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====== Can we break it? Yes we can! ====== | **Authors **| Patricio López-Serrano, Hendrik Schreiber, Jonathan Driedger, Richard Vogl, Sebastian Böck| | **eMail** | {patricio.lopez.serrano,jonathan.driedger}@audiolabs-erlangen.de,hs@tagtraum.com| EDM (Electronic Dance Music) is often constructed from 8 //samples// or //loops//, stacked on top of each other. A common pattern of EDM artists is to start a song with a single loop. While the song builds up, more and more loops are added. {{ :step1.jpg?nolink&400 |}} As an example, listen to this exerpt of Moby's song "Porcelain". {{:Moby_Porcelain_FullSong.mp3|}} The goal of our hack was the following: Given an EDM song that was build up in the above described way, we want to *break it into all the separate loops that were used to create it*. To this end, we came up with an iterative strategy. ===== Step 1: Identifying Isolated Loops ===== In a first step, we need to identify a loop that occurs without other loops stacked on top of it. {{ :step2.jpg?nolink&400 |}} I.e. the task is: - Find a sample that's as //pure// as possible. - Removethe sample wherever it occurs in the song. - Repeat. //Pure// in this context is shall mean //standalone//, i.e. a sample that is not polluted by another sample yet. ===== Finding pure Samples ===== - SSM (diagonal median filtered) - Identify paths that have a certain length and length/distance relationship - Pick a path according to the super-secret rules - Find similar locations in the song To find similar locations in the song, we weren't able to use a regular cosine distance function, because we are not looking for absolute similarity, but rather a "Sample A contains Sample B" relationship. ===== Removing samples from the Song ===== In order to remove samples (loops) from the song, we simply subtract the magnitude spectrogram from the original spectrogram and re-synthesize both signal—the remains of the song and the sample we subtracted. ===== Repeat ===== We can continue this process for a number of iterations. Results get stranger and stranger...
