We briefly discussed watermarking schemes in the previous section. Cinavia, from Verance, is an audio watermarking scheme which has ended up inconveniencing a number of consumers. In particular, owners of the PS3 have been vocal enough to warrant the appearance of sites dedicated to bypassing the Cinavia triggers on the PS3. What exactly is the Cinavia watermark? How is it embedded in a soundtrack? When does a consumer encounter the watermark? What is the result when the encounter happens? These are some of the questions we will try to answer in this section.

Verance's DVD-A Watermark

Verance is no newcomer to the audio watermarking market. DVD-Audio adopted their technology in the late 90s. Audio watermarks can be robust or fragile, and Verance's DVD-A watermarking scheme as well as Cinavia belong to the former category. Robust watermarks can't be destroyed by digital-to-analog conversion, re-encoding or addition of small amounts of noise to the track.

In fact, Verance was one of the companies involved in the infamous Felten-SDMI Challenge case, where Prof. Edward Felten was threatened with legal action if he wanted to discuss how Verance's DVD-A watermark scheme (along with a host of other audio protection schemes) was deciphered and overcome. Readers interested in the full technical details of Felten's attack in the SDMI challenge can peruse this paper [PDF] presented at the 10th USENIX Security Symposium. In short, Verance's watermarking scheme involved frequency domain modifications, hiding multiple time-varying echoes. Note that the human ear is not sensitive to echoes involving speech and music where the delay is less than 50 ms. In fact, only echoes with a time difference of 100 ms or more become annoying. Verance's scheme involved echoes with delays varying between 0.5 ms and 1.75 ms, rendering them indecipherable to the human ear. By placing these echoes regularly in an audio track, it is possible to detect the watermark in any clipped segment.

Cinavia

In the DVD-A watermark discussed in the previous subsection, Verance could have different echo patterns to indicate different watermarks. Though we don't have the exact details, it is widely believed that Cinavia could be something similar. The fundamental requirement for Cinavia is the presence of a watermark detector in the playback device, i.e, when a Cinavia-infected audio track is being processed, the system must be able to identify the presence of the watermark pattern.

There are at least four different Cinavia watermarks to identify the following situations:

  1. Professional content (say, copies of movies made in a theater) being played on an unlicensed device (say, a Blu-ray player at home)
  2. Professional content being copied using an unlicensed device
  3. Content being played back on an unlicensed device
  4. Content being copied from an unlicensed device

Scenarios (2) and (4) result in copying being stopped. They are comparatively rare (not many users use devices with the watermark detector to copy content). However, scenarios (1) and (3) are more common. Currently, Cinavia audio watermarks are embedded in the audio track(s) of some Blu-ray movies and a number of theatrical releases. The type of watermark in each of these cases is different. While the watermark in the first case may lead to Scenario (1), the second case may lead to Scenario (3).

We set out to observe Cinavia in action. Our first two test cases involved Blu-ray backups of the movies 'The Losers' and 'Battlefield LA' with re-encoded audio and video tracks. The files were played back on a PS3. The third scenario was triggered in both cases. In the former case, the triggering was within a minute, but took more than 20 minutes in the latter case.


Cinavia - Message Code 03 - The Losers by anandshimpi


Cinavia - Message Code 03 - Battlefield LA - 20... by anandshimpi

The current PS3 firmware has the Cinavia watermark detection routines. When the audio track of a file being played back has the Cinavia watermark for Scenario (3), the PS3 usually waits for 20 odd minutes before muting the audio. This scenario is also triggered when lossless backups of Blu-rays are played back. For example, some Blu-ray players have the ability to play back unprotected ISOs (created with AnyDVD HD or DVDFab) or MKVs (created with MakeMKV) which don't even have re-encoded audio / video tracks. These are the most common form of backups used by legitimate Blu-ray consumers. I will touch upon the need for such backups in a later section, but suffice to say that any discs with Cinavia backed up in such a manner (i.e, with the AACS protection removed) will trigger the muting of the audio on Cinavia-enabled Blu-ray players.

Our third test case involved a 5 minute sample clip from a CAM print of the movie 'The Wolfman'. For those not familiar with scene releases, the Wikipedia article explains about the scene and the various qualities in which scene releases are available. A CAM print is made using a camcorder in a theater. The audio can be either recorded using a microphone or explicit line input. In the latter case, the audio track doesn't have a lot of noise. However, our sample clip had very noisy audio, and in all probability, the audio was recorded using a microphone. Within a few seconds of starting playback of the file on a PS3, Scenario (1) was triggered. Playback automatically stopped with the appropriate error message.


Cinavia - Message Code 01 - The Wolfman by anandshimpi

Cinavia and Blu-ray Players

One of the common aspects in the above three videos is the fact that both of them involved the use of a PS3 as the media player. Currently, Cinavia watermark detection is mandated only in the AACS licensing agreement. This means that only players which are licensed by the AACS are required to have this detection routine. An update to the AACS licensing agreement indicated that all players sent to the BDA (Blu-ray Disc Association) for licensing after February 1st, 2012 should have the Cinavia detection routine embedded in the firmware. There is no legal licensing requirement for previously certified players to include Cinavia in firmware updates, but, if the manufacturer wishes to do so, there is nothing to prevent them from doing so.

Note that the licensing requirement doesn't state that all players sold after February 1st, 2012 need to be Cinavia-enabled; it is only those sent for certification after that date. This means that a number of Blu-ray players (older models) will continue to be sold in the market without Cinavia for some months to come. The BDA certification process involves putting each applicant through a rigorous test suite to ensure that all Blu-ray features are properly supported. Since Cinavia is a recently introduced licensing requirement, it is not clear when the Cinavia tests will become part of the BDA certification test suite. We spoke to some industry insiders who stated (on the conditions of anonymity) that it will be at least another 8 - 12 months before the BDA certification test suite starts testing for Cinavia compliance. They also indicated that they fully expect players to be certified in the meanwhile without Cinavia in the firmware.

