The above link points to a story about "modifying the timing and modulation of the light" to degrade the image that a camcorder would capture if someone tried to videotape a movie from a theatre's screen.

It seems that with the current 35mm film technology, there would already be some serious degradation. A camcorder is capturing interlaced video at 60 fields per second (30 frames per second). A movie theatre's screen (assuming a standard 2-blade shutter) displays 24 frames per second in the form of 48 light-dark cycles with each frame being flashed to the screen twice. The screen is lit for 1/96 of a second, then is dark for 1/96 second, repeating 48 times per second. A device capturing at 60 fields per second should capture a significant number of fields as darkness (or parts of fields as darkness) -- half the time in fact. It seems that a videotape from a theatre screen would exhibit very noticeable flicker due to the frame rate difference and the "lit only half the time" nature of the theatre screen.

I cannot imagine being able to modify the shutter mechanism for a projector to made camcorder recording any worse without hurting the efficiency of the shutter or creating an irregular refresh situation.

Ideas? Has anyone looked at a videotape of a theatre screen? I'd like to watch a slow-motion replay of such a tape to see if areas of black occur in many fields, or if many fields are black. If the VCR in "pause" shows two fields at a time, it may not be as noticeable, but degradation should occur. Has anyone tried this?

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Evans A Criswell
Huntsville-Decatur Movie Theatre Information Site

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Herndon, Va.-based Cinea, the company Schumann co-founded after Divx folded in 1999, is close to unveiling a beta for its Cosmos digital cinema security system that will help movie distributors keep track of how their products are used while protecting them from piracy.

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I am curious about the videotaping of film images though. I've never seen a bootleg tape made that way, so I have no idea how good or bad they are. I have seen a brief news clip on TV that was videotaped inside a theater with a film projected on the screen as the background, and it seemed to have sync issues.

According to the article, this company just got a $2 million grant from NIST to develop this technology.

That's right folks! One of the people behind the failed Divx DVD format is now spending millions of your tax dollars to develop copy protection mechanisms for digial cinema, which people are already speculating about how to get around. Why is the government spending so much money on something like this, which will probably turn out to be a complete waste? I can think of a lot better uses of that money.

There are camcorders with adjustable frame rates (possibly some high-end broadcast quality ones) which will record a more stable image, but you will get a "pulse" effect like someone is messing with the brightness control on your TV. About the same rate as the flicker, but instead of going completely dark, the screen would just get dim instead. A good example of this is if you've seen the TV show, "Trigger Happy TV" where they do hidden-camera stunts in movie theaters sometimes.

I also assumed they meant some sort of protection for digital cinema, not film. Film has it's own "copy protection" already, which is another reason why it is better than digital.

Bootlegger's paradise

This camera was released to the market yesterday. It records in MiniDV "digital" format and has adjustable capture settings...one of them being 24P which is an exact match to 35mm film's framerate. With this camera, all a bootlegger has to do is point it at the screen and viola, perfect flicker free copy.

What's that I'm smelling? There is a weird odor in here. Mr. V?

With all the talk in the press about bootlegs being swapped online I downloaded a couple of files to see what was what. One turned out to be from a screener tape (tapes given to critics who can't manage to catch a proper screening)...now there's a hole that ought to be plugged.

The other was a bonafide bootleg...shot off a theatre screen with horrible AGC effects on the sound and oddly enough overlaid with Japanese or Chinese or whatever subtitles (done by the bootlegger). Picture quality was poor but there was no major flicker problem. This didn't really seem to be an issue and I doubt they did anything special (anyone who doesn't know to turn off the AGC isn't very technically oriented). If the camera had a shutter or acted electronically like it did then there would be a problem with it interacting with the projector shutter but instead I think the CCD just accumulates the image as the light falls on it and reads it out at the TV scan rate just like a digital framestore where you can update the memory with new data as it comes in while cranking it out at a completely different rate.

The AG-DVX100 camera that was released yesterday shoots at 24P, but exports via NTSC at 60i so it is directly playable (and copyable) on any television in the US.

The reason your foreign dubbed bootleg did not appear to flicker is because the PAL video format that is used overseas runs at 25 frames per second. That's close enough.

Lindsay,

I'm betting your camera is going into low light mode (aka: gain up) and as such is slowing the shutter to the point of hiding the shutter. Many of the higher end cameras have adjustments that can be made to do this, but you do lose full motion when shooting in those low light conditions.

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But that will result in a 24P tape which would presumably need converting for distribution, not that that would be insurmountable.

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"The camera directly sends the digital data back to the computer (via firewire) in 24fps."

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No it doesn't Mike. Like I said in the last post, this camera exports at 60i. Yes it exports via firewire, but not at 24fps. The framerate conversion is done inside the camera before it records onto the tape. For consumers, this camera represents the first "affordable" 24P camera on the market. As such there are even special programs being written to convert that 60i back down to a pure 24P. The camera even has two special settings just for this, depending on whether you want to get that 24FPS look and stay in the video domain, or whether you want to eventually export to film.

This camera is not the real problem though. The REAL problem is caused by the Academy for sending out all of those tapes. If someone wants to have a vote in the Academy, then they should get off of their butts and attend special screenings. No videos should be permitted. I'm amazed the filmmakers even want the Academy members to see their films on video. I sure wouldn't!

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Just for laughs, some reporter should ask Jack Valenti what his position is on video cameras that can record at 24p.

Anime fans know this problem all too well--camcorder pirating is BIG business in Hong Kong (Cantonese and English subtitles), Taiwan, and China (Mandarin and sometimes English subtitles). Many many VCDs and on-line downloads available for $1-5 US in these areas and in the various US Chinatowns.

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