[kortilla]

The glitch isn’t in ffmpeg, it’s in the receiving phone since you sent them a format which isn’t supported by that phone’s hardware decoder. The trick of youtube isn’t just a quick upload, it’s the auto transcoding to formats for anything that requests it over any arbitrary link speed.

[londons_explore]

Yep. And if the opensource world wanted to match that functionality, you would want ffmpeg to have an option to output all common formats, packaged together in a mega-file.

Then, when a user wants to watch a video, they could use HTTP range requests to download just the data they want to view from the megafile, in the format they need. If, midway through watching, their internet gets a bit slow, the browser could auto-switch to a different lower-res format. The megafile would have the necessary indexes etc to know which timestamps of which audio and video feeds are at which byte locations, and where keyframes are for easy switching.

Things like youtube have proprietary code to do this. But the opensource world doesn't have much comparable - at least nothing widely deployed to be able to just send a video to a friend, and know that whatever device and internet connection they have, they'll have a good experience.