/* Video settings:
vcodec: output codec
- vquality: output quality (0.0..1.0)
- if < 0.0 or > 1.0, bitrate is used instead,
- except with x264, to use its real QP/RF scale
- vbitrate: output bitrate (kbps)
+ vquality: output quality (if < 0.0, bitrate is used instead)
+ vbitrate: output bitrate (Kbps)
vrate, vrate_base: output framerate is vrate / vrate_base
cfr: 0 (vfr), 1 (cfr), 2 (pfr) [see render.c]
pass: 0, 1 or 2 (or -1 for scan)