Startup Tries Watermarking Instead of DRM

Loosehead Prop writes "A U.K. startup called Streamburst has a novel idea: selling downloadable video with watermarks instead of DRM. The system works by adding a 5-second intro to each download that shows the name of the person who bought the movie along with something like a watermark: 'it's not technically a watermark in the usual sense of that term, but the encoding process does strip out a unique series of bits from the file. The missing information is a minuscule portion of the overall file that does not affect video quality, according to Bjarnason, but does allow the company to discover who purchased a particular file.' The goal is to 'make people accountable for their actions without artificially restricting those actions.'"

Comments

Still doesn't solve the real problems

[sokoban]

So, people who pay for a movie from these guys won't be able to share it via Kazaa or bittorrent or whatever is popular right now. I don't think that many people who pay to download a movie really do so with the intent of putting it on a filesharing network. I mean, why the hell would you do that? The people I know who do the whole illegal filesharing thing, don't pay for media they can get for free, and the people I know who buy digital download media, don't use illegal filesharing sites. Buying something legally kinda defeats the purpose of using a filesharing site, amirite?

Re:re-encode the movie

[Anonymous Coward]

Have you tried removing an industrial strength watermark (e.g. DigiMarc)? I tested various watermarks in a course project (Steganography) and it's not so trivial. A large number of watermarks were resistant to encoding, cropping, affine transformations, rotations, etc.

The only way I could successfully remove the watermark without making the image unusable was by diff'ing the original with the watermarked. But where are you going to get the original?

I had a similar idea

[kasperd]

At some point I did a scetch of a somewhat similar idea in some net forum. Though I would not remove bits, rather I'd do an encoding with slightly increased quality in a few random places. (That way I would hope to prevent people bitching about reduced quality). And how much the watermarking costs in terms of extra space could be computed exactly. I haven't done any calculations on the extra space, but I would expect a few KB for a full movie.

To explain what my idea was I'll first give a short reminder of how jpeg works. Blocks of image data are transformed using something based on fourier transformations. The resulting coefficients are then rounded to different scales. For high frequency components a scale with larger steps can be used as errors in these components are not easilly noticed. There is a table of standard steps to be used for each combination of horisontal and vertical frequency. (I left out the part about how to handle colour components, which is not relevant for the following idea).

Making a minor change to one of the step sizes is not going to cause a major difference in the size of the compression or the quality. By picking some of the entries at random and reducing the step size you are going to increase the quality of random parts of the picture. Now what I want to do is to make a redundant encoding of a signature on the text from the watermark and use those bits to choose places to increase the quality. The signed text itself is included in the begining of the file.

First of all removing the signature would means you couldn't compute the step sizes, and thus you couldn't correctly decode the file. And if the file was reencoded, you might still be able to extract the watermark by comparing with the original uncompressed movie. You would just have to find enough of the places where quality was increased. (And enough is a lot less than all of them).

The signature used in the encoding should be performed using the buyer's private key. In addition to this, I would sign the entire encoded movie using the seller's private key to be able to detect if a file is corrupted (as a service for the users). The part about the user signing something could be replaced with just using a hash of the text, but that might weaken the proof of origin of a particular movie a bit.

Now all of this could be combined with features to prevent users from accidentially losing a copy to a cracker/pirate. Since this is not intended to prevent users from intentionally copying the file, it could be a lot better and less intrusive than DRM.

Re:Ohhhhh...

[Omestes]

Quick correction, MPAA, not the RIAA. It is easy to confuse your media giant defenders of.. er... themselves, I know.

I'm not sure if I agree or disagree with this, though. I do like it better than nasty DRM, but it seems... Underdone, and perhaps still a step in the wrong direction. I think the various **AAs should learn that the problem isn't piracy, but that piracy is the symptom of a larger underlying problem, that their business model is outdated and self-defeating (may I add draconian?), and their prices are unfair.