Generally, if you don't have enough memory to filter an image on CPU, you won't have enough to filter on GPU either. If you've more information on if that isn't strictly true, would love to know about it.
At this time, Altus still only runs on 1 GPU at a time. If your system has multiple GPUs, you can run multiple instances of Altus (i.e. on different images).
The --device-id flag selects which GPU Altus uses, with which you can only specify 1 GPU.
Multiple GPU support is on our roadmap, but low priority. In many cases using multiple GPUs makes things slower, unless you're filtering very large images. It's an architectural problem we're working on fixing.
Any chance you could shoot those images over to support@innobright? We'd love to take a look at them.
So, a 720p image may be small enough (especially if it has black space) to run so quickly on a GTX 1070 that the GPU never spins up. Depending on how many AOVs you have you could probably filter 3–4 images at the same time on a card w/ 8 GiB RAM, as Altus is typically memory limited.
@ptemoche So, other than the first frame not filtering, is there a problem?
Also, we've noticed problems with the CUDA version of Altus that is run by default when you run "altus.exe". If you're still having problems, do you mind using the OpenCL version of Altus?
Doing so outside the GUI is a little involved: you'll need to go to C:\Innobright\Altus\bin\ and run opencl.exe with the command-line arguments you would have used for the GUI.
1.6.1 mistakenly was compiled against the CUDA 8 SDK, meaning you must have an NVIDIA driver 367.4x or later (just added this to our changelog/known issues document). We'll be releasing Altus 1.6.2 shortly to address this.
In 1.7, we're formally moving to the CUDA 8 SDK (possibly dropping it altogether), and making the OpenCL version default again.
(1) Using multiple GPUs for filtering. Altus does not support this; we hope to do so in a quarter or so.
(2) Selecting the GPU on which to perform filtering. Unfortunately Altus does not do this either, but we're hoping to release device selection in our 1.7 release. At the moment the device with the most graphics RAM is automatically selected.
Hello! I think we went over this in the support ticket… Altus needs two images, with noise in different places (i.e. different seed) to filter each frame of a render. This is done by checking and unchecking "Sample Lock" when generating when generating your "b0" or "b1" images.