vrimg2exr and 4GB vrimg file issue

[tricky]

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

Please tell me there is a quick way to do this.

[vlado]

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).

Best regards,
Vlado

[tricky]

Will give it a try. We have 4GB ram in our machines - what would be the best setting? Why is the default only 10MB?

[vlado]

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.

Best regards,
Vlado

[tricky]

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)

[vlado]

This should work, yes.

Best regards,
Vlado