Author Topic: half float 16 bit or full float 32 bits EXR or tiff ?  (Read 20476 times)

2014-05-23, 13:41:35

Fibonacci

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Hello,

any experience ? Which one is the better choice ? For CC and for faster post...or in most cases...

Cheers!
Holy Corona : the materials is the clue.

2014-05-23, 14:18:01
Reply #1

johan belmans

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HI

I make ue of EXR - 16 bit in After Effects. the full float option doesn't benefit more for me.


2014-05-24, 15:07:53
Reply #2

Captain Obvious

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OpenEXR is better than TIFF, and 16-bit mode is sufficient for all reasonable use cases. Keep in mind though that most software that loads floating point images will load them as 32-bit regardless of the file's bit depth. A 16-bit OpenEXR file will load as a 32-bit file in After Effects, Nuke, Photoshop, etc. The only thing you're saving is hard drive space. But because 16-bit files have more than enough colour precision anyway, you might as well use them and save some space. They probably load faster too.

2014-05-24, 19:11:27
Reply #3

Ondra

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There was one rather big problem I encountered, that 16bit EXR cannot save direct sundisk or its specular reflection. Because of that corona saves everything in 32bit
Rendering is magic.
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2014-05-24, 19:44:27
Reply #4

Fibonacci

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So, what do you offer to the output ?

The space is dosn't matter now, but if the Corona saves everthing in 32 bit...I have made already lot of renders for post, but those has in 16 bit tiff...and if the Corona saves in 32...that's mean I "lost" the half color information?.
It's ok now, because the render time was more than a week...but next time, I just would like to know, what do you recomend.

If I want to make 4K pictures...for the new 4K monitors ( i don't have yet), then the great way sould be the 32 EXR...isn't it?
Holy Corona : the materials is the clue.

2014-05-24, 20:09:11
Reply #5

DeadClown

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There was one rather big problem I encountered, that 16bit EXR cannot save direct sundisk or its specular reflection. Because of that corona saves everything in 32bit

What type of saving are you talking about? I made a quick test with max's common render output and got 16 and 32 bit as expected (32 bit exrs are about 4 times the size of a 16 bit exr) so I guess you're referring to the autosave/resume exrs corona is saving?
Any sufficiently advanced bug is indistinguishable from a feature.

2014-05-24, 20:31:49
Reply #6

Ondra

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So, what do you offer to the output ?

The space is dosn't matter now, but if the Corona saves everthing in 32 bit...I have made already lot of renders for post, but those has in 16 bit tiff...and if the Corona saves in 32...that's mean I "lost" the half color information?.
It's ok now, because the render time was more than a week...but next time, I just would like to know, what do you recomend.

If I want to make 4K pictures...for the new 4K monitors ( i don't have yet), then the great way sould be the 32 EXR...isn't it?

Actually it is not half the color resolution, the 32bit float resolution is 4096 times finer than 16 bit. But 16 bit is usually enough.

The problem is that 16bit is limited in the terms of maximal possible luminance - standard sun color is brighter than any finite value expressable as 16bit float.


DeadClown: I mean Corona autosave, save/resume/load features, and DR
Rendering is magic.
Private scene uploader | How to get minidumps for crashed/frozen 3ds Max | Sorry for short replies, brief responses = more time to develop Corona ;)

2014-05-25, 00:36:26
Reply #7

Captain Obvious

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There was one rather big problem I encountered, that 16bit EXR cannot save direct sundisk or its specular reflection. Because of that corona saves everything in 32bit
The max value is 65536, so anything that's brighter than that will be clamped. I guess if you render with a bit of highlight compression, you'll be able to squeeze in a greater range. It's pretty trivial to remove a known global tonemapper anyway.

2014-05-25, 12:13:22
Reply #8

Ondra

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it actually won't get clamped on its own, but turned to INF, which is hella fun to deal with. But maybe 3dsmax is intelligent enough to check and clamp when saving it (hahaahaha)
Rendering is magic.
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2014-05-25, 12:45:23
Reply #9

DeadClown

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But maybe 3dsmax is intelligent enough to check and clamp when saving it (hahaahaha)

Nope ;) You can easily run into this problem if you're rendering a huge (dimensions) scene and try to use the world position pass in post. Exrs are actually saving #inf values.
Any sufficiently advanced bug is indistinguishable from a feature.

