Digital watermarking fundamentals for DRM-protected video assets

A watermark is a digital code inserted into a video sequence to provide additional security to DRM protected content, containing information about the content’s origin, ownership, destination, copy control, and transactions.

A watermark that is effective should typically have a set of characteristics that include fidelity (the watermark should be difficult to notice and should not harm the quality of content), robustness (it should be able to survive common distortions), tamper resistance (it should resist malicious attacks), ease of computation (easy to insert and detect, scalability and affordability), and the ability to coexist with other watermarks Watermarking solutions should also have low false positive rates, meaning they should not flag an unwatermarked video for detection as having a watermark.

This limitation on the amount of information that a watermark can hold also affects the information itself. It is also limited by the length of a video. When using video watermarking solutions, the data payload must be taken into consideration. It is up to the application to determine which of these characteristics is more important than others.

Using a cloud-based watermark extraction service that works well even with low-quality and recompressed videos, it is possible to verify the owner of the content and track down the source of the piracy. Client-side watermarking, A/B or manifest-level watermarking, and bitstream-based watermarking are three broad categories of watermarking solutions.

An effective video watermarking service must be able to deter piracy, identify the piracy outlets, and take the necessary steps to prevent leakage of the video content. In order to detect piracy, keep an eye out for suspicious activity and compare the digital fingerprints of suspicious files to the production fingerprint. The watermarking software is then able to identify the watermark and extract the information contained therein. Resize and collusion attempts, for example, shouldn’t affect the robustness of the watermark. It should also remain legible even after the content has been altered. It’s also possible to take legal action after discovering the source of a stream that is being illegally downloaded.

Video watermarking solutions should have the following additional prerequisites for compressed video data transmissions in addition to the aforementioned essential characteristics in order to be effective as a real-time technique:

  • In the absence of the original unwatermarked data, it should be possible to extract the watermark information (for example, in case of a set-top-box or recorder which lack the original data).
  • Low-complexity applications in customer products necessitate speed and efficiency. As a result, watermarking methods should be simple and cost-effective.
  • The original dimensions of the compressed host data should not be augmented by the watermark. In hardware decoders, buffers can run out of space when transmitting data at a predetermined bit rate. It may become more difficult to maintain audio and video synchronisation as the compressed MPEG-video stream’s dimensions grow. During the watermark insertion process, the encryption of the watermark information must be appended to the host data. It is possible that the keys used in these techniques will change over time. When it comes to watermarking methods, care must be taken to ensure that the cryptographic protocols are aware of the key management intricacies.

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