If you are under linux, you can use this:
http://www.sprocketandlube.com/shownews/item/67
I used:
mencoder -noodml input.avi -of avi -o /media/disk/OUTPUT_VID.avi -ofps 15 -vf-add scale=320:-2,expand=320:240 -srate 44100 -ovc xvid -xvidencopts bitrate=400:max_bframes=0:quant_type=h263 -oac lavc -lavcopts acodec=mp2:abitrate=96
My chip is:
ATTRS{vendor}=="RockChip"
ATTRS{vendor}=="0x10de"
ATTRS{subsystem_vendor}=="0x1849"