I am working on a high resolution image (around 8500x5000 pixels or so) with a few multimatte channels. I am rendering to a vrimg file and the resulting file is about 4GB. I have extracted the exr rgb image without a problem. Now I am trying to extract the mattes I have saved, but it seems to be very very slow. It has been going for half an hour or so on the first one and it is only at 30% or so. I cannot afford to wait this long. Are there any setting I should use to speed this up?
I am running this on a local drive, and the format I am using is:
vrimg2exr imagefile.vrimg -channel matte01
Use the -bufsize option to increase the internal memory buffer for vrimg2exr; this will speed up the converting of large images (the default is 10 MB, but you can try 100 or 200 or even more).
It depends on how many channels you have in the .exr file, as each channel will take its own buffer, so if you have 10 channels, the conversion will take a total of 10 x 10 = 100 MB. Also it depends on whether your OS is 32- or 64-bit and whether you are using the 32- or the 64-bit version of vrimg2exr.
So, if I have 4 channels and I am running the 64bit version of vrimg2exr, with 4GB in my machine, I could set it to 800MB? (4 x 800 = 3.2GB leaving 800MB or so left for the OS etc)