Film-Tech Forum ARCHIVE: Making movie theatre images "camcorder-proof"

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Posted by Evans A Criswell (Member # 381) on 10-11-2002, 02:43 PM:

I thought there was already a thread here on this from the past few days, but I can't seem to locate it. Anyway, I chose this forum because I wish to discuss technical details:
http://news.com.com/2100-1023-961484.html?tag=fd_lede2_hed

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?

------------------
Evans A Criswell
Huntsville-Decatur Movie Theatre Information Site

Posted by David Stambaugh (Member # 1102) on 10-11-2002, 03:03 PM:

Isn't that technology specifically aimed at digital cinema, rather than film?

quote:
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.

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.

Posted by Aaron Haney (Member # 747) on 10-11-2002, 04:24 PM:

Yes, it's for digital cinema only. This sounds like it's designed to deal with the issue of people being able to point a camcorder at a screen showing being projected from DLP and get a flicker-free image. But I find this part to be a lot more interesting:

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.

Posted by Thomas Procyk (Member # 1170) on 10-11-2002, 05:26 PM:

To see what a standard camcorder would record off of a 35mm movie screen, just try to blink your eyes as fast as you can, repeatedly. Slightly more flicker than that.

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.

=TMP=

Posted by Brad Miller (Member # 2) on 10-11-2002, 07:10 PM:

Bootlegging just got easier.

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?

Posted by Steve Kraus (Member # 476) on 10-11-2002, 07:43 PM:

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

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.

Posted by Lindsay Morris (Member # 1430) on 10-11-2002, 07:54 PM:

My recent experience with my own Canon UC1000 8mm Video camera showed absolutely NO FLICKER when pointed at a 35mm screen both in my home pre view cinema and at the outdoor.
In the preview case I was capturing a segment of old newsreel for a friend who wanted to have a video tape of her brother riding a motor cycle to victory in a race in Sydney in the 1970's.
I just set the camera up on a tripod slightly in front of the projector (which is in the audience area) zoomed it up to capture the full screen area I wanted and set it going.
The only problem I had was that the Canon does not have a sound input jack so I could not exclude the chatter of the the Raycophone J3 as it ran the news clip. I just turned up the sound levels a bit above normal and it became just a quiet murmur.
Copied it then to VHS and handed it to her and she was delighted and there was no indication that it was anything other than a VIDEO.
The second time I wanted some promo shots of the outdoor on video so I again used the Canon and again on a tripod (and the Canon has a rather neat little remote unit which works many feet away) and captured assorted shots around the cinema.
Such as patrons having their meals and settling back into the deckies
a few of clips of screen ads (slides), then trailers and finally some quite long segments of the main feature at the time which was Titanic.
Apart from the conflict with aspect ratio of video to scope again there was no indication that it was anything other than video.
I had wondered if there would be flicker as I had previously seen this with 8mm film shots I took years ago of a drive-in projector operating and the strobe beat between the camera shutter and the projector shutter was horrible.
I think these new video cameras are very smart devices and the shutter speeds are extremely high and completely avoid the strobing that otherwise occurs.
The little Canon (a few years old now) can produce quite good images in candlelit situations and apart from the slight grainy effect due to the very low light levels the images are good enough for TV use.
Would have killed to have this sort of resolution on 8mm cameras years back.
So I am not surprised that reasonable pirate images can be captured with a video camera taken into a cinema. They are small, compact, have extremely sensitive mics on them and if held steady and IF the user avoids the "heads" would produce good results. But of course a MONO only soundtrack which would immediately be a give-away that it was a pirate recording.
The only down side would be audience noises during quiet soundtrack segments otherwise the higher levels of sound in most cinemas would give very good sound to the pirate video.
The Canon is completely automatic and I just let it have its own way doing things and it works well.
It does have a manual over ride where you can drive the shutter to settings you want but I have found that generally I got the best results letting the camera do its own thing.
So there you are, it can be done, and quite easily at that.

Lindsay

Posted by Brad Miller (Member # 2) on 10-11-2002, 10:41 PM:

Steve, FYI stuff here.

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.

Posted by Mike Olpin (Member # 1115) on 10-12-2002, 12:49 AM:

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

Since the camera is miniDv, and most illegal movie distribution takes place on the net, framerate is irrelivent. The camera directly sends the digital data back to the computer (via firewire) in 24fps. Most people are going to be watching these movies on their computer (sad but true) which is capable of displaying exactly 24fps video.

Posted by Brad Miller (Member # 2) on 10-12-2002, 02:43 AM:

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

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!

Posted by Bobby Henderson (Member # 840) on 10-12-2002, 11:37 AM:

DVD screener discs for film critics and press people are the top way how pirated DVDs get made. A friend of mine here in town bought a bunch of these things (titles like "Spiderman," "Episode II" and "Ice Age" when they were still in theatrical release). I think most of these discs are getting duped off by the millions in China and other far east Asian countries.

As for the Panasonic AG-DVX100 camera, its 24P mode can be output in native 24P form for Internet or other types of multimedia use (along with 30P output). The camera has an internal 3:2 pulldown converter to turn the 24P content into 60i as well. I'd love to have one of those cameras, but the $3500 price tag is a little steep. I'm going to have to save up for a while and get a lot more freelance graphics jobs done.

Posted by Mike Olpin (Member # 1115) on 10-12-2002, 11:57 AM:

My bad, Brad. I jumped the gun before I read your post.

Posted by Frank Angel (Member # 248) on 10-12-2002, 12:48 PM:

Hmmmm, do you think the MPAA or any of its members (like Disney and Universal) will try to slap an injunction on the manufacturer -- preventing them from selling these "pirating devices" like they did against Sony and Mitshushita from making VCRs, which, they claimed, would be used to infringe on their copyrighted works? Even the judge couldn't keep a straight face when they read that claim in court.

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

Frank

Posted by Paul Mayer (Member # 355) on 10-12-2002, 01:21 PM:

Wasn't there a discussion a few years ago about putting infrared sources behind theatre screens in order to interfere with camcorders? (Most camcorders are sensitive to IR). But I suppose this technique would only work until the pirates figure it out and put IR filters on their cameras...

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.

Paul

Posted by Brad Miller (Member # 2) on 10-12-2002, 05:19 PM:

Bobby, if you read up on that camera, it does not actually output 24P, but there are programs being written right now that can extract the original 24P out of the converted 30P with the 3:2 pulldown. It's not possible straight out of the camera though.

Posted by Steve Kraus (Member # 476) on 10-12-2002, 07:19 PM:

What other than piracy would be the point of a 24P camera if it only outputs regular NTSC? The only legit purpose for 24P would be someone wanting to make a "movie" with it; I suppose the conversion process would produce some of the artifacts people associate with the "film look." According to the brochure the tapes are all regular NTSC; if you want 24P endresults you need editing software to undo the conversion. If on the other hand they want to create a pirate's toy they could have it detect images flickering at approx 48Hz and adjust their scan rate to match.

Good point about 25 fps on the pirate video although given the English track it might have originated stateside all the same. When I've played with transferring 16mm using a 1-tube stripe filter camera flicker was present but only faintly. What results did people get with that device with the mirror and the tiny rear projection screen?

Posted by Brad Miller (Member # 2) on 10-12-2002, 10:48 PM:

The "film look" is precisely why people are flocking to this camera. Within a few years, this will become a standard item on all reasonably decent cameras. 60i video looks really amateurish. 30P (like from the XL1) looks much better, but it still looks videoish. This cheezy look can be helped with good lighting, but until the motion looks like film transferred to video, anything shot at 30P or especially 60i will always look like a home video.

Getting back to the point of this thread though, if someone actually wants to "videotape the screen" at a cinema to make themselves a bootleg, just head on down to your local DLP cinema with any camcorder, point and shoot. You'll walk away with one hell of a damned nice copy. DLP is pirate-friendly. Just another reason to do away with it.

