Best V1U Settings For Post-Production Color Correction

[Steve Mullen]

Originally Posted by Keith Moreau

Thanks Marcus, this makes sense to me. I did some more shooting, using the histogram on the V1U and yes there is still some lattitude above 100. There is an orange line in the histogram when Zebras are set to 100IRE I can see some extra space (lattitude) beyond the orange line.

According to Sony the V1 records to 108IRE. So if you allow the histogram to peak half way between the orange line and the top you are really safe in terms of recording.

But, this is misleading if your NLE clips the signal at 100IRE. In this case -- the orange 100IRE really is the peak of what you should record. You really want only a tiny tiny bit of zerba -- especially if going to film.

[Keith Moreau]

Thanks for the info Steve. I'm using Final Cut Pro which does support +100IRE. I plan to use the scopes in FCP to bring it down to 'safe' level and make other adjustments when the time comes. Do you think this is a good idea?

[Steve Mullen]

Originally Posted by Keith Moreau

I plan to use the scopes in FCP to bring it down to 'safe' level and make other adjustments when the time comes. Do you think this is a good idea?

Yes -- in theory, all FCP calculations until the end can use the full range up to 110IRE. But, what happens at the "end?"

If you go to NTSC -- you lose 7.5IRE on the low end since black is at +7.5IRE. So the NTSC output has a range limited to only 90IRE. Which means the 108IRE range has to be compressed to 90IRE. Ouch!

If you stay in HD, you get 0 to 100IRE for output -- which is a 100IRE range.

Thus, there is never more than a 100IRE range going to your audience. So lately I've been trying to use the orange 100IRE as my visual peak. That leaves 8IRE as a safe zone in case highlights slip though. In another words -- I no longer push the peaks right to the limit just because the camera and NLE can handle it.

I'll admit that's also because I use 5 different NLE's and only FCP supports more than 100IRE. So it's easier to not record to hot.

[Bob Grant]

Originally Posted by Steve Mullen

Yes -- in theory, all FCP calculations until the end can use the full range up to 110IRE. But, what happens at the "end?"

If you go to NTSC -- you lose 7.5IRE on the low end since black is at +7.5IRE. So the NTSC output has a range limited to only 90IRE. Which means the 108IRE range has to be compressed to 90IRE. Ouch!

If you stay in HD, you get 0 to 100IRE for output -- which is a 100IRE range.

Thus, there is never more than a 100IRE range going to your audience. So lately I've been trying to use the orange 100IRE as my visual peak. That leaves 8IRE as a safe zone in case highlights slip though. In another words -- I no longer push the peaks right to the limit just because the camera and NLE can handle it.

I'll admit that's also because I use 5 different NLE's and only FCP supports more than 100IRE. So it's easier to not record to hot.

There's seems to be some errors in this.
1) Every camera HD or SD that I've looked at on scopes records over 100IRE.
2) There's no 7.5IRE setup on digital video. Setup should only be added during analogue to digital conversion and removed during the reverse process. You also need to know what you're working with, not all NTSC has setup.

FCP is not the only NLE that supports more than 100IRE, Vegas if anything does the reverse, it really works in Computer RGB rather than Studio RGB so 110IRE is no problem and it's easy enough to convert to Studio RGB if needed.
Again you need to be very careful. Not everything expects legal video, delivering legal video for web content can leave your video looking a bit flat.

I'd be pretty surprised at any NLE that cannot handle 110IRE, it's going to have major issues with most cameras if not so I'd hazard a guess that FCP and Vegas are not the only NLEs that can handle 110IRE.

Also FCP does nothing to it's ouput, 110IRE goes back to tape as 110IRE. I've got plenty of tapes out of FCP that go to 110IRE that I have to legalise for DVD content as DVD players almost always clamp at 100IRE.

[Steve Mullen]

Originally Posted by Bob Grant

There's no 7.5IRE setup on digital video. Setup should only be added during analogue to digital conversion and removed during the reverse process. You also need to know what you're working with, not all NTSC has setup.

USA NTSC must have +7.5IRE set-up because that's the standard. There's no confusion about this. Web video has nothing to with NTSC -- so I'm not sure why you even brought it up.

The fact that low cost DV camcorders came into the USA with 0IRE didn't change the NTSC standard one IRE.

Pro analog gear uses the NTSC spec correctly because if they didn't they would cause havoc at every broadcast facility.

NLE's that use YUV do not support greater than 100IRE internally --and so clip anything above that digital value. Which is what FCP does if you do not set SuperWhite. And you've only restated what I said -- FCP does support up to 110IRE. What was the point of your post, again? :)

Yes -- RGB does allow values up to 255. However, that doesn't mean when RGB values are converted to YUV before output -- that they don't limit the signal to the YUV range.