I recently got myself an MP4 player from China, the unit is fair enough but I kept having problem converting FLV to it's own little AVI format. Quite a nuisance as I had to do multiple passes (one to AVI, then it's AVI through the supplied software).
Here is a picture of the device that I got from a China-based eBay reseller:
Finally, I got onto a forum and found a solution.
viDrop is an excellent software that basically writes the conversion details for you and it's has presets for the Rockchip format. I recommend the Generic Rockship (medium) preset.
The site is not in english, but if you scroll and keep looking right you will see VIDROP in bit red letters, clicking on it will trigger the .MSI download.
For your convenience, here is the script that I use to convert from FLV to my Rockchip AVI format using mencoder:
mencoder "c:\input.flv" -idx -forceidx -ovc xvid -xvidencopts bitrate=300:me_quality=6:max_bframes=0:quant_type=h263:turbo:nochroma_me:notrellis:vhq=0 -vf-add scale=-2:240 -vf-add crop=320:240 -vf-add expand=320:240:-1:-1:1 -vf-add eq2=1.1:1:0:1.2:::: -ofps 22 -oac twolame -twolameopts br=112:mode=stereo -af volnorm=2:0.25 -af channels=2 -srate 44100 -o "c:\output.avi" -vf-add harddup -noodml -of avi