Posted by Thomas Procyk (Member # 1170) on 10-13-2002, 01:14 PM:

Here's an article along the same lines from yesterday:

-------
Industry Urges Students on Piracy
Saturday October 12 1:33 PM ET

SAN FRANCISCO (AP) Film and recording industry advocates are appealing to universities nationwide to help crack down on Internet-based piracy, which costs the entertainment world billions of dollars in lost revenues every year.

In a letter sent to more than 2,300 colleges, entertainment industry leaders called on the universities to educate students against pirating music and movies over broadband Internet lines available on most campuses.

"We're simply trying to appeal to the universities for their help in making students aware of Internet theft," Jack Valenti, the president and CEO of the Motion Picture Association of America, said Friday. Valenti was one of four signatories on the letter.

"Students need to know that just because everyone is doing it doesn't make it right," he added.

In addition to educating students that piracy is tantamount to "electronic shoplifting," the industry trade groups called on the universities to implement penalties on violators.

Most universities offer high-speed Internet connections in dorm rooms and computer labs, which some students use illegally to share or swap MP3 files and some film files. Peer-to-peer technology now allows computer users to tap into one another's hard drives and share files.

Using 56K, or dial-up connections, films can take up to 12 hours to download, Valenti said. By comparison, high-speed connections allow feature films to be downloaded to a computer in minutes.

Universities have been targeted because they are a common source of high-speed connections in the United States, where only 13 million homes have high-speed Internet access.

The exchange of copyrighted files is not only a violation of federal law, it consumes valuable academic resources, the letter signatories said.

"Stealing is stealing is stealing, whether it's done with sleight of hand by sticking something in a pocket or it's done with the click of a mouse," the letter's authors said.

Ever since the music-swapping software Napster emerged in the late 1990s, students have been using enormous swaths of university bandwidth intended for the exchange of research data and other academic-oriented files.

Quoting the Chronicle of Higher Education, the letter's authors said one university discovered that at least 75 percent of its available bandwidth had been used by students and people outside the university while exchanging files using peer-to-peer technology.

Songwriters Guild of America President Rick Carnes warned that copyright violations threaten the future of the recording arts in the United States.

"Copyright encourages the promotion of new arts in our culture," said Carnes, who has written songs for Garth Brooks and Reba McEntire. "Without those copyright protections, the future of the arts is threatened."

The letter also was signed by Hilary Rosen and Edward Murphy, the presidents, respectively, of the Recording Industry Association of America and the National Music Publishers' Association.
-------

Here are my questions/corrections:

Internet piracy is a relatively new thing, no more than about five years old. If I am not mistaken, the Motion Picture Industry had a record box office year last year, and is on-track for another one this year. Where are these "billions of dollars" lost? Certainly not in the home video market as DVDs are flying off the shelves...

quote:
which some students use illegally to share or swap MP3 files

This statement makes it sound that ALL MP3s are illegal. And our university has taken exactly that approach. If you transfer an MP3 file over the University's network, even if it's your own grandma singing some song she made up while drunk, your account will be suspended.

quote:
By comparison, high-speed connections allow feature films to be downloaded to a computer in minutes.

Incorrect. Any video file, no matter how much you compress it, (unless it's at a postage-stamp resolution) will exceed 150mb for about a half hour of footage. That sized file would take a little over an hour to download on a high-speed connection. (Unless you have a dedicated high speed connection, not sharing it over hundreds of computers like most colleges do.) The only exception would be the RealVideo format, but who wants to watch a feature film in THAT?!?

quote:
"Copyright encourages the promotion of new arts in our culture,"

Just the opposite. And I believe this was discussed in another thread so I won't go into it now. Maybe that's why these corporations are screaming that the 20-year extension on copyrights not be overturned. Disney still wants their $0.62 every time a clip of "Steamboat Willie" is shown on TV.

I wonder exactly how the Universities will "educate" students on the horrors of internet file-swapping. Hopefully not the same way that Jr. High Schools educate kids in sex. "See how much fun it can be? Now don't do it!"

