[MEncoder-users] Video for YouTube, getting extremely low quality movies

[Apple7777]

Hello,

I'm trying to encode uploaded movies with highest possible quality. I'm joining
two videos (logo and movie).

My command line is:
first pass: /usr/local/bin/mencoder -really-quiet -vf
scale=448:-3,expand=448:336 -sws 9 -of lavf -ovc lavc -lavcopts
vcodec=flv:vbitrate=250:trell:v4mv:mv0:mbd=2:cbp:aic:cmp=3:subcmp=3:vpass=1
-frames 800 -ofps 24000/1001 -oac mp3lame -lameopts abr:br=64:mode=0 -channels 1
-srate 22050 -of lavf -lavfopts format=flv -o /home/re/video/2/25.flv
/home/re/ff/logo7.avi /home/re/video/2/27temp

second pass: /usr/local/bin/mencoder -really-quiet -vf
scale=448:-3,expand=448:336 -sws 9 -of lavf -ovc lavc -lavcopts
vcodec=flv:vbitrate=250:trell:v4mv:mv0:mbd=2:cbp:aic:cmp=3:subcmp=3:vpass=2
-frames 800 -ofps 24000/1001 -oac mp3lame -lameopts abr:br=64:mode=0 -channels 1
-srate 22050 -of lavf -lavfopts format=flv -o /home/re/video/2/25.flv
/home/re/ff/logo7.avi /home/re/video/2/27temp

The output is here:
http://www.roamearth.com/video/2/27.flv


I wonder how can I increase quality of the output movie?

I could increase bitrate little bit (maximum is 350 with sound), but when I use
vbitrate=285, for example, I get movies with higher bitrates. Is there command
for a hard video bitrate limit?

Also, this output movie is really jerky (as the other ones) with 15 fps, and
even with 24 fps!

I wonder how can I fix this?

Could you answer all three questions please.