Beating a dead horse :)

megabit wrote on 11/10/2014, 11:01 AM

OK, so after so many lengthy and insightful threads, dealing with levels (in general and as Vegas Pro handles them in particular) - I'll ask a related question again:

- back when it was so easy to do, I used to simply put a generated media "black" video event at the very bottom of my project to be rendered for DVD, change its color by setting RGB to 16,16,16 instead of 0,0,0, and forget about "illegal" blacks.

Is using the Sony's "Broadcast Colors" FX at the video bus level equivalent to the above method?

Piotr

Comments

NickHope wrote on 11/10/2014, 11:14 AM

No. Dissolves, transitions etc. need that legal black underneath them on the timeline. Doing it "after the event" at video bus level is not the same. It will for example clip the darkest part of a fade before it has completely faded.

Stick with the generated media track and type the HTML code 0x101010 into the Color field. This will give you accurate 16,16,16.

musicvid10 wrote on 11/10/2014, 12:24 PM

I agree with Nick.
A point of information -- Broadcast Colors is fine for DVD, but some broadcasters (PBS) won't accept chroma outside 16-235. Levels Filter will hard-limit chroma, if used last in the fx chain.

NickHope wrote on 11/10/2014, 10:41 PM

Also Piotr, when you say "forget about illegal blacks", I assume you know that a 16,16 16 underlay track in itself won't cure illegal blacks. You might still have "illegal" blacks in the tracks above it, as well as illegal whites. The underlay track is more about making translucency work correctly in a video environment.

Kit wrote on 11/10/2014, 11:42 PM

What and why are certain colours illegal? Thanks.

farss wrote on 11/10/2014, 11:48 PM

[I]"What and why are certain colours illegal?"[/I]

Because the specified colour space for video does not include every possible colour and using RGB it's quite possible to create colours that are not inside the video colour space. Google "out of gamut" for information.

Bob.

Warper wrote on 11/11/2014, 10:08 AM

Chroma 16-240 is quite legal according to mpeg standards, it's luma legal range that is 16-235. Unfortunately, we have no direct control of chroma/luma in Vegas, since it operates in BGRA (8-bit or 32-bit) color space. There is a possibility for illegal colors in resulting compressed video due to compression artefacts.

Legal black (16,16,16) underpadding is useful for fades, since Vegas creates them with transparency, but not in direct color fade. Underlying legal black will pop up after this. AFAIK if you don't make underpadding and render in alpha-capable format, you can get real alpha instead of illegal colors. Neither broadcast colors nor levels/color curves/LUT will fix it unless you deal with alpha directly.