Broadcast Colors & 7.5 IRE

swarrine wrote on 2/23/2004, 4:44 AM

I don't understand the Extremely Conservative - 7.5 IRE setup.

If you put up colorbars and apply this filter the 7.5 IRE is checked by default. If you look at the Vegas waveform, it is at 0, not 7.5 as you would expect.

If you UNcheck the 7.5 IRE checkbox it jumps from 0 to 7.5 and you can see the color shift.

Am I missing any reason why the 7.5 IRE checkbox does what it does? Or, should I ignore it and just uncheck the 7.5 IRE checkbox to get true NTSC color safe colors?

Thanks

Comments

farss wrote on 2/23/2004, 5:28 AM

I think if you're in the USA then your NTSC system needs the 7.5 setup to be technically valid. However the camera should have applied that when the footage was capture, generated media is a different matter of course.

Sorry if I'm a bit vague as I work in the PAL realm.

Bill Ravens wrote on 2/23/2004, 6:33 AM

Be sure to check or uncheck the 7.5 IRE box in the vectorscope window as well as in the Broadcats Filter menu.If you don't, the scale in the vectorscope is wrong.

swarrine wrote on 2/23/2004, 1:21 PM

Thanks Bill-

I missed that setting.

craftech wrote on 2/23/2004, 8:43 PM

If you have a Japanese camera then you probably have one which is set to Japanese NTSC at 0 IRE. Many editors are set up for 0 IRE because of this and it is a good idea to use your eye if it is going to DVD, an external Proc Amp if it is going to VHS, and the software vectorscope or a real one if it is going to Broadcast.
If you are capturing VHS tape to edit, you should change the black level to 0 IRE before you capture it to keep it consistent with the DV footage which is probably at 0 IRE set by the Japanese Mfg. Co. Again use an external Proc Amp.

John