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?

score 38 · Accepted Answer · edited Feb 20 '20 at 18:47

38

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

edited Feb 20 '20 at 18:47

Mitch McMabers

answered Jun 18 '18 at 17:30

Gyan

You may want to add `-map_metadata 0` too in order to preserve any metadata – Mikael Finstad May 04 '20 at 10:05
Is there any way to "fully optimize" with ffmpeg instead of mp4box? I would be doing a transcode with ffmpeg, so it would be nice not to run a separate command. – Dmitry Minkovsky May 14 '20 at 16:18
@Gyan I'm sorry, I meant is there also a way to **interleave** with ffmpeg like with mp4box. Or, are you saying `faststart` will interleave the results? Not finding anything on Google – Dmitry Minkovsky May 14 '20 at 16:41
1

The MP4 muxer in ffmpeg does not support custom interleaving delta. faststart only relates to where the metadata is placed. – Gyan May 14 '20 at 17:53
@Gyan just seeing your reply now. Thanks a lot. – Dmitry Minkovsky Nov 06 '20 at 02:41
1

The ffmpeg command above (with either "+faststart" or just "faststart") gives me "moov atom not found" (the same error I'm trying to fix) I'm running on an .m4v file. – Jonathan Hartley Nov 16 '21 at 16:24
Is there a way to not do it under a new file and add it to the same header of the main file without reading the entire data of the file, so that we can reach the goal faster? – Nabi K.A.Z. Aug 27 '22 at 12:36

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