I want to make remixes/mashups of songs on YouTube. The way this will work is I enter the name of 4 songs ("artist name - song name"), 2 of which I want to use as instrumentals and 2 of which I want to use as acapellas, along with the rough start time for the mashup to begin (eg 12.5 seconds). The tool will visit YouTube and download the URL of each song. It will then get the bpm tempo of each. Next it will extract the acapellas of the first 3 and instrumentals of the next 3. Next, it will extract the downbeats and bpm of each song. Next, it will look for the nearest "downbeat" to the start timer that user specified, and cut the instrumental/acapella from that point, beginning there and finishing 64 beats later (approx 16 bars, ie a full verse). Next, it will then calculate the amount that the acapella needs to be sped up or slowed down by, and execute the pitch shift/time stretch. Finally, it will combine both of these audio files in one file, and return the 64 beat "remix/mashup" MP3. It will of course repeat this for all 4 remixes/mashups (so we have 2 instrumentals x 2 acappelas = 4 total mashup mp3s returned).