It appears that this is not an issue with ARC/not ARC (I've tried GPUImage builds with and without ARC enabled).
What I have found instead is that before releasing the GPUImageVideoCamera, you need to stop it from capturing any frames. Then schedule the call to [camera release]
on the GPUImageContext.contextQueue
, which will make sure the release is called after all frames have been processed.
Sorry for not posting more sample code, right now using GPUImage from Xamarin/C# hence translations a bit cumbersome.