Lucas Digital Releases OpenEXR Format

frankie writes "Although George Lucas may have gone over to the dark side, at least some of his staff prefer Freedom and light. ILM has released OpenEXR, a graphics file format and related utilities, under a BSD-style license. Among other things, it supports the same 16 bit format used by Nvidia CG and the Geforce FX. OpenEXR runs on Linux, Jaguar, and Irix; other platforms are likely to work with a little help from the community."

Comments

I am your father Luke

[valisk]

Looks like we could well see a nice improvement in editing software for all those with DV cams in the near future.
Thank you very much ILM

Not for Windows?

[Anonvmous Coward]

That's a bummer. Lightwave loves HDRI imagery.

Out of curiosity, has anybody used HDRI images for textures? I'm curious if the floating point data makes a difference. I could see it being particularly useful for the diffuse and lumination channels. What about color?

Re:Not for Windows?

[dhess]

I'm sure somebody will port it to Windows in time. The libraries themselves are pretty vanilla code, so it should be easy to port. We don't really use Windows for effects work here so it hasn't been a priority for us.

Other uses for 16-bit formats?

[NanoGator]

Hey dudes,

I was just curious if anybody out there uses HDR imagery (like the OpenEXR format) for anything besides global illumination?

I've been fiddling with the .HDR format (similar to OpenEXR, I imagine) in Lightwave's various texture channels and have gotten interesting results. (Especially the diffuse channel.) It strikes me that you could lose the diffuse channel all together in favor of a floating point color channel. In english, that means that you have one texture that responds properly to light, as opposed to having to assign the color of the surface in one channel and it's light reflectance in a seperate one.

That's seriously cool, but I'm in my infancy here with regards to these floating point formats. I'm just curious, who's using HDR in ways besides global lighting? It seems like there's a whole new door opening here.

Re:So they would like you to write tools for them

[womprat]

So? They create a format which open source tools can use. We get a standard format and all the tools. And they also get the free tools.

This helps both them and us. win-win

It's cool that they have the file format

[exp(pi*sqrt(163))]

But have you watched any movies with ILM effects lately? The dynamic range sucks! Episode II was basically characters jumping between matte paintings and each painting looked like it had been painted with an 8 bit paint package. Unless you actually bother to collect data on set that is high dynamic range having the file format is as good as useless.

Great, another format to be ignored

[Kickstart70]

PNG has been accepted as far as browser support, but is relatively (in comparison to JPG and GIF) unused. Unless this image format has vastly improved abilities over the conventional method, this is a non-starter.

Kickstart

Re:The license, /.-ed but interesting clauses:

[Anonymous Coward]

Apparently no one reads posts before they moderate them anymore. The parent is FUNNY not Informative.

...IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. STAR TREK IS STUPID. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE...

Reason: Don't use so many caps. It's like YELLING.
Your comment violated the "postercomment" compression filter. Try less whitespace and/or less repetition. Comment aborted.
Please try to keep posts on topic.

Not off topic.

[Anonvmous Coward]

"Out of curiosity, has anybody used HDRI images for textures? I'm curious if the floating point data makes a difference. I could see it being particularly useful for the diffuse and lumination channels. What about color?"

Okay, somebody modded me down as 'Off-Topic'. I'm just going to assume he/she/but probably he didn't understand what I was talking about here.

OpenEXR is a format for High Dynamic Range Imagery. What this essentially means is that instead of describing a pixel by having 3 channels @ 8-bits per channel (which has a maximum value of 255), you get a floating point 16-bit value per channel which is a measure of intensity. The result? Instead of having just color data there, you have color data & intensity data. The sky's blue, right? If you take a 24-bit picture of the sky, you get blue pixels. Is that enough data? No. Try looking up at the sky without squinting your eyes. Can't do it, can ya? The sky is *very* bright. With the HDRI format, you can store that luminosity as well as the color. That's why they use it for global illumination. You're capturing light sources, intensities, and color at the same time.

Thing is though, a floating point format has uses in other areas of 3D such as texture mapping. It means you can create/capture textures that deal in intensity as well (just like real life), thus you get a much more realistic response from lights in the scene.

I have no idea if I'm making any sense here or not, but the main point I'm trying to make here is that I am nowhere near off-topic. That's the reaason this format is interesting. It's not another .PNG or .JPG format, it's a more accurate way of storing information about light, and us people that work in 3D have a lot to be excited about. Since it's just recently become involved in the major 3D Apps out there, the capabilities of it are still in their infancy and I'm curious what people have discovered about it.

Lucas controls all

[McSpew]

I saw a rare interview/profile of Lucas just before AOTC was released, and they pointed out that Lucas is intimately involved in the important decisions for all of his businesses (and he has lots of them). While he might allow small decisions to be made by subordinates, Lucas pretty much nearly micromanages his empire. Can't argue with his management style because it's clearly worked for him. Come to think of it, I wonder if the folks at Pixar would have preferred to stay with Lucas vs. going to work for Steve "Reality Distortion Field" Jobs.

Available for Atari?

[cant_get_a_good_nick]

OpenEXR runs on Linux, Jaguar , and Irix

I'm glad someone is finally releasing software for the Atari Jaguar, it was such an unloved system.

Bad jokes aside, too many damn codenames that mean the same thing. Sometimes i realize why folks make stupid names like Itanium and Infinium.... no one else will be stupid enough to use them.

Re:It doesn't look like it's tiled

[dhess]

You're right, tiling support is missing. We've been able to get away without it because we don't typically work in tiles.

You can load the image in pieces using the FrameBuffer object, but it's scanline-oriented, not tiled. Dunno if apps can get away with that or not.

Does Shake actually load the original file-based image in tiles, or does it simply tile its internal representation of the image and page that out to/from disk?

Tiling is irrelevant

[Namarrgon]

Thousands of layers? The most complex composition I've seen personally was the Swordfish Ventura Bank explosion, and that required somewhat over 500 layers (at 4K). Definitely qualifies as heavy duty, but still a far cry from "thousands" of layers. "Often" would be less than 100 layers, in my experience.

Anyway, tiling as you describe is rarely used in motion picture image processing work, regardless of the number of layers. Breaking down a large (4000x3000 or larger) image does improve memory usage (sometimes at a cost in efficiency for certain algorithms), but when this is done, it's usually broken into scanlines or groups of scanlines, not square tiles. This works just as well and fits better with how images are processed, stored, displayed etc. The number of layers to be composited does not affect this at all.

DPX and Cineon do not support tiled image packing. TIFF does, but I've never seen a post-production app actually output a tiled image - it just complicates things unnecessarily.

And it's rarely necessary to re-read an entire image if you just want a subrectangle of it - many formats make it relatively easy to read a limited region. Compression can complicate things, but you can usually limit your reading to just the scanlines involved.