There is no best Quality at the lowest Filesize
(there are more possibilites of Setting Combinations with x264/x265 as People in China xD. What is considered good today, can look like *hit in 10 years ! Example: DivX5 1CD Ripps, that looked nice back in the day on our 19" CRT Monitors and CRT TV’s over S-Video, but look horrible on a Flat Screen, even more if the Flat Screen is big)
Lossy Encoding got always sacrifices and compromises, the Question is where (Priority) and if it’s tolerable at the given Filesize.
Auto Judgement stuff like Psy-Rdo/Psy-Trellis, MB-Tree & AQ Mode just push Prioritys around (and i dont trust AQ-Mode & MB-Tree anymore)
Examples how they just push Prioritys around.
Example1: AQ Mode → The Higher the Strenght, the more Bitrate in CRF will be used. The Higher the Strenght, the more Ringing Risk.
The Higher the strenght, the more Priority for complex DCT Blocks (Fine Detail) and less for low Complex Blocks (wall, hart contures, surfaces with allready low detail).
Ok let us think again about what i wrote.
There was a x264 Coder back in the day, who selled the Idea to use more Bitrate to keep more fine Detail, as a Function ! (any Codec can do this !)
The only thing that allowed him that he got not *aped from the doom9 guys is, that
it mostly fixed the Problem that h264 washed out fine Detail.
Ok, so what is, if AQ-Mode is used with CRF ?
Way More Bitrate is used, and we got slightly more Ringing at hart contures (something that XVid does by nature ! because it sees more, and tries to keep more, even if it looks bad afterwards) and better fine Detail preservation (something that XVid does by nature ! no deadzone cheating)
What is if AQ-Mode is used in 2 Pass ? The Filesize doesnt change, but because x264 need way more Bitrate to keep Fine Detail, we lose cleary detail at any place, that was not complex, and the only reason why there is not a ton of Ringing & Blocking is because h264 got the luck of having a Deblocking Function (and loves to >dont see what is there< ! That’s what the deadzone-inter & deadzone-intra parameters do. What can’t be seen, cant be processed. Result = Washed Out High Frequency Detail, i call it Cheating to create less Blocking & Ringing at the same Bitrate as XVid)
It’s no wonder, that most people dont use 2 Pass anymore, and that those x264 guys recommend CRF, it hides better the fact, that they did sell “using more Bitrate to keep more Detail” as some kind of brand new special function.
I can use a Custom Matrix in XVid, and can configure the Priority from 64 DCT Blocks from I, and P&B Frames like i want, and XVid will do it exactly like that, no flawed Auto Judgement, no Deblocking Cheating.
Example2: Psy-Rdo, Psy-Trellis.
Good: Does not make the File bigger ! like AQ Mode.
Bad: Doesnt try to ReCreate Complex Blocks, if it would cost to much Bitrate.
It ReCreates something that looks similar complex, but cost less Bitrate.
The Problem: It’s a Auto Judgement Function (like AQ Mode) so things that are important can be distorted (*ussy Lip in a shadow, shadow on a *ick → Both are a important Combination in Pron ^^) especialy if grain is in the Source.
Example3: MB-Tree
Tracks Detail over Time ! So it sacrfices the Detail of static parts, for moving parts.
Good: Helps to keep Motion Sharpness (because it sacrificed on other places) and need less Bitrate at the same CRF. Very good for normal Movies !
Bad: Static Parts (lets say a Chick on a bed that doesnt move much) lose more Detail, or moving but unimportant parts (like a ton of tree leaves that move, because a Person walks in front of it, and the Cam follows) got to much priority.
Another Problem: If there is grain and the Grain Intervall & Size matches the “Tracks Detail over Time” range, then MB-Tree will have Problems to judge what has to be prioritized.
All those functions push problems around, and in the end, there are way to much possibilites to find “the best quality” for given filesize ! (especialy if some codecs do better at some resolutions and lightning as other)
So i take the least pain in the *ss Codec, with a behavior that is more predictable (no psy, and a Matrix that i know) and honest !
No Deblocking Cheating ! No 0 Effect @ value Change (because Deblocking negated the effect of the Value Change)
8 from 10 times XVid does a better job (and is way faster) at the content that i process (mostly Euro Pron DVD’s until 2007, most times i dont upscale. I get the best out of the SD Res.) and the Bitrate that i use, even on 59.97 fps.
Yeah i cheat too xD with a Custom Matrix (that i select by use case) and Special BFrame Values ^^ that work good with the Bitrates that i use.
