Fastest way to add -movflags +faststart to an MP4 using FFMPEG, leaving everything else as-is

Question

I want to add -movflags +faststart to an mp4 file. Basically that is all I want to do, nothing else should be changed. I am using ffmpeg.

What's the fastest way to do this? Do I have to re-encode the whole video? Or is there a better/easier way?

Answer 1

As simple as:

ffmpeg -i in.mp4 -c copy -map 0 -movflags +faststart out.mp4

Or if you can compile FFmpeg from source, make the tool qt-faststart in the tools/ directory and run it:

qt-faststart in.mp4 out.mp4

You can also use mp4box, which lets you move the MOOV atom to the start via this command:

mp4box -inter 0 in.mp4 -out out.mp4

Or if you want to fully optimize for streaming by also interleaving the audio/video data so that the file can be easily streamed in realtime:

mp4box -inter 500 in.mp4 -out out.mp4