horizontal lines appear in horizontal movement [Archive]

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bakman

21st July 2005, 10:16

I am reencoding 1080i HDTV captures to 1024x576 (so my xbox with XBMC can play it).

The output that I get shows subtle horizontal lines when there is horizontal movement; example 1 (http://www.readrss.com/images/bscap000.jpg), example 2 (http://www.readrss.com/images/bscap001.jpg)

I am using :
- Koepi's XviD 1.0.3
- DVD2AVIT3 (Tom Barry's mod for TS)
- avisynth 2.5.5

The AVS script contains:

Loadplugin("C:\Program Files\AviSynth 2.5\plugins\mpeg2dec3.dll")
Loadplugin("C:\Program Files\AviSynth 2.5\plugins\decomb521.dll")
Loadplugin("C:\Program Files\AviSynth 2.5\plugins\simpleresize.dll")
Loadplugin("C:\Program Files\AviSynth 2.5\plugins\undot.dll")
mpeg2source("G:\hollow\hollow.d2v")
Telecide(order=1,guide=1,post=2,vthresh=30)
Decimate()
crop(0,0,0,-8)
UnDot()
simpleresize(1024,576)

The xvid settings:

- single pass
- target bitrate 5500kbps (it doesn't necessarily have to be small, but needs to look good)
- quantization: MPEG
- B-VOPs: max consecutive: 2, ratio: 1.50, offset: 1.00
- mode precision: 6, VHQ:1, use chroma motion: on
- chroma optimizer: on

I am just starting with this stuff and I am sure that I am not doing everything correctly;

- how can I fix these lines ?
- an advice on getting better quality/size ratio. I was trying to avoid 2-pass as it already takes 7 hours avg.

I have tried autoGK in 2-pass, but the sharpness seems to dissappear. Therefore I'd rather do some more work in the manual area.

dinolib

21st July 2005, 14:27

Why don't you use latest koepi's XviD 1.1b2?
It rocks!

Didée

21st July 2005, 16:02

Quick note:

Drop SimpleResize, give a try on Bicubic or Lanczos, and see if it gets better.

Shinigami-Sama

21st July 2005, 17:11

well the vertical res isn't quite 1/2, so those may be stray interlace artifacts

bakman

21st July 2005, 17:37

well the vertical res isn't quite 1/2, so those may be stray interlace artifacts

ok this makes sense indeed.
I took values from this guide (http://www.samek.neostrada.pl/hdtv/hdtv2xvid.htm) and decided to just crop the gray bar at the bottom;

the original values were 8,6,-8,-10, does that make more sense to whether it is 1/2 ?

I have done one with the original values and now I think of it, that didn't show these lines.

Shinigami-Sama

21st July 2005, 20:23

wow never saw that guide before, anywyas you may have had a typo in your scipt that caused that, but by reducing the vertail res buy 1/2 you effectivly de-interlace it, which why your not-quite 1/2 encode my have had some stry interlace leftovers, or decom didn't load sometimes happens

lamer_de

22nd July 2005, 09:45

bakman

22nd July 2005, 17:04

He uses telecide+decimate, so he should get a progressive stream... No interlacing.
EDIT: If you don't care too much about filesizes, use fixed quantisizers. A quant range of 3-5 should probably be feasible.

CU,
lamer_de
Indeed I am deinterlacing the files (all 1080i to 1024) 23.97fps. I have adjusted the crop settings, the lines are gone. I have installed the XviD 1.1b2 which looks good. I don't see any difference between lanczos and simple resize, not in encoding speed either.

Are the fixed quantizers better or faster ? Faster would be nice; LOTR is running now for 11 hrs, total estimated 15 hrs :(

thanks, BaKMaN

Shinigami-Sama

22nd July 2005, 19:19

Caroliano

24th July 2005, 02:34

Are the fixed quantizers better or faster ? Faster would be nice; LOTR is running now for 11 hrs, total estimated 15 hrs
They are faster because you only need 1-pass. But the filesize is imprevisible and you don't get the best quality/size relation.

bakman

24th July 2005, 13:15

They are faster because you only need 1-pass. But the filesize is imprevisible and you don't get the best quality/size relation.
uhhm, I am doing 1-passes as well...