Cinavia: Difference between revisions
→Controversy With DTS-HD Master Audio: rv per WP:SYNTHESIS. You need sources that actually say this; rather than sources that say other things, and to combine them to imply a third result. |
As requested added an RS stating the contraversary. See talk page before undoing my edits as this has been discussed. |
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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)".<ref>{{Cite web | title = Whitepaper for a Verance Audio Watermark Detector | url = http://www.verance.com/pdf/DetectorPCSDMI6-12-01.pdf | accessdate = 5 June 2011}}</ref> The two CCI bits in the example contain Digital Copy Control Information, while the succession of SDMI bits contains [[Secure Digital Music Initiative]] data when reconstructed. Also in the Compliance Verification Suite the lowest sample rate test is at 16k samples/s with 16 bits per sample.<ref name="CSV_WP"/> This could indicate that the bandwidth requirements top out at 8 kHz. |
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)".<ref>{{Cite web | title = Whitepaper for a Verance Audio Watermark Detector | url = http://www.verance.com/pdf/DetectorPCSDMI6-12-01.pdf | accessdate = 5 June 2011}}</ref> The two CCI bits in the example contain Digital Copy Control Information, while the succession of SDMI bits contains [[Secure Digital Music Initiative]] data when reconstructed. Also in the Compliance Verification Suite the lowest sample rate test is at 16k samples/s with 16 bits per sample.<ref name="CSV_WP"/> This could indicate that the bandwidth requirements top out at 8 kHz. |
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==Controversy With DTS-HD Master Audio== |
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The DTS-HD Master Audio format claims that it is bit-for bit identical copy to the studio master. <ref>http://www.dts.com/professionals/sound-technologies/codecs/dts-hd-master-audio.aspx</ref> Since Cinavia relies on modifying user data, there have been concerns expressed by many, especially by the [[Audiophile]]<ref>http://www.avsforum.com/t/1285522/audiophiles-vs-cinavia-drm-that-kills-lossless-sound-on-blu-ray</ref> community since this appears to be a misrepresentation of the format. If Cinavia is used on a DTS-HD Master Audio file, technically it is no longer bit identical to the original studio master. |
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==History== |
==History== |
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Revision as of 09:07, 2 September 2012
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| Product type | Digital rights management |
|---|---|
| Website | http://www.cinavia.com |
Cinavia is an analog watermarking and steganography system under development by Verance since 1999, and released in 2010. In conjunction with the existing Advanced Access Content System (AACS) digital rights management (DRM) inclusion of Cinavia watermarking detection support became mandatory for all consumer Blu-ray players from 2012.
The watermarking and steganography facility provided by Cinavia is designed to stay within the audio signal and to survive all common forms of audio transfer, including lossy data compression using discrete cosine transform, MP3, DTS, or Ogg Vorbis. It is designed to survive digital and analogue sound recording and reproduction via microphones, direct audio connections and broadcasting, and does so by using audio frequencies within the hearing range. It is monaural and not a multichannel codec.
Cinavia's in-band signaling introduces intentional spread spectrum phase distortion in the frequency domain of each individual audio channel separately, giving a per-channel digital signal that can yield up to 20 kilobits per second—depending on the quantization level available, and the desired trade-off between the required robustness and acceptable levels of psychoacoustic visibility. It is intended to survive analogue distortions such as the wow and flutter and amplitude modulation from magnetic tape sound recording. On playback no additional audio filters are used to cover up the distortions and discontinuities introduced.
The signal survives temporal masking and sub-band coding by operating on the fundamental frequency and its subharmonic overtones, and by dealigning the phase relationship between the strongest signal and its subharmonics. Each phase discontinuity introduced by the encoder will result in a corresponding pulse of wideband white noise, so a further range of additional distortions are introduced as a noise mitigation strategy to compensate. The desired hidden digital data signal is combined in the distortion step using a pre-determined pseudorandom binary sequence for audio frame synchronization and large amounts of forward error correction for the hidden data to be embedded. The watermark is only embedded when certain signal-to-noise ratio thresholds are met and is not available as a continuous signal—the signal must be monitored for a period of time before the embedded data can be detected and recovered. Extraction of the hidden signal is not exact but is based on recovering the convolutional codes through statistical cross-correlation.
The Blu-ray implementation of Cinavia is designed to cover two use-cases: the first is the provision of a Cinavia watermark on all movie theater soundtracks released via film distribution networks; the second use-case is for the provision of a Cinavia watermark on all Blu-ray releases that points to the presence of an accompanying AACS key. If a "theatrical release" watermark is detected in a consumer Blu-ray audio track, the accompanying video is deemed to have been sourced from a "cam" recording. If the "AACS watermark" is present in the audio tracks, but no accompanying and matching AACS key is found on the disc, then it is deemed to have been a "rip" made by copying to a second blank Blu-ray disc.
As of March 2012[update] known hardware players which can detect Cinavia watermarks include the PlayStation 3 (began with v3.10 System Software), as well as newer Blu-ray players.
Overview
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 the intent is to prevent all copying, 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.[1]
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.[2]
Commercial solutions to completely bypass the Blu-ray backup restrictions imposed by Cinavia exist for the PS3 and are claimed to be in progress for other domestic players.[3], and workarounds to prevent Cinavia reading the audio stream by disabling HDMI audio outputs and using optical audio out, or forcing DTS output work with some current generation players. [4][5]
Technical aspects
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"[6] 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.[7]
Furthermore, the system "enables different copies of identical works to be distinguished".[6] This would enable to track an (illegal) copy of a work back to its origin (traitor tracing).
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)".[8] The two CCI bits in the example contain Digital Copy Control Information, while the succession of SDMI bits contains Secure Digital Music Initiative data when reconstructed. Also in the Compliance Verification Suite the lowest sample rate test is at 16k samples/s with 16 bits per sample.[7] This could indicate that the bandwidth requirements top out at 8 kHz.
Controversy With DTS-HD Master Audio
The DTS-HD Master Audio format claims that it is bit-for bit identical copy to the studio master. [9] Since Cinavia relies on modifying user data, there have been concerns expressed by many, especially by the Audiophile[10] community since this appears to be a misrepresentation of the format. If Cinavia is used on a DTS-HD Master Audio file, technically it is no longer bit identical to the original studio master.
History
On June 5, 2009, the licensing agreements for AACS were finalized, which were updated to make Cinavia detection on commercial Blu-ray disc players a requirement.[11]
Cinavia was first introduced into the PlayStation 3 with the November 19, 2009 update of the system software to Version 3.10.[citation needed]
References
- ^ "Verance Technology". Retrieved October 11, 2010.
- ^ "Cinavia Technology". Retrieved 26 May 2011.
- ^ http://www.dvdfab.com/cinavia.htm
- ^ http://www.digitalworldz.co.uk/283793-playstation-three-cinevia-error.html
- ^ http://club.myce.com/f116/cinavia-protection-319523/
- ^ a b "Verance Technology". Retrieved 5 June 2011.
- ^ a b "Compliance Verification Suite" (PDF). Retrieved 5 June 2011.
- ^ "Whitepaper for a Verance Audio Watermark Detector" (PDF). Retrieved 5 June 2011.
- ^ http://www.dts.com/professionals/sound-technologies/codecs/dts-hd-master-audio.aspx
- ^ http://www.avsforum.com/t/1285522/audiophiles-vs-cinavia-drm-that-kills-lossless-sound-on-blu-ray
- ^ "AACS Issues Final Agreements, Enabling Commercial Deployment of Cinavia in Blu-ray Disc Players" (Press release). Verance. June 5, 2009. Retrieved October 11, 2010.