Cinavia is particularly worrisome for DMAs (Digital Media Adapters) that have also licensed Blu-ray capabilities. Examples of such units include the Popcorn Hour C300 from Syabas, the Dune Smart series from HDI, and players such as the Kaiboer K860i / Asus O!Play BDS-700. Fortunately, all of these units have already obtained BDA certification. However, it will be interesting to see how they tackle the Cinavia issue in the next generation units. DMAs are quite popular because of their ability to play networked media of all types (be it Blu-ray backups in ISO / MKV format or downloaded content). Cinavia throws a spanner in the works for such units. As we demonstrated earlier in this section, audio either gets muted or playback stops completely, depending on the media source.

In the next section, we will present some comments (in the hope that people in the AACS LA and BDA are paying attention), and leave it to them / readers to decide whether Cinavia really helps as an effective DRM measure.

DRM Measures in Blu-rays Analyzing Cinavia
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  • SpaceRanger - Wednesday, March 21, 2012 - link

    One of the common aspects in the above three YouTube videos is the fact that both of them involved the use of a PS3 as the media player.


    Those aren't youtube videos..
    Reply
  • ganeshts - Wednesday, March 21, 2012 - link

    Thanks for the note. We had initially uploaded to YouTube, but later shifted to DM on account of copyright concerns (Fair use and all that is good to talk about, but the possibility of tussling that out with YouTube is not something we really want to do). I have fixed the text. Reply
  • yelped - Wednesday, March 21, 2012 - link

    Yup, this idiocy is really getting out of hand.

    I personally don't watch movies at all, but I hate watching all this big-brother bullying.

    So, thanks for writing this article!
    Reply
  • zxr250cc - Friday, March 23, 2012 - link

    I worked for a medium size consumer electronics manufacturer in Japan when DVD was about to launch as a director or marketing. Many of the regional distributors in various global markets for future DVD players were asking me about the Regional encoding for disks and how it would affect their sales or ability to have content. I told them then that the stupid idea of having a region for disks would create a so called 'black market' for region free players. I have also worked in the US high end manufacturing sector and followed the 'breaking' of all encryption schemes with great interest.

    I have done many public AV demonstrations with disk based source material and I always have been EXTREMELY OFFENDED by the FBI label telling me I am a thief for disks that I purchased at retail for my use. Anyone ripping the titles will choose to delete that stupid and offensive section of the disk and the only loser is the normal retail user. Any copy protection code will be broken quickly. ANY... If Blu-Ray wants to be succeed for a longer period of time it should be attempting to be easier to use. HDMI and HDCP are only short term solutions that have caused more trouble than they have fixed, by a long sight. USELESS FEATURES, FORCED TRAILER VIEWS and other such idiocy merely feed into consumer dissatisfaction with the format.

    Make it easy to use for the normal retail customer, make it have good simple features and put the stupid FBI and trailer views in the back of the disk, if they are there at all, and let the consumer watch their purchase in peace. I hate the various encumbering schemes attempted to make using products that we have paid good money for and irritated by while trying to enjoy a movie.

    Cheers,

    zxr250cc
    Reply
  • SlyNine - Wednesday, March 21, 2012 - link

    DVDFab has a free DVD/Blueray decryptor. Which will burn a bluray in to a folder structure on your HDD.

    I use ClownBD to get demux the video/audio and MKVtoolnix's MKVmerge to remux into MKVs.

    Sorry to hijack your thread but I wanted this on the first page.
    Reply
  • SlyNine - Wednesday, March 21, 2012 - link

    And to save money on backups, Flexraid is AWESOME. Snapshot based raid for free baby. Reply
  • Aankhen - Thursday, March 22, 2012 - link

    I liked the bit about both of the three videos too. ;-) Reply
  • Death666Angel - Wednesday, March 21, 2012 - link

    "A look at the market trends seem to indicate that online streaming services like Netflix and Hulu are overtaking conventional media distribution channels such as DVDs and Blu-rays."
    I guess you are solely talking about the North American market? I haven't seen such numbers for Germany or Europe, much less for Russia, Asia and Africa....
    Reply
  • ganeshts - Wednesday, March 21, 2012 - link

    I believe that the European market already has some online streaming services such as LoveFilm and even Netflix is setting up shop over there soon. In India, the first VoD subscription service was started last month. Internet infrastructure needs to come up to speed first for online streaming services to be effective. So, yes, many comments in the piece are based upon our opinion, being here in the US, but we do feel that the trend will soon reflect worldwide. Reply
  • Kristian Vättö - Wednesday, March 21, 2012 - link

    I have to say that the offerings are pretty much non-existent here in Finland. A couple ISPs offer some kind of movie rental services but the quality is 480p and you have to be a customer of that ISP to get access. Usually, you also need a specific plan which may not be available everywhere (at one point, they offered it only for ADSL contracts, high-speed optics were left out). iTunes offers HD quality but the selection is rather small, at least right now.

    As far as I know, there is no online streaming service similar to Netflix. All services are pay as you watch, which is quite expensive.

    Also, it's definitely not the internet infrastructure that is causing it here. The average internet speed is faster here than in the US according to NetIndex. Plus we don't have any caps.

    I think one of the key things is dubbing/subtitling. I think UK is a lot ahead of us because their native language is English so all content is ready for them. However, other countries have their own language. Dubbing or subtitling takes time and money, so it makes sense that the companies are concentrating on English countries first.
    Reply

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