Ramesh,

My top 5 reasons for using PPro over Avisynth:

1. PPro lets me see changes in real-time. Real time is important, so I can get a feel for pace, flow, timing. That is why people spend money on hardware, use proxy files (like I described above), and/or purchase a real-time codec like Cineform. If I only had Avisynth, I would need to compile an output everytime I made an edit in order to check if it was correct or not. And, as I'd be guessing my edits blind, it would take an awful long time to complete even a short sequence. Lets say I had two clips, one wide-angle and one close-up. I want to cut from wide-angle to the close-up at exactly the right point. In PPro I can find that point very quickly, make the edit and then watch the result instantly. With Avisynth I'd have to guess, compile, watch, change, recompile, watch, etc. So, if I knew beforehand that I needed to cut at frame 150, increase saturation by 3% and reduce gamma by 2%, Avisynth is no problem. But, I don't know without seeing it first, and that is where PPro comes in.
2. I work in a team, and not everyone in the team would appreciate using a text-based editor.
3. Adobe software, like Microsoft Office, is widespread enough to be considered a standard, and standards are good for team working.
4. PPro works with 10-bit (or greater) precision, Avisynth is 8-bit only.
5. Adobe Media Encoder has a nice GUI. Sometimes it is more convenient to drag-and-drop than it is to type commands.

Avisynth is an excellent tool. As you say it is more stable than Premiere (at least on my system), and there is excellent community support and development. But it is not a replacement for Premiere, and it was never designed to be.

I can't confirm what you are saying but it makes sense. I do know that cineform claims to go straight to 10-bit in the first conversion and stay there. I also know that my RGB parades look good when I convert 5D2 video immediately into Neo Scene Cineform files. I do see stuff right up against 100 and stuff down at 0 in the parades which scares me a bit. Is the stuff outside that range being kept around or is it clipping. I haven't researched that yet.

I do know (as I said before) the files from QT 7.6 going straight into Premieres shows parades that have banding (missing values) like crazy. The Cineform is as smooth at silk.

If you're on CS4, then it's clipping. CS4 can't interpret the Cineform files (yet) so it doesn't know there is stuff <0 and >100. If you follow my steps above, you'll find exactly the same smooth histogram, but also the stuff <0 and >100 is available to bring into range. That aside, if I've done the maths right, there will only be 2 differences between Cineform and my method:

1) Method above has an 8-bit conversion from 709 to 601, which will most likely be slightly lossy. Cineform won't be lossy in this respect.
2) Method above is otherwise completely lossless, Cineform is slightly lossy (but should not be visible).

If you're on CS3, my understanding is Cineform have an importer that correctly interprets the files. So you should be able to use the Procamp to reduce contrast and increase brightness.

That is good news for me. I have no reason to upgrade from CS3 to CS4 yet. (Don't tell me why I should, I'm covering my ears. NANANANANANA).

Ha ha! I'm still on CS3 for the rest of the range (InDesign, Photoshop, etc), I seem to be out of sync on Premiere upgrades!

Can you bring up the RGB parade, drag a ProcAmp filter onto your clip, enable max bit depth rendering on the sequence, then increase/decrease brightness. Do you see more detail magically appear?

It works! My sequence was already 10-bit YUV 4:4:4. I imported the .avi file Neo Scene produced directly from my 5D2 .mov file. As I said before, things looked crushed, and they were (named "flat" pics below).

But the data was still there above 100 and below 0. I did what you said and used the procamp to adjust brightness and contrast to get all the data within 0 to 100. I had to reduce the contrast from 100 to 75 and push the brightness back up by 12.5 to get it to fit (named "fit" pics below).

Parade with default procamp: http://elleh.com/public/parade-flat.jpg
Parade with adjusted procamp: http://elleh.com/public/parade-fit.jpg

Notice that there is a blob in the upper right part of the red parade that went from totally missing to visible.

Photo with default procamp: http://elleh.com/public/pic-flat.jpg
Photo with adjusted procamp: http://elleh.com/public/pic-fit.jpg

Notice the highlight in the white fan and the dark books to the immediate right. I obviously wouldn't use a curve like this to make such a lousy image, but the crushed highlights and crushed blacks are definitely back in the photo.

Having 25% of the photo out of the 0-100 range seems high to me. 16-235 is only missing 7% of 0-255. It doesn't matter though if I can get to all of it.

I owe you one (or two or three).

Ha!

If you want to see things as they came out of the camera, I think the Fast Color Corrector filter could be more 'faithful' as you can enter specific RGB numbers rather than trying to guesstimate the the correct level percentage by eye.

Drag the Fast Color Corrector onto your clip (instead of the Procamp), go down to the Input Levels/Output Levels section and enter the following:

Input Levels: 0.0, 1.0, 255.0
Output Levels: 16.0, 235.0

You sure make me work hard. I did what you said. While I admit this particular image looks better, there is still stuff hidden outside the 0-100 range. i guess a little headroom never hurts. Here are the parade and photos with your new settings...

Parade with fast color corr: http://elleh.com/public/FCC-16-235.jpg
Photo with fast color corr: http://elleh.com/public/FCC-16-235-PHOTO.jpg

We're now into analogue video and broadcast intricacies. Instead of using the RGB parade to set brightness and contrast, look at the YC waveform with chroma disabled. You'll see that using the 16-235 figures blacks are exactly 0 (nothing below) and whites are exactly 100 (nothing above). This is correct, as anything outside should be considered clipped.

Turn on chroma, or look at the RGB Parade, and you should see levels extending below 0 and above 100 for certain intense colors. Whether this is a problem or not will depend on what equipment further down the line can handle; for NTSC -16 to +121 is acceptable, possibly higher for certain colors. You can fix over-saturated colors by continuing to reduce brightness/contrast as you did with procAmp, but most likely this would result in an over-dark picture, as it is the intensity (saturation) of certain colors that is problematic and needs to be fixed, not the overall brightness level.

If you're not broadcasting, I wouldn't worry about Chroma just now, you can always fix that later as required. The important thing is to get the luma correctly between 0-100 to avoid clipping.

If your final output is to 8-bit RGB (YouTube/Vimeo??? haven't checked yet what they require), I would say it is best as a final step to expand back from 16-235 to 0-255 while you're still in 10-bit Premiere Pro. Otherwise, you'll be outputting reduced contrast, and the final video renderer will be expanding to 0-255 (hopefully), but with 8-bit precision.

Hi Thane. This is all great information and I really appreciate you putting in the time here. I have a question in relation to all this, none of which I'm familiar with. For what kind of files does 8 bit RGB come into play? If I want to export to, let's say Blu-Ray or DVD, would it be relevant?

Also, assuming the workflow of 5D .MOV > Cineform > Premiere CS3 max bit depth project with range recovered using ProcAmp or Fast Color Corrector,........when I'm exporting to some compressed file format (to be used for an upcoming screening of my work on a digital projector via computer) do I have to worry about this 8 bit RGB issue that you mention.

Ignorance was bliss for me for many years working with DV. It's only since I got into photography that the significane of of colour space issues have been brougth home to me.

'Typical' Blu-Ray discs use YV12, 8-bit. So you don't need to worry about RGB 0-255 or 16-235, but you do need to worry about luma (0-100) and chroma levels*. The Blu-Ray player sends the 8-bit YV12 signal to the TV, and the TV converts it to whatever it needs to display RGB on the screen. Or, if you have an expensive setup, the Blu-Ray player upscales the 8-bit YV12 signal to something like 12-bit HDMI Deep-Color format and sends that to your home projector, to make you feel better about spending £££ on your latest gold-plated HDMI interconnect.


*Does anybody know about what we need to consider regarding chroma levels for Blu-Ray?


For internal company/home use, output in whatever format gives the best quality on your hardware. For a PC with a regular graphics card and regular monitor, that would be RGB with the full 0-255 range. For a PC with an expensive HD card and HDMI setup, that could be 12-bit - check the specs. For a cheap portable projector, or a really low-end TFT, it could well be 6-bit, although in this case I'd probably still output in 8-bit RGB and let the chip in the projector decide what bits it wanted to lose.

Thanks. It didn't occur to me that I was looking at RGB when my sequence was YUV.

My final output will be film.

We're making an indie with a bunch of people who want to branch out on their resumes. The producer/director/writer is a writer who sold the script for the next Halloween saga. We know two actors on cable dramas and one from a major soap. We know about ten people who want to be grips, pullers, anything they can. They are all working for free (well, tiny bit of sales) including the DP (me). The director and I have never done this before, so it should be interesting. :-) We are going to practice on a music video for a friend to try to avoid making complete idiots of ourselves.

The writer is hooked up with a guy who sells indies, mainly overseas. Unlike Jon, we are not going to try a short first and it definitely won't be film festival material, but we are going to give it our best because you never know what can happen.