picture too dark with avisynth script

[91638]

Hi,

i noticed that the picture ist too dark when i use avysinth as frameserver. No matter what Version of Avisynth i use, always the same problem. If i open the *.d2v file in TMPG the picture is O.K.
Does anybody know a solution for this problem. I used the search in this forum but found no thread helping me.

I know my english is worth to improve but maybe you can understand my problem and help me. Thanks.

[Guest]

Please post your Avisynth script and tell us what you were frameserving it into when you observed the dark colors.

[91638]

I used the following script just to if the problem occurs in Avisynth. For this reason i did not
use any filters. Source Material is from DVD.

LoadPlugin("D:\Videobearbeitung\AviSynth 2.5\plugins\MPEG2DEC3dg.dll")

Mpeg2Source("G:\chucky.d2v")

ConvertToYUY2()

To solve the problem i inserted the following line

Levels(0,1.18,255,0,255,false)

the colors seems to be correct now, but i do not know if this is the best way.

Thanks for your help.

[DarkNite]

If you check the documentation you will notice that the luminance offset of MPEG2Dec3 is by default -2, and I don't recall if that was changed in MPEG2Dec3dg.

[Didée]

mpeg2dec3 does not perform any luma offset.

it's LumaFilter() which defaults to a -2 offset.

- Didée

[Leak]

Originally posted by 91638
Hi,

i noticed that the picture ist too dark when i use avysinth as frameserver. No matter what Version of Avisynth i use, always the same problem. If i open the *.d2v file in TMPG the picture is O.K.
Does anybody know a solution for this problem. I used the search in this forum but found no thread helping me.

What do you do with your AviSynth files? Open them in a media player?

If so, maybe the media player uses the graphics card's video overlay while TMP doesn't - since you should be able to control contrast, brightness, saturation, gamma and hue of the overlay independently from the desktop settings, that might explain the difference...

Which graphics card do you have? Which OS? What other software do you use?

np: The Orb - Orb Is (Shopping Version) (Bicycles & Tricycles)

[Wilbert]

If you feed your avs script to TMPGEnc (I guess you do that, but that's not entirely clear from your post), you should end with

ConvertToRGB24()

I think that will solve it. As for the cause of this. Could you open the script

LoadPlugin("D:\Videobearbeitung\AviSynth 2.5\plugins\MPEG2DEC3dg.dll")
Mpeg2Source("G:\chucky.d2v")
ConvertToYUY2()

in VDub, and tell us which decoder is used (under file -> file information)?

[91638]

i feed the script in vdub and recognized the darker picture in comparison to open the vobs in DVD2AVI or the created d2v file in TMPG.

I only opened the d2v file in TMPG to check if the problem is caused by DVD2AVI, but the result shows that the error appears in Avisynth.

In VirtualDub the used decoder is YUV 4:2:2 (YUY2).

Maybe this helps you for a hint to solve the problem. Thanks a lot.

[Wilbert]

The error is not in AviSynth, the problem is the luma range when converting YUV to RGB (in VDub or TMPGEnc).

Try

LoadPlugin("D:\Videobearbeitung\AviSynth 2.5\plugins\MPEG2DEC3dg.dll")
Mpeg2Source("G:\chucky.d2v")
ConvertToRGB()

and open it in VDub. Do you still have that problem?

Originally posted by 91638
I used the following script just to if the problem occurs in Avisynth. For this reason i did not
use any filters. Source Material is from DVD.

LoadPlugin("D:\Videobearbeitung\AviSynth 2.5\plugins\MPEG2DEC3dg.dll")

Mpeg2Source("G:\chucky.d2v")

ConvertToYUY2()

To solve the problem i inserted the following line

Levels(0,1.18,255,0,255,false)

the colors seems to be correct now, but i do not know if this is the best way.

Thanks for your help.

i agree,the same here. a few months ago,gerti67 post here great explanations about levels and send me this link with pictures to do comparisons : http://free.pages.at/gerti67/pictures/tweak-levels.jpg
and i did that *thread with his link and Wilbert post his great impressions and observations cos i was getting the same problems like 91638 posted and without use ConvertToYUY2() or ConvertToRGB() in the script. i always get dark scenes using avisynth comparing with the dvd source. this thread here will give me great clarifications about this problems cos i always post about it but don't knew that avisynth give this "darkness" in the scenes(if is avisynth the reason)
before all my encodes (always from dvds) i test the script with levels to get the seamless brightness as the source using from 1.02 to 1.2 in gamma adjusts. last week i did "chicken run" and i'm doing again cos is too dark in tv using gamma 1.03!

edited> forgive me,
i forgot to post the thread with Wilbert clarifications:
http://kvcd.net/forum/viewtopic.php?...ghlight=levels

screenshots for comparisons.

from vob in vdubmpeg2: http://img37.imageshack.us/img37/6026/vob.jpg

from avisynth script(using dvd2avi project) in vdubmpeg2: http://img37.imageshack.us/img37/541...ynthscript.jpg

[91638]

Thanks jorel. That is exactly the problem i tried to describe. I will read the threads and hope that i will see clear after that.

