[FFmpeg-user] After demuxing 50i = 50p (...I think...)

Hornung, Bastian bastian.hornung at wur.nl
Tue May 3 17:19:33 CEST 2016

Hey guys,

I have stumbled upon some weird problem, and I'm not sure how to solve it. Actually I'm also not sure if I really have identified the problem, but I think it's the most likely one.

So I have some video, MPEG2 video, LPCM16 audio, MP4 container, recorded in 1920 * 1080, 50i (shows up as 25 in VLC).

Since this is apparently an invalid combination (according to specifications, and Adobe Premiere 2015 doesn't import it; CS6 does, but I don't have that available anymore), I'm trying to convert the audio into WMAV2 (that seems to work; there are other problems with other codes), but leave the video as it is, and change the container to AVI (because Premiere apparently also has some problems with MP4).

The command (on ffmpeg 3.0.1, Ubuntu 14.04):

ffmpeg  -i /input/F131_1873_01.MP4  -c:v copy  -map 0 -c:a wmav2  /input/F131_1873_01_converted_video_copy_audio_wmav2_default.avi

The resulting video plays fine in VLC, but the metadata suddenly says 50 fps instead of 25 fps before.

This results to problems in Adobe Premiere, which now actually plays it in 50 fps (sound is fine though).

If I use -r 25 in the conversion to fix the frame rate, the video itself will get blurry.

So somehow, after demuxing, my 50i video is recognized as 50p (....right....? I'm not a professional in videos, maybe I'm misinterpreting the problem).

Has anyone stumbled upon this before, and if so, how can I fix this?

Thanks guys :),


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