# US 8,542,868 B2 · Embedding interactive data into an audiovisual content by watermarking

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- Number: US 8,542,868 B2
- Document ID: US8542868B2
- Status: Granted
- Kind: B2
- Application number: 12/808,896
- Filed: 2008-12-17
- Published: 2011-01-27
- Granted: 2013-09-24
- Earliest claimed: 2007-12-17
- Assignees: Csp - Innovazione Nelle Ict Scarl; Universita' Degli Studi Di Firenze; S.I.Sv.El Societa' Italiana Per Lo Sviluppo Dell'elettronica S.P.A.
- Applicants: Giovanni Ballocca; Roberto Borri; Roberto Caldelli; Rudy Becarelli; Francesco Filippini
- Inventors: Giovanni Ballocca; Roberto Borri; Roberto Caldelli; Rudy Becarelli; Francesco Filippini
- Web page: https://patentgrep.com/patent/US8542868B2

## CPC

- H04N 7/162: {Authorising the user terminal, e.g. by paying; Registering the use of a subscription channel, e.g. billing}
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/18: the unit being a set of transform coefficients
- H04N 19/467: characterised by the embedded information being invisible, e.g. watermarking
- H04N 19/61: in combination with predictive coding
- 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)}
- H04N 21/23892: {involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level}
- 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)}
- H04N 21/6332: directed to client
- H04N 21/654: Transmission by server directed to the client
- H04N 21/858: Linking data to content, e.g. by linking an URL to a video object, by creating a hotspot
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## 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

### Claim 1

Method for embedding interactive data into an audiovisual content by watermarking, said method comprising the step of inserting a digital watermark into said audiovisual content during an audiovisual content encoding step, said digital watermark being used for allowing a user to reproduce or exploit additional contents supplementing those provided by said audiovisual content, wherein said audiovisual content is an interactive television (iTV) audiovisual content, and wherein said digital watermark is inserted into said iTV audiovisual content by subdividing the digital watermark into a plurality of consecutive ‘I’ frames of said iTV audiovisual content.

### Claim 2 (depends on 1)

Method according to claim 1, wherein said plurality of consecutive “I” frames of said iTV audiovisual content consists of three consecutive frames.

### Claim 3 (depends on 1)

Method according to claim 1, wherein said digital watermark comprises a plurality of information bits and is inserted into coefficients of the Discrete Cosine Transform of said consecutive frames comprising 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 is subdivided.

### Claim 4 (depends on 3)

Method according to claim 3, wherein said coefficients remain unchanged if the value of the last bit of the coefficients corresponds to an information bit of the digital watermark to be inserted, whereas the coefficients are modified if the value of the last bit of the coefficients does not correspond to an information bit of the digital watermark to be inserted.

### Claim 5 (depends on 4)

Method according to claim 4, wherein said modification of said coefficients of the Discrete Cosine Transform of said consecutive frames consists in modifying the parity/non-parity of said coefficients.

### Claim 6 (depends on 4)

Method according to claim 4, wherein the value of said coefficients of the Discrete Cosine Transform of said consecutive frames is either increased or decreased by one unit in order to modify said parity/non-parity of said coefficients.

### Claim 7 (depends on 6)

Method according to claim 6, wherein said modification is carried out only if said coefficients have a value other than zero, so as to avoid altering the “run-length” coding.

### Claim 8 (depends on 1)

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

### Claim 9 (depends on 1)

Method according to claim 1, wherein said plurality of consecutive “I” frames of said iTV audiovisual content consists of three consecutive frames, and wherein said digital watermark comprises a plurality of information bits and is inserted into coefficients of the Discrete Cosine Transform of said consecutive frames comprising 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 is subdivided.

### Claim 10 (depends on 9)

Method according to claim 9, wherein said coefficients remain unchanged if the value of the last bit of the coefficients corresponds to an information bit of the digital watermark to be inserted, whereas the coefficients are modified if the value of the last bit of the coefficients does not correspond to an information bit of the digital watermark to be inserted.

### Claim 11 (depends on 10)

Method according to claim 10, wherein said-modification of said coefficients of the Discrete Cosine Transform of said consecutive frames consists in forcing the parity/non-parity of said coefficients.

### Claim 12 (depends on 10)

Method according to claim 10, wherein the value of said coefficients of the Discrete Cosine Transform of said consecutive frames is either increased or decreased by one unit in order to modify said parity/non-parity of said coefficients.

### Claim 13 (depends on 10)

Method according to claim 10, wherein said modification is carried out only if said coefficients have a value other than zero, so as to avoid altering the “run-length” coding.

### Claim 14

Method of operation of a decoder able to decode embedded interactive data into an audiovisual content by watermarking, said method comprising the steps of:
finding a digital watermark in said audiovisual content;
comparing said digital watermark with a list of digital watermarks known to said decoder;
carrying out a certain action corresponding to said digital watermark, wherein said audiovisual content is an iTV audiovisual content, and wherein said digital watermark is subdivided into a plurality of consecutive “I” frames of said iTV audiovisual content.

### Claim 15 (depends on 14)

Method according to claim 14, wherein said watermark is inserted into three consecutive “I” frames of said iTV audiovisual content.

### Claim 16 (depends on 14)

Method according to claim 14, wherein said digital watermark comprises a plurality of bits and is inserted into coefficients of the Discrete Cosine Transform, said plurality of bits being located in the positions 2,2 and/or 3,3 of an 8×8-pixel block into which each of said consecutive “I” frames of said iTV audiovisual content is subdivided.

### Claim 17 (depends on 14)

Method according to claim 14, further comprising the steps of storing the value of said coefficients of said plurality of consecutive “I” frames into a memory buffer associated with said decoder, and verifying if a header of said digital watermark can be found in said memory buffer.

### Claim 18 (depends on 17)

Method according to claim 17, wherein the structure of said digital watermark comprises a sequence of information bits, wherein if said header is found, the sequence of information bits of said digital watermark is compared with codes contained in a look-up table and, if said digital watermark matches one of said codes, a corresponding action is carried out.

### Claim 19 (depends on 18)

Method according to claim 18, wherein said corresponding action comprises the launch of an application.

### Claim 20 (depends on 18)

Method according to claim 18, wherein, if said header does not refer to a digital watermark, said memory buffer is emptied and subsequent “I” frames are analyzed.

### Claim 21 (depends on 14)

Method according to claim 14, wherein said digital watermark represents a Uniform Resource Identifier string, in particular a Uniform Resource Locator string.

### Claim 22 (depends on 14)

Decoder for referencing and interconnecting contents, applications and metadata to an audiovisual content, utilizing the method according to claim 14.

### Claim 23 (depends on 22)

User terminal comprising a decoder according to claim 22.