Cinavia is a digital rights management system created by Verance. It requires two parts to work: a proprietary imperceptible audio watermark, and a piece of hardware which is able to detect that watermark. Known hardware which can detect Cinavia watermarks include the PlayStation 3 (began with v3.10 System Software), as well as newer Blu-ray players. Cinavia is not detected in a DTS audio stream on PS3 (Must have Optical Out (S/PDIF) or HDMI, w/DTS receiver).
Cinavia works to prevent copying via the detection of a watermark recorded into the analog audio of media such as theatrical films and Blu-ray discs. Note that all copying is prevented, both pirate copies and legal copies of one’s own content for example for format shifting.
The watermark is able to survive recording through microphones (such as recording a film in a movie theater with a camcorder), as well as compression and encoding, yet still be imperceptible to human hearing. Verance claims that the presence of the watermark does not affect audio quality.
When media with the watermark is played back on a system with Cinavia detection, its firmware will detect the watermark and check that the device on which it is being played is authorized for that watermark. If the device is not authorized (such as not being an authorized movie projector in the case of a cam bootleg, or not utilizing AACS in the case of a copy of a commercial Blu-ray disc or CSS in the case of a copy of a commercial DVD), a message is displayed (either immediately or after a set duration) stating that the media is not authorized for playback on the device and that users should visit the Cinavia web page for more information. Depending on the device and firmware, once the message is triggered, the audio may be muted, or playback may stop entirely.
One channel of audio is sufficient to detect the mark: As stated above, the watermark would be able to survive re-recording through a microphone. Verance claims that “Verance audio watermarks can survive typical distortions introduced during the production, duplication, distribution, broadcast, and consumer handling of recorded content” this should include down mixing as well. Also in the white paper for their “DVD-Audio Detector Compliance Verification Suite” all tests are single channel files.
Furthermore, the system “enables different copies of identical works to be distinguished”.This would enable to track an (illegal) copy of a work back to its origin.
The data throughput for a watermarking system used for DVD-Audio is described as follows “Watermark Output: 3 water-mark data bits per 15 seconds (2 CCI bits and 1 SDMI Trigger Bit)”. Also in the Compliance Verification Suite the lowest sample rate test is at 16k samples/s with 16 bits per sample.This could indicate that the bandwidth requirements top out at 8 kHz.