The goal is to support just about anything you can throw at us, but the reality is that's going to take months of debugging whatever insanity the internet can throw at us. Derek from the Vimeo/VideoLAN team gave a really great talk on just how awful the world of user uploads can be at Demuxed 2017: https://www.youtube.com/watch?v=cRSO3RtUOOk&list=PLkyaYNWEKc...
That being said, we should handle most modern codecs you can throw our way. PDFs are going to fail (you'd be shocked at how often I've seen this). If you can, use h264 video and AAC audio as that's what our system is optimized for and will you give you the best performance.
In an ideal world, you'd send 1080p high profile h264 encoded with a bitrate above 8Mbps (or CRF 18 for x264 nerds), with a max keyframe interval of around 5 seconds. Closed GOPs also makes processing more efficient.