@ Wilbert

there is no difference between ConvertToYUY2() and ConvertToRGB().

@all

To make the difference visible i've uploaded the following three pictures

Picture in DVD2AVI

http://img31.imageshack.us/my.php?lo...e=dvd2avi2.jpg

or

http://de.geocities.com/saufkopp2001/dvd2avi2.jpg
("Right-click" and "Save target as..." )


Picture in VirtualDub with the AVS-Script

LoadPlugin("D:\Videobearbeitung\AviSynth 2.5\plugins\MPEG2DEC3dg.dll")
Mpeg2Source("G:\chucky.d2v")
ConvertToYUY2()

http://img31.imageshack.us/my.php?lo...=avisynth0.jpg

or

http://de.geocities.com/saufkopp2001/avisynth0.jpg
("Right-click" and "Save target as..." )


Picture in VirtualDub with the script from above and

Tweak(0 , 0.87 , 10.0 , 1.0)

http://img31.imageshack.us/my.php?lo...age=tweak2.jpg

or


http://de.geocities.com/saufkopp2001/tweak2.jpg
("Right-click" and "Save target as..." )

i can't see the pictures posted (geocities problems-Diese Seite ist nicht verfügbar),try "host" your pictures here(thanks DDogg): http://www.imageshack.us/

[91638]

Try "Right-click" and "Save target as..." and have a look at them.

Also posted the images at ImagShack. Links in the thread above.

[baz00ie]

Hello 91638,

I haven't seen much disscussion on this topic, but i know that it can be an issue. Here are some AviSynth settings that i've found to be effective when dealing with a "too dark" image from a DVD

Levels(0,1.22,255,8,255)

... and if you think the colours seem a little too thin you might try boosting the saturation a bit as well...

Tweak(hue=0.0,sat=1.2,bright=0.0,cont=1.0)

good luck
baz

[91638]

Thanks for your hints baz00ie. I will test your settings.

[Wilbert]

I would like to see the same screenshot (in VDub) for the following script

LoadPlugin("D:\Videobearbeitung\AviSynth 2.5\plugins\MPEG2DEC3dg.dll")
Mpeg2Source("G:\chucky.d2v")
ConvertToRGB()

[91638]

Picture with the following script:

LoadPlugin("D:\Videobearbeitung\AviSynth 2.5\plugins\MPEG2DEC3dg.dll")
Mpeg2Source("G:\chucky.d2v")
ConvertToRGB()

http://img32.imageshack.us/my.php?lo...age=chucky.jpg

Maybe you have an idea Wilbert.

[trevlac]

@91638

Your black level in the avs jpg is set to 0 while in the d2v jpg, it is set to 16. It of course should be 16. The white level is the same in both.

You should not muck with the gamma, the hue, the sat ...

To move the black level up and keep the same white level do:

Tweak(bright=14, cont=.89)

This is what I see when I measure the samples with a histogram. BTW, I would not use levels. It will also change the saturation. The theoretical fix is Tweak(bright=16, cont=.93). So the 'right' answer maybe somewhere in between, seeing that I had to convert a bit to get a working sample.

It seems to me that Wilbert is on the right track. The difference could be due to how MPEG2DEC3dg serves RGB data vs YUV data. It could also be due to how YUV data (which is what comes out of avs) gets converted to RGB on your machine. RGB is what you see in vdub and TMPGEnc, btw. Wilbert is trying to determin the latter.


[edit]

Now with your ConvertToRGB I would say look at MPEG2DEC3dg. It must output YUV to Avisynth and RGB to VDub/TMPGEnc. I'm not sure how to get it to output RGB to Avisynth. Can't say I know much about it, so do don't take my word on it.

[Wilbert]

Your black level in the avs jpg is set to 0 while in the d2v jpg, it is set to 16.

So that means that MPEG2DEC3dg.outputs [0,255] (well, at least in this case)? How can this be?

@91638,

Could you upload 10 (dark) frames of the vob somewhere (cutting it with vobedit)?

If that's not possible, could you make the same screenshots with mpeg2dec3 (v1.10) and dvd2avi (v1.76)?