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View Full Version : x264 goes not as expected

Agarsen
23rd September 2009, 21:32
I tried to encode in x264 with ps3 - xbox profile from a lossless in lagarith, which was also from a .ts source.

However, the result is:

Lossless
http://xs843.xs.to/xs843/09393/snapshot20090923211641326.jpg.xs.jpg (http://xs.to/xs.php?h=xs843&d=09393&f=snapshot20090923211641326.jpg)

Encoded in x264
http://xs843.xs.to/xs843/09393/snapshot20090923211719111.jpg.xs.jpg (http://xs.to/xs.php?h=xs843&d=09393&f=snapshot20090923211719111.jpg)

As you can see, x264 destroys all that detail on the top "darkening" it :/
With xvid encoding i don't get that result.
I used the ps3-xbox profile on megui, but i will anyway post the settings:
program --profile high --level 4.1 --preset fast --crf 20.5 --thread-input --deblock 0:0 --bframes 3 --b-adapt 2 --direct auto --b-bias 0 --scenecut 40 --ref 3 --ipratio 1.1 --pbratio 1.1 --vbv-bufsize 24000 --vbv-maxrate 24000 --qcomp 0.5 --rc-lookahead 40 --no-mbtree --aq-mode 1 --aq-strength 1.0 --merange 12 --me umh --subme 7 --partitions p8x8,b8x8,i4x4,i8x8 --trellis 2 --psy-rd 1.0:0 --output "output" "input"

Is there something that i can change?

Hope u can help me :)
Dark Shikari
23rd September 2009, 21:36
x264 doesn't do anything; your luma levels are broken.
LoRd_MuldeR
23rd September 2009, 21:42
See here:
http://forum.doom9.org/showthread.php?t=143689

And next time:
:search:
Agarsen
23rd September 2009, 21:50
So my fault it's about the colorimetry?

When i encoded in lossless, i'm sure i used
ColorMatrix(hints=true, threads=0)

or was it better if i used
ColorMatrix(clip, mode="Rec.709->Rec.601")?

the source was mpeg2, any case.

PS: Thx for the link, Lord :)
G_M_C
23rd September 2009, 22:27
So my fault it's about the colorimetry?

When i encoded in lossless, i'm sure i used
ColorMatrix(hints=true, threads=0)

or was it better if i used
ColorMatrix(clip, mode="Rec.709->Rec.601")?

the source was mpeg2, any case.

PS: Thx for the link, Lord :)

AFAIK HD material need to be in (Rec.)709 format, not in 601. So that might explain the difference in the luma ?
Dark Shikari
23rd September 2009, 23:51
AFAIK HD material need to be in (Rec.)709 format, not in 601. So that might explain the difference in the luma ?Rec 709/601 has absolutely nothing to do with PC vs TV luma levels.
Comatose
24th September 2009, 00:27
Most likely you're using CoreAVC and have it set to TV->PC... which also happens elsewhere. This is what you get when you do it twice.
G_M_C
24th September 2009, 09:28
Rec 709/601 has absolutely nothing to do with PC vs TV luma levels.

Fistrly, i wasn't replying to you, I was replying to this:


So my fault it's about the colorimetry?
[...]
or was it better if i used
ColorMatrix(clip, mode="Rec.709->Rec.601")?
[...]

That would be incorrect, cause HD uses Rec709 (i think he'd better use ColorMatrix(mode="Rec.601->Rec.709", hints=true))

And secondly, the difference in 601 and 709 could lead to differences in perceived luma. See for instance this post: http://forum.doom9.org/showthread.php?t=133982#post1090068

(It makes some colors seem darker, others brighter). In relation to the post he made before, it could have been a viable answer to his question.

PS: The darker/brighter as result of 601/709 happened regularly when people used CCE MPEG2 encoder, without remembering that CCE requires REC709 as input.
Blue_MiSfit
24th September 2009, 20:01
Make sure your playback chain is displaying luma levels as you think it is...

How exactly did you create those screenshots?

709/601 is a small issue - relative to your screenshots, which clearly illustrate a TV / PC luma levels issue. Also, 709/601 mostly affects chroma.

~MiSfit