Black levels for broadcast

I've cut a documentary in FCP 4.5 (on a dual 2.0 G5), shot on DVCam. I'm prepping it to take to an online facility to output to Digi-Beta for delivery to PBS, who has licensed the show. Aside from PBS specs in general making my brain melt -- the one item I'm particularly unclear about is black levels.

The online facility took a look at my show (which looks great on my NTSC monitor), and told me that too many of my clips have black levels that are not at zero, and so before they do their output, I have to bring the blacks down in each clip to zero, which I've now done. But the visual result on the NTSC monitor (and on dubs played on my TV), is that the image is WAY too dark/contrasty.

I also understand that the blacks on the Digi-Beta need to be at 7.5, and that this will happen in the output process.

My question is this: is the image in the zero-black sequence the actual level of visual darkness we will see broadcast on PBS -- or will the zero to 7.5 conversion when going to Digi-Beta brighten the image so it will look like it used to?

In other words, is the 7.5 just another way of describing the same level of digital blackness in my zero-black sequence (meaning it will still look the same to the eye), or will they actually be brightening up the image on the Digi-Beta?

Thanks....

Yes, that drives us crazy when the black levels and brightnesses drift all over the map during playback. It screams "Highschool Project."


Did you calibrate any of these monitors before you tried to use them as a viewing standard?

Put colorbars and tone (Effects Tab, Video Generators) up on your timeline and play it into all the monitors that your'e trying to use to view the work.

Adjust the brightness (black level) *on the monitor* so you can just barely see one short very dark gray vertical stipe on the lower right of the pattern. Adjust the control down until the bar vanishes and advance the control slowly until the bar just appears. It should be hard to see.

This adjustment changes with room brightness, so don't change the room lights after you do this.

Now, don't change anything and watch the show.

Very diffrerent show, isn't it? Some of your clips (first show) pop very bright now and are pretty annoying.

Yes, all the clip videos on the FCP timeline should just touch zero on the waveform monitors. This will be converted to broadcast levels when the show goes to DigiBeta.

By the way, most Mac monitors are way too bright and most Mac people are horrified the first time they see their work on broadcast monitors that aren't trying to "help them."

I'm not in front of a Mac right now, but there are settings to make all the monitors in the system; computer and television, match.

Koz

<< Yes, all the clip videos on the FCP timeline should just touch zero on the
waveform monitors. This will be converted to broadcast levels when the
show goes to DigiBeta. >>

My monitor was already calibrated. So my question remains -- will this "conversion" to broadcast levels actually increase the black levels (and visual brightness) so the show looks like it used to (and should) -- or will it look exactly like it looks on my monitor in the zero-black sequence -- which is way too dark to my eye?

Thanks.

Use the 3 way color corrector to do the adjustments instead of the proc amp filter. It gives more control over lights and darks and you can then fine tune it to what is correct visually and broadcast safe.

Good luck!

Kevin



"A problem can never be solved by the same consciousness that created it"
Einstein

If you shot on DVCAM, there's no reason why blacks wouldn't be at the correct 0% in FCP. Unless someone's been fiddling with the camera settings and got them wrong. You've got to really watch out for this.

All digital video records black at 16 on the 0 t0 255 scale. FCP represents this 16 value as 0% in it's scopes.

[www.kenstone.net]

explains it all....

Graeme



[www.nattress.com] - Plugins for FCP-X

Based on this dicussion, does the Broadcast Safe filter have any value at all?

- Loren
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Loren Miller wrote:

> Based on this dicussion, does the Broadcast Safe filter have
> any value at all?

As long as you throw it on last, it does. At least it does according to Apple.

Absolutely put the Broadcast Filter on last. Otherwise, once you render, the whites that it brought down will mysteriously be too hot again. But you should still double check it after rendering. Sometimes it needs to be repeated.

To be perfectly honest, as a Final Touch/daVinci coulourist, I'm horrified that the Final Cut video filters are trusted in any way. As far as DV blacks go, I just made my way through a project where all the black levels (in a cut version) were up around 15 units or so. At first I thought it was an NTSC pedestal mismatch, but it was way too big for that.

But no, CCIR601 black should be at zero. Thats for SDI. But when it comes out of the machine into the YRB world in analog, the 7.5 IRE pedestal is shoved under it all -- but fear not, analog video displays (CRT's) are supposed to be set/clamped to 7.5 as the start point to start producing brightness.

Agreed, though, this difference is a huge pain in the neck, and there will be no end to the confusion until Standard Def finally bites the dust.