High FPS exported video is black if video includes fading

[Geoff]

When exporting at 50 fps or higher at any resolution using h.264 or mpeg4 (any container) and at any quality, the video file is always black if the edited video contains fading at the start and/or end.

The exported video only displays properly at 30 fps or less.

The bad 'black' exported video file is quite small (e.g. 283.3 kb) as opposed to a 'working' export at 30 fps (e.g. 17.0 MB).

No errors are shown during the export.

The original (imported) video file is 1080p60 h.264.

I have tried playing the exported video back using the Ubuntu 'Videos' app, VLC 2.2.2, Handbrake 1.0.4 and Xine 0.99.9-1.2. All show the same result.

OS: Ubuntu 16.04 64bit
Openshot ver. 2.3.1 (installed via PPA)
FFmpeg (libavcodec) ver. 7:2.8.11-0ubuntu0
Melt ver. 6.0.0-2

NOTE: This process works as it should in Openshot ver. 1.4.3, but not in the newer version 2.3.1.

[Cristiano Fava (cristiano.fava)]

I verified the same issue with both 2.4.1 and 2.4.3.
Output format ok : 1280x720 24FPS
Output format ko : 1920x1080 50FPS (faded video segments completely black).
Since my video standard is 1920x1080 50FPS, I would sadly use another editor if no fix is available...