2014-05-25, 14:23:05
Reply #10

Captain Obvious

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it actually won't get clamped on its own, but turned to INF, which is hella fun to deal with. But maybe 3dsmax is intelligent enough to check and clamp when saving it (hahaahaha)
Yeah that'll happen ;-)

2014-05-25, 14:47:12
Reply #11

blank...

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I would say 16 bit half float. You would need some really specific situation to absolutely NEED 32 bit.
Disk space isn't a problem these days, but it's not about disk space. It's about having to work with 30mb file vs. 3mb file. When you start your post processing and get dozens of nodes in there (even hundred or more for the big boys who do really complex stuff), things can get a bit laggy with large files (you will be adding other passes as well).

Corona saves everything as 32bit? Not a problem, in Fusion you can bring down bit depth in the loader it self or in a separate node. There is probably something similar in other compositors.

2014-05-26, 17:49:13
Reply #12

Fibonacci

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I agreed.

Weel...Maybe the 32 bit is unnecessary for the color pass, just 16 enought. But for the transiton beetwen white and black much smoother in ZDepth and AO pass (Guassian blur is ok for that, but...maybe not the same). And I think this is sould be important for the high quality post production.

And 32 same good for the reflections and GI channels...I thinks.
Ofcourse I don't wanna make hundred and hundreds node in a "simple" post. But when I see some really high-end post production...than I feel I have to try to achieve that. Ofcourse, those guys has a lot of experience and practice...

Not mentioned the HDR.
Holy Corona : the materials is the clue.

2015-02-10, 15:11:40
Reply #13

SairesArt

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Weel...Maybe the 32 bit is unnecessary for the color pass, just 16 enought.
Old threads need love too.
I really wanna correct this: If you plan on doing Depth of Field or Motionblur in post, it's essential to have Superwhites, which only work in 32-bit, otherwise the Bokeh from DoF and Lightstreaks from MoBlur will have the wrong color and the wrong brightness.

If you don't Plan on doing DoF or MoBlur in Post (eg. 16-bit exrs), there is no reason to go EXR in the first places, due to compatibilty issues, that may arise. PNG deliver the same color info with less space wasted and a saved color profile. And combining multiple passes in one EXR often screws with Aftereffects. If you are on Nuke, exr's are preffered. If you only Photoshop or AE, just stick with dem bloddy PNG's.

2015-02-10, 16:06:31
Reply #14

DeadClown

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I really wanna correct this: If you plan on doing Depth of Field or Motionblur in post, it's essential to have Superwhites, which only work in 32-bit, otherwise the Bokeh from DoF and Lightstreaks from MoBlur will have the wrong color and the wrong brightness.

I (also) really wanna correct this...
16 bit float exrs ("half float") save values between 65504.0 and  5.96^–8  (http://http.developer.nvidia.com/GPUGems/gpugems_ch26.html) . So "superwhites" wise, this is more than you'll probably ever need. The important thing is precision here. For nearly everything 16 bit float (not integer) is enough. color, lighting, gi, reflections doesn't matter, it's precise and fast enough for compositing tasks. The only real exception here are world position and zdepth passes  - since those can easily go beyond those values AND need to be very precise. You may not see it right away but if you use a wpp to displace the rendering you see the precision difference between 16 and 32 bit float.

Quote
If you don't Plan on doing DoF or MoBlur in Post (eg. 16-bit exrs), there is no reason to go EXR in the first places, due to compatibilty issues, that may arise. PNG deliver the same color info with less space wasted and a saved color profile. And combining multiple passes in one EXR often screws with Aftereffects. If you are on Nuke, exr's are preffered. If you only Photoshop or AE, just stick with dem bloddy PNG's.
PNG does not deliver the same information. Png ist not linear (so if you want to do any image operation on it you will have to linearize your image first and that means you have already lost a good amount of information). PNG also does not save anything above 1.0, so as soon as you have some overbright pixels you're f*****. I also don't see embedded color profiles as an advantage, but this is another story.
I'm not using multichannel exrs with AE, so I can't say anthing to that. Photoshop is different - since ps is neither able to work linear nor respect gamma of alphas or able to do predivision you're lost anyways, no matter which format you're using...
« Last Edit: 2015-02-10, 18:08:29 by DeadClown »
Any sufficiently advanced bug is indistinguishable from a feature.