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 :search:

presets updated: v67

[dirk362]

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.

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 (http://forum.doom9.org/showthread.php?t=139827)), 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.

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-]

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]

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.

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.

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]

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?p=1173951&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 :D
(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]

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]

I can try. But can't test until new version of profiles is out :D
(I assume the whole package is updated each time?)
options->update then right click on the profiles and selct "force (re)install"
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?

[Sharktooth]

already answered that one :)
https://forum.doom9.org/showthread.php?p=1170270#post1170270

[egrimisu]

one question : Audio - force decode via Directshow or not? some versions of the presets have the setting checked some versions not... now i don't know witch is best!!! updated to the latest preset on my notebook and seting was unchecked, updated on my pc and setting was checked. Now who is checking!! updater or some ghost in my pc ;) ?

[Sharktooth]

there is no best. use what works best for you.
ensure you have the same versions of the presets

[florinandrei]

One feature that I would very much appreciate would be the ability to just "Select All" when new presets are being released. Clicking through that big list is not a lot of fun.
And yea, I don't necessarily use all of them, but I'd like to stay updated in case I decide to use a new preset.

I guess this is a MeGUI feature request?

[Sharktooth]

it's already there... right click->check all.

[florinandrei]

more etherogeneous quants distribuition.
that means less visual difference between frametypes since TVs are usually overrbright and that may expose some artifacting that wont be visible in the correct viewing conditons.
the obvious counterpart is a small overall quality hit but that is compensated from the above situation. if you're targeting a well calibrated device you should consider using a PC as player with a good Display/TV and then use the DXVA or the Unrestricted presets.

Keep in mind some of us actually do calibrate their TVs, and use a PS3 as a player. So these profiles are now less than optimal for people with calibrated screens.

I think there should be no penalty for correctly setting up your gear. If anyone takes a penalty, it should be people with non-calibrated displays. Those tend to care less about quality anyway.

Personally, I use the AVCHD profile (I create AVCHD disks on DL DVD) and I'm not sure where that profile stands on this issue (and I can't verify right now), but I'm speaking in principle.

It's those who care less that should take the hit.

[egrimisu]

Of course i selecteed them all the diference is that on my pc for all the preset the decode via directshow was activated and on my notebook not. Do you think that i uncheke/check the settings for about 30 presets? the idea was that i want to keep the quality as closer to the original and i don't know in what metter directshoe affect the quality. Thanks

One feature that I would very much appreciate would be the ability to just "Select All" when new presets are being released. Clicking through that big list is not a lot of fun.
And yea, I don't necessarily use all of them, but I'd like to stay updated in case I decide to use a new preset.

I guess this is a MeGUI feature request?

[Sharktooth]

@grimisu: it's impossible... all the presets come with "Force directshow decoding" disabled... so either you didnt import the profiles or megui cant write to the profiles dir but that will result in a crash...

@florinandrei: simple answer. most ppl do not calibrate it, also consoles have questionable output quality (for example the same DVD looks different from the PS3 to the X360), so..

[egrimisu]

i found the bug, probably is because ui'm using vista x64 : once i set the filter to use directshow and save the profile, all the profiles remain with that setting checked.If you have vista x64 test. Thanks again

[lithiumus]

Keep in mind some of us actually do calibrate their TVs, and use a PS3 as a player. So these profiles are now less than optimal for people with calibrated screens.

I think there should be no penalty for correctly setting up your gear. If anyone takes a penalty, it should be people with non-calibrated displays. Those tend to care less about quality anyway.

Personally, I use the AVCHD profile (I create AVCHD disks on DL DVD) and I'm not sure where that profile stands on this issue (and I can't verify right now), but I'm speaking in principle.

It's those who care less that should take the hit.

Though I don't disagree with your comment, you are not bound in any way to use these profiles. You can adjust the profiles to your liking. The key is that you now understand why and can adjust to YOUR personal liking.

The quality hit is so small that it's hard to tell the quality difference unless you are doing screen cap comparisons and zooms.

On the other hand, the trellis 2 increases encode time significantly i.e. 30-40% longer so unless you've got a nice quad core, you might want to stick with trellis 1.

[Sharktooth]

exactly. nothing stops you to restore the default values or any other settings you like most.

[gav1577]

Hi i have a question about the avchd and bluray profiles what is the cmd --mvrange 511 for what does it do and do i really need it in the cmd line ?

Thanks

[Sharktooth]

it shouldnt, but i always forgot to check if BD/AVCHD needs 511 or can accept the default 511.75...

