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-   -   Broadcast Legal? (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/53483-broadcast-legal.html)

Javier Urena October 27th, 2005 11:27 PM

Broadcast Legal?
 
I Read A Thread That Said The Colors From The Panasonic 24p Cameras Are Not "broadcast Legal."

Can Someone Explain What This Means And Are There Any Issues With The Xl2?

Tia

Glenn Chan October 27th, 2005 11:32 PM

Perhaps it's disinformation?

2- Many cameras can record colors that are not broadcast legal. (It may be that all DV cameras can do this.)

Many/all DV cameras will record "superwhites", which are values above digital white level. This is a good thing as you can pull this detail into the legal color range to gain more exposure latitude.
I believe they do this (instead of other methods) to maintain linear gamma by the time the image reaches the home viewer.

I presume the XL2 records superwhites like every other camera.

3- For NTSC, colors can be illegal for broadcast (which is different from DVD) if the composite value is too high. All DV cameras will record illegal colors too.
You could be dealing with these illegal colors in an online edit session (or color correction session), or you just let the broadcaster deal with those illegal values.

Chris Hurd October 27th, 2005 11:33 PM

If the content is compelling enough, then it's definitely "broadcast legal."

CNN runs tiny little 160x120 videophone clips -- small, choppy, grainy, ugly -- from overseas journalists fairly frequently. Make your video worth watching and nobody will care too much about the color!

Ash Greyson October 29th, 2005 12:17 AM

Broadcast legal is not 100% mandate but illegal colors will look terrible once they are put to tape, dubbed, compressed for broadcast and then decoded. Reds are the worst, especially on the DVX. The XL2 is the best 1/3" DV cam for broadcast colors. Almost every NLE has a filter or scope to help you with getting legal colors. Anytime you use a low shutter the colors will go crazy on the scope and are hard to curb.


ash =o)

A. J. deLange October 29th, 2005 01:53 PM

TV signals are broadcast with the composite video amplitude modulating the carrier with blacks increasing its amplitude (maximum power transmitted during the peak of the horizontal sync pulse which is blacker than black) and whites decreasing it. The composite signal is the sum of the luma and chroma. If the sum of the luma and chroma excedes the maximum allowable amplitude it will try to turn the carrier more off than off. This, of course, it can't do but if it turns it solid off quickly this results in spectral "splatter" i.e. noise in adjacent channels. That's why the FCC sets limits for the whitest white and the peak chroma signal amplitude (which is proportional to color saturation). NLE programs like FCP have filters which will take a signal which excedes the FCC limits and push them to within the limits.

Javier Urena October 29th, 2005 10:25 PM

Thanks for the replies. A TV editor told me it had to do with the reds, and that you usually have to pay a guy to color correct footage to broadcast standards. TV networks obviously have their own guys for this, which is why they can broadcast video from cell phones.

He said the feature on FCP 5 that makes the footage broadcast legal is a filter and a relatively new one. So he's not sure if it actually works or not, but I hope it does in order to avoid having to pay someone for that one function.

(I'm on a very tight budget.)

Steve House October 30th, 2005 08:29 AM

Don't know FCP but I'd exp[ect it to have colour correction tools in addition to the plugin filter. Adjust the colours so everything lies between 16 and 235 and you should be fine.

Greg Boston October 30th, 2005 09:43 AM

FCP does have extensive color correction capabilities and does have a video filter called 'broadcast safe'.

-gb-

Glenn Chan October 30th, 2005 03:37 PM

FCP doesn't show you the video values in a scale from 0-256, and it doesn't directly show you what the video values are. However, you can use the waveform monitors in it (which should not be confused with other waveform monitors, since FCP does its own thing [like all software waveform monitors]).
0% corresponds to digital black level, 100% corresponds to digital white level.

see http://www.kenstone.net/fcp_homepage..._nattress.html

You also need to watch out for the composite video levels as A.J. points out. I believe the broadcast safe/colors filter in FCP does this... the (110) or (120) preset should be appropriate.
You may need to get the broadcaster's document for their technical requirements to figure out the maximum composite IRE values you can have on your master.


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