The piracy of DRM-protected content using cam-recording can be prevented by two video-watermarking solutions: Forensic watermarking and visible watermarking. Watermarking is essentially the technique of embedding data into digital content that can be extracted as it is even if the content itself has undergone modification. A forensic watermark, also known as a digital watermark, is a code or a set of characters embedded into the digital document, video, audio, image or program, which enables the unique identification of the content creator and its authorized user.
Forensic watermarked content should be completely indistinguishable from its non-watermarked counterpart. An effective forensic watermarking solution should also be capable of storing a large payload and be unfeasible to remove or modify without damaging the original content. Forensic video watermarking usually functions via a few basic steps, such as video encoding, embedding of identifiers to the encoded content, distribution to the intended audience, capturing and monitoring of leaked content, and finally extraction of the embedded identifiers to detect the source of leakage.
Based on who is inserting the watermark in the media, forensic watermarks can be categorized into operator marks (distributor marks) and session marks. While an operator mark is inserted by the content owner and is used to track the distribution of the content, a session mark is inserted by the service provider in order to track the end-user information. Forensic watermarking of video content has several applications in the digital media industry. It can be applied to pre-release content as a static mark for preventing their leakage, to digital cinema for tracking illegal recording, and as subscriber mark to OTT-VOD content.
Visible watermarking, on the other hand, consists of overlaying a perceptible logotype or textual information or both, usually related to ownership, into the original content. Generally, a visible watermark might reduce the commercial value of the content or hamper user experience, but there are a few instances where a permanent visible watermark is a more suitable option. Some of the major applications of a visible watermark are in digital libraries,distribution of content with-in organisation or to vendors as pre-production work, e-commerce, and digital press. Insertion of visible watermarks in videos follows a basic algorithm. The video is first read in the .avi format and separated into individual frames. The image on the frames is then split into three planes and the logo is inserted into the frames following which the images are again converted into frames and a video output is written. The presence of visible creator information or logo on digital content, while not completely preventing misuse, can certainly discourage unauthorized usage.
