The modular Voukoder successor is planned to not rely on FFmpeg encoders only.
Do you plan to implement VFW or directshow version of Voukoder? Again, they work well not only in avi output container, but VFW and directshow codecs can work nice in mp4 mkv ts/mts flv etc.. other container formats too.
The FFmpeg is so buggy (and dumb) for HW encoding, that's why it was cancelled by Staxrip and Hybrid transcoders among their HW encoding options, and they replaced it with Rigaya's encoder engines. FFMPEG did not know the internal transcoding option, when both the decoding and encoding data were processed internally within the videocard. It makes transcoding much faster in a comparison with FFMPEG traditional transcoding when the process goes trough the CPU & system memory etc... .