[gav1577]

it shouldnt, but i always forgot to check if BD/AVCHD needs 511 or can accept the default 511.75...

Ok i will try without it i cant see .75 being a big issue thanks for your reply :)

[Sharktooth]

please report back

[gav1577]

please report back

Ok will do

EDIT ok done a few test clips and played back on a pc and ps3 and and i cant tell the difference between the two IMHO

[Sharc]

All Standalone profiles have very short GOPs (Keyframe Interval, Min GOP Size) as opposed to the Unrestricted profiles.
Is the GOP size limitation given by standalone compatibility constraints?

[nurbs]

Is the GOP size limitation given by standalone compatibility constraints?

Yes. :)

[Sharc]

Thanks. Is this specified in Blu-Ray standard or similar? I idn't find anything about the GOP constraints.
Why this limitation to short GOPs? Lower HW decoder cost / less complexity, I presume.

[hajj_3]

where is the "HQ Slower" profile, i liked that 1, cant remember what settings it used, can someone help me, thanks.

[Sharktooth]

Unrestricted 2pass HQ or, if you want DXVA compatibility for playback, DXVA SD/HD HQ

[nurbs]

Thanks. Is this specified in Blu-Ray standard or similar? I idn't find anything about the GOP constraints.
Why this limitation to short GOPs? Lower HW decoder cost / less complexity, I presume.

It's in the blu-ray standard as far as I know. I think they use it so you can have a smooth fast forward and rewind, because you have at least one seekable frame about every second.

[Atak_Snajpera]

It's in the blu-ray standard as far as I know. I think they use it so you can have a smooth fast forward and rewind, because you have at least one seekable frame about every second.
Good explanation! You don't have to use those crazy keyint values.

[Sharc]

So I could actually use larger keyint (like 250, x264 default) and the files - authored with tsmuxer - should still be playable on a BD standalone which claims to be AVC HD compliant?

[Seraphic-]

When encoding to HD DXVA specs with Megui's preset (1276x716p - 6,000 bitrate), I had some playback issues that are not there when using software decoding.
Have two ATI 3870's in crossfire and their GPU usage is at 4% with software playback and they go to 10% using hardware.
But with the playback slowdowns/stops, not sure if I should continue to use DXVA or just go unrestricted. (thinking unrestricted at this point)

(I'm encoding for internet distribution)

[nurbs]

So I could actually use larger keyint (like 250, x264 default) and the files - authored with tsmuxer - should still be playable on a BD standalone which claims to be AVC HD compliant?

I don't know what AVC-HD allows, sorry, but I don't think you can use larger gops if it is still supposed to work in a normal BD structure.

Have two ATI 3870's in crossfire and their GPU usage is at 4% with software playback and they go to 10% using hardware.

Wouldn't you expect the GPU usage to go up if you use it for decoding instead of the CPU?

But with the playback slowdowns/stops, not sure if I should continue to use DXVA or just go unrestricted. (thinking unrestricted at this point)

Unrestricted probably doesn't offer that many advantages in your case. At that resolution you can use up to 7 refs IIRC, the VBV restrictions also shoudn't be a problem and p4x4 probably doesn't offer any significant quality gain.

edit: About the playback issues, maybe it's because the resolution is not mod16.

[Seraphic-]

Wouldn't you expect the GPU usage to go up if you use it for decoding instead of the CPU?

Yes, yes you would.
Was pointing out the how much of a difference there was though.
To be honest. I thought it would be higher then just 10% usage on the GPUs.

About the playback issues, maybe it's because the resolution is not mod16.

Most my videos will not be mod16. Not sure if that causes the playback issues though.

[Sharc]

Good explanation! You don't have to use those crazy keyint values.
It's in the blu-ray standard as far as I know. I think they use it so you can have a smooth fast forward and rewind, because you have at least one seekable frame about every second.
Thanks guys, I finally found the discussion on the subject here: http://forum.doom9.org/showthread.php?p=1118032#post1118032
Seems that using max keyint 24 is on the safe side for BD standalones compliancy.

[Sharktooth]

Most my videos will not be mod16. Not sure if that causes the playback issues though.
DXVA requires mod 16.
Good explanation! You don't have to use those crazy keyint values.
false. you have to use them to be sure all BD players can play your encodings (and not only PS3s) and all authoring softwares accept your encoded streams... PS3 is NOT a blu-ray player. it's a console that can play blu-rays... and does not strictly follows/enforces the bd specs.

[nurbs]

In my defence, I never said you could use longer intervals. I just gave my opinion on why they chose such a short maximum GOP lenght.