Megui speed settings-Faster equals smaller sizes-Could someone explain why?

[headhunter03]

I'm under the impression the slower the speed setting the more accurate the decisions and the smaller the file size..Here's my dilemma--My faster settings are producing smaller file sizes and I can't figure out why, unless I'm just wrong..Not that its a big deal..More of a curiosity I guess.Testing was done on the same source using the 3 different settings...And I tried the same settings on other movies as well, encoding 3 times with the settings to see maybe if it was a fluke, but got the same results.. Medium setting would always be about 3 gigs larger than the fast setting and around 5 gigs larger than the faster setting..Doesn't make sense to me...The settings are the same...I only change the speed...I understand it makes adjustments to the settings when you move the slider, but shouldn't the medium setting make a smaller size?

[poisondeathray]

I'm under the impression the slower the speed setting the more accurate the decisions and the smaller the file size..Here's my dilemma--My faster settings are producing smaller file sizes and I can't figure out why, unless I'm just wrong..Not that its a big deal..More of a curiosity I guess..I've tried it on numerous movies using medium on up to the faster setting...And the medium setting would always be about 3 gigs larger than the fast setting and around 5 gigs larger than the faster setting..Doesn't make sense to me...The settings are the same...I only change the speed...I understand it makes adjustments to the settings when you move the slider, but shouldn't the medium setting make a smaller size?

"numerous movies"? Was this testing various settings on the same source? Because different sources will give different filesizes because of different content complexity

But that's the general trend but there are exceptions. On some sources it is very linear relationship, on others one setting might be deviated from the trend for whatever reason.

[headhunter03]

I'm under the impression the slower the speed setting the more accurate the decisions and the smaller the file size..Here's my dilemma--My faster settings are producing smaller file sizes and I can't figure out why, unless I'm just wrong..Not that its a big deal..More of a curiosity I guess..I've tried it on numerous movies using medium on up to the faster setting...And the medium setting would always be about 3 gigs larger than the fast setting and around 5 gigs larger than the faster setting..Doesn't make sense to me...The settings are the same...I only change the speed...I understand it makes adjustments to the settings when you move the slider, but shouldn't the medium setting make a smaller size?

"numerous movies"? Was this testing various settings on the same source? Because different sources will give different filesizes because of different content complexity

But that's the general trend but there are exceptions. On some sources it is very linear relationship, on others one setting might be deviated from the trend for whatever reason.

Let me clarify-Yes--Testing was done on the same source using the 3 different settings...And I tried the same settings on other movies as well, encoding 3 times with the settings to see maybe if it was a fluke, but got the same results..

[poisondeathray]

It's just a general trend - you usually get smaller filesize at higher preset settings at the same CRF value .

But often there are "out of place " results. If you search many people "complain" about the same thing

eg.
http://forum.doom9.org/showthread.php?t=163754

The size itself is meaningless unless you measure quality in some manner (eyes preferrably, but you can use objective measures like SSIM, PSNR as well)

Moreover you will see the "rank order" will change on different sources. You tested only 3 sources, but if you test a dozen more you will see the order swap