[FFmpeg-user] DASH and Variable framerate

Moritz Barsnick barsnick at gmx.net
Fri Aug 7 14:25:33 EEST 2020

On Thu, Aug 06, 2020 at 15:00:55 +0200, Alfred E. Heggestad wrote:
> I am wondering if DASH muxer supports variable framerate.
> What I have seen is that DASH and HLS behaves differently
> regarding variable framerate input.
>    muxer:               format:   audio delay:
>    DASH:                m4s       yes
>    DASH w HLS playlist: m4s       yes
>    HLS muxer:           mpegts    no

I suspect this is due to the fact that ffmpeg does not handle variable
framerate in MOV/MP4 well (which m4s is a variant of, IIUC).

> in m4s the audio and video track is stored in separate .m4s files.
> after some time they become out of sync.

I don't think the separate files are the issue. HLS can also separate
video and audio into separate files, as far as I remember.


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