How do I change IRE black levels?

[echo1434]

Hi,

I'm looking for something that can easily change a video file from IRE 0.0 to 7.5 and vice versa. I was hoping to use something simple like VirtualDub, but am open to suggestions. Are there any filters or plug-ins made specifically for this that work with VirtualDub?

I have Adobe Premiere Pro, and I believe it can do this, but I really hate this program. It is very user un-friendly and makes no sense to me!

Thanks in advance.

[lordsmurf]

TMPGENC can do it.
Of course, whatever you do, you have to re-encode.

[echo1434]

Really? I have pretty much all the TMPGEnc programs. It seems that the Xpress 3.0 is the workhorse of the bunch that can do the really good stuff. Where should I be looking for this feature? Thanks!

[lordsmurf]

It's an CUSTOM COLOR CORRECTION filter.
"YUV DESCALE CCIR601"

But it only goes from 7.5 to 0.0

So nevermind.

And I could be wrong, this may not be IRE correction, but I have no idea what else it could be. TMPG is weird in this regard anyway, lots of non-sense names for certain settings and filters.

[manono]

Hi-

Not really my field, but after a short search, and if you use AviSynth, it looks to me as if adding:

ColorYUV(Levels="PC->TV")

to your script will do what you want. For more info, try this thread:

http://forum.doom9.org/showthread.php?t=70140&highlight=IRE+black

and the link to the capture FAQ in there. One comment from the thread that stuck out was this:

IRE is a generic analog scale. Once in digital, this is the wrong thing to use. When your DVD player outputs a value of 16, it should set black to IRE 7.5 in the US and IRE 0 elsewhere.

I'm not really sure if this will help you, but I hope so.

[edDV]

I haven't done it with either TMPGENC or AviSynth filters* but if you do you want a linear rescale (stretch) of black level from 7.5 IRE (digital 32) to 0.0 IRE (digital 16) without changing 100 IRE white (digital 235).

* I use Vegas levels filter to do it.

IRE is a generic analog scale. Once in digital, this is the wrong thing to use. When your DVD player outputs a value of 16, it should set black to IRE 7.5 in the US and IRE 0 elsewhere.

The IRE scale simply means a 0-100 scale from blanking to white and is used in both analog and digital.

The way your quote uses the term, it refers to the digital to analog output scaling for a DVD player. In 8 bit digital, luminance Y black is always defined as level 16 and white as level 235.

In US NTSC black gets mapped to analog 7.5 IRE, in Japanese NTSC and PAL it gets mapped to zero IRE. In both cases white gets mapped to 100 IRE.