Video Encoded Invisible Light

rdf:langString Video Encoded Invisible Light

rdf:langString September 2017

rdf:langString Definitely not the US, where cricket isn't aired on television.

rdf:langString Video Encoded Invisible Light (VEIL) is a technology for encoding low-bandwidth digital data bitstream in video signal, developed by . VEIL is compatible with multiple formats of video signals, including PAL, SECAM, and NTSC. The technology is based on a steganographically encoded data stream in the luminance of the videosignal. A recent application of VEIL, the VEIL Rights Assertion Mark (VRAM or V-RAM) is a copy-restriction signal that can be used to ask devices to apply DRM technology. This has been seen as analogous to the broadcast flag. It is also known as "CGMS-A plus VEIL" and "broadcast flag on steroids." There are two versions of VEIL on the market: * VEIL-I, or VEIL 1, has raw speed of 120 bits per second. It is used for unidirectional communication (TV→devices) with simple devices or toys, and to deliver coupons with TV advertising. It manipulates the luminance of the video signal in ways difficult to perceive to human eye. * VEIL-II, or VEIL 2, has speed of 7200-bit/s and is one of the technologies of choice for interactive television, as it allows communication with VEIL servers through devices equipped with backchannels. VEIL-II-capable set-top boxes can communicate with other devices via WiFi, Bluetooth, or other short-range wireless technologies. VEIL 2 manipulates the average luminance of the alternate lines of the signal, where one is slightly raised and the other one is slightly lowered (or vice versa), encoding a bit in every pair of lines. The symbols (groups of 4 data bits) transmitted by VEIL-II system are encoded as "PN sequences", sequences of 16 "chips". Groups of 4 chips are encoded in pairs of lines. Each line pair is split to 4 parts, where the luminance is raised or lowered (correspondingly vice versa in the other line). In NTSC, 4-bit symbols are encoded in groups of 8 scan lines. With 224 lines per field this equals 112 bits per field, or 7200 bits per second of broadcast. VEIL-II uses scan lines 34 to 258. The PN stands for "pseudo noise" and signifies the 0.5/0.5 relative frequencies of ones and zeroes. In practice, 20 chips per line are preferred, increasing redundancy and allowing for better error detection. The PN encoding is a form of spread spectrum modulation. Stripping the VEIL signal from the video is supposed to be more difficult than tampering with the VBI, therefore VEIL-I is proposed as a DRM tool. The signal can survive recording to video, and various sorts of digital compression. The detection devices are low-cost and can be used in a range of devices, from toys to cellphones.