There’s a new application in the Echo Nest developer showcase called SynchStep. SynchStep is an iPhone/iTouch application (currently only for jailbroken devices) that automatically synchronizes the music to your walking or running pace. SynchStep uses the Echo Nest Analyze API to extract the tempo for each song in your collection and when you are out for a walk or a run it will pick a song that matches your tempo.
I’ve seen a few academic systems that do this sort of thing. For instance, at last year’s ISMIR there was a paper called Development of an automatic music selection system based on runner’s step frequency that described a similar system. But SynchStep is the first system I’ve seen that is available to the general public on a popular platform like the iPhone.
SynchStep is a great example of a context-sensitive playlister. Instead of a list of songs selected via a random number generator, or via a DJ sitting in some dark, smoke-filled sound booth you get a playlist that matches what you are doing. I think we are going to see more attention paid to context-sensitive playlists: ‘Music for the root canal’, ‘Music that synchronizes with my windshield wipers’, ‘music for that first date with that girl who you think may be kind of emo’, and so on. To make these kind of playlists, the playlist generators will have to know what you are doing, and they’ll have to know what the music sounds like. Platforms like the iPhone already provides lots of context – the iPhone knows where you are, what time it is, it can hear you, it can see you, it can feel you move, it knows that the emo girl just sent you a ‘dear john’ IM, it can even hear your heartbeat. Signal processing and music analysis provides the other piece of the puzzle – knowing what the music sounds like. Just like SynchStep picks a track with a tempo that matches your pace, these next generation, context-aware playlisters will select music that fits the context. So when that kind-of-emo girl dumps you, your iPhone will know about it and will try to cheer you up with a little Katrina & The Waves. This song has super powers, it can even make the emo boys happy.