EXR Channels changed

[am_wilkins]

Hi,

We've noticed that while updating to newer Houdini and Arnold that the EXR Channels have changed?

Previous

A:{2 0 1 1},B:{2 0 1 1},G:{2 0 1 1},R:{2 0 1 1}

New:

RGBA.A:{1 0 1 1},RGBA.B:{1 0 1 1},RGBA.G:{1 0 1 1},RGBA.R:{1 0 1 1}

This is causing some issues with certain processes in our pipeline such as ffmpeg not recognizing them anymore etc.

Is this a known change? Is it coming from Arnold or perhaps Husk/Houdini etc.?

We are saving out a USD and using Husk to command line render the frames.

edit update:

1. Karma produces the correct/previous result.
2. Arnold in 19.5 produces the correct/previous result, however in Houdini 20 produces this new result.

All the best,

amwilkins

--

Houdini Core Version 20.0.590
Arnold Core: 7.2.5.2

HotA: 6.2.5.2

CPU: AMD Ryzen TR 3990x

RAM: 128GB
GPU: NVIDIA RTX A4000
OS: Windows

[Stephen.Blair]

Houdini 20 and the latest HtoA (I haven't tested older versions yet)

With the Arnold product type, I can get R,G,B,A

oiiotool" -v --info C:\temp\test.exr
Reading C:\temp\test.exr
C:\temp\test.exr : 1920 x 1080, 4 channel, float openexr
    channel list: R, G, B, A

[am_wilkins]

Hi Stephen,

Running that OIIO tool command, on Houdini 20:

channel list: RGBA.R, RGBA.G, RGBA.B, RGBA.A

1143 x 1080, 4 channel, float openexr
    channel list: RGBA.R, RGBA.G, RGBA.B, RGBA.A
    pixel data origin: x=387, y=0
    full/display size: 1920 x 1080
    full/display origin: 0, 0
    comment: ""
    compression: "zips"
    Copyright: ""
    date: ""
    DateTime: "2024:03:06 14:03:22"
    name: "RGBA"

In Nuke View Metadata: A:{2 0 1 1},B:{2 0 1 1},G:{2 0 1 1},R:{2 0 1 1}

Here's an example of the Houdini 19.5 render

channel list: R, G, B, A

1145 x 1080, 4 channel, float openexr
    channel list: R, G, B, A
    pixel data origin: x=386, y=0
    full/display size: 1920 x 1080
    full/display origin: 0, 0
    comment: "none"
    compression: "zips"
    DateTime: "2024:02:23 11:13:34"
    frame: 101
    FramesPerSecond: 24
    ImageDescription: "Created using Houdini 19.5.682"

In Nuke View Metadata: RGBA.A:{2 0 1 1},RGBA.B:{2 0 1 1},RGBA.G:{2 0 1 1},RGBA.R:{2 0 1 1}

So there does appear to be a difference...

example of our sudden ffmpeg issues:

All the best,

amwilkins

[Stephen.Blair]

Yeah, without Arnold product type. But with Arnold product type, it's R, G, B, A

That's all I'm saying.

[am_wilkins]

Not entirely sure what you're saying.
We are using a default "Arnold Render Settings" node in all render tests (19.5 and 20), in which the Product Type is set to "raster".

Have you tried with Houdini 19.5?

All the best,

amwilkins

[Stephen.Blair]

Seems to have changed from HtoA 6.2.5.1 to 6.2.5.2, and in Houdini 20 only.

C:\Users\blairs>"C:\Program Files\Autodesk\Arnold\maya2024\bin\oiiotool" -v --info C:\temp\test_20_6251.exr
Reading C:\temp\test_20_6251.exr
C:\temp\test_20_6251.exr : 1920 x 1080, 4 channel, float openexr
    channel list: R, G, B, A
    comment: ""
    compression: "zips"
    Copyright: ""
    date: ""
    DateTime: "2024:03:06 11:36:17"
    name: "RGBA"
    PixelAspectRatio: 1
    renderMemory: 1.36031e+09
    renderMemory_s: "1.27 GB"
    renderTime: 8.181
    renderTime_s: "0:00:08.18"
    screenWindowCenter: 0, 0
    screenWindowWidth: 1
    typeSemantics: "color"
    oiio:ColorSpace: "Raw"
    oiio:subimagename: "RGBA"
    oiio:subimages: 1

C:\Users\blairs>"C:\Program Files\Autodesk\Arnold\maya2024\bin\oiiotool" -v --info C:\temp\test_20_6252.exr
Reading C:\temp\test_20_6252.exr
C:\temp\test_20_6252.exr : 1920 x 1080, 4 channel, float openexr
    channel list: RGBA.R, RGBA.G, RGBA.B, RGBA.A
    comment: ""
    compression: "zips"
    Copyright: ""
    date: ""
    DateTime: "2024:03:06 11:49:53"
    name: "RGBA"
    PixelAspectRatio: 1
    renderMemory: 1.25915e+09
    renderMemory_s: "1.17 GB"
    renderTime: 8.832
    renderTime_s: "0:00:08.83"
    screenWindowCenter: 0, 0
    screenWindowWidth: 1
    typeSemantics: "color"
    oiio:ColorSpace: "Raw"
    oiio:subimagename: "RGBA"
    oiio:subimages: 1

[Stephen.Blair]

---

@am_wilkins wrote:

Not entirely sure what you're saying.
We are using a default "Arnold Render Settings" node in all render tests (19.5 and 20), in which the Product Type is set to "raster".

Have you tried with Houdini 19.5?

All the best,

amwilkins

---

Product Type raster is not the same as Product Type arnold.

If you change the Product Type to arnold, then husk uses the Arnold drivers. And then, for example, you get all the EXR metadata that the Arnold drivers write, .like cryptomatte.

In the Arnold Render Settings LOP, there's a check box for the Arnold product type

[Stephen.Blair · Accepted solution]

Logged as 

HTOA-2561
In Houdini 20 with HtoA 6.2.5.2 and later, husk renders with different channel names

[am_wilkins]

Hello,

Ah okay, I see that checkbox now!

Is it worth enabling? Do you think it would fix this issue?

Edit:

We tested and this doesn't solve the problem.

"HTOA-2561
In Houdini 20 with HtoA 6.2.5.2 and later, husk renders with different channel names"

Okay, so there is a bug involved?

Thanks

amwilkins

[am_wilkins]

Hello,

We updated to latest Houdini and HtoA etc. but this problem still persists.

It's quite pipeline breaking as it messes with ffmpeg, render farm stuff, Nuke, etc. We're very keen to get it solved.

Any luck progressing with solving this problem?

Can you confirm the issue in relation to Arnold, SideFX or OpenEXR?

I see you did log a an issue so I'm assuming Arnold?

Are there any work-arounds that you know of to force the channel names back to:

channel list: R, G, B, A

all the best,

amwilkins