Analyzing YouTube's Audio Fingerprinter

Al Benedetto writes "I stumbled across this article which analyzes the YouTube audio content identification system in-depth. Apparently, since YouTube's system has no transparency, the behaviors had to be determined based on dozens of trial-and-error video uploads. The author tries things like speed/pitch adjustment, the addition of background noise, as well as other audio tweaks to determine exactly what you'd need to adjust before the fingerprinter started mis-identifying material. From the article: 'When I muted the beginning of the song up until 0:30 (leaving the rest to play) the fingerprinter missed it. When I kept the beginning up until 0:30 and muted everything from 0:30 to the end, the fingerprinter caught it. That indicates that the content database only knows about something in the first 30 seconds of the song. As long as you cut that part off, you can theoretically use the remainder of the song without being detected. I don't know if all samples in the content database suffer from similar weaknesses, but it's something that merits further research.'"

Comments

Slashdot brainstorm here

[eclectro]

Here's an idea. Start out the video with a useless narrative for the first thirty seconds "blah blah blah skip until :30 and ignore this intro blah blah" then start the music. That way everybody is happy. All google employees are too elitist to read slashdot, right?

Re:Slashdot brainstorm here

[Anonymous Coward]

I see where you're going with this: put an advertisement at the start :-)

Re:Slashdot brainstorm here

[VeryLargeNumber]

Even better - upload the video backwards.
Someone should make backward youtube plugin for firefox. It even might autodetect backward songs and play them properly.

I'd rather lose the last 30 seconds

[Knave75]

An unfortunate result. The last 30 seconds of most songs are not usually as interesting as the first 30 seconds.

I wonder if he tried mangling the first 30 seconds at all. For example, keep the first 5 seconds, mess up the 6th and 7th seconds, and then continue on. Or perhaps adding in a base line that would be hard to hear. Or something at the high end of the audio frequency spectrum, to annoy all those teenagers while I listen to my free music in peace.

Re:Research?

[radtea]

This is not riddle posed by Nature

This is one of the wonderful things about science: it doesn't matter where the puzzle comes from, the same techniques work to solve it.

Reverse engineering of this kind is one of the most useful areas of applied science, and it is as much research as any other area of scientific enquiry. It is frequently the case that there are many ways to find the answer to a puzzle, and this guy has chosen one of them based on the resources he has available. More power to him for demonstrating how good science can be used to discover what others want to keep secret.