My refuse to x264 ended when I discovered the qc parameter!

[unplugged]

Why is the quantizer compression set so high by default? (0.6)

On first tries I remember movies looked like CBR encoded, then when I tryed the qc at 0.2 or 0.3 (after tweaking to death any other parameter...) then the quality was very consistent.

(900 kbit/s, 704x304...)

[GodofaGap]

Your observation makes no sense. lowering --qcomp only makes the video MORE CBR like, not less.

--qcomp <float> QP curve compression: 0.0 => CBR, 1.0 => CQP [0.60]

[Sagittaire]

Why is the quantizer compression set so high by default? (0.6)

On first tries I remember movies looked like CBR encoded, then when I tryed the qc at 0.2 or 0.3 (after tweaking to death any other parameter...) then the quality was very consistent.

(900 kbit/s, 704x304...)

very consistant quality .... ???????????????????????

qcomp at 0.2 will done certainely something like cbr. Very bad quality for high motion part.
It's really not the more accurate setting for qcomp ... lol

If you want comparison then RC for XviD try to make constant quantizer in second pass.
For make that with x264 you must use qcomp at 1.0.

[unplugged]

But isn't 'quantizer compression' the opposite of 'curve (bitrate) compression' ?

[GodofaGap]

No, although I don't know where the term "quantizer compression" comes from (it is not in x264cli). But since the default of --qcomp is 0.6 I assume you are talking about that.

[akupenguin]

But isn't 'quantizer curve compression' the opposite of 'bitrate curve compression' ?
Yes. That's why x264's qcomp=0 is equivalent to xvid's curve compression=100%, which both produce CBR.

I don't know where the term "quantizer compression" comes from (it is not in x264cli). That's what "qcomp" stands for.

[unplugged]

Maybe I have found what was misleading to me
Quantizer Curve Compression

Regulates how much the quality can fluctuate within the target Average Bit Rate that
has been set. Lower settings constrict quality changes, producing a file that will have
a more constant quality throughout, while reducing the codec's ability to adapt to complex
scenes where loss of detail may not be as important. Higher settings increase variability
of quality, which may improve visual quality throughout the video by reducing quality
where fine detail can't be seen and increasing it where fine detail is more noticeable.
Setting this to 0 would result in constant quality. Setting this to 1 would create highly
erratic quality changes

[akupenguin]

The help context is wrong

[Sharktooth]

It will be corrected in the next MeGUI version.

[unplugged]

Ah, and I see that the latest version of the help context, with modified and shorter text for this option, it's wrong yet. (MeGUI 0.2.3.2191)

:p

[Sharktooth]

The latest version is in the SVN... :p