Ok,
So I have an Archos 704. It has a screen resolution of 800x480, I bought it so i could watch video in high quality on the road. I couldnt wait to leverage MCs ability to convert on the fly all my Hi-def files to a format that this device would support without having to keep duplicates on my drive. I was dissapointed to find that I only had 3 options for encoding the files on the fly so I posted this question to the forum. After a few days with no response I again started trying to figure out how to do this myself. Turns out it was eaisier than i thought it would be.
In the plugins directory is a file called ffmpeg.xml
it contains the settings for the PSP encode profile (among others).
here is the line as it exists from JRiver
<psp>-y -i - -f psp -b 600k -s 320x240 -r 29.97</psp>
by changing it to this
<psp>-y -i - -f psp -b 1100k -s 720x480 -r 29.97 -acodec libfaac -ac 2 -ab 160kb </psp>
I was able to generate files of high quality/resolution, that would play on my archos 704. Just select the encode to psp option. By changing the resolution setting this also works on my 504. Im sure that it can be altered to fit whatever portable device you have. I hope this helps someone else out there. If i can assit in any way, just let me know!!!