Quality loss from Avisynth?

[kitanai]

Hi!

I wonder why I get different qualities in VirtualDubMod from the same source.

First picture is from the source file loaded:
http://www.nt-internet.de/doo9/avi.gif

The second one through Avisyth:
http://www.nt-internet.de/doo9/avs.gif

The script just says:
avisource("src.avi")
SwapUV()


:confused:

[esby]

could it be possible to get some more info on the file you tried to load?

Which codec is it using?
Do you tried to reinstall a recent version? (in order to get around the swapUV()...)
If you are using winXp, try killing the prefetch files (delete all files in windows\prefectch\)?
Without swapUV(), does it show the same dithering? (except the different color tonality...)

esby

[IanB]

What are the parameters of "src.avi"? i.e.

What codec was it compressed with?

What codec are you using to process it?

Where was it captured from?

Frame size?, Frame rate? etc, ....

The VDmod "File"->"Information" splash panel show lots of this info.

On a hunch tryavisource("src.avi", pixel_type="RGB32")
then
avisource("src.avi", pixel_type="YUY2")
then
avisource("src.avi", pixel_type="YV12")to see if these change anything.

IanB

[albertgasset]

It seems that only one field is decoded so lines are duplicated. Try changing the options of your decoder. Are you using morgan mjpeg? I remeber having the same problems with this codec some months ago.

[kitanai]

Ok, I tried (without SwapUV()):

avisource("src.avi", pixel_type="RGB32")
-> correct colors, good picture

avisource("src.avi", pixel_type="YUY2")
-> correct colors, good picture

avisource("src.avi", pixel_type="YV12")
-> inverted colors, bad picture

My codec to compress the source file is Morgan MJPEG.
Now, that codec seems to cause the problems... I read something about this inversion bug. But what causes this behavior?

avisource("src.avi", pixel_type="YUY2") should work fine for me now.

[cweb]

I don't think Morgan returns YV12, that's why it didn't give correct colours.
Try following the avisource(...."yuy2") by .converttoyv12() to change the colourspace.

[Wilbert]

I don't think Morgan returns YV12, that's why it didn't give correct colours.
If it doesn't output YV12, it would output YUY2.

Try Morgan 3.12 beta: http://forum.doom9.org/showthread.php?s=&threadid=72332 (btw, the link doesn't work at the moment).

[sh0dan]

Morgan MJPEG is buggy. Download a newer version that fixes the problems from the Morgan forum (http://www.morgan-multimedia.com/ubb/new/topic.asp?TOPIC_ID=230&FORUM_ID=1&CAT_ID=1&Topic_Title=YV12+output+broken%2E&Forum_Title=Morgan+MJPEG+codec).

[kitanai]

Thank you, works!

But how do I get rid of that little Morgan logo in top right corner??? :confused:

[sh0dan]

By buying it ;)

[kitanai]

Cropping does the job ;)

There is just one strange thing about the MJPEG 3.11beta:
http://www.nt-internet.de/doom9/beta.gif
Why do I get these messed up stats here?
I hope its just a display error and does not effect the cap... :scared: