METHOD AND DEVICE FOR TRANSMITING DATA

• US 20090319682A1
• Filed: 06/18/2009
• Published: 12/24/2009
• Est. Priority Date: 06/19/2008
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Nassor, Eric, Maze, Frederic
• Granted Patent: US 8,812,724 B2
• Time in Patent Office: Days
• US Class Current: 709/235
• CPC Class Codes: H04L 65/65 Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04N 19/105 Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/142 Detection of scene cut or scene change
• CPC Class Codes: H04N 19/149 by estimating the code amount by means of a model, e.g. mathematical model or statistical model
• CPC Class Codes: H04N 19/164 Feedback from the receiver or from the transmission channel
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/573 Motion compensation with multiple frame prediction using two or more reference frames in a given prediction direction
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/23412 for generating or manipulating the scene composition of objects, e.g. MPEG-4 objects
• CPC Class Codes: H04N 21/23418 involving operations for analysing video streams, e.g. detecting features or characteristics television picture signal circuitry for scene change detection H04N5/147; filtering for image enhancement G06T5/00; methods or arrangements for recognising scenes G06V20/00; arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 21/23424 involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement
• CPC Class Codes: H04N 21/2343 involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements video transcoding H04N19/40; media packet handling at the source H04L65/762
• CPC Class Codes: H04N 21/234309 by transcoding between formats or standards, e.g. from MPEG-2 to MPEG-4 or from Quicktime to Realvideo conversion of standards in analog television systems H04N7/01
• CPC Class Codes: H04N 21/234318 by decomposing into objects, e.g. MPEG-4 objects
• CPC Class Codes: H04N 21/234345 the reformatting operation being performed only on part of the stream, e.g. a region of the image or a time segment
• CPC Class Codes: H04N 21/23439 for generating different versions
• CPC Class Codes: H04N 21/238 : Interfacing the downstream path of the transmission network, e.g. adapting the transmission rate of a video stream to network bandwidth; Processing of multiplex streams hybrid fiber coaxial [HFC] networks for downstream channel allocation for video distribution H04L12/2801; flow control in packet networks H04L47/10; real-time communication protocols in data switching networks H04L65/00; scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04N 21/2402 : Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• CPC Class Codes: H04N 21/6377 : directed to server one-way streaming services wherein the source is controlled by the destination H04L65/613
• CPC Class Codes: H04N 21/6437 : Real-time Transport Protocol [RTP]
• CPC Class Codes: H04N 21/658 : Transmission by the client directed to the server
• CPC Class Codes: H04N 21/6583 : Acknowledgement

Abstract

A video consisting of data organized in the form of a plurality of images is transmitted in a communication network. The method comprises a step of coding images with motion compensation, which consists in compressing the images of the video and in creating dependencies between compressed images, a step of scheduling the transmission of packets representing the compressed images, which consists in sending the compressed images over the network in a selected order, and a step of controlling the rate of the video. At least one of reconsidering the selected order of sending already compressed but not yet transmitted images and deleting at least one compressed image is performed at the time of coding a new image. Furthermore, the dependencies between the new image to be compressed and the compressed images are selected by taking into account the reconsidered sending order at the time of coding the new image.

Claims

1. A method for transmitting a video consisting of a plurality of images in a communication network, said method comprising:

a step of coding images with motion compensation, which consists in compressing the images of the video and in creating dependencies between compressed images,

a step of scheduling the transmission of packets representing the compressed images, which consists in sending the compressed images over the network in a selected order, and

a step of controlling the rate of the video,

wherein at least one of reconsidering the selected order of sending already compressed but not yet transmitted images and deleting at least one compressed image is performed at the time of coding a new image.

2. A method according to claim 1, wherein the dependencies between the new image to be compressed and the compressed images are selected by taking into account the reconsidered sending order at the time of coding the new image.

3. A method according to claim 2, wherein the dependencies between images and the sending order of the compressed images are selected as a function of the available bandwidth of the network, and/or the number of packets waiting to be sent and the content of the video.

4. A method according to claim 3, wherein it furthermore comprises a step which consists in evaluating said available bandwidth by means of a mechanism for controlling the congestion on the network.

5. A method according to claim 4, wherein the congestion control mechanism is of the TFRC (“

TCP Friendly Rate Control”

) or AIMD (“

Additive Increase/Multiple Decrease”

) type.

6. A method according to claim 2, wherein the selection of the dependencies between the new image and the compressed images consists in defining a coding mode for the new image with or without dependency.

7. A method according to claim 6, wherein, when a coding mode with dependency is defined, said selection of the dependencies between images furthermore consists in defining at least one possible reference image.

8. A method according to any one of the preceding claims, wherein the deleting of at least one compressed image that have not been transmitted is performed after a reordering of the compressed images.

9. A method according to claim 1, wherein the selection of the order of sending of the packets consists in deciding to delay or bring forward the sending of at least one compressed image.

10. A method according to claim 1, wherein the packets representing each compressed image are assigned a certain priority and a certain expiry time, after which the sending of the packets becomes useless, and in that the packets are sent in a decreasing priority order and in an increasing expiry time order.

11. A method according to claim 1, wherein the video is coded in the H.264 format.

24. Means for storing information that can be read by a computer or a microprocessor holding instructions for a computer program, characterized in that it makes it possible to carry out a transmission method according to any one of claims 1 to 7.

25. A computer program product which can be loaded onto a programmable apparatus, comprising sequences of instructions for carrying out a transmission method according to any one of claims 1 to 7, when this program is loaded and executed by the programmable apparatus.

12. A server for transmitting a video consisting of a plurality of images in a communication network, said server comprising:

means for coding images with motion compensation, compressing the images of the video and creating dependencies between compressed images,

means for scheduling the transmission of packets representing the compressed images, adapted to send the compressed images over the network in a selected order, and

means for controlling the rate of the video,

wherein at least one of reconsidering the selected order of sending already compressed but not yet transmitted images and deleting at least one compressed image is performed at the time of coding a new image.

13. A server according to claim 12, wherein the dependencies between the new image to be compressed and the compressed images are selected by taking into account the reconsidered sending order at the time of coding the new image.

14. A server according to claim 13, wherein it is adapted to select the dependencies between images and the order of sending of the compressed images as a function of the available bandwidth of the network, and/or the number of packets waiting to be sent and the content of the video.

15. A server according to claim 14, wherein it furthermore comprises means adapted to evaluate said available bandwidth by means of a mechanism for controlling the congestion on the network.

16. A server according to claim 15, characterized in that the congestion control mechanism is of the TFRC (“

TCP Friendly Rate Control”

) or AIMD (“

Additive Increase/Multiple Decrease”

) type.

17. A server according to claim 13, wherein it furthermore comprises means adapted to define a coding mode for the new image with or without dependency.

18. A server according to claim 17, wherein said means adapted to define a coding mode with dependency is adapted to define at least one possible reference image.

19. A server according to any one of claims 12 to 18, wherein it comprises means adapted to decide to delete at least one compressed image that have not been transmitted after a reordering of the compressed images.

20. A server according to claim 12, wherein it furthermore comprises means adapted to decide to delay or bring forward the sending of at least one compressed image.

21. A server according to 12, wherein it furthermore comprises means adapted to assign to packets representing each compressed image a certain priority and a certain expiry time, after which the sending of the packets becomes useless, and wherein it is adapted to send the packets in a decreasing priority order and in an increasing expiry time order.

22. A server according to claim 12, wherein the video is coded in the H.264 format.

23. A telecommunications system comprising a plurality of terminal devices connected via a telecommunications network, wherein it comprises at least one terminal device equipped with a server according to any one of claims 12 to 18.