To clarify what is meant by “best picture quality”

Picture quality can be defined using a set of objective standards. So what defines picture quality is not necessarily subjective.

However, whether or not one individual thinks that the picture looks best with a particular set of settings is always going to be subjective.

This is how “picture quality” can be objective and subjective at the same time :)

Also, just wanted to clarify that I am not against a softer look per se (although I personally do prefer a sharper image), but bilinear filter is not the way to do it, for the reasons I’ve given, and there really isn’t a good way to achieve this on the raspberry pi, unless, perhaps, you are using a 720p native display and shaders.