<p>The really short answer to your headline question: Yes, and it is the file it self. (Or a pre-optimized version)</p>

<p>On the specific answer of YouTube's system, they <a href="http://www.revenews.com/search-engine-marketing/goog-to-outsource-youtube-filtering-to-audiblemagic/" rel="nofollow">out source</a> to <a href="http://audiblemagic.com/index.php" rel="nofollow">AudibleMagic</a> (You can request the white papers for their technology from their site if you are interested). The way their fingerprinting system works is content holders submit the content. And then files are compared against this set of fingerprints, this means that each copyrighted audio/video sample has a unique fingerprint in their system, <strong>not every file</strong>. The files are merely sent to them to be compared against their database (which they can optimize offline, to achieve their sub-second speeds).</p>

<p>The specific how could vary widely. I would start by looking at pattern recognition (the wikipedia article is good).</p>

CC BY-SA 3.0
2012-03-21T23:33:13.137Z
2012-03-21T23:42:02.283Z
2012-03-21T23:42:02.283Z
Mason Bially
<p>Disclaimer: I am not a CS person but this question is more philosophical in the sense i could not get a good enough answer ANYWHERE ELSE as to how systems such as Youtube content id work.</p>

<p>In Youtube content id system copyright video and audio files have unique fingerprints and every new file added is compared with all these files to identify the similarity. </p>

<p>If every file does have a unique fingerprint , can fingerprints of similar files (e.g. the same video with different qualities) be compared statistically ?</p>

<p>If not every file are there classes of encryption systems that work with different types of files like video, audio and image (with lot of relevant metadata)</p>

<p>I believe this is the best place on the internet to get the answer to this question and flocked here with great hopes</p>

CC BY-SA 3.0
2012-03-19T21:01:49.417Z
The fingerprints are obviously used to detect copyrighted material, too. They work well with audio (noise/resampling/distortion resistant) and there are many papers on the subject (http://www.google.it/search?q=Robust+Audio+Fingerprinting+System).
Marzio De Biasi
CC BY-SA 3.0
2012-03-20T02:28:00.683Z
Fingerprints are not unique, but assuming that fingerprints are assigned uniformly at random (which they are not, but they are close enough to work in practice), then the probability that there is a collision during the lifetime of YouTube (or Google, or the earth) is vanishingly small.
Tyson Williams
CC BY-SA 3.0
2012-03-20T09:14:17.823Z
This is not a research-level question in theoretical computer science (although it could become one with some careful editing).  Please see the [faq].
Jeffε
CC BY-SA 3.0
2012-03-20T22:27:28.217Z
the typical term used is "watermark" for audio or video files. imho advanced watermark/algorithm techniques/research are legitimate TCS
vzn
<cr.crypto-security><unique-solution>
Can every digital file have a unique fingerprint?
Sandeep
# Can every digital file have a unique fingerprint?

(Asked by: username_0 on 2012-03-19)

Disclaimer: I am not a CS person but this question is more philosophical in the sense i could not get a good enough answer ANYWHERE ELSE as to how systems such as Youtube content id work.

In Youtube content id system copyright video and audio files have unique fingerprints and every new file added is compared with all these files to identify the similarity.

If every file does have a unique fingerprint , can fingerprints of similar files (e.g. the same video with different qualities) be compared statistically ?

If not every file are there classes of encryption systems that work with different types of files like video, audio and image (with lot of relevant metadata)

I believe this is the best place on the internet to get the answer to this question and flocked here with great hopes

**Tags:** cr.crypto-security, unique-solution

> **Comments:**
> **username_1**: The fingerprints are obviously used to detect copyrighted material, too. They work well with audio (noise/resampling/distortion resistant) and there are many papers on the subject (http://www.google.it/search?q=Robust+Audio+Fingerprinting+System).  
> **username_2**: Fingerprints are not unique, but assuming that fingerprints are assigned uniformly at random (which they are not, but they are close enough to work in practice), then the probability that there is a collision during the lifetime of YouTube (or Google, or the earth) is vanishingly small.  
> **username_3**: This is not a research-level question in theoretical computer science (although it could become one with some careful editing).  Please see the [faq].  
> **username_4**: the typical term used is "watermark" for audio or video files. imho advanced watermark/algorithm techniques/research are legitimate TCS  

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## 1 answers

### Answer by username_5 on 2012-03-21. Score: 2

The really short answer to your headline question: Yes, and it is the file it self. (Or a pre-optimized version)

On the specific answer of YouTube's system, they [out source](http://www.revenews.com/search-engine-marketing/goog-to-outsource-youtube-filtering-to-audiblemagic/) to [AudibleMagic](http://audiblemagic.com/index.php) (You can request the white papers for their technology from their site if you are interested). The way their fingerprinting system works is content holders submit the content. And then files are compared against this set of fingerprints, this means that each copyrighted audio/video sample has a unique fingerprint in their system, **not every file**. The files are merely sent to them to be compared against their database (which they can optimize offline, to achieve their sub-second speeds).

The specific how could vary widely. I would start by looking at pattern recognition (the wikipedia article is good).


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