JP2009118193A - Image distribution system and image distribution method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a real-time distribution of moving images, and to decrease a deterioration of an image quality. <P>SOLUTION: In a system or method of dividing moving image data into packets and transmitting each packet through a plurality of lines, an image dividing portion 11 adjusts a division size (data amount) of a packet according to a bandwidth of each line to be distributed to each line. A line monitoring portion 19 monitors whether or not a deficit ratio of a received packet per line has become equal to or more than a fixed value, and when it has become equal to or more than the fixed value, the image dividing portion separates the line and distributes the moving images by using the remaining normal lines. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image distribution system and method for dividing moving image data captured on an image distribution apparatus side into packets and distributing each packet to a reception side through a plurality of network lines.

  In this type of image distribution system, as shown in FIG. 2, for example, a video (video) image terminal (encoder) 1 converts an image captured by a camera into MPEG format data by an encoder, and an image distribution apparatus 2 The image distribution apparatus 2 distributes the MPEG data to each personal computer 3 and the personal computer 3 individually reproduces and displays the data. At this time, the MPEG data is divided into packets and transferred, but is connected to each personal computer through one line.

In such an image distribution system, there are cases where image data cannot be received in real time when the receiving side has low processing capability or when the line has a narrow bandwidth. As a countermeasure, image data is divided into a plurality of packets and transmitted / received, and can be reconstructed by managing the continuity of packets on the receiving side. Furthermore, the image is divided into tiles on a two-dimensional plane, these are compressed, multicast transmitted over a plurality of lines, and decompressed (decoded) on the receiving side to reconstruct the image (for example, see Patent Document 1). .
JP 2002-320226 A

  In the method of Patent Document 1, when the amount of data that can be transferred by one line is small, such as a line having a low transmission band (32 kbps) such as a cellular phone, multicast transmission using a plurality of lines is performed and images are received on the receiving side. Rebuild.

  In this distribution method, when a reception failure occurs in a part of the receiving side device, the transmission of the packet is stopped for a predetermined time, and then the transmission speed of the packet is decreased by the predetermined time. For this reason, when the packet transmission is stopped, it becomes the same as the packet discard, and the real-time property is impaired.

  Further, in the period in which the packet transmission speed is reduced, the image quality is deteriorated in the same manner as when data is thinned out when the bandwidth is narrow.

  An object of the present invention is to provide an image distribution system and an image distribution method that improve the real-time property of moving image distribution and reduce deterioration in image quality.

  In order to solve the above-described problem, the present invention divides moving image data into packets, and in a system or method for transmitting each packet through a plurality of lines, the packet division size (data amount) is set according to the bandwidth of each line. In addition, by monitoring the packet loss rate of each line, when a certain line becomes abnormal, a moving image is distributed through the remaining normal lines, and the following system and method are characterized.

(1) Image distribution in which image data from an image terminal is converted into MPEG data, divided into packets, transmitted to a receiving side through a plurality of lines, and the receiving side reconstructs an image from packets received through each line. A system,
An image dividing means for adjusting the packet division size (data amount) according to the bandwidth of each line and distributing the packet to each line is provided.

(2) Provided with line monitoring means for monitoring whether or not the loss rate of received packets for each line has exceeded a certain level,
The image dividing means includes means for disconnecting the corresponding line and distributing the moving image using the remaining normal lines when the packet loss rate exceeds a certain level.

(3) Image distribution in which image data from an image terminal is converted into MPEG data, divided into packets, transmitted to the receiving side through a plurality of lines, and the receiving side reconstructs an image from packets received through each line. A method,
An image dividing procedure for adjusting the packet division size (data amount) according to the bandwidth of each line and distributing the packet to each line is provided.

(4) It has a line monitoring procedure for monitoring whether or not the loss rate of received packets for each line has exceeded a certain level,
The image segmentation procedure includes a procedure of disconnecting the corresponding line and distributing a moving image using the remaining normal lines when the packet loss rate becomes a certain level or more.

  As described above, according to the present invention, in a system or method for transmitting each packet through a plurality of lines, the packet division size (data amount) is adjusted and distributed according to the band of each line, so the bands are different. Image transmission using a line can improve the real-time performance and reduce image quality degradation.

  In addition, the degree of freedom in selecting the line to be used can be increased.

  Further, by monitoring the packet loss rate of each line, if a certain line becomes abnormal, a moving image can be distributed through the remaining normal lines.

  FIG. 1 is a configuration diagram of an image distribution system showing an embodiment of the present invention. In this system, basically, image data is divided on the image distribution apparatus side, and the image data is transmitted to a personal computer as a receiving apparatus using a plurality of lines simultaneously. On the personal computer side, data sent through a plurality of lines is assembled into one continuous motion data and a moving image is reproduced.

  The image dividing unit 11 divides one piece of image data of a moving image taken by the image terminal 1 into packets according to the bandwidth of the line. This division is performed according to the bandwidth data stored in the bandwidth management table 12 of the line. That is, the packet size (data amount) is increased if the bandwidth of the line is wide, and the packet size is decreased if the bandwidth is narrow.

  A sequence number and a line number are added to each packet divided by the image dividing unit 11 and passed to the image distributing unit 13. The image distribution unit 13 transmits the packet passed from the image division unit 11 from each line.

  The receiving unit 14 on the personal computer side registers the sequence number of the received packet received through each line in the sequence number management table 15 and sequentially stores / updates the image data (packet) in the image reconstruction buffer 16 for a plurality of packets. .

  The image construction unit 17 scans the sequence number management table 15 at a constant period (t1), and if a completed image (image data with no missing sequence number) is received, the image construction unit 17 reconstructs the image data. The image is transferred to the reproduction unit 18 and reproduced. Further, the image construction unit 17 discards the image data being constructed when the image is not reconstructed within a predetermined time and the image sent later is reconstructed.

  Note that the image construction unit 17 determines that all of the image data having the packet remains when the image data sent later is completed, or even after a predetermined time (t2) has elapsed since the reception of the first packet of the image data. Discard items that are not aligned.

  The line monitoring unit 19 on the image delivery apparatus side periodically inquires about the number of packets received by the receiving unit 14, compares the number of transmitted packets and the number of received packets for each line, and the ratio of packet loss is n% or more. The monitoring result is written in the bandwidth management table 12. When dividing the packet, the image dividing unit 11 disconnects the line with a high packet loss rate, divides the packet into the remaining normal lines, and transmits the image data.

  According to the image distribution system configuration and the distribution method described above, a plurality of lines are used simultaneously, the packet division size (data amount) is adjusted according to the band of the line, and transmission is performed for each line. With this distribution technique, high-quality image transmission can be performed by distribution using lines with different bands, and the degree of freedom of selection of lines to be used can be increased.

  For example, different types of lines such as mobile phones, PHSs, and disaster prevention radios can be used in combination as lines for dividing and transmitting packets. Moreover, even in the event of a disaster (when it is difficult to make a mobile phone or the like), even if the quality drops (becomes a flip video), it is possible to send a video.

  Further, by monitoring the presence / absence of abnormality in each line from the packet loss rate of each line, even if a certain line becomes abnormal, a moving image can be transmitted through the remaining normal lines. By disconnecting from this line management, the real-time property is ensured and the deterioration of the image quality is reduced as compared with the conventional countermeasures for stopping the packet transmission for a predetermined time and for reducing the packet transmission speed thereafter.

  In the embodiment, the mechanism between the image distribution apparatus and the personal computer (image display client) is shown, but the present invention can also be applied to moving image transfer between the image terminal 1 and the image distribution apparatus. In this case, packet transmission is performed in the reverse direction in the order of image distribution device → image terminal, personal computer → image distribution device.

The block diagram of the image delivery system which shows embodiment of this invention. An example of an image distribution system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Image division part 12 Band management table 13 Packet transmission part 14 Packet reception part 15 Sequence number management table 16 Image reconstruction buffer 17 Image construction part 18 Image reproduction part 19 Line monitoring part

Claims (4)

This is an image distribution system that converts image data from an image terminal into MPEG data, divides it into packets, transmits the packets to a receiving side through a plurality of lines, and the receiving side reconstructs an image from packets received through each line. And
An image distribution system comprising image dividing means for adjusting a packet division size (data amount) according to a bandwidth of each line and distributing the packet to each line. Line monitoring means for monitoring whether or not the loss rate of received packets for each line has exceeded a certain level,
2. The image dividing means according to claim 1, further comprising means for disconnecting the corresponding line and distributing a moving image using the remaining normal lines when the packet loss rate exceeds a certain level. Image distribution system. This is an image distribution method in which image data from an image terminal is converted into MPEG data, divided into packets and transmitted to a receiving side through a plurality of lines, and the receiving side reconstructs an image from packets received through each line. And
An image distribution method comprising an image division procedure for adjusting a packet division size (data amount) according to a bandwidth of each line and distributing the packet to each line. A line monitoring procedure for monitoring whether or not the loss rate of received packets for each line has exceeded a certain level,
4. The image according to claim 3, wherein the image segmentation procedure includes a procedure of disconnecting the corresponding line and distributing a moving image using the remaining normal lines when the packet loss rate becomes a certain level or more. Delivery method.

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