How do i calculate the correct bitrate for Xvid codec?

[Ingolf]

Hi

I want to hit an exact filesize, using the xvid codec, but i've got problems calculating the correct bitrate.

No matter what bitrate calculater i use, i get the same "correct bitrate", that i should use for encoding my videofile.
It is the correct bitrate if i choose DivX,. But for some strange reason, the target size of my Xvid video file ends up either way above or way below the target. What is up with that ?

I use VdubMod, latest version, to make my Xvid file, using the latest Xvid codec v1.1.3. I encode the video in 2 passes.

After many attempts to correct the bitrate i still cant hit the desired filesize. Offcourse its ok, it does'nt hit the exact filesize, but 100mb+/- is not acceptable imho.

So... is there a way to calculate the correct bitrate when using Xvid, so i don't have to encode the 2nd pass over and over again?

Regards
Ingolf

[guns1inger]

I like vcalc, but if all the calculators are giving you the same numbers then that isn't your problem. Are you taking audio size into account ?

[manono]

After many attempts to correct the bitrate i still cant hit the desired filesize. Offcourse its ok, it does'nt hit the exact filesize, but 100mb+/- is not acceptable imho.

So, it works with DivX but not XviD? Of course, when doing the same movie with the same audio and for the same filesize, the bitrate should be the same, no matter the codec. My suggestion is to first get rid of your XviD codec through Add/Remove Programs and then reinstall it. Size problems can occur when you haven't uninstalled an older XviD before upgrading. You should be coming within a couple of hundred KB of the desired size.

If, by chance, you're using AutoGK with the ESS chipset option turned on, then uninstall your XviD and upgrade your AutoGK to the latest ver 2.50, at the same time reinstalling the included XviD.

[Ingolf]

I like vcalc, but if all the calculators are giving you the same numbers then that isn't your problem. Are you taking audio size into account ?

Yes.

So, it works with DivX but not XviD? Of course, when doing the same movie with the same audio and for the same filesize, the bitrate should be the same, no matter the codec. My suggestion is to first get rid of your XviD codec through Add/Remove Programs and then reinstall it. Size problems can occur when you haven't uninstalled an older XviD before upgrading. You should be coming within a couple of hundred KB of the desired size.

If, by chance, you're using AutoGK with the ESS chipset option turned on, then uninstall your XviD and upgrade your AutoGK to the latest ver 2.50, at the same time reinstalling the included XviD.

I'm not using AutoGK, but VirtualDub Mod. I've tried on 3 different computers now, and still the size varies wildy in size. Actually the new test i just made, was on a fresh install of WinXp, upgraded to sp3. After that i installed xvid codec.

I like the codec, but this is frustrating. I've hit the correct size once, using Handbrake, but i want to use some filters in vdubmod, so it puzzles me why it wont work, using vdubmod

Any suggestions?

[Ingolf]

Ok, i tried to set a target filesize instead of bitrate, and it hit it spot on! Great!

Does that mean that the bitrate setting in xvid is buggy?