How-to export loops for games with Live and DP

Mike and I are creating the Snowferno soundtrack in Ableton Live and Digital Performer. Each track is meant to loop of course, so (at least within the limitations of the phone hardware) we want the loop's seams to be as transparent as possible.

Both Live and DP have great features for looping playback, but exporting the final audio from each app as a loop requires two different approaches.

Live is totally loop-centric out of the box, so there is simply a switch in the "Export Audio/Video..." window to "Render as Loop". This switch causes Live to do something pretty cool. It makes *two* passes of the track and uses the first pass to calculate what reverb tails, delay feedback, and so on should carryover and be sounding at the beginning of the exported audio file.

DP is more linear by design, so it doesn't provide a one-click solution. You need to fake it -- which I do by pasting a copy of the final measure of MIDI again before the first measure of the loop. My "Bounce to Disk" selection area includes that pre-measure as well as one extra measure of breathing space beyond the last measure of the loop. I set the "Bounce to Disk" window Import setting to "Add to Sequence" and then bounce it. Next, I slice out the exact region of the loop from the just-bounced/imported soundbite minus the extra pre/post measures and export that soundbite from the Soundbites List. It helps if you rename the sliced soundbite and delete the unused bits. It's little more work, but it gets all the material that will still be sounding at the end so that it can be triggered and sounding still at the beginning of the track. Plus, I've found DP needs a little space for things to ramp-up and down. Adding those pre/post measures lets all my Waves processors get humming far away from the parts of the audio where a loop seam will be.

The final loops go in to Unity as AAC-encoded files so that the iPhone decodes it in hardware. We're still experimenting with what the final bitrate will be -- once all the tracks are done, we're going to find the balance between great-sounding music and needless app size bloat.