[MPlayer-users] Encoding performances

[Reimar Döffinger]

Hello,
On Mon, Sep 03, 2007 at 05:05:24PM +0200, Lucio wrote:
[...]
> 1. How long does it take approx to convert 30 seconds of jpegs into mpeg4 at 
> 800kbit/s and 30 fps, using a fairly slow CPU (Via C7 1GHz)?

If I had to guess, I'd say you can tune the options to make it take
anything between 20 and 2000 seconds.

> 2. Assuming 30fps and 30 seconds I should have 900 jpegs. Assuming I have, 
> say, 1800 jpegs because the original swf had been made at 60pfs, is it 
> possibile to ask mencoder to drop 30 fps, which is one frame every two?

That happens automatically when setting -mf fps to 60 and -ofps to 30,
but you might not like the result.
You can also use -vf framestep=2 (with -mf fps set to 30 I think).

> 3. What's the best quality/speed/fps tradeoff to have a decent mpeg4 playing 
> smoothly with mplayer on a Via C7 1Ghz with Unichrome Pro IGP graphics 
> adapter, openchrome drivers at 1024x768x32?

I don't know how much this Unichrome model sucks, but on my old Athlon
800 I always had enough CPU left during MPEG4 decoding (though
resolutions were only around 720x576, but I'd expect it could have
handled 1024x768 as well).
But honestly, the only proper answer is: Try it out!

Greetings,
Reimar Döffinger