Must it be oiiotool?
I think a very short Python script might be a lot more efficient. It would
perhaps look like this:
# Make an ImageBuf for your template file and read the spec.
# Note: this will avoid reading the pixels until needed, only opens
# the file and reads enough to get the spec, should be cheap!
b = ImageBuf("template.exr")
templatespec = b.nativespec()
# Make a new image with the same spec -- should initialize to black pixels
newbuf = ImageBuf(templatespec)
# Write it
newbuf.write("out.exr")
Caveats:
1. I'm typing this off the top of my head, not testing it, but you'll get the
idea.
2. I make no promises about OIIO 1.7. Please try 2.0 or master if at all
possible. A lot about
the python bindings has changed and improved since 1.7.
> On Jul 25, 2019, at 11:55 AM, Will Anielewicz <[email protected]>
> wrote:
>
> Yeah I figured you would suggest that ... I do want to keep all the metadata
> and channel names.
>
>
> On Thu, Jul 25, 2019 at 11:17 AM Larry Gritz <[email protected]
> <mailto:[email protected]>> wrote:
> Is there a reason you're reading a file to make a black image? Is that just a
> way of setting up the right resolution and channel names and metadata?
>
> The stats are probably a little misleading. When inputting a big image (4k x
> 27 chans!) it will be backed by ImageCache and tiles read on demand, so all
> the input costs are actually showing up in the --ch (it's reading bits as it
> needs it).
>
> I think it should be fast to just create a new image from scratch:
>
> oiiotool -create 4096x2000 37 -chnames R,G,B,A,alice,bob,charlie -d half
> -o black.exr
>
>
>
>> On Jul 25, 2019, at 9:06 AM, Will Anielewicz <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>> Im using a bit older a version 1.7.17.
>> Im trying to find the quickest way to set the RGBA default channels of a 37
>> channel 4k openexr file to a 0.0 value. Im doing this to replace missing/bad
>> frames in a sequence. On my fairly hefty workstation its taking 48 seconds.
>> I could just do this once per sequence and duplicate for every other
>> missing/bad frame but ... Im trying to keep everything else in the file
>> intact like resolution and metadata etc
>> At first I tried this ... which understandably takes 48 seconds.
>>
>> oiiotool -i frame.exr --mulc 0.0 -o foo.exr
>>
>> after reading the programmer document with it's excellent examples I did
>> this:
>>
>> oiiotool -threads 0 --autitile 1 --threads 0 --autotile 1 -i:ch=R,G,B,A
>> frame.exr --ch R=0,G=0,B=0,A=1 --compression "zip" -o foo.exr
>>
>> still took 21 seconds ... ...
>>
>> Threads: 32
>> oiiotool runtime statistics:
>> Total time: 21.29s
>> --ch : 21.13
>> -o : 0.14
>> input : 0.01
>> unaccounted : 0.00
>> Peak memory: 2.0 GB
>> Current memory: 2.0 GB
>>
>>
>>
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>
> --
> Larry Gritz
> [email protected] <mailto:[email protected]>
>
>
>
>
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--
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[email protected]
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