Just a brain dump to future me, hi future me!, I had a 140mb MP4 file but it failed to upload via wordpress’s media page, got to like 10% and stalled. So I uploaded it via sftp and I used a plugin to integrate it into wordpress. Only to find the mp4 doesn’t play. Odd, it said it was a mp4 file, but maybe it uses HEVC encoding or something else “weird”. So I eventually converted it to something more “standard” and web friendly using this command (which is the only reason you came to this page right?):
ffmpeg -i SourceVideo.mp4 -movflags faststart -crf 26 DestVideo.mp4
Interestingly, the resulting file was about 47mb, so it was smaller. I uploaded it successfully using WordPress’s UI this time and it seems to play.
https://blog.addpipe.com/converting-webm-to-mp4-with-ffmpeg/
Copied the command from that page above ^.