Exporting looping samples

Skaven252 wrote on 9/26/2006, 10:23 PM
I use Vegas to create individual sound effects for computer games. It's really handy since you can non-destructively trim, mix and add effects to stock and self recorded audio material. Also, if you need to create a large set of similar sounds (like a set of randomized footstep sounds), you can put them all in the same project and render them into individual samples. Yep, many reasons to use Vegas for this kind of work instead of a destructive sample editor like SF.

One problem area, though, is looping. To make a looping sample (either looping from start to end, or at a set point), you first have to render the project into a separate WAV, then crossfade loop it in an external application (like Sound Forge). It's an extra hoop to jump through, and alas, Sound Forge only does linear crossfade which causes a volume dip. Vegas' equal power crossfades give much better results.

There are some tricks you can employ to render a looping sample straight out of Vegas. It involves taking snippets of every event used in the project and fading them in/out accordingly. But it's tricky, and the resulting WAV may have a few bytes of glitch data at the loop point, and the WAV still has to be processed in SF to add the actual loop (Vegas can only save Markers and Regions, not Loop Points).

So... could Vegas be enhanced with built-in looping functionality? You could determine a Looping Region into the project, and when rendering the WAV, Vegas would automatically take care of the crossfading and adding the loop points to the WAV header, and check that the loop won't click (some kind of a preview would help here).

It would at least make my work easier. What do you guys think?

If not, here's a trick you can do to make things a bit faster: Associate your preferred output files (eg WAV) with your preferred sample editor. Then you can use the "Preview in Player" function in Vegas to directly render and open the sample in a sample editor for looping.

(Or, is there a better way to do this? Lemme know.)

Comments

Chienworks wrote on 9/27/2006, 4:40 AM
Why can't you do the crossfade in Vegas? I do this with video to create loops all the time and it should work perfectly for audio too. Say you have a 23 second audio sample and you want to make a 21 second loop out of it. Split the sample somewhere, anywhere not within 2 seconds of either end. Drag the right part back to the beginning of the timeline. Drag the left part so that it ends at 21 seconds. The two parts now overlap 2 seconds somewhere in the middle with a crossfade. Choose the fade type you want. Render to a new file. Done.
Skaven252 wrote on 9/29/2006, 12:46 AM
The problem with the approach I described, then you described again, is that it gets too fiddly if there are multiple sound tracks with several short events that may even have reverb tails. With those, the looping has to be done in an external application.

No biggie, just though that some looping feature would make work a little easier.
Chienworks wrote on 10/1/2006, 4:11 AM
Hmmm. I can't think of any reason at all why it would make any difference which program you used. Sound Forge cuts, copies, pastes, crossfades, and saves to a new file. Vegas cuts, copies, pastes, crossfades, and renders to a new file. *shrug* Absolutely identical processes, just easier to fiddle with it in Vegas. The content of the file you're working on has absolutely no bearing on the process at all.
Skaven252 wrote on 10/4/2006, 10:04 PM
1) Sound Forge still only does Linear crossfade, which dips the volume. Solution: you could always use WaveLab.

2) Vegas Audio can't output a sample with loop points in it. It can output regions and markers, but not loops. Because of this, the sample has to be post-edited in an external application even if you got it to loop right.

3) Even if Vegas did write loop points, there's no way to make absolutely sure the resulting loop doesn't click. Except by getting *really* fiddly with the fades manually and not using convolution effects (reverb, delay).

.. so in practice the pipeline for creating looping samples goes Vegas --> SF / WL.