Bitrate Variability CLI-version of x264

[[DSL]Sensenman]

Hi there,
i just wanted to ask what the unit used to describe the bitrate variability in the CLI-version is. Is it % like in VFW-version (so that 1,0 [the standard value] is 10%?), or another unit?

Thanks for your explanations :D

[akupenguin]

What is "the standard value"? and why would 1.0 be 10% in any units?

In VfW, bitrate variability is on a scale of 0-100%, default 60%.
In CLI, --qcomp is on a scale of 0.0 - 1.0, default 0.6.

[[DSL]Sensenman]

--qcomp is quantizer compression i think (this standard value is 0,6), but my question is about bitrate variance (I used the wrong word, sorry) and its standard value is 1,0.
Don't know why I thought 1.0 would be 10% (perhaps i thought so because 0,1 % steps would be pretty useless, so multiply with 10..., whatever)

[akupenguin]

So you mean --ratetol? That's not in any units at all, though a value of 1.0 happens to be on the order of +/- 1% filesize in a 1pass encode of decent length.

[[DSL]Sensenman]

So "bitrate variance" only applies to 1pass encodes and has no effect on 2-/multi-pass encodes?

[akupenguin]

It applies to 2nd pass also, but there's no reason to change it, since 2nd pass will be accurate no matter what value you set ratetol.

[[DSL]Sensenman]

OK, thanks for your help, akupenguin :D