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]> 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]>
> 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]
>
>
>
>
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