Colorimetry basics (and clamping)

[Ranguvar]

I'm trying to understand the basic idea of colorimetry. So, say I have a DVD which uses the Rec.709 matrix. What do I need to do in AviSynth in terms of this to get a proper output, when encoding with Xvid or x264? Or is colorimetry only essential to know about when converting between colorspaces?

Another thing, too... DVD's are clamped in terms of color to 16-235, for TV playback correct? Same for cable or broadcast TV? So, it would be smart to unclamp, if you will, to the full 0-255? Is this only possible when going from YV12 to RGB24? Can ColorMatrix() do this?

And I've been hearing quite a bit about the Output settings in ffdshow-tryouts... what should these be set to in most cases?

I just really want to understand all this :p

Thank you very much to all who try to help!

[Blue_MiSfit]

It all depends on how you view your content.

Haali renderer gives you control over how content is displayed, both in terms of colorimetery and levels. Most other renderers do not.

DVDs *should* be at 16-235, as should be broadcast / cable / satellite. It's not _always_ the case.

You can't magically recover more information than there is, so there's no point IMO in resampling 16-235 to 0-255. Most devices assume TV levels anyway, so it's a safe target.

I'm still learning about all this stuff too :)

~MiSfit

[Ranguvar]

Okay, thanks. Wait, now I see... ColorMatrix basically tells the renderer to use a different way of going from the 16-235 YV12 to 0-255 RBG24? I think.

[Blue_MiSfit]

Well no, ColorMatrix doesn't talk to the renderer. It changes the actual colorimetery of the video.

~MiSfit