Method and apparatus for modifying a video stream to encode metadata

• US 9,852,489 B2
• Filed: 04/06/2016
• Issued: 12/26/2017
• Est. Priority Date: 12/12/2012
• Status: Active Grant

• Current Assignee: Grass Valley USA Incorporated
• Original Assignee: Snell Advanced Media Limited (Belden Inc.)
• Inventors: Diggins, Jonathan
• Primary Examiner(s): Liew, Alex
• Application Number:
  US15/091,704
• Publication Number:
  US 20160217544A1
• Time in Patent Office: 629 Days
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0061 Embedding of the watermark in each block of the image, e.g. segmented watermarking
• CPC Class Codes: G06T 2201/0065 Extraction of an embedded watermark; Reliable detection

Abstract

A watermark encoder receives a current video image together with current metadata associated with the current image. A metadata delay also makes available to the watermark decoder delayed metadata associated respectively with four or more of the preceding. Then the watermark encoder modifies pixel values of the current image not only to encode the current metadata but also the delayed metadata. At a decoder, if metadata for the current image is corrupted or missing, it can be recovered from one of the succeeding images.

Claims

1. A method of processing a video data stream to encode metadata, comprising:

receiving in a video processor a sequence of video images, the pixel data of one video image having been modified to encode current metadata associated with that image and to encode other metadata for N other images respectively in the sequence of images, where N is equal to or greater than four;

testing for validity of the metadata encoded in an image;

if the metadata encoded in that image is valid, extracting in the video processor the metadata associated with that image and the other metadata for said N other images; and

associating said other metadata respectively with said N other images.

2. A method according to claim 1 comprising:

measuring the frequencies of occurrence of at least two combinations of values of low-significance pixel-value bits within a first spatial region within a field or frame;

measuring the frequencies of occurrence of at least two combinations of values of low-significance pixel-value bits within a second spatial region within the said field or frame; and

determining an encoded metadata parameter from a comparison of the frequencies of occurrence of combinations of low-significance pixel-value bits in the said first and second spatial regions of the said field or frame.