Video for the web, 100% or 109% Hypergamma

[Anthony Trotter]

These days my footage is primarily shown on the web. There’s minimal or no grading in post, so the footage must be good-to-go when it comes out of the PMW-200. When I do shoot for broadcasters, I let them worry about post production and grading. My question is, when is comes to shooting video to be displayed on the web, is it better to shoot with a hypergamma which clips whites at 100% (HG1, HG2) or with a hypergamma which clips whites at 109% (HG3, HG4)?

[Jack Zhang]

I shoot 109% with the gain at -3db. Internet is still Video legal levels, so if you shoot at 0db, may want to use a 100% gamma.

[Alister Chapman]

Computers and thus the internet use bit 255 for white, which is 109% in video terms. TV broadcasting uses bit 235 as white, 100%. If you shoot at 100% and then place that web clip on a white web page, any white in the video will appear slightly grey.

So for web delivery you want to use 109%. Just be very careful that your edit software passes video that is above 100% correctly and does not clip it. Some of the filters in Premiere clip at 100%.

[Anthony Trotter]

Thanks for the replies. This is good info. Adobe Premiere Pro is the software I use. The footage shot with 109% white registers on the waveform monitor at 109%, so I'm fairly sure the software is passing the footage without clipping. Offhand, do you know which filters in PPro clip at 100%? Again, thanks for the very useful info.

[Marcus Durham]

Do check the scope *after* rendering to be sure. I forget the plugin but years back I had an issue with sky highlights clipping in Premiere and it turned out a plug-in was clipping the video but only on the final rendered result.

[Anthony Trotter]

Marcus, I'll be sure to check the scopes after applying the plug-in and rendering. Was it Magic Bullet that caused the clipping, perhaps?

[Marcus Durham]

Not on that occasion although it is very easy to clip levels with the Magic Bullet tools if you aren't careful.*I once enhanced a sunset scene with it only to find that when rendered the sky looked flat as it was all clipped.

[Anthony Trotter]

Thanks, Marcus.

[Alister Chapman]

The most important thing in Premiere is your filter order. Always have any colour correction filters at the top of the stack, before any other filters to avoid clipping issues. If you do run into clipping issues use the fast color corrector as the first filter in the stack and use the input/output sliders with input at 255 and output at 235. This forces premiere to remap the video from "computer" levels up to bit 255 to "video" levels up to bit 235.

[Tom Roper]

Originally Posted by Alister Chapman

The most important thing in Premiere is your filter order. Always have any colour correction filters at the top of the stack, before any other filters to avoid clipping issues. If you do run into clipping issues use the fast color corrector as the first filter in the stack and use the input/output sliders with input at 255 and output at 235. This forces premiere to remap the video from "computer" levels up to bit 255 to "video" levels up to bit 235.

Works this way in Sony Vegas as well, the order of precedence of the filters requires that the levels adjustment be first in the chain so as to avoid clipping issues.

[Walter Brokx]

The old Colorista plugin used to clip. Colorista II doesn't anymore as far as I can see.

Sometimes greyish white are caused by Quicktime, but that is a totally different story about gamma.