How Can I Set Video Bit Rate Using Nreco

A bit late but I didn't see any answers for this question.

It is rather trivial to set video bitrate (say, 64 kbit/s) with NReco VideoConverter component:

var ffmpeg = new NReco.VideoConverter.FFMpegConverter();
ffmpeg.ConvertMedia("input.avi", null, "output.mp4", null, 
 new ConvertSettings() {
  CustomOutputArgs = " -b:v 64k -bufsize 64k "
 });

more options you can found in the ffmpeg documentation.