I think Media Center may already be a step ahead of you.
When you mix analyzed and not-analyzed files, the not-analyzed files use the average (or maybe median, I don't remember) replay gain of the analyzed files. It works pretty well in real world use.
For the most part the current implementation works very well with a mix of analysed and non-analysed files but is there a way to set a default 'reference' volume for when the now playing zone doesn't contain any analysed files to use as a reference?
You are both quite right, automatic is good, but it can go quite wrong when non-analyzed tracks replace analyzed tracks in the PN list.
A usable fix would be to use the whole library as a reference.
I calculated the average and median Replay Gain values of my complete audio library and a few subsets:
Genre All Classical Rock & Pop Metal
Average -10.56 -4.36 -10.82 -13.46
Median -10.82 -5.15 -11.13 -13.91I think it would work fine. For example, if the user has mostly Classical the default attenuation would be smaller than if the user has mostly Metal.
I wonder if this would be technically possible and if it could cause speed problems? Excel had no speed problems with my about 80,000 test files. It calculated the "All" value in an instance. The only problem was the limit of 64,000 rows. I had to split the All column to two separate columns and create formulas for the combined result values.