I added some 4K video to Proclaim, and the performance is terrible. I can play the video locally through VLC with no difficulty (my laptop has an i7 processor). If I upload the file to Proclaim, both in the preview and while On Air, the video freezes and I just get sound, or I might get one frame every 5 or 6 seconds or so. On my desktop PC, which has a discrete GPU, I get about 10fps, and the video lags significantly behind the audio.
If I store the file locally, it's better, but still nowhere near good enough. In that scenario I get 2-3 frames per second on the laptop.
The file was shot on an iPhone and is using the H264 codec.
If you want to test this, I've created a presentation called Faithlife test.