=TMP=

Posted by Dave Williams (Member # 299) on 10-13-2002, 02:23 PM:

I once caught a guy setting up a video camera on a tripod during the opening previews. He was the only person in the showing, on a late sunday. I let it go for about half an hour, then changed the sound over to a cd of metallica. The movie was Perfect Storm.

After about ten minutes, he packed up and left. Of course only to be pulled over by the police that were waiting for him.

Dave

Posted by Steve Kraus (Member # 476) on 10-13-2002, 06:24 PM:

Egad...what an idiot! He must have been pretty stupid to think he could be so blatant. The MPAA ought to distribute a trailer offering money or passes to anyone who notices someone taping and brings it to the attention of theatre staff. Of course that won't stop "inside" jobs but if Cap Code traces a bootleg to a specific venue and investigators start interviewing the entire staff it would sure put the fear of God into most people.

Posted by Bobby Henderson (Member # 840) on 10-13-2002, 10:19 PM:

I wonder if it is possible to put some kind of sequential serial number or specific watermark on DVD screener discs --y'know, something that might be permanently stuck in the MPEG-2 video stream that is impossible to erase. The press people need to be just as accountable as John Q. Public on film piracy.

On the 24P thing, applications like Cinema Tools for Final Cut Pro can handle 24P, full HDTV level bitstreams and lots of other cool stuff. FCP, DVD Studio Pro and Cinema Tools for FCP are really the only things that have me wanting to buy a Mac. Apple has a killer app in FCP.

Posted by John Moriarty (Member # 1153) on 10-14-2002, 03:06 AM:

Bobby said:

quote:
I wonder if it is possible to put some kind of sequential serial number or specific watermark on DVD screener discs

It is possible, but there are a number of limitations. Obviously, if the disk is indivually marked in some way then it will have to individually cut/pressed, which could increase costs. Unfortuneately recordable DVD formats (that are compatible with home DVD players) have a lower capacity limit than standard DVDs, and some films may have to be spread accross more than one disk (esp. if higher quality soundtracks are to be used).

The second problem is that the video files are often (substantially) further compressed for distribution on the internet, and so any marking system will have to be resistant to this level of modification.

John

Posted by Leo Enticknap (Member # 534) on 10-14-2002, 03:49 AM:

You can get about an hour of 8.0mbps (720x526 PAL at 25fps) in DVD video format (i.e. playable on a set-top machine) onto a single 4.7gb DVD-R disc. By reducing the bit rate you can increase available running time, but IMHO anything over 80 minutes on a disc starts to look pixellated and generally nasty.

Posted by Scott Norwood (Member # 30) on 10-14-2002, 07:33 PM:

In multiplex where I fill in occasionally, there are two booths; in the "main" booth, there is a small B&W monitor, connected to two security cameras pointed at the screens serviced by the smaller booth. The idea is to provide a quick way to check on picture and framing when shows start in the other booth by automatic timers. Anyway, the security cameras are old tube models and the "look" of the picture on the monitor is interesting. It does flicker, but much less noticeably than it would if CCD cameras were used, due to the "lag" of the tube cameras. On the other hand, the actual picture quality is absolutely horrible (probably a result of the age of the cameras and monitor) and it is all but impossible to see what is actually going on in the onscreen images. I've used CCD cameras to record projected 16mm images (nothing copyrighted; just home movies and such) and the flicker is very annoying (this is using a machine with a 3-bladed shutter).

I don't know about the consumer 24P camera, but the Sony HDCAM model does record at 24P natively and the playback deck can output at 24P. We had this equipment at a film festival where I helped out recently and we really should have tried recording a filmed image (with the permission of the filmmaker, of course) if someone had thought about it.

Posted by Frank Angel (Member # 248) on 10-15-2002, 03:44 AM:

That's an interesting concept -- video cameras watching the various screens in a multiplex. They idea could be extended to watching the audience as well.

