[XviD-devel] Re: 2 pass

[Guillaume POIRIER]

Hi Karine,

karine.yviquel <karine.yviquel <at> laposte.net> writes:
> The solution to use the two-pass mode is as follow:
> xvid_encraw.exe -i video.yuv –type 0 –w 448 –h 256 –frames 3 –o code.yuv
–pass1 data1.txt and then,
> xvid_encraw.exe -i video.yuv –type 0 –w 448 –h 256 –frames 3 –o code.yuv
-bitrate 300000 –pass2 data1.txt
> The first pass is coded with a constant QP.
> But the 2nd pass is perform in VBR mode that why we need the bitrate too.

Right, I forgot to mention that.

One thing you probably should know is that AFAIK, rate control kicks in when you
do a 2-pass encode with at least enough frames fo fill the RC buffer.
If the RC doesn't have enough frames to play with, AFAIK, you'll get the same
result as if you were doing a 1-pass encode (more or less CBR).

(I mention that as you _seem_ to encode just 3 frames. I'm not quite sure
though, as I don't know the syntax of xvid_encraw.)

Regards,

Guillaume