Depulse?

[dragon25]

http://forum.doom9.org/showthread.php?t=84481&highlight=depulse

saw the name on here, but cant find ny details on what it does.

and im kinda guessing it helps take away the white pulsing on videos?

[StainlessS]

see:-

http://avisynth.org/oldwiki/index.php?action=history&page=DePulse

Dont think it will be of any great use, seems a little
garbled. Author (German) says something about
fluorescent lamps and generators, so it's to
eradicate eg electrical interference in vids.

(I Googled "Depulse Avisynth"), dont seem to be
much else except in Japanese. :)

[Lyris]

Ah, perhaps it refers to the pulsing you get from fluorescent lamps when they're out of sync with the camera. I have a 60hz camcorder and sometimes get weird pulsing (depending on the Shutter speed) when I use it here in the UK (50hz).

I have some material like this, so I'll test it when I get a spare second.

[StainlessS]

Yeh Lyris,

Could be right, think this might be called strobing, a sort of temporal moire inteference pattern.

Edit: Temporal meaning raster lines rather than frames.

[Lyris]

Ah, ignore me - it's a dropout remover. I'm gonna try it out:

http://www5e.biglobe.ne.jp/~hoe/dv-and-movie/tipsxxx/index.html

[zilog jones]

That works pretty well with solid white/black VHS dropouts like in the picture. I was trying Descratch for the same thing before but it would always remove good horizontal lines too.

[StainlessS]

@ Zilog Jones
Thanx for that, Descratch() can be a little destructive if not used carefully, nothing preventing you using
this for de-scratching (after 90 degree swizzle), think I d/l it and give a try. (Z80 still live?)

EDIT:- Had another look, may be only for interlaced, maybe not for 90 degree rotation.

[Lyris]

Yes, it seems to be made especially for analog dropouts, so will only affect 1 pixel height.

[StainlessS]

Have had a look at the source to see exactly what this plugin does and thrown together a little usage text
which I hope is easier to understand than the authors explanation linked in the second post.


DePulse 2005/04/10, 2005/04/11 update

Author Unknown

Function:
Dropout remover, removes white/black noise horizontal streaking in
analogue captures. Spatio-Temporal.

Usage instructions.

Assumes TFF (top field first) field order interlacing.

YUY2 only.

Syntax is: DePulse(clip, h=180[0-255], l=60[0-255], d=30[0-255], debug=false[true/false])


Pixel brightness values greater than h (high) are targeted as white noise.
If a pixel (t) is target'ed as white noise then surrounding pixels
(above, below, before and after [temporal], Not left and right) are tested
and if ALL of them are less than (t - d) the target pixel t is
depulsed.

Pixel brightness values less than l (low) are targeted as black noise.
If a pixel (t) is target'ed as black noise then surrounding pixels
(above, below, before and after [temporal], Not left and right) are tested and
if ALL of them are greater than (t + d) the target pixel t is
depulsed.

In debug mode, pixels judged to be black or white noise are coloured pink or green.

EDIT: added the default values.

[StainlessS]

There is also a plugin called "DepulseC" which does similar with coloured streaks. Link to that, below:

http://www5e.biglobe.ne.jp/~hoe/dv-and-movie/tipsxxx/index.html

Took a quick look at the source, almost identical to source for "Depulse". Both deal only with YUY2, (YUYV) and pretty much the only difference between the luma & chroma versions is that it uses index's 0 and 2 in the luma version (Y_Y_) and index's 1 and 3 in chroma version (_U_V), the args are exactly the same as for chroma, and so DepulseC works identically for both U and V channels. For description of how it works can just see the previous usage post and apply that to BOTH U and V channels.

EDIT: Does not concern itself with the 128 chroma offset, so args 'h' and 'l' are range 0 255 (16-240).


EDIT: Fixed URL

[Mounir]

I get an error 404 for the Color version of Depulse, somone reupload for me thanks

[cobo]

That's because the link in StainlessS's post is truncated. It should be same as in post #5.
DepulseC is at the bottom of the page