Broadcast safe levels and DVD output

Question

Broadcast safe levels and DVD output

Some of my video levels are above 100 IRE. I am only outputting to DVD or Blu-ray, never broadcast.

Should I compress the dynamic range down to broadcast safe, or leave the slightly higher dynamic range?

I think that this is probably a question of how FCP, Compressor, and the DVD or Blu-ray plays handle 110 IRE. All the video I am referring to is HDV and the over 100 IRE is in the original captured video. I understand that I need to set the RGB to YCbCr conversion in the sequence settings to match my output strategy.

All my sequence renders are to ProRes.

Obviously, if I use 110 IRE as my max output level, I don't what it clipped somewhere down the path.

Thanks
Rick

Mac Pro 2009, MBP, Mac OS X (10.5.7), FCS 3, MXO Cinema Display

Posted on Sep 12, 2009 1:04 PM

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Answer 1

Sep 12, 2009 1:20 PM in response to Rick Llewellyn

Not really sure, but no matter what anyone tells you, I would suggest that if you want to keep levels about 100 IRE, I would do extensive testing.

The fact is, that when I'm working on a project and send screeners out, I never pay attention to make sure levels are not above 100 ire and I've never seen a problem or had one reported to me.

But I haven't burned any blu-ray disks, yet.

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Answer 2

Sep 12, 2009 2:14 PM in response to Rick Llewellyn

IRE is an analogue video measurement. It is only applicable if you are transferring to analogue:
http://www.kenstone.net/fcphomepage/video_levelsnattress.html

8-bit digital video uses a level of 16 for 0% and 235 for 100%.
So you are talking about levels that are above 100%, a.k.a. superwhites.
Since ProRes is 10-bit, the digital code numbers are different,
but superwhites are still luma values that are above 100%.

Although DV-type codecs can handle superwhites, DVD encoding does not,
so it would be safest to eliminate them by using the Broadcast Safe filter
set to 100%, even though you're not broadcasting.

Clamping your superwhites may cause you to lose highlight detail.
For that reason, you should color-correct to bring the highlights
down to below 100% (while looking at the Waveform Monitor)
and then use the Broadcast Safe filter as insurance.
That way, you can determine how you'd like the highlights to look,
instead of just letting them get all set to 100%.

If you're doing a lot of color-correction, the extra resolution
will be useful. Just be sure to get things below 100% for output to DVD.

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Answer 3

Sep 12, 2009 4:27 PM in response to stuckfootage

Stuckfootage
Thanks for the info and the link.

I tried a few experiments and I confirmed what you and Larry said. I would like to add some detail.
Compressor does saturate at 100%. Also the FCP 7 Canvas saturates at 100%, so you only can see the above 100% values in the video scopes.

Rick

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