🚀 go-pugleaf

One reason (not the only one) this can happen is that the clip material within the transition has to be rendered while the clip material before and after the transition is not rendered. This is more often seen with some third party transitions (some HollywoodFX transitions are prone to this). One way to avoid the change im luminosity is to force rendering for the whole clips before and after the offending transition. The less time consuming way to do that is to apply a simple effect to these 2 clips: say a Fast Blur with 0.0 blur.

I've been doing some further investigating.

It seems like this is some kind of bug in Premiere. If the luma levels are above 100% (don't ask me how) it will clip back the luma during the transition. It's very obvious when you look at the luma graph that this is happening.

If you reduce the luma levels to 100% (e.g by using the video limiter), it doesn't happen.

How I'm ending up with luma levels above 100% to begin with I don't know. But since Premiere appears happy with these levels the rest of the time combined with the fact I am using industry standard kit (the Sony Z1) I'm not sure.

I do usually run a limiter over any finished production, but it's annoying that Premiere has this bug. Unless it's me who is doing something wrong. But I can't see how. It's hard to avoid peak white in an image from time to time (espcially if working with a high contrast scene).

Some apps allow greater than 100 IRE, some don't. Premiere in general does not, and as you have found, it will clip any signal above 100 IRE. There are one or a few transitions or effects that will not clip the signal, but I do not remember what they are. If you do a forum search, you may discover which one(s) preserve the peak levels, as this has been discussed at least once before.

That's interesting. In short that means I will need to keep the video to 100 IRE when shooting it.

Easier said then done. One would assume that the camera would not allow more than 100 IRE but it appears not!

I wonder how other people cope? I can't be the only person who is encountering this. I mainly experience it in high contrast scenes (for example a street with a cloudy sky). In such a scene it doesn't matter if the clouds are peak white because the main thing that people are looking at is the street.

Likewise another shot I had a problem with was in a radio studio. There was peak white on a monitor in the background but that was very small and it wasn't important if it was clipped. However that also threw Premiere into a fit.

Anyone got a workflow that isn't disruptive that can get around this? Is it fixed in V2?

Thanks.

Your camera should have a zebra option. Use it.

Another very handy tool is DV Rack from Serious Magic. You can use DV Rack's Waveform Monitor to ensure your recorded signals never go over 100 IRE. DV Rack is one of the 2 or 3 most useful software packages I have ever seen.

Apple's FCP has a setting to allow RGB processing to accommodate "super white". The problem with this is that super white is not broadcast legal, and that is probably why PPro clips it for you. Read how FCP handles it, and the attendant warnings about super white, here:

 <http://docs.info.apple.com/article.html?artnum=60864>

PS - PPro 2.0 handles RGB peak signals the same way as 1.x.

You would think though that Premiere would clip the entire production, not just the clips it feels like which is what I find annoying. Or at least have an option to do so (which so far eludes me unless you apply it per clip using the video limiter).

I do use Zebra on the camera at all times with success. As I say, it is those occasions where you have a high contrast range where it is desirable to clip the whites that are the problem. I only get this problem very occasionally on SD although it seems far more common on HD or downconverted HD. Could it be that HDV allows a far higher peak white?

All finished productions are legalised when encoded.

I guess I'll just have to keep an eye out for those occasions when I do need to clip the whites and then clip them further in Premiere.

Thanks for all the help. At least I now know what to keep an eye out for and can solve it by applying a limiter to the affected shots. Its not ideal but if it is more common with HDV then I guess Adobe will have to address it in a more elegant way.

Cheers.

Premiere processes RGB video internally as YUV, so there is no clamping going on in clips that are not rendered.

It's only when rendering effects and transitions or exporting (to a different codec) that the video has to be processed as RGB, which introduces the clamping that you see.