DIGITAL VIDEO FINGERPRINTING

• US 20130208942A1
• Filed: 09/30/2011
• Published: 08/15/2013
• Est. Priority Date: 09/30/2010
• Status: Active Grant

• Current Assignee: British Telecommunications PLC (BT Group PLC)
• Original Assignee: British Telecommunications PLC (BT Group PLC)
• Inventors: Davis, Andrew Gordon
• Granted Patent: US 9,330,426 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06F 16/783 using metadata automatically derived from the content
• CPC Class Codes: G06F 21/1063 Personalisation
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: G06V 20/46 Extracting features or characteristics from the video content, e.g. video fingerprints, representative shots or key frames
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/177 the unit being a group of pictures [GOP]
• CPC Class Codes: H04N 19/18 the unit being a set of transform coefficients
• CPC Class Codes: H04N 19/48 using compressed domain processing techniques other than decoding, e.g. modification of transform coefficients, variable length coding [VLC] data or run-length data motion estimation in a transform domain H04N19/547; processing of decoded motion vectors H04N19/513
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

A digitally encoded video fingerprinting system for generating and comparing/matching finger-prints from digitally encoded video which has been encoded according to an encoding method which involves the generation of residual macroblocks of pixels and the generation of quantized transform coefficients of the residual macroblocks, or of portions of the residual macroblocks, comprises a fingerprint database (5) and a video processing subsystem (10). The video processing subsystem (10) includes a fingerprint sequence selection module (14, 24) which is operable to select one or more sets of frames from input video content to be processed in order to generate a fingerprint; a fingerprint calculation module (14, 26) which is operable to generate a fingerprint based on a set of frames selected by the fingerprint sequence selection module; and a fingerprint comparator module (14, 28) which is operable to compare two fingerprints and to output a similarity score of the compared fingerprints. The method used by the fingerprint selection and fingerprint calculation modules includes selecting a group of frames of the encoded video content; processing the digitally encoded video content to obtain a set of quantized transform coefficients of residual macroblocks or portions of residual macroblocks associated with each of the selected frames; identifying a set of residual macroblocks per frame whose transform coefficients satisfy a threshold criterion; and generating a digital video fingerprint for the encoded video content in dependence upon the identified macroblocks or some property thereof within each of the selected frames.

Claims

1. A method of generating a digital video fingerprint from a piece of digitally encoded video content, the video content having been encoded according to an encoding method which involves the generation of residual macroblocks of pixels and the generation of quantized transform coefficients of the residual macroblocks or of portions of the residual macroblocks, the method comprising:

selecting a group of frames of the encoded video content;

processing the digitally encoded video content to obtain a set of quantized transform coefficients of residual macroblocks or portions of residual macroblocks associated with each of the selected frames;

identifying a set of residual macroblocks per frame whose transform coefficients satisfy a threshold criterion; and

generating a digital video fingerprint for the encoded video content in dependence upon the identified macroblocks or some property thereof within each of the selected frames.

2. A method according to claim 1 wherein identifying a set of residual macroblocks per frame whose transform coefficients satisfy a threshold criterion includes generating a test value in respect of each macroblock, comparing the test value of each macroblock with a threshold value and identifying some of the macroblocks as having transform coefficients which do satisfy the threshold criterion and some of the macroblocks as having transform coefficients which do not satisfy the threshold criterion in dependence upon the comparison of the respective macroblocks'"'"' test values with the threshold value.

3. A method according to claim 2 wherein identifying a set of residual macroblocks per frame whose transform coefficients satisfy a threshold criterion is a multistage process which involves comparing a test value of a macroblock with different threshold values at different stages.

4. A method according to claim 1 wherein the step of selecting a group of frames of the encoded video content includes identifying a group of frames such that a digital video fingerprint generated therefrom has high levels of robustness and reliability.

5. A method according to claim 4 wherein the step of selecting a group of frames of the encoded video content comprises generating fingerprints from a plurality of different groups of frames of the encoded video and then ascertaining the degree of match found between each fingerprint derived from a respective one of this plurality of different groups of frames with a respective fingerprint generated from a corresponding group of frames taken from an encoding of the same video content using a different encoding method.

6. A method of identifying a digitally encoded and compressed piece of unknown video content, the method comprising:

generating a database of fingerprints from a plurality of known pieces of video content using a method according to claim 1;

generating a fingerprint from the unknown video content using the method comparing the fingerprint generated from the unknown video content with each of the fingerprints in the database; and

identifying the unknown piece of video content as being likely to be the known video content whose fingerprint within the database of fingerprints satisfies a similarity criterion when compared with the fingerprint generated from the unknown video content.

9. A digitally encoded video fingerprinting system comprising:

a fingerprint database; and

a video processing subsystem, the video processing subsystem including;

a fingerprint sequence selection module which is operable to select one or more sets of frames to be processed in order to generate a fingerprint;

a fingerprint calculation module which is operable to generate a fingerprint based on a set of frames selected by the fingerprint sequence selection module using a method according to claim 1; and

a fingerprint comparator module which is operable to compare two fingerprints and to output a similarity score of the compared fingerprints.

10. A digitally encoded video fingerprinting system according to claim 9 wherein the fingerprint comparator is operable to compare a fingerprint generated by the fingerprint calculation module with a fingerprint extracted from the fingerprint database.

11. Processor implementable instructions for causing an apparatus including a processor to implement the method of claim 1 during execution of the instructions.

12. Carrier means carrying the processor implementable instructions of claim 11.

7. Apparatus for generating a digital video fingerprint from a piece of digitally encoded or partially decoded video content, the video content having been encoded according to an encoding method which involves the generation of residual macroblocks of pixels and the generation of quantized transform coefficients of the residual macroblocks or of portions of the residual macroblocks, the apparatus comprising:

a processor unit and a memory unit, the memory unit including;

fingerprint sequence selection module code means for causing the apparatus to select a group of frames from the encoded or partially decoded video content; and

fingerprint calculation code means for causing the apparatus to identify a set of macroblocks per frame whose residual transform coefficients satisfy a threshold criterion and to generate a digital video fingerprint for the encoded or partially decoded video content in dependence upon the identified macroblocks or some property thereof within each of the selected frames.

8. Apparatus according to claim 7 further including a video decoder for generating partially decoded video content from digitally encoded video content, the partially decoded video content including residual transform coefficients.