Encoding speed up and down

I heard a lot of people saying the encoding speed of XviD-1.0-RC1 is faster. But it seems it's not the case for me.

The encoding fps is very strange for me, sometimes, it can go up to 16 fps and sometimes, it suddenly drop to 2 to 3 fps. I am using virtualdub-mpeg2 to do the encoding.

I tired 2 machines, P4 3.2 and Dual 2600MP. The performance is the same for both machines.

Does anyone have the same problem?

I guess motion estimation is a very big part of encoding. When you have a low complexity scene like credits FPS, goes up, when there is too much or too complex movement in a scene, FPS goes down. Even so, I never experienced such a big diference in FPS but I haven't encoded anything significant since I bought a DVD-RW. (About 1 Year ago) I believe XVid has evolved it's motion estimation engine quite a lot since then so it's possible...

My encoding speed is usually about 25 fps for 1st pass and 10 fps for second pass. Credits encode at about 20fps. I'm using a Mobile P4 2,2GHz and a full average (1h30') 2-pass encode is about 4h30' here. I agree with duartix, as long as total encoding time is not annoying for your specs or quality is bad you shouldn't worry about speed fluctuations. It's just the encoder doing its job

this looks kinda like the speed variations i report here

I have noticed a simular speed varaiation when using GMC. But its not a problem for me as generaly it seems fast enough.

maybe ill try 100 bframes for laugh but its a little pointless as i doubt there will be many situations where more than 3 bframes are used

As chilledoutuk said this is mostly due to GMC, I have seen these same speed jumps if GMC gets used a lot then it will slow down. Trellis quantization also seems to cause speedups and slow downs but usually it is hardly noticable. Also, if you are using b-frames and vhq this can also happen, if you get a lot of pframes it will slow down and then speed up again when you use more b-frames etc. This is because vhq is not used for b-frames.

Thanks a lot. I think GMC is the cause. When I disable it, the speed getting more stable.

Is it normal to have around 11-13 fps if I encode from a dvd (720x480) to xvid (640x480)? I do not use any filter, just resize in virtualudb-mpeg2. If I turn on turbo, the speed can go up to 16-18 fps.

Bear:

use an aviysnth/vdubmod YV12 process chain. Your speeds are in normal range in average (dunno your system config though, and really - xvid does a proper job speed- and qualitywise).

Find infos about proper encoding that way in the avisynth forum (sticky thread about YV12) or in 's guides.

Regards
Koepi