EMBEDDING INTERACTIVE DATA INTO AN AUDIOVISUAL CONTENT BY WATERMARKING

• US 20110019870A1
• Filed: 12/17/2008
• Published: 01/27/2011
• Est. Priority Date: 12/17/2007
• Status: Active Grant

• Current Assignee: S.I.Sv.El. Societa' Italiana Per Lo Sviluppo Dell'Elettronica S.P.A. (Fineur International S.A.), Universita' Degli Studi Di Firenze (Repubblica Italiana)
• Original Assignee: CSP - Innovazione nelle ICT SCaRL, Sisvel S.p.A. (Fineur International S.A.), Universita' Degli Studi Di Firenze (Repubblica Italiana)
• Inventors: Filippini, Francesco, Caldelli, Roberto, Borri, Roberto, Becarelli, Rudy, Ballocca, Giovanni
• Granted Patent: US 8,542,868 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/18 the unit being a set of transform coefficients
• CPC Class Codes: H04N 19/467 characterised by the embedded information being invisible, e.g. watermarking
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• 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 21/23892 involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/44008 involving operations for analysing video streams, e.g. detecting features or characteristics in the video stream arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 21/6332 directed to client
• CPC Class Codes: H04N 21/654 Transmission by server directed to the client
• CPC Class Codes: H04N 21/858 Linking data to content, e.g. by linking an URL to a video object, by creating a hotspot
• CPC Class Codes: H04N 7/162 Authorising the user terminal, e.g. by paying; Registering the use of a subscription channel, e.g. billing

Abstract

A method for referencing and interconnecting contents, applications and metadata to an audiovisual content is described, especially for iTV of for distribution on DVD, which comprises the step of inserting a digital watermark into the audiovisual content during an audiovisual content encoding step, the digital watermark being possibly used for allowing a user to reproduce or exploit additional contents supplementing those provided by the audiovisual content, wherein the digital watermark is inserted into the audiovisual content as data frame with header and body by subdividing it into a plurality of consecutive ‘I’ frames and forcing the parity of LSBs of mid-frequency providing an auxiliary watermark channel, e.g. in an MPEG2 transport stream.

Claims

1. Method for referencing and interconnecting contents, applications and metadata to an audiovisual content, comprising the step of inserting a digital watermark (5) into said audiovisual content during an audiovisual content encoding step, said digital watermark being possibly used for allowing a user to reproduce or exploit additional contents supplementing those provided by said audiovisual content, characterized in that said digital watermark (5) is inserted into said audiovisual content by subdividing it into a plurality of consecutive “

I”

frames (11a,11b,11c) of said audiovisual content.

2. Method according to claim 1, wherein said plurality of consecutive “

I”

frames (11a,11b,11c) of said audiovisual content consists of three consecutive frames.

3. Method according to claim 1, wherein said digital watermark (5) comprises a plurality of information bits and is inserted into coefficients (21,23) of the Discrete Cosine Transform of said consecutive frames (11a,11b,11c).

4. Method according to claim 3, wherein said coefficients (21,23) correspond to spatial frequencies to which the human eye is least sensitive, in particular the medium frequencies.

5. Method according to claim 3, wherein said coefficients (21,23) of the Discrete Cosine Transform of said consecutive frames (11a,11b,11c) comprise the spatial frequencies of the Discrete Cosine Transform which are located in the positions 2,2 and/or 3,3 of an 8×

8-pixel block into which each of said consecutive “

I”

frames 11a,11b,11c) can be subdivided.

6. Method according to claim 4, wherein said coefficients (21,23) remain unchanged if the value of the last bit thereof corresponds to an information bit of the digital watermark (5) to be inserted, whereas they are modified if the value of the last bit thereof does not correspond to an information bit of the digital watermark (5) to be inserted.

7. Method according to claim 6, wherein said modification of said coefficients (21,23) of the Discrete Cosine Transform of said consecutive frames (11a,11b,11c) consists in forcing the parity/non-parity of said coefficients (21,23).

8. Method according to claim 7, wherein the value of said coefficients (21,23) of the Discrete Cosine Transform of said consecutive frames (11a,11b,11c) is either increased or decreased by one unit in order to force said parity/non-parity of said coefficients (21,23).

9. Method according to claim 6, wherein said modification is carried out only if said coefficients (21,23) have a value other than zero.

10. Method according to claim 1, wherein said digital watermark (5) comprises a first portion (5a) including a header and a second portion (5b) including an information content.

11. Method according to claim 10, wherein said header (5a) consists of a 24-bit string and said information content (5b) consists of a 336-bit string.

23. Encoder for referencing and interconnecting contents, applications and metadata to an audiovisual content, utilizing the method according to claims 1.

12. Method of operation of a decoder which allows for referencing and interconnecting contents, applications and metadata to an audiovisual content, said method comprising the steps of:

finding a digital watermark (5) in said audiovisual content;

comparing said digital watermark (5) with a list of digital watermarks known to said decoder; and

carrying out a certain action corresponding to said digital watermark, wherein said digital watermark (5) is subdivided into a plurality of consecutive “

I”

frames (11a,11b,11c) of said audiovisual content.

13. Method according to claim 12, characterized in that said watermark (5) is inserted into three consecutive “

I”

frames (11a,11b,11c) of said audiovisual content.

14. Method according to claim 12, wherein said digital watermark (5) comprises a plurality of bits and is inserted into coefficients (21,23) of the Discrete Cosine Transform.

15. Method according to claim 14, wherein said coefficients (21,23) correspond to spatial frequencies to which the human eye is least sensitive, in particular the medium frequencies.

16. Method according to claim 14, wherein said digital watermark (5) consists of a plurality of bits located in the positions (2,2) and/or (3,3) of an 8×

8-pixel block into which each of said consecutive “

I”

frames (11a,11b,11c) of said audiovisual content is subdivided.

17. Method according to claim 14, further comprising storing the content of said coefficients (21,23) of said plurality of consecutive “

I”

frames (11a,11b,11c) into a memory buffer associated with said decoder, and verifying if a header (5a) of said digital watermark (5) can be found in said memory buffer.

18. Method according to claim 17, wherein, if said header (5a) is found, the information content (5b) of said digital watermark (5) is compared with codes contained in a look-up table and, if said digital watermark (5) matches one of said codes, a corresponding action is carried out.

19. Method according to claim 18, wherein said action comprises the launch of an application (47).

20. Method according to claim 18, wherein, if said header (5a) does not refer to a digital watermark (5), said memory buffer is emptied and subsequent “

I”

frames are analyzed.

21. Method according to claim 12, wherein said digital watermark (5) represents a Uniform Resource Identifier or a Uniform Resource Identifier string.

22. Method according to claim 21, wherein said URI string is a Uniform Resource Locator or a Uniform Resource Locator string.

24. Decoder for referencing and interconnecting contents, applications and metadata to an audiovisual content, utilizing the method according to claims 12.

25. User terminal comprising a decoder according to claim 24.