In a way i have done quantitative anylises cause ive have done a project on my own where i have ripped 4 different movies; all with 2 and 6 passes. I ripped scarface (wich have poor quality originally), gladiator (long movie with good quality), grapes of wrath (black/white) and cypher (good quality, not so long).
Then i examined before and after on each rip and looked for differences. I took the same scene and zoomed in 300% of normal size. What i found was this:
Scarface: Slight quality difference, Gladiator: significant difference, grapes of wrath: didnt notice any difference, cypher: slight differece.
My conclusion was that the lower bitrate (longer movies) and good sources need more passes while the higher bitrate and poorer source quality need fewer passes. Even though i only on gladiator saw a significant difference in quality i would do 5 passes or more on all my rips since i did see a slight difference on the rest. Thats the whole point: i would ensure the best possibly quality even though you gain little quality in a long time. I think if you start to compromise quality you can get into a “bad” circle. Just like people compromise their media quality to save money. You buy the media that suits how much money you got. This is the same case: I would always advice people to buy tayo yuden since its the best, and i would always advice to do 5 or more passes to ensure the best quality. That doesnt mean that 2 passes gives you bad quality, but its not the best. It depends on how much time you wanna spend getting it.
I use two passes with CCE and get excellent results in under two hours with a long movie.
Sure you can get good quality, but not the best.
I think that sounds weird. That would be to decrease functionality and why would he do that ?