What command are you using for a RMD session? Or are you using a GUI?
I’ve made various length Inkscape tutorials with RMD using a Konsole command as I find it pretty easy, even for a non-nerd like me. This may not apply to you but this is the command I use to record a windowed session...
recordmydesktop -windowid $(xwininfo |grep "Window id:"|sed -e "s/xwininfo\:\ Window id:\ // ;s/\ .*//") -fps 15 -device hw:1,0
-windowid $(xwininfo |grep "Window id:"|sed -e "s/xwininfo\:\ Window id:\ // ;s/\ .*//") is the window you what to record. If you what to record your whole desktop just drop this portion of the command.
-fps 15 = frames per second
-device hw:1,0 = microphone location (I use a USB Mic)
Time wise, my videos are the exact same length, ogv to avi, but I’ve also found that converting ogv to avi makes the final file size smaller than the original ogv.