I'm making some SD h264 mp4 files in Premiere from some Youtube rips, and AME insists on preparing 42 audio files before making the (mono) audio output. It goes through each of the 42 quite quickly but it massively increases the processing time.
Whatever the codec the Youtube files may have had originally, they have been rendered out into Adobe Audition beforehand so they are standard wav files.
Why is it doing this with these particular files? It doesn't normally, when processing similar SD video files using the same settings.
Try removing unused audio files from the PPro project.
Alas, there are no unused tracks,
Today, in a virtually identical project, it is processing not 42, but 19 audio files. No idea why the difference, or why it is happening at all. The video files are on a different PC on my home network, if that makes any difference?
I believe the problem may be down to some of the files being sampled at 44.1khz. They need to be converted to 48khz in Audition before being sent back to Premiere.