But what about when it has been tested and proven that people cannot discern the difference? I don't know if this is what was done with the per-title encoding that the parent comment was referring to, but I know it is the situation with audio. So many audiophiles swear they can hear a difference between FLAC and high quality VBR MP3, but it has been repeatedly demonstrated that, when presented with both, humans cannot distinguish them better than chance.
> But what about when it has been tested and proven that people cannot discern the difference?
The way people perceive (and how to measure it) is in fact not a solved problem. There are studies done and we can often say with a high degree of certainty that something is probably not visible/distinguishable, but claiming something like that for everyone is too strong and also misrepresenting the state of our learning.
