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For some reason +faststart is not working.

ffmpeg -i original.mkv -vcodec h264 -acodec aac -vf format=yuv420p -strict -2 -movflags +faststart result.mp4

ffmpeg -i original.mkv -c copy -movflags +faststart result.mp4

I run both of these commands. Neither applies the faststart. The video takes around 5 minutes to play in the browser due to the flag not being there. I'm assuming it's something to do with the argument order, but every post on here I see has it after the codec.

Joe Finlo
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  • `faststart` doesn't necessarily mean "start faster". `-movflags +faststart` is used for placing the "moov atom" at the beginning of the file. Check [this post](https://superuser.com/questions/559372/using-ffmpeg-to-locate-moov-atom), and [this post](https://stackoverflow.com/questions/56963790/how-to-tell-if-faststart-for-video-is-set-using-ffmpeg-or-ffprobe). Compare the MP4 file with and without the flag. In case it has no affect, update the version of FFmpeg. – Rotem May 15 '22 at 16:19
  • FFMpeg is fully updated. My MP4 videos require the full thing to load before they can play. Never had this issue before – Joe Finlo May 16 '22 at 04:47
  • Please execute `ffmpeg -i original.mkv -c copy result1.mp4` and then `ffmpeg -i original.mkv -c copy -movflags +faststart result2.mp4`. Compare `result1.mp4` and `result2.mp4`. If the files are identical, there is a problem... If not, verify that the position of the moov atom of `result1.mp4` is at the end of the file, and for `result2.mp4`, the moov atom is at the beginning of the file. – Rotem May 16 '22 at 05:33

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