[FFmpeg-user] fragmented mp4 and playing while converting

Dennis Mungai dmngaie at gmail.com
Wed May 5 13:52:43 EEST 2021

On Sun, 2 May 2021 at 04:54, Julien Dotsev <j.docev at gmail.com> wrote:

> Hi, I'm looking for a possibility to play the output file during the
> conversion. I tried with fragmented mp4 and this command:
> ffmpeg -i input.avi -movflags
> +frag_keyframe+separate_moof+omit_tfhd_offset+empty_moov output.mp4
> The problem I have is that when I play the output it plays until the
> momentary time duration of the video. For example If I hit play and I have
> 2 min converted video at that moment it will play just the 2 minutes and it
> will not play more even if at the end of that 2 minutes all the video is
> converted.
> Is there any way to let the video play all the way during its conversion?
> Maybe some way  to insert the real time duration of the video? or maybe
> another video format? Anything that can let me play the video in an html
> <video> tag during its conversion.
> Thank you.

Try this:

ffmpeg -re -i input.avi -movflags
+faststart  output.mp4

That will encode the file in real time, allowing for real time playback.

The other movfpags are useless unless you’re writing fragmented content,
such as fmp4 for HLS or DASH. The faststart movflag is sufficient.

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