Rendereing and Cineform

[Gladiator]

I have two questions

1) Does rendering multiple times in the timeline reduce the quality? There are times after I color correct I go back and add a bit of contrast and maybe some shadow or highlight and render 2-3 times.

2) Is it better (quality wise) to color correct with native avchd, or to transcode with cineform to 4:2:2 10 bit and then color correct and add other effects? Which way is the most tolerant of color correction? Thanks!

 

[KenP]

As I understand it each time you render it does it from the source files so multiple renders should not make it worse. It is not like when you use a jpeg on stills and keep resaving and the artefacts get worse and worse.

On question 2 I would think the 4:2:2 10bits of cineform would be the best bet.

Quote from cineform web site

"When Neo Scene detects 4:2:0 chroma it properly interpolates the source chroma to 4:2:2 for more accurate color processing during editing and effects work. And if you ever "key" your material, CineForm’s chroma interpolation will substantially improve your resulting visual fidelity. "

 

[Robert M Wright]

If you are color correcting (or otherwise changing the images), then rendering, and then making further changes to the rendered images and rendering again, that degrades quality (unless you are rendering using a lossless codec at 10bits of precision - both Cineform's codec and AVCHD use lossy methods of compression).

Cineform's codec should work considerably better than AVCHD encoding (especially at the highest quality setting). It's better compression, image quality wise, and at 10bits you don't wind up with slight degradation due to round off error, when you do go to render the final version encoded for viewing (at 8 bits).

As a practical matter, you likely won't see any noticeable difference between 1 or 2 generations of Cineform compression, in the final result.

 

[Gladiator]

If you are color correcting (or otherwise changing the images), then rendering, and then making further changes to the rendered images and rendering again, that degrades quality (unless you are rendering using a lossless codec at 10bits of precision - both Cineform's codec and AVCHD use lossy methods of compression).

Cineform's codec should work considerably better than AVCHD encoding (especially at the highest quality setting). It's better compression, image quality wise, and at 10bits you don't wind up with slight degradation due to round off error, when you do go to render the final version encoded for viewing (at 8 bits).

As a practical matter, you likely won't see any noticeable difference between 1 or 2 generations of Cineform compression, in the final result.

So, it seems like using the cineform codec at it's highest quality setting, making any effects changes such as cc, shadow or highlight enhancements, contrast, etc...and rendering once is the highest quality workflow within reason. Is that correct, or am I missing something?