System and process for adaptive and progressive scrambling of video streams

• US 20050185821A1
• Filed: 03/28/2005
• Published: 08/25/2005
• Est. Priority Date: 10/03/2002
• Status: Active Grant

• Current Assignee: Nagra France SAS (Kudelski SA)
• Original Assignee: Medialive (Kudelski SA)
• Inventors: Sarda, Pierre, LeComte, Daniel, Parayre-Mitzova, Daniela, Georges, Sebastien
• Granted Patent: US 7,613,298 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: H04N 19/142 Detection of scene cut or scene change
• CPC Class Codes: H04N 19/157 Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/88 involving rearrangement of data among different coding units, e.g. shuffling, interleaving, scrambling or permutation of pixel data or permutation of transform coefficient data among different blocks
• CPC Class Codes: H04N 21/234327 by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/23476 by partially encrypting, e.g. encrypting the ending portion of a movie
• 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 21/44055 by partially decrypting, e.g. decrypting a video stream that has been partially encrypted
• CPC Class Codes: H04N 21/631 Multimode Transmission, e.g. transmitting basic layers and enhancement layers of the content over different transmission paths or transmitting with different error corrections, different keys or with different transmission protocols
• CPC Class Codes: H04N 21/835 Generation of protective data, e.g. certificates protecting software against unauthorised usage in a vending or licensing environment G06F21/10
• CPC Class Codes: H04N 7/162 Authorising the user terminal, e.g. by paying; Registering the use of a subscription channel, e.g. billing
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

A process for distributing digital video sequences in accordance with a nominal stream format including a succession of frames, each frame including at least one digital block regrouping a plurality of coefficients corresponding to simple, digitally coded visual elements, including: a step of modifying at least one block of the stream, wherein the modification step acts in an adaptive manner on the original stream as a function of at least a part of characteristics representative of structure, contents and parameters of an original video stream, of a profile of an addressee, and of external events, and the modification step includes replacing a part of the coefficients to produce a modified main video stream in nominal format and complimentary modification information that allows reconstruction of the original stream by a decoder of addressed equipment, and wherein the scope of modifications is variable and determined by the representative characteristics, and the modified main video stream and the complementary information are transmitted by separate paths.

Claims

1. A process for distributing digital video sequences in accordance with a nominal stream format comprising a succession of frames, each frame comprising at least one digital block regrouping a plurality of coefficients corresponding to simple, digitally coded visual elements, comprising:

a step of modifying at least one block of the stream, wherein the modification step acts in an adaptive manner on the original stream as a function of at least a part of characteristics representative of structure, contents and parameters of an original video stream, of a profile of an addressee, and of external events, and the modification step comprises replacing a part of the coefficients to produce a modified main video stream in nominal format and complimentary modification information that allows reconstruction of the original stream by a decoder of addressed equipment, and wherein the scope of modifications is variable and determined by the representative characteristics, and the modified main video stream and the complementary information are transmitted by separate paths.

2. The process according to claim 1, wherein the complementary modification information comprises at least one digital routine suitable for carrying out a function.

3. The process according to claim 1, wherein the complementary modification information is subdivided into at least two subparts.

4. The process according to claim 3, wherein subparts of the complementary modification information can be distributed by different media.

5. The process according to claim 3, wherein subparts of the complementary modification information can be distributed by the same media.

6. The process according to claim 1, wherein the complementary information is transmitted on a physical vector.

7. The process according to claim 1, wherein the complementary information is transmitted online.

8. The process according to claim 1, wherein the digital images in the video sequences use technologies based on wavelets.

9. The process according to claim 1, wherein the video streams are organized in frames comprising blocks corresponding to at least one plane I, one plane P corresponding to differences from an image P, at least one other image I or P that can contain at least one plane B corresponding to differences between two P images or S planes corresponding to a static image.

10. The process according to claim 9, wherein the images I, P, B and S are modified in a differentiated manner as a function of their type, namely, I, P, B or S.

11. The process according to claim 9, wherein the images I, P, B and S are modified in a differentiated manner as a function of the characteristics of the video stream in terms of the structure of the GOP groups of images and proportions between quantities of I, P, B S images present in the video streams, which latter are characterized by a constant or variable number of planes per second.

12. The process according to claim 9, wherein images I, P and B are modified in a differentiated manner as a function of a constant or variable number of planes (frames) per second for the streams characterized by time-dependent scalability.

13. The process according to claim 9, wherein images I, P, B and S are modified in a differentiated manner as a function of characteristics of scenes contained in the stream in terms of fixed, static or dynamic planes and/or of the visual forms contained.

14. The process according to claim 9, wherein images I, P, B and S are modified in a differentiated manner as a function of their granular scalability.

15. The process according to claim 9, wherein images I, P, B and S are modified in a differentiated manner as a function of characteristics of the streams in terms of size of its planes (in number of pixels), whether it is constant or variable for the streams characterized by spatial scalability.

16. The process according to claim 9, wherein images I, P, B and S are modified in a differentiated manner as a function of characteristics of the streams in terms of throughput in bits per second of the video stream.

17. The process according to claim 9, wherein I, P, B and S are modified in a differentiated manner as a function of characteristics of the video streams in terms of composition in objects, profiles and levels.

18. The process according to claim 9, wherein images I, P, B and S are modified in a progressive manner increasing a degradation effect until complete scrambling of the video stream.

19. The process according to claim 9, wherein images I, P, B and S are modified by random generation of scrambling parameters and configurations.

20. The process according to claim 1, further comprising a preceding analog/digital conversion step in a structured format applied to an analog video signal.

21. The process according to claim 1, wherein the video stream reconstituted from the modified main stream and from the complementary information is strictly identical to the original stream.

22. A system for distributing video sequences comprising a video server with means for broadcasting a modified stream in conformity with the process of claim 1, a plurality of pieces of equipment provided with a scrambling circuit, wherein the server further comprises means for recording a digital profile of each addressee and means for control command of modification means as a function of input variables corresponding to at least a part of the characteristics representative of the structure, the contents and the parameters of the original video stream, of the profile of the addressee and of external events.