XVid conversion - controlling the quality

[madcat]

I watched today a recorded show that was converted to XviD using the detaults (I think):

Code:

<Conversion name="XviD" cmd="-y -i {SOURCE_FILE} -f avi -ab 224 -ac 2 -acodec mp3 -vcodec mpeg4 -b 1400 -vtag XVID {DEST_FILE}" targetExtension=".avi" />

The result had quite a poor quality. I was wandering how can I force it to convert, still maintaining better quality result.
The converted file properties show video Frame-rate=29 f/s and Data-rate=199kbps.
What does the -b 1400 value mean?

[EDIT] Ah, it also seems to messed a bit the aspect ration, although nothing in the parameters suggest that. any idea?


Thanks

[sub]

You can find documentation on the command line parameters at ffmpeg.sourceforge.net.