We found that old vidicon tube cameras were infrared sensitive - if you flooded the area with infrared light, the cameras would "see" a perfectly lit picture, even in the dark. This became invaluable for the stage manager of live stage shows where props and actors needed to be in place on the stage before the curtain could go up. With a few infrared lamps lighting the stage, even in a blackout (of white light), the stage manager could see a stage that looked fully "lit' on the monitor and could check places before he called "curtain go."

This same principle could be used to watch audiences and check for the camcorder pirates. It also wouldn't hurt to use it to keep an eye out for roudy patrons as well. Disruptive patrons is one of the top reasons given why people, especially the older age groups, would rather wait to see pictures at home.

Frank

Posted by Thomas Procyk (Member # 1170) on 10-15-2002, 12:31 PM:

Bobby:

quote:
I wonder if it is possible to put some kind of sequential serial number or specific watermark on DVD screener discs

I thought they already did this with screener VHS tapes. My friend was a manager at a video store, and whenever they recieved screener tapes, every 15 minutes or so a message would scroll at the bottom, ("...if you have rented or purchased this cassette, please call 1-800-NO-COPYS...") and afterwards a 4 to 6 digit number would appear in the upper-right corner of the screen for a while.

=TMP=

Posted by Paul G. Thompson (Member # 655) on 04-20-2003, 11:50 PM:

Here's something from the Local Seattle Rag that might prove interesting.

Hollywood comes up with a high-tech way to foil movie pirates

By GARY GENTILE
THE ASSOCIATED PRESS

LOS ANGELES -- Hollywood sends enforcers with night-vision goggles into movie theaters and puts metal detectors outside advance screening rooms, but still the industry can't stop pirates from recording films and selling illegal copies before their theatrical debuts.

The problem is that the pirates are adopting ever more sophisticated technology, using tiny camcorders in purses and digital recorders about the size of a fountain pen.

Some hand-held computers "have an attachment that can record up to 122 minutes," said Jeffrey Godsick, executive vice president of marketing at 20th Century Fox. "Well, that's a whole movie in many cases. You can take the attachment and run it through a small hole in a tie or a shirt."

This is big business. The Motion Picture Association of America estimates that studios lose more than $3 billion a year from piracy in various forms. So the movie industry is trying to fight back with a high-tech solution of its own.

Cinea LLC, which created an encryption system for DVDs, and Sarnoff, a technology research firm, are developing a system to modulate the light cast on a movie screen to create a flicker or other patterns that would be picked up by recording devices, making the resulting images unwatchable. The disruptive flickers would be unseen by the human eye in the movie theater.

The "forensic watermark" system is designed to be used with digital projectors, which show movies stored on computer discs rather than traditional 35mm film. Only a few theaters have digital projectors, although most are expected to go digital by the end of the decade.

The research is funded by a $2 million grant from the Advanced Technology Program of the National Institute of Standards and Technology, a government agency.

The technology takes advantage of the fact that the human eye and camcorders see the world differently. For example, a computer screen constantly refreshes an image, creating bars that travel across the screen. A camcorder picks up those bars, but not the naked eye.

Researchers are mindful that creating too rapid a flicker could trigger seizures in some people. They also discovered that using the flicker to write words across the image, such as "Copy," is not disruptive enough.

"It turns out that text isn't that annoying," said Robert Schumann, Cinea's chief executive. "Also, if it's just a static image, it's easier for the pirates to take out."

This technology would be a major improvement over the industry's current measures of trying to block pirate recorders, including night-vision goggles and metal detectors. Some of the piracy is an inside job: A pirate bribes a projectionist to set up a tripod in the projection booth.

"It is a system that will not stop camcording," said Ken Jacobsen, director of worldwide anti-piracy operations for the Motion Picture Association of America. "The best we can do is try to keep it out of the marketplace before a full domestic release."

Still, the industry knows that whatever technological gains are made over pirates will eventually be thwarted, requiring even more sophisticated countermeasures.

"There is a lot of money in piracy," Jacobsen said, "so it is worth people's efforts to try and defeat security."