use FFDShow as the encoder.
Download FFDShow here (free):
http://sourceforge.net/projects/ffdshow-tryout/files/Old%20releases/generic%20builds/ffdshow_beta6_rev2527_20081219.exe/downloadInstall it and then click Start/Programs/ffdshow/VFW configuration
In there you can tell FFDShow what kind of file to create and what bitrate to use. Encoder: H.264 FOURCC: x264.
Now you have to open your PLR file,
{C:\Program Files\rFactor\UserData\MS7XWDC} scroll to the very end and look for the line that reads "AVI compressor fourcc="CVID"" and change it to "AVI compressor fourcc="FFDS"". Now rF will create much smaller files and will be much faster.
While you're in the PLR file you can also manually change the size of the video it exports. When your in the replay fridge it only has a limited list of video sizes like 800x600, 640x480 and a few others. I export at 1280x720 so that it is treated as HD when I upload it to YouTube. My PLR file looks like this:
[ Miscellaneous ]
Key Repeat Rate="1"
AVI export width="1280"
AVI export height="720"
AVI export framerate="30.00000"
AVI export quality="100.00000"
AVI compressor fourcc="FFDS" // Changes compression algorithm
you can 'copy' 'split' 'delete' etc etc ... you can change camera views just like when on track, add driver labels to cars with TAB
this video took 6 minutes per lap:
The trick to getting sound in exports is to start the export, let it run for 2secs, then hold the X key to cancel, then click export again. This works 100% of the time. For what ever reason the first export almost always produces no sound. I used to let the first export run all the way to the end but later realized I could simply cancel the export a few seconds in and then restart it.