How can I properly export video w/ bars to Rec709 (16-235 in 8-bit) from Premiere's RGB (0-255)?

Question

I have hit some real frustrations in working with Premiere to meet broadcast Rec709 standards for DVD & Blu-Ray. Avid Symphony works in a Rec709 space and clearly operates with its video signal from 16-235 (which matches IRE 7.5 to 100), but Premiere doesn't seem to have this understanding in its programming and engineering. Here are my issues:
1) I can't manually enter in the digital values in the RGB Curve tool's points. Why would Premiere's engineers lock this basic feature out? It's in Photoshop.
2) I can't properly export Premiere's color bars. In order to export to Rec709 standards, to get around issue #1, I hack into the RGB Curves preset XML file to lift the Master Curve's point 1 from 0 to 16 and set the final white point from 255 to 235. If I use Premiere's bars, on the waveform, I can see the sub-black values, but when I lift the blacks with the curves preset, it clips all sub-black values upon export. WHY?! To get around this problem, I import bars generated by a camera (for example, by a Sony EX-350, i.e. XDCAM footage). All of this wouldn't be an issue if there were an export function that specifies exporting to rec709's 16-235 values instead of 0-255, as Avid does.
3) Particularly, the Waveform scope lies to me. The 7.5 IRE setup button does NOTHING for me, it's just a preview option that causes more confusion than clarity. Does Premiere map 0 out of 0-255 as 0 IRE or 7.5 IRE? I think it does the former and just uses that setup button to make you think that it's at 7.5. so if you do set it to 7.5, how then do you export it to match that option? Also, why can't the waveform scope have multiple options for the units - not just IRE, but also digital values (8-bit, 10-bit, linearized, etc.)?!
4) Speaking of importing the bars and footage. To continue the example of the Sony EX-350 - it imports the bars automatically by putting the black values at 0 IRE, not 7.5 IRE.
If Adobe wants industry professionals to take Premiere seriously, it needs to open up these options and clearly present what happens to tonal values in the image. It's very frustrating to figure out all of these problems and create cockamamy work-arounds.
http://www.avsforum.com/avs-vb/showthread.php?t=1090642
http://www.glennchan.info/articles/technical/setup/75IREsetup.html

Answer 1

Steve,
Thanks for your reply! However, I hope you don't take my response the wrong way, but, with no meaning of disrespect to you personally, the notion that curves are the wrong tool for numeric adjustments extremely infuriates me and displays a real lack of understanding of why a colorist or cinematographer such as myself would want to use curves in the first place.
First, any LUT generation program or coloring program, such as Apple Color, gives complete access to numerical control to give precise, repeatable changes that you cannot get with the drag of a mouse. Photoshop, Avid Symphony, etc. all have curves tools with the ability to manually enter points.
Second, on a user level, there should be no wrong tool for numeric adjustments, especially curves - they are the most precise means to obtain a specific contrast response. Levels or RGB corrector will only give gamma, pedestal, and gain operations, but curves gives every possible shape of a contrast response in between. If I wanted to create a very specific S-curve, I must use the curves tool to do so.
Third, the question at hand is not Premiere Pro's ability to process natively in Rec709 with signal from 16-235 - Premiere's native ability to process all types of video input is the sole reason why I've switched to it as a platform. 'Sub-black values are not necessarily clamped'?! How then can I export a TIFF, for example, of Premiere's bars, with the sub-black values left intact? How do I even access these sub-black values, when all footage clips below 0 IRE? The primary question is, how does Premiere handle and export these IRE values with respect to digital values, whether they are 8-bit, 10-bit, 12-bit, etc.?
Adobe's video workflow lacks a concise, cohesive FAQ or explanation of its numerical signal chain. At least, I have missed it and can't find it anywhere. If I want to properly color grade footage with a proper final output in mind, I need to know my end goals to take the proper intermediary steps.
SteveHoeg wrote:
Hey Tim - Premiere Pro can process natively in Rec709 with signal from 16-235 you do not need special adjustments. Curves are the wrong tool for numeric adjustments, try Levels or RGB Corrector. Sub black values are not necessarily clamped on export.  --sh