Voukoder R2 produces x264 video with Incorrect timebase. I encoded 10 seconds 59.94 fps video using Voukoder 2.0.8 and 1.2.1 in PrPro CS6, Some video hostings consider those videos VFR. I have very limited knowledge in this area and am not sure if I understand this problem correctly. But i think it appeared in 2.0.0-beta1 release and could be related to this issue.
Here are ffprobe output:
Voukoder 1.2.1:
codec_time_base=1001/120000 (in my understanding this is correct)
r_frame_rate=60000/1001
avg_frame_rate=60000/1001
time_base=1/60000
duration_ts=600600
duration=10.010000
nb_frames=600
Voukoder 2.0.8:
codec_time_base=599599/72000000 (In some other tests I saw different weird numbers)
r_frame_rate=60000/1001
avg_frame_rate=36000000/599599
time_base=1/60000
duration_ts=599599
duration=9.993317
nb_frames=600