WO2010136616A1

WO2010136616A1 - Dual transmission method for multimedia contents

Info

Publication number: WO2010136616A1
Application number: PCT/ES2010/000203
Authority: WO
Inventors: Jesús MARTÍNEZ BARBERO; Eugenio SANTOS MENÉNDEZ
Original assignee: Universidad Politécnica de Madrid
Priority date: 2009-05-26
Filing date: 2010-05-07
Publication date: 2010-12-02
Also published as: ES2326514A1; ES2326514B2

Abstract

Dual transmission method for multimedia contents applied to a system with at least one transmitter node and one receiver node, which method comprises at least the following stages: (a) a first stage of dividing the file into two depending on the transmission window and the establishment of a cost threshold; (b) a second stage of transmitting the two files on independent paths with the possibility of varying the quality threshold depending on the results obtained during transmission; (c) a third stage of combining the two files in a single file in the receiver centre.

Description

METHOD OF DUAL TRANSMISSION OF MULTIMEDIA CONTENTS

Field of the invention

The present invention falls within the digital communications for the transmission and / or diffusion of multimedia content, as well as in the control and recovery in case of errors.

Background of the invention

At present, multimedia companies have been introducing traditionally office automation technologies in the production and distribution of their products, and every day a greater variety of types of transmission is used for their contents. From the traditional offer of radio links, fibers or connections by analog satellites, these same physical means have been transferred to digital, and at the same time a great variety of different types of technologies for the transmission of the signal are being joined. The generated contents are sent through two clearly differentiated types of transmission:

Shipping in real time. The generated video material is reproduced in baseband for coding in a compression format resistant to errors or loss of data in the transmission for transmission to the destination through a data link. On the other side of the link a decoder is connected to return the data stream in baseband. Once in the baseband, it is encoded to the production format of the chain. It can be defined as an unsecured transfer, where the final content may not be identical to the original.

File submission. Through this way of sending, the transfer to baseband, the encoding to another format, the decoding to the baseband and the coding to the production format of the chain is saved. The edited file is sent through a data link to the destination, where it is transcoded in case it has a different format than the production of the chain. It can be defined as a secure transfer, where the target file is identical to the original.

The real-time sending has a series of disadvantages: greater number of processes involved in the coding, as well as lowering quality due to the loss of information in the link and the transcoding of the image.

But depending on the type of transmission line, the second option has a clear disadvantage: the copy of the file requires block retransmissions until the file is identical; This fact implies that it is not possible to predict the time it takes for a transfer. All equipment with error control protocols are designed so that the information is transferred without any error. For most applications, it is essential that the information is not degraded, but in the case of multimedia content this is not absolutely necessary in all cases: a slight variation of tone in a pixel does not imply a great failure and it is possible to reconstruct the Lost information.

When data packets are sent and there is some content error, the packet is destroyed, invalidating all the data contained within it, discarding the entire packet and requesting a retransmission of it, so that such information is retransmitted within the network as many times as there have been mistakes. Not only in the plot of the transmission can there be errors, since the recording / reproduction of the information is subject to possible errors so that the files presumably correct, at the time of reproduction, have errors and cannot be opened by the applications , so that its content ready to be broadcast, cannot "go into" broadcast. To mitigate this effect, manufacturers produce increasingly expensive equipment, with greater redundancy, greater process capacity and systems that routinely perform controls on image files. In the transmission-reproduction of the audiovisual material, the basic idea is that there are always images on the screen, with the highest possible quality. With the links and analogue diffusion, this was achieved by appearing on the screen the errors of said type of transmission. With digital technology, the correction of errors is prioritized and great efforts are made to maintain immediacy and orderly reception of packages.

At present there are different systems to "accelerate" the sending of multimedia content on files, such as the caching of content on servers distributed in nodal centers, the extension of the sending window or ignoring errors both in reception and in the different nodes, as reflected in the invention patent application P200802356, currently in the process of being granted.

Description of the invention To alleviate the problems set forth above, the method of dual transmission of multimedia content is presented, object of the present invention patent application, where the basic idea is to divide the file into two parts for transmission; One part is transmitted in safe mode and the other part in unsecured mode. The multimedia file data must be cataloged depending on its influence on the quality of the image to be transmitted and the size of said data. This relationship can be referred to as the transmission cost and would be the ratio between the size and the average quality that ensures said data.

Depending on the time window available for the transfer of the original file, it will be divided depending on the cost of the transmission. For each type of file there will be a scale of quality values giving priority to some data over others. The concept of quality value scale is defined as scaling of the different types of data depending on the influence they have on the quality of the image in case of loss of said data. If the transmission window is minimal, only the vital data of the file for reproduction will be included in the secure delivery; If the time window is infinite, the complete file will be sent in safe mode.

Depending on the size of the window, a cut quality or quality threshold can be defined, considered as the average quality ensured by the data that is sent securely or, which is the same, the minimum quality of an image if it loses the Information sent as unsecured. The sending node divides the content in two depending on the nature of the data, depending on the cost of the shipment (size) and the effect produced by its loss. One of the parts will be sent safely, while another part will be sent by an unsecured method, allowing the possibility of errors in the transmission.

Thus, the method object of the invention consists in dividing the file to be sent in two files that are sent differently, according to its scale of quality values. There will be a first stage of division of content depending on the nature of the data, depending on the cost of shipping (size) and the effect produced by its loss. One of the parts will be sent safely, while another part will be sent by an unsecured method, allowing the possibility of errors in the transmission.

The use of the unique file identifier is a great help so that the information can be processed and reconstructed after the use of the file for archiving purposes.

The data that imposes the assured quality or quality of cut is the window of time available for the transmission, and depending on the result that is obtained in the same, the quality margin of the transmission may be varied, or depending on the needs of transmission, the material considered as vital or insurance can be sent beforehand so you can have a time frame for forwarding in case of errors.

The way in which the multimedia file is recovered from the two segregated files will depend on the file format to be sent, and the generation and sending of marks and sizes in the secure transfer file may be necessary so that unification is possible.

In the case of errors in the unsecured transmission, the receiving node will mark the data sequence as an invalid sequence with a reconstructed mark, so that its reliable reconstruction is possible when the time window is considered infinite.

For use in recording / playback, the file considered as safe may be stored on servers or discs with greater redundancy than that considered as unsafe.

The main advantages and applications of the method proposed in the present invention are listed below:

(a) Sending files through Mobile Units. At present, the edited image is sent to the satellite through a real-time encoder, and at the destination station Ia receives it with a decoder. The type of transmission is unidirectional. If it is necessary to send a file of the edited news, it is necessary to reproduce the video in real time, encode it, decode it and record it again at the destination station. Through this system, the unsecured file would be sent over the classic unidirectional link and the sending of the secure file over an added bidirectional link of smaller capacity than the unidirectional.

(b) Sending files through broadcast signals. Through this system it would be feasible to send files of audiovisual material through broadcast networks, such as the DTT broadcast network. Services of "loading audiovisual material" could be performed on remote servers for later reproduction; East material can be movies for movies, music for music services, ads for remote service stations, etc. The sending of the secure part can be done through other means, such as the Internet.

(c) Transmission "without cuts" through the network to computers. At present, if there are errors of transmission or loss of packets in vital parts of the image, it can be noticed that the player "stops" when the image is playing. To avoid this effect, networks that contain multimedia content are often oversized to avoid errors in the transmission. Through this system, it will be possible to ensure the shipment of the vital material and it will not be necessary to perform said oversizing.

(d) Broadcast video over the Internet. Similar to the previous point, you will have a better response with less bandwidth, being able to put higher quality content in the bandwidth currently used.

(e) Sending videos through the network. The file transmission speed will be greatly improved.

(f) Use of two types of storage for the archive, so that there is a file considered as "expensive" for the parts that need a safe treatment and another "cheap" for the unsafe ones.

(g) Distribution of movies to cinemas, so that the unsecured file can be sent by some type of multicast network and secure through bidirectional protocols.

Preferred embodiment of the invention

In a preferred embodiment of the present invention, the method of transmission of multimedia content is applied on a system with at least one sending center and one receiving center, comprising at least the following steps: (a) a first stage of dividing the file into two depending on the transmission window and the establishment of a cost threshold;

(b) a second stage of transmission of the two files by independent paths with the possibility of varying the quality or size threshold of each of the parts depending on the results that are obtained in the transmission;

(c) a third stage of unification of the two files into one at the receiving center.

The sending node is configured to qualify the quality threshold according to the transmission window and to add labels for its correct grouping at the destination.

Claims

1. - Method of dual transmission of multimedia content applied on a system with at least one sending node and one receiving node characterized in that it comprises at least the following stages: (a) a first stage of content division depending on the nature of the data, depending on the cost of the shipment (size) and the effect produced by its loss. One of the parts will be sent safely, while another part will be sent by an unsecured method, allowing the possibility of errors in the transmission; (b) a second stage of transmission of the two files by independent paths with the possibility of varying the quality or size threshold of each of the parts depending on the results that are obtained in the transmission;

2- Method according to claim 1, characterized in that both the sending and the receiving node are enabled in the handling of two types of transfer, the size of the data that goes securely or unsafe dynamically can vary depending on the status of the transmission , of the time window available and the desired quality threshold.

3- Method according to claims 1 and 2 characterized in that the sending node is configured to define a cut quality or quality threshold considered as the average quality ensured by the data sent securely.

4- Method according to claims 1 to 3, characterized in that in the case of image regeneration the invalid sequence will be marked with a reconstructed mark, so that if the same package is received again with a valid mark, it will replace the previous one.