Question / Help Remuxing creates variable framerate file?

[obstribble]

I'm recording in mkv instead of mp4 because a crash will leave the recording intact up until the crash. Then I remux the mkv into mp4, because I'm editing with Premiere and it needs a mp4. Here's where OBS creates a problem:

the remuxing function of OBS Studio turns a constant framerate mkv into a variable framerate mp4.

Most editing programs don't like variable framerate files. So now I have to recode the ruined mp4 into a constant framerate mp4 with Handbrake. Of course then I could just recode the mkv with Handbrake...but I want a quick remux, not recode every single file I record for hours and hours.

Now, 2 questions:

1. Is the remuxing function of OBS Studio broken, is this a bug? Or is there some setting I'm missing?!
   
2. Is there another program I could use instead that will reliably remux a constant framerate mkv into a constant framerate mp4?

 

[obstribble]

Anyone have an idea why I'm getting variable framerate mp4 from remuxing when OBS is supposed to put out constant framerate?

 

[Suslik V]

I have an idea that your recording just not so perfect as you think - how you get VFR? Or more clear: why you are thinking that remuxed mp4 is VFR?

 

[obstribble]

Mediainfo recognizes the original mkv as constant framerate. The remuxed mp4 is recognized as variable framerate. This variable framerate causes audio desync in Premiere. So 2 very clear indicators:
1. analysis software sees the change to VFR
2. editing software can't handle the VFR

So something is happening during the remuxing process of OBS.

 

[Suslik V]

Understood.

@Harold , hey I know that it out of importance only life is important but look how imperfect all this world of GNU GPL stuff. Example. Man want to use proprietary software together with open one and had difficulties now.

@obstribble as far as I know, the both tracks in a movie has different scale (base sample size is different for video and for audio), so it can potentially indicate different track size. Maybe this info interpreted wrongly by mkv_to_mp4 remux but only because of media containers difference. Anyway, this should not introduce any sync issues into your video (all sync issues already present in original mkv file, I think).
Try to record using Custom Muxer Settings. More info on this: Stopping recording never ends And see, if it helps or not.

 

[obstribble]

The mkv isn't desynched on playback with any player, so I think it's happening with the remuxing.
How do I use this "movflags=frag_keyframe min_frag_duration=4000000"?

 

[Suslik V]

Just insert this info into the Custom Muxer Settings field when recording mp4/mov. Just in case, OBS Studio Help Guide: https://obsproject.com/forum/resour...ware-studio-multiplatform-help-guide-pdf.365/

 

[Boildown]

For some reason the media info for OBS MP4s (that I've seen anyways) is always variable, even if you recorded at constant. Its just metadata though, doesn't mean it really is variable. Have you tried the files anyways to see if they work?