diffrence between 1pass and 2 pass encodeing?

[sarmin]

hi i'm a noob but i think you already know.

is there a big diffrence in quality when making a 1pass encode compared to a 2pass encode?

cuz i though is there isn't a bigg diffrence then i can make 1 pass encodes and save 40min of encoding time. and when i say quality diffrence i mean when you are whatching a move in it's normal size not like making in 300% bigger just to see a diffrence. so my question is there a big diffrence? and how big is the diffrence?

[Guest]

Quantifying qualitative factors is difficult and arguably misguided. Try it both ways and if you are happy with one pass, then do it that way. If not, then try two passes and see if things are better and whether you can accept the longer encoding time.

[sarmin]

haven't some1 made a test to see how big the diffrence is?

[CWR03]

Even if someone has, their perception of the differences may be different from yours, which is why your question is frequently answered with "what's best is what works for you." There are many factors that affect quality between single- and two-pass, as well as settings within the codecs that affect each encoding style individually, so someone else's results would be almost useless.

[CRCC]

The Difference is .... totally depending on your configurations :readfaq:

2 pass encoding is usefull if you want a chosen file size and want compatebility with standalone dvd players (don't use gmc or qpel and 1 B Frame)

twopass-1st pass full quality encoding is excellent if you don't care about filesize. use quantz between q2/q3 inc a custom matrix 6of9 or heine_mr the output is fantastic

1 pass CBR is fast encoding quality is decent at best imo

personally i use 1st pass quantizer q2/q2.46 and a .CQM keeps the noise intact aswell and saves time ..uhm well kinda ...3/4fps normally :P (limitedsharpen gotta love it !)

why don't you read this thread :
http://forum.doom9.org/showthread.php?p=841263#post841263

has all the information you need on 2 pass encoding xvid setting etc..

and i agree with neuron2 do some small test encodes and see what you like best

[Teegedeck]

In case it got past you sarmin, there's a thread just a little bit down the page which is pretty exactly about what you ask here:

Quant 3 versus 2-pass VBR (http://forum.doom9.org/showthread.php?t=114177)

[sarmin]

ok sorry for not saying wich type of 1 pass i mean. i mean that 1 pass were you can choose bitrate i think it's called 1 pass cbr.

i Teegedeck's hq 1-2 rips presets:
XviD '>30% comp. check' (HQ): MSP=6, VHQ=4, VHQ for b-frames, QPel, AQ, EQM v3 ULR rev.3, curve-compr. H30, L15, quantizer-restrictions min. 3, max. 5

so is the quality diffrence big if i just make one pass?

will your eye notice the diffrence when you make 1cbr pass instead of 2pass?

[GodofaGap]

with a quant restriction of 3-5 I doubt you will notice a lot of difference (also if you will hit the target bitrate).

[sarmin]

what do you mean "also if you will hit the target bitrate)".

[BigDid]

...2 pass encoding is usefull if you want a chosen file size and want compatebility with standalone dvd players (don't use gmc or qpel and 1 B Frame)
Hi and welcome to the forum.

If I may, I'd rather formulate like this:
"don't use gmc or qpel and if you use B-frames, limit to 1 consecutive"

See this post related to the most restricting SAP, the Philips DVP 642 with ESS chipset: http://forum.doom9.org/showthread.php?p=854923#post854923

More infos can be found in the SAP-HArdware-chipset section.

Did

[CRCC]

Originally Posted by BigDid
Hi and welcome to the forum.


Thank you :)

sarmin :

Q 01: so is the quality diffrence big if i just make one pass?
A 01: do your own tests 1 1pass cbr and 1 2pass and see what you like best ...been mentioned before and if you don't know how to do a 2pass :readfaq: ;) and there are lots of good guides.

Q 02: will your eye notice the diffrence when you make 1cbr pass instead of 2pass?

A 02: hmm maybe my left eye wont .. :P just kidding .. yes if your a quality freak/nut and do a frame by frame comparison or watching XviD encodes on a lcd tv or tft monitor you will notice blocks in fast motionscenes specially with toons and anime.

so you want/like to use this preset
XviD '>30% comp. check' (HQ): MSP=6, VHQ=4, VHQ for b-frames, QPel, AQ, EQM v3 ULR rev.3, curve-compr. H30, L15, quantizer-restrictions min. 3, max. 5

shoot me if i'm wrong but quantizer-restrictions min. 3, max. 5 only work in 2pass mode if you use it in 1 pass cbr and filesize input is to small wouldn't it just get bigger than the target filesize because of the quantizer restrictions ?

sarmin maybe you want to try this
CQM - EQM v3 ULR rev.3

1st pass quantizer 3 MSP=6, VHQ=1, VHQ for b-frames, and use chroma motion, turbo on
2nd pass MSP=6, VHQ=4, VHQ for b-frames, curve-compr. H30, L15, turbo off
its pretty much the same as the xvid preset you want to use minus qpel and aq which slows down encoding and only gives just a little sharper/better (aq mostly worse imo) picture.

[GodofaGap]

what do you mean "also if you will hit the target bitrate)".
Restriciting quants to 3-5 is rather harsh. You can't ask a codec to use any random bitrate and then expect to hit it if you use such restictions. You might as well do a 1pass q4 encode then.