Renders inside of PP are often best not used for anything but viewing difficult content real time inside of PP, so this issues is largely moot.
How does the export look?
I think you can answer your own question by choosing a different codec for Previews, eh? Instead of a Long-GOP codec, why not try something intraframe, and see what results you get?
BTW, yes, I've seen something similar to what you're seeing: changes to the image after the timeline is rendered. In my case, the scaling of rendered files has changed, leaving black bars on the side of the frame that weren't there before. There are bugs in Pr. Luckily, creative people are usually good at workarounds.
I have tried exporting (without pre-rendering) using the same sequence setting.
Tried opeing up and dragging the clips onto several of the 1090x1080i timelines such as; Sony XDCAM HD422, Sony XDCAM EX 1080i HQ, AVC-I 100 1080i60 and even tried exporting a targa sequence.
In all cases, the final export or render, once played in Premiere Pro, the luma levels on the yc waveform will expand behyond the safe range (even though effects are applied to limit).
Perhpas the Premiere rendering engine processed the color space differently than the preivew, and is using the wrong color space. I believe the Sony EX footage should be processed at 4:2:0 as that is what the card creates. The Sony EX1 camera can output 4:2:2 if you have another device hooked up, but I did not.
Maybe the rendered/exported footage is actually being limited at 100 IRE (like the effects setting) and the waveform in Premiere is somehow showing extra levels?
Either way I can't find a way to export from Premiere Pro to get broadcast safe levels from the Sony XDCAM EX footage. Guess the duplication house will have to run it thought a hard limiter to automatically fix this. An ugly and expensive way to get the levels safe.
Do you have Ae? You could import your rendered movie there, and put the Synthetic Aperture Color Finesse plug-in on your footage, then open up the interface to look at the WFM there. Might tell you something.
For that matter, you could also use the limiter in the plug and render from Ae.
Yes I tried Color Finess inside After Effects before but didn't post anyting as that would probalby belong in the AE forum. Plus I didn't get good results and also would like to get everything working in Premiere Pro to save the extra time and cost.
The limiter in Color Finess does not have a luma minimum setting. So there are still levels bellow what is broadcast safe. If I raise the pedstal to 0 to make it legal, the blacks are washed out. I toggled the raise to 7.5 black level just to make sure something wasn't switched, but in both cases the same problem. Also tried chaging the color space between 16-235 and 0-255, and other settings.
The YCbCr WFM shows levels up to 110. The broadcasters are actully looking for peak Y,Cb,Cr no more than 0.7v which doesn't that mean 100 IRE?
So this process would take much longer, and still doesn't limit the lower end of the signal.
I brought up Color Finesse because I was wondering if the scopes there match what you're seeing in Pr. If so, that would seem to support the reliability of what you're seeing in Pr.
I dislike the limiter in CF. It clips the overbrights in a harsh, unsubtle way. I apologize for appearing to endorse it. It sounded like you are using the one in Pr. Curves would be my preferred tool, so I could control the shoulder myself.
BTW, I do most of my CC work for broadcast in Ae. I use the Test Gear scopes from Color Finesse, and so far, I haven't had a single spot out of over a couple of hundred done this way and submitted to DG FastChannel rejected by any station. My work flow is to render a master to ProRes422, and transcode to MPEG2 for broadcast distribution in Squeeze.
Jim, I prefere curves as well. Never used Test Gear before, looks like some nice scopes. I'm using a PC so ProRes is out.