VFX with Natron - E0089 - PNG vs EXR - Deeper in depth
In this episode we are going to explore some of the differences between how Blender renders PNG and EXR files, and why the later is currently the preferred format for use when exporting CG image sequences from Blender to use in most compositing software including Natron. Particularly when one desires to use a depth pass in conjunction with Natron's zDefocus node. We are going to look at a PNG format limitation when exporting a Blender depth pass that causes them to fundamentally break and see if we can do anything overcome this limitation for PNG's in some way. Then we will examine how hard it might be to match the depth and mist passes to see if the two are able to be made compatible. This all aids in showing two things. First how depth passes, which we looked at in the previous episode, are not standardized even in a single program like Blender. Second that EXRs are a much better format when doing multi-pass rendering and compositing. The last thing we will look at is if file size, the main argument for using PNG sequences, really holds any weight when one factors in EXR compression options like Dream Works Animation type A (DWAA).
Contents:
0:00:00 - Intro
0:00:17 - Preamble
0:01:25 - The simple Blender test scene
0:04:23 - Dealing with an EXR
0:06:19 - Depth pass vs Mist Pass and why we are looking at these
0:09:22 - Dealing with multiple PNG passes
0:12:03 - PNG Issue 1: clutter & potential naming issues
0:13:00 - PNG Issue 2: file color space typically defaults to sRGB not linear (meta data)
0:15:15 - Why is the EXR depth pass white? (white points to low)
0:20:57 - Why is the cube now black? (it exists between depth value units 10 to 25 out of 65536)
0:23:37 - How the zDefocus node uses this (the focal plane for it defaults to 20 depth units)
0:24:07 - Lets look at the PNG depth pass, and why it is" broken" (throws away 65535 values)
0:25:29 - Lets try and fix the lost information in Blender
0:28:52 - Evaluating our potential Blender solution
0:32:39 - PNG format limitation or file color space limitation?
0:37:54 - A look at linear data on a PNG with linear file color space (lacks detail)
0:38:50 - A look at linear data on a PNG with sRGB file color space (better, but not perfect)
0:45:20 - A normalized z buffer would be dynamic, unless a clamped range were used (mist)
0:46:00 - The mist buffer just limited z-depth variant (with anti-aliasing and different falloff)
0:51:34 - Issue 2(a): PNG currently can't deal with a full depth pass (zDefocus incompatible)
0:53:02 - Are PNGs really smaller than EXR's? (Debatable)
0:55:29 - Issues 3: EXR can be made smaller than PNG at a minimal cost
1:03:55 - Final thoughts on PNG vs EXR
1:05:50 - Thanks for watching and outro
There are currently no project files currently associated with this video.
Live stream from July 10, 2021
With: Pirate Bill
Смотрите видео VFX with Natron - E0089 - PNG vs EXR - Deeper in depth онлайн без регистрации, длительностью часов минут секунд в хорошем качестве. Это видео добавил пользователь Peanut Butter and Natron 15 Июль 2021, не забудьте поделиться им ссылкой с друзьями и знакомыми, на нашем сайте его посмотрели 893 раз и оно понравилось 27 людям.