[MEncoder-users] How do I use a cbr with vpass that works for both high and low def vids?

David Smith dcsmith2 at gmail.com
Sat Jul 12 07:00:58 CEST 2008


I am using lavc to try and create a one-size-fits-all command line
outputting flv's that works efficiently for both low and high definition
vids.  I want to set a baseline of, say, 300kbps with a max of 3000kbps and
a min of 128kbps, and mencoder will simply convert my videos somewhere in
that range automagically.  Is this possible?  I have tried using -vqscale to
achieve this, but I never get quite as good a quality as a double pass, so I
am really stuck on using vpass now.

For example, when I do something like this:

mencoder in.wmv -o out.flv -oac mp3lame -lameopts abr:br=32 -srate 22050
-ovc lavc -lavcopts
vcodec=flv:vbitrate=300:mbd=2:trell:v4mv:last_pred=3:vpass=1:turbo -mc 1
-ofps 30 -of lavf -vf harddup

mencoder in.wmv -o out.flv -oac mp3lame -lameopts abr:br=32 -srate 22050
-ovc lavc -lavcopts
vcodec=flv:vbitrate=300:mbd=2:trell:v4mv:last_pred=3:vpass=2 -mc 1 -ofps 30
-of lavf -vf harddup
I get low bitrate warnings from high def vids that should really be encoded
around 3000-4000kbps.  However, I also have "normal" videos that I don't
want to overinflate with a 3000kbps constant bitrate since they look just
perfect at 300kbps (or even at 196kbps).   So how do I reconcile this?

I see options for min and maxrate, but I don't know whether those can help
me with [whatever]-to-flv.

BTW, I have been told in previous emails that I should try using 264
encoding and that I can run the mp4 output in Flash, but I have not seen any
command line examples to do this.  If 264 is the way to go, please advise.
I didn't know Flash could play other formats besides flv.  I'm not familiar
with "containers" so if you say just output the 264 into a playable
container, please elaborate.  Thanks in advance for your advice.



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