Method and device for selecting a transcoding method among a set of transcoding methods

• US 20040006644A1
• Filed: 03/14/2003
• Published: 01/08/2004
• Est. Priority Date: 03/14/2002
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Labelle, Lilian, Henocq, Xavier
• Granted Patent: US 7,453,937 B2
• Time in Patent Office: Days
• US Class Current: 709/246
• CPC Class Codes: H04N 19/147 according to rate distortion criteria rate-distortion as a criterion for motion estimation H04N19/567
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 21/234354 by altering signal-to-noise ratio parameters, e.g. requantization
• CPC Class Codes: H04N 21/234363 by altering the spatial resolution, e.g. for clients with a lower screen resolution
• CPC Class Codes: H04N 21/234381 by altering the temporal resolution, e.g. decreasing the frame rate by frame skipping
• 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 21/25808 Management of client data terminal profiles in network data switching protocols H04L67/303
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
• CPC Class Codes: H04N 21/6582 Data stored in the client, e.g. viewing habits, hardware capabilities, credit card number arrangements where receivers interact with the broadcast H04H20/38

Abstract

The invention relates to a method of selecting a method from a set of methods of transcoding digital multimedia data, said data being liable to be transferred between at least two communication apparatuses via a communication network, the method comprising the following steps:

for each transcoding method, obtaining a distortion value from a mathematical model for establishing the distortion taking into account said transcoding method, the distortion model being applied to information representing digital data, and,

selecting a transcoding method as a function of the different distortion values obtained for the set of transcoding methods.

Claims

1. A method for selecting a method from a set of methods of transcoding digital multimedia data, said data being liable to be transferred between at least two communication apparatuses via a communication network, said selection method comprising the following steps:

for each transcoding method, obtaining a distortion value from a mathematical model for establishing the distortion taking into account said transcoding method, the distortion model being applied to information representing digital data, and,

selecting a transcoding method as a function of the different distortion values obtained for the set of transcoding methods.

2. A selection method according to claim 1, wherein it comprises the following steps:

for each transcoding method, obtaining a rate value from a mathematical model for establishing the rate taking into account said transcoding method, the rate model being applied to information representing digital data, and,

selecting a transcoding method according to, on the one hand, the different rate values, and, on the other hand, the different distortion values obtained for the set of transcoding methods.

3. A selection method according to claim 1, wherein it comprises, prior to the obtaining step, a step of adapting the model to each transcoding method.

4. A selection method according to claim 1, wherein it comprises, prior to the obtaining step, a step of processing the digital data in a manner adapted to each transcoding method.

5. A selection method according to claim 4, wherein the adapted processing is applied to information representing digital data.

6. A selection method according to claim 1, wherein it comprises a step of testing the compatibility of each transcoding method with at least one constraint associated with at least one of the communication apparatus and/or with the network.

7. A selection method according to claim 6, wherein a constraint corresponds to the authorized rate over the communication network.

8. A selection method according to claim 6, wherein a constraint corresponds to one or more characteristics of one of the communication apparatuses which is intended to receive the digital data.

9. A selection method according to claim 1, wherein the distortion model establishes a relationship between the distortion and the energy of the signal represented by the digital data.

10. A selection method according to claim 9, wherein the distortion model has the following form:

11. A selection method according to claim 2, wherein the rate model establishes a relationship between the rate and the energy of the signal represented by the digital data.

12. A selection method according to claim 11, wherein the rate model has the following form:

13. A selection method according to claim 1, wherein the digital data are video data.

14. A selection method according to claim 13, wherein the set of transcoding methods comprises methods of reducing the spatial resolution and/or re-quantization methods and/or methods of reducing the frame rate.

30. Information storage means which can be read by a computer or a microprocessor containing code instructions of a computer program for executing the steps of the method of selecting a method from a set of methods of transcoding digital multimedia data according to claim 1.

31. Information storage means which is removable, partially or totally, which can be read by a computer or a microprocessor containing code instructions of a computer program for executing the steps of the method of selecting a method from a set of methods of transcoding digital multimedia data according to claim 1.

32. Computer program which can be loaded into a programmable apparatus, wherein it contains sequences of instructions or portions of software code for implementing the steps of the method of selecting a method from a set of methods of transcoding digital multimedia data according to claim 1, when this computer program is loaded and executed by the programmable apparatus.

15. A device for selecting a method from a set of methods of transcoding digital multimedia data, said data being liable to be transferred between at least two communication apparatuses via a communication network, the device comprising:

for each transcoding method, means for obtaining a distortion value from a mathematical model for establishing the distortion taking into account said transcoding method, the distortion model being applied to information representing digital data, and,

means for selecting a transcoding method according to the different distortion values obtained for the set of transcoding methods.

16. A device according to claim 15, wherein it comprises:

for each transcoding method, means for obtaining a rate value from a mathematical model for establishing the rate taking into account said transcoding method, the rate model being applied to information representing digital data, and,

means for selecting a transcoding method according to, on the one hand, the different rate values, and, on the other hand, the different distortion values obtained for the set of transcoding methods.

17. A device according to claim 15, wherein it comprises means for adapting the model to each transcoding method

18. A device according to claim 15, wherein it comprises means for processing the digital data in a manner adapted to each transcoding method.

19. A device according to claim 18, wherein the adapted processing is applied to information representing digital data.

20. A device according to claim 15, wherein it comprises means of testing the compatibility of each transcoding method with at least one constraint associated with at least one of said apparatuses and/or with the network.

21. A device according to claim 20, wherein a constraint corresponds to the authorized rate over the communication network.

22. A device according to claim 20, wherein a constraint corresponds to one or more characteristics of one of the communication apparatuses which is intended to receive the digital data.

23. A device according to claim 15, wherein the distortion model establishes a relationship between the distortion and the energy of the signal represented by the digital data.

24. A device according to claim 23, wherein the distortion model has the following form:

25. A device according to claim 16, wherein the rate model establishes a relationship between the rate and the energy of the signal represented by the digital data.

26. A device according to claim 25, wherein the rate model has the following form:

27. A device according to claim 15, wherein the digital data are video data.

28. A device according to claim 27, wherein the set of transcoding methods comprises methods of reducing the spatial resolution and/or re-quantization methods and/or methods of reducing the frame rate.

29. A communication apparatus, wherein it comprises a device for selecting a method from a set of methods of transcoding digital multimedia data according to claim 15.