Help with luma levels & bit rate

seanfl wrote on 12/2/2006, 3:36 AM

I'm providing an uncompressed .mov than runs in a movie theater. They have specifics on what they're looking for and I'm a touch confused.

They say: Peak luminance (white level) shall not exceed 100 IRE

Setup levels (black levels) must not fall below 0 IRE (7.5 on an NTSC waveform monitor).

Chroma levels shall not exceed 110 IRE.

My question: on the broadcast colors filter, should my luma then be set minimum of 7.5 or 0 based upon how they worded that? And I guess I need to ask, based on what you tell me, is that with the 7.5 ire setup box checked?

Also, quick question: on one render I had a larger file size than another (by a couple gigs). Turns out one was rendering 32 bit color, the other was 24 bit color. Where did I switch that and since they don't specify what type they want, is 24 bit pretty standard for a file like this?

Thank you much. Sean

Comments

rs170a wrote on 12/2/2006, 4:04 AM

I personally find the broadcast colors filter way too aggressive. By that, I mean that it hard clamps anything above or below the preset limits.
I prefer to use either color curves or secondary color corrector (choose the computer to studio RGB preset).
Be advised that I use these on a clip by clip basis as opposed to globally (i.e. track level).

On the 24 vs. 32 bit render, look in the Custom > Video tab of your render template. Odds are that the Compressed depth box option is set to 32 bit. AFAIK, this is used for an alpha channel but I stand to be corrected.

Mike

GlennChan wrote on 12/2/2006, 8:42 PM

For *quicktime* no codec (and not DV AVI):

- (Nest your .veg, and) apply the color corrector "studio RGB to computer RGB" preset. This is because Quicktime (typically) always wants computer RGB levels; your video is typically (but not always) studio RGB levels.
- Apply the broadcast safe filter too. (*Although this may be unnecessary if they are using some connection other than composite to their projector.)

You should use the checkbox that corresponds to computer RGB. i.e. uncheck studio RGB.
For the 7.5 IRE setting, choose the setting that corresponds to your country's TV system. If it's US, choose 7.5 IRE.
For luma min, choose 0.
luma max = 100
composite min = -20
composite max = 110 (in your case)
chroma max 100.00

-use 24 bpp; 32 bpp is for images with an alpha channel.

2- Do they mean no codec, or apple 8-bit uncompressed?

3- If you find that the broadcast colors filter impacts your colors negatively, then you can use the secondary color corrector before the broadcast safe filter. use the secondary CC to bring "gain" down for highly saturated+bright colors.