AMIA (The Association of Moving Image Archivists) are offering an online webinar ($40) on Tuesday for how to use Shutter Encoder - https://www.eventbrite.com/e/i...

I am so glad someone made a tool like this (and free!!). i had a liitle play and it looks like very powerful though I definitely feel like I need a walkthrough the interface

I suspect the issue is deeper than just unsupported codecs. Isadora does scan the media to ensure file type and codec support, but unusual variations may cause issues. I have seen this mostly with downloaded media from archives etc..

My guess is h.264 and/or MP4 files are at the root. These can have a nearly limitless mix of meta data, audio codecs, and compression variations. 

Playback will be more reliable/predictable if you ensure media is matching. I recommend processing your files with Shutter Encoder in batches before import. This will ensure you have consistency. https://www.shutterencoder.com...