Last month a friend tried to set a video from her iPhone as her Telegram profile video. Telegram accepted the upload, spun for a second, then quietly did nothing. No error message. The video just never appeared.
The cause is boring: iPhones have recorded HEVC (H.265) by default since iOS 11, and Telegram's video avatar pipeline only accepts H.264. Telegram never tells you this. It fails silently, and you're left assuming your video is somehow broken.
I spent an evening figuring out the exact requirements, wrote an ffmpeg wrapper around them, and ended up shipping the whole thing as a Telegram bot. This is the build log.
What Telegram Actually Requires
The docs describe video avatars only vaguely, so most of this came from testing uploads until they stuck:
