SNDTRK is a custom soundtrack composer.
SNDTRK overlays a control surface on top of any video you'd like to score and tracks mouse or touch position over time to help you add a bespoke backing track for your video. As the cursor moves up and down in the control window, it activates each track and also those below. This lets users watch their video and dial up and down the musical intensity in real time based on what is happening in the video.
When the score's all done, the final track can be exported and added to your video, and then uploaded to any video sharing site. Wham. A custom SNDTRK for each of your videos.
The song in the demo video was created by Sam Carmichael.