I have a project that
- generates a .jpg file with a caption (using imagemagick convert)
- creates a .mp4 file by combining the .jpg file from step 1 and an .aac audio file
- concatenates several videos from step 2 into one large .mp4 file.
It all works well enough but what I'm finding now is that the final combined .mp4 file from step 3 plays just fine in Windows via Chrome or VLC or whatever. But when I try to watch the same video on my phone using android/chrome, it doesn't seem to know how to play it.
I'm sure it's something with framerates (step 1 above?) or encoding or something, but does anybody have any hints that'll get me steered in the right direction? Just can't seem to figure it out. The server this is all happening on is Ubuntu Server 20.04.