I think what you’re expecting is that when you select ‘Use Previews’ and your Preview File Format is the same as your desired export format, AME will just use the already created preview files as the exported file, which would actually be fairly ‘instant’.
However, this isn’t the way it works – it merely uses the previews to transcode from, rather than the raw timeline data. So there probably isn’t any time savings in selecting ‘Use Previews’, and in some cases, it may actually hurt you time-wise.
Sounds like you are wanting to do a rapid export of your timeline for use in another encoder perhaps? If I’m right, you would benefit from checking in on the development of the Advanced Frameserver project…
https://forums.adobe.com/thread/727162?start=0&tstart=0
The AFS lets you instantaneously create an reference AVI of your timeline data. No actual video file is created, it just wraps your timeline into a very small AVI, ready for use in any other program you like.
Steve Brame
creative illusions Productions