prboom+ -viddump GPU hardware encoding

[cybermind]

Hi there, haven't found if somebody did that already before me.

I've managed to use NVIDIA hardware encoding for -viddump command. Hope this guide will be helpful to somebody.

Here is how:

(0). Ensure that your prboom+ configuration is able to run -viddump command properly (download oggenc2, mkvmerge etc)
1. Download latest ffmpeg here: https://www.ffmpeg.org
2. Place ffmpeg.exe to prboom+ directory.
3. Open your gl(pr)boom-plus.cfg configuration file.
4. Modify cap_videocommand line to this:

cap_videocommand          "ffmpeg -y -an  -f rawvideo -pixel_format rgb24 -video_size %wx%h -framerate %r -i - -c:v h264_nvenc -preset llhp -rc:v cbr -cq:v 16 -bf:v 3 -b:v 6M -maxrate:v 8M -profile:v main -bufsize:v 8M output.mp4"

(4.1). Customize it to your needs (e.g. change encoder to hevc_nvenc, increase bitrate, I'm not a big expert in ffmpeg encoding commands)

5. Save it.
6. Run your demo file: gl(pr)boom-plus.exe -viddump test.mp4 -timedemo demo.lmp

On my notebook (Asus TUF Gaming FX505DT, Ryzen 5 3550H, NVIDIA GTX 1650) hardware encoding takes more than 2 times less time compared to CPU encoding with x264.exe

Tested with glboom-plus.exe -timedemo lv23-208.lmp, 60 fps, 1280x720: GPU - 73.3 fps, CPU - 31.3 fps.