Its production relies on the Echo Nest Remix API Python library for beat & pitch analysis. The API divides video into A/V segments, each described by a pitch, timbre, and loudness matrix (a PCA on a PAM on an FFT). Segments are drawn from the traffic video to match the music of Reich's "Violin Phase", drawing from the set of candidate segments using an algorithm that provides a criteria for evaluating the similarity of two segments.
In Road Phase, a YouTube performance of "Piano Phase" provides a soundtrack and rhythmic direction for a stuttering, syncopated story taken from the homemade travel video Syria to Georgia.
In Street Phase, a YouTube performance of "Piano Phase" provides a soundtrack and rhythmic direction for a stuttering, syncopated story taken from the homemade travel video Drive in Kabul.
Along the way I also made other remix experiments in the same vein, which are also on YouTube. In the two variations to Traffic Phase, various segment-matching parameters are set to gradually increase over the length of the video in order to add a bit of climax to the piece (this effect is very subtle in these variations; the idea of adding a very obvious build & climax seemed to me to run contrary to the minimalist aesthetic of Reich's phase pieces). In the driving videos I play with telling a "story" by introducing time into the segment-scoring metric, in effect limiting the choice of candidate scenes to a small sliding time window. I've also remixed "In God We Trust" with itself, choosing to substitute various segments with similar-sounding segments from the same video.