Avidemux reads large OBS .flv files wrong!

[phadeb]

I always record in .flv for crash safety. After recording I cut and remux them to .mp4 using avidemux.
However when I create a big file avidemux seems to get the wrong duration, this only appears to happen with relatively large files.

The first time I experienced this was when I recorded lossless (qp=0) and got a 8GB file with a duration of 20 minutes, avidemux falsely though the file was only 9 minutes long. I figured it was due to recording lossless, so I switched to crf=18 instead. I then recorded another video with the new settings that came in at around 5GB with a duration of 1 hour 14 minutes. avidemux thinks its 18 minutes long and thus only reads the first 18 minutes.

Thanks for your help!

[eumagga0x2a]

Please state the exact version of Avidemux and the platform it is running on. What does ffprobe report for your flv videos? Is ffplay capable of playing them correctly?