information according to identification importance in header information and executing a packet generation process. 9. In the packet generation step, a high priority destination port number as high priority information is set as data of high importance with data including reference information from other data as importance of the data. 9. The data transmission method according to claim 8, wherein low-priority destination port numbers are set as low-priority information for data that does not include reference information from the data. 10. The data stored in a packet generated in the packet generation step is MPEG data. The data generation in the packet generation step includes the steps of: I picture, P picture, B picture The data transmission method according to claim 8, wherein a destination port number as priority information according to which of the pictures is included is set in the header information, and the packet generation process is executed. 11. The method according to claim 1, wherein the packet generation step includes, in a destination port number setting field in a UDP (User Datagram Protocol) UDP header, a different destination port number according to the importance of data stored in each packet. 9. The data transmission method according to claim 8, wherein a UDP packet generation process is performed by setting. 12. The method according to claim 1, wherein the packet generation step includes a TCP (Transmission Control Protocol)
9. The TCP packet generation process according to claim 8, wherein a different destination port number is set in the destination port number setting field in the P header according to the importance of the data stored in each packet, and the TCP packet generation process is executed. Data transmission method. 13. The destination port number as priority information set in the packet generation step is QoS (Quo).
9. The data transmission method according to claim 8, wherein the information is information associated with a service quality according to the quality of service. 14. The destination port number as priority information set in the packet generation step is a selection criterion of either a guarantee type as bandwidth guaranteed data transfer or a best effort type as bandwidth non-guaranteed data transfer. The data transmission method according to claim 8, wherein the information is associated information. 15. A program storage medium for providing a computer program for causing a data transmission process to be executed on a computer system, wherein the computer program generates a transfer data as a packet according to a communication protocol. The packet generation step identifies the importance of data to be stored in each packet, sets a destination port number as priority information according to the identification importance in header information, and performs packet generation processing. A program storage medium, comprising a step of executing.