Keep in mind that you can use the GLBoom to run this with OpenGL renderer, which will boost the framerate more than original software renderer in PrBoom.
One thing I would like to ask is how do you go about converting .lmp files into files that can be processed on this site (for example, .avi, .wmv, etc.)? I tried uploading a file that has the .lmp extension and it failed.
lmp files are simply containing the information of demo files; they are not video recordings that you can upload directly on RU-vid. You need to record the demo file manually by using the video recording utilities, like Bandicam or Fraps. Alternatively, you can use the -viddump parameter on prboom with additional settings: www.doomworld.com/forum/topic/64647-converting-lmps-to-video/
