MeGUI x264 presets.

[Octo-puss]

One more somewhat lame question. I was suggested to use constant quality for encoding one particular HD stuff - and also to make it DXVA compatible if possible. But there's no constant quality preset in the DXVA category, all are 2pass. Using constant quality would be bad for some compatibility or how is it? I am pretty new to this, only have experience with DVDs so far, so it's quite confusing.

[Sharktooth]

1pass VBV compliancy is not optimal.
just use 2 passes if you have VBV restrictions (DXVA has them...).

[Octo-puss]

edited

When using DXVA presets, the video must be resized to mod16? I tried to encode something and was given an error message:

Your AviSynth clip has the following problem:
AviSynth clip doesn't have mod16 dimensions:
Width: 1920
Height:1080
This could cause problems with some encoders,
and will also result in a loss of compressibility.
I suggest you resize to a mod16 resolution.
Continue anyway?

I think I don't get this with unrestricted profiles.

[dant3s]

The posts from Dirk362 & Avenger007 are very interesting. Thanks to take time to explain taking experience in count.
I just have a question about deblock 1:0:0, how it can be modified in the preset, I see the Deblocking window in Main Tab... but It doesn't appear in the command line window?

[Sharktooth]

@octo-puss

presets updated: v67

[dirk362]

Originally Posted by dant3s

The posts from Dirk362 & Avenger007 are very interesting. Thanks to take time to explain taking experience in count.
I just have a question about deblock 1:0:0, how it can be modified in the preset, I see the Deblocking window in Main Tab... but It doesn't appear in the command line window?

x264 has lots of default values. If you enable a setting, such as deblock, it will use its default unless you change it. Therefore unless you change any settings in the Main Tab to be anything other than 0 and 0, it will assume defaults, which are 1:0:0. If you wish to put this in use the custom command line optional area in Advanced tab, but it will be irrelevant. If you change the settings in the Main tab to anything other than 0, the command line window will be updated accordingly.
If you type in a command prompt when x264.exe is located x264 --longhelp you will find all the settings, and default values etc.

Originally Posted by Avenger007

With the new B-Frame optimization patch (coming soon ) the encoding time will take a lot longer with each additional B-frame.
3 b-frames is generally the most practical; higher values offer little advantage except perhaps for anime.

Having read in detail (and re-read a couple of areas as its quite a complex subject) that forum entry (link), I can see that in future values for b-frames might be 3 as you've suggested. But that is a while away, and I was commenting on non-patched x264 versions of parameters etc. I fully expect to have to test and potentially refresh all my profiles and parameters once this --b-adapt=2 becomes available and the default.

Originally Posted by Avenger007

Higher MERange would be useful for high resolution sources with fast motion, i.e. objects travel over many macroblocks between each frame. 64 might be good for 1080p (just a guess, I haven't tried it)

Most of my testing is with 1080p, and I've found 32 works well across a wide range of live action movies. When encoding time isn't an issue, and only for 1080p, setting to 64, whilst dramatically increasing encoding time, lends itself to higher perceived quality due to better ME.

[Seraphic-]

Originally Posted by tetsuo55

The DXVA profiles will create a file guaranteed to work on any DXVA decoder. The file will also work on any Software decoder so its win-win. However the stream might not work on all standalone players like blu-ray players.

Are the DXVA profiles unable to attain the same quality as the Unrestricted ones since they are bound by setting limitations?

Also, are profile settings interchangeable? Meaning, if the preset is set to Automated Two-Pass, can it be changed to say Const. Quality and vis versa without complications? Or are those settings only meant to be used with their default mode?

Last, if you use Const. Quality of say 18 and after the encode it says the output bit-rate was around 4956, would using that number with VBR two-pass return the same quality?

[nurbs]

Originally Posted by Seraphic-

Are the DXVA profiles unable to attain the same quality as the Unrestricted ones since they are bound by setting limitations?

There are some restrictions for the DXVA profiles that limit the number of reference frames depending on resolution, the number of b-frames and there are the VBV constraints. While you can get better quality with the unrestricted profiles the quality gain will generally be small. Cartoons would probably benefit most from breaking the restrictions.

Originally Posted by Seraphic-

Also, are profile settings interchangeable? Meaning, if the preset is set to Automated Two-Pass, can it be changed to say Const. Quality and vis versa without complications? Or are those settings only meant to be used with their default mode?

Generally they can be changed, but x264 is not as good at sticking to VBV restraints in 1pass as in 2pass. That might also lead to quality issues.

Originally Posted by Seraphic-

Last, if you use Const. Quality of say 18 and after the encode it says the output bit-rate was around 4956, would using that number with VBR two-pass return the same quality?

Basically yes.

[Seraphic-]

Thanks.

Also, when you enable Turbo mode, it allows for faster encoding, but causes a quality drop, correct?

And does it matter if MeGUI shows my CPU as an Intel Pentium III Xeon when it is an Intel Core 2 Quad (like not taking advantage of all cores during encoding)?

[Sharktooth]

turbo mode allows a faster first pass. the drop in quality is negligible.
also megui is just a gui... the encoding is done by the encoder... so it doesnt really matter what CPU is shown.

[Octo-puss]

Originally Posted by Octo-puss

Not sure if it has anything to do with the presets, but after doing regular update and importing some presets, I get this:

http://forum.doom9.org/showpost.php?...&postcount=182
and again after updating presets via autoupdate

[Sharktooth]

doesnt happen here.
i updated the presets as well and everything is working and didnt crash.

[Octo-puss]

It happens to me ALL THE TIME. I don't know. Right after I click to overwrite the last preset or after checking "don't ask again". And so it does if I delete the presets first. The only working method is manually importing.

[Sharktooth]

i do it every time i publish the new presets... and it doesnt crash...
is your system up to date? have you tried reinstalling megui from scratch?

[Octo-puss]

I can try. But can't test until new version of profiles is out
(I assume the whole package is updated each time?)

[Dark Eiri]

No Fast-PSkip is really not needed on Unrestricted HQ? I remember reading somewhere that disabling it can cause blocky backgrounds, right?

[lithiumus]

How does going from Trellis 1 to 2 affect encoding time in general vs. quality?

[Dark Shikari]

Originally Posted by Dark Eiri

No Fast-PSkip is really not needed on Unrestricted HQ? I remember reading somewhere that disabling it can cause blocky backgrounds, right?

Not anymore, with AQ, but I'd definitely put it in an "ultra high quality" profile, especially if tesa or trellis 2 is already being used.

[Sharktooth]

Originally Posted by Octo-puss

I can try. But can't test until new version of profiles is out
(I assume the whole package is updated each time?)

options->update then right click on the profiles and selct "force (re)install"

Originally Posted by lithiumus

How does going from Trellis 1 to 2 affect encoding time in general vs. quality?

in general, it slowers the encoding, and gives better quality.

[check]

Why does the PS3-Xbox360 preset have nonstandard --ipratio and --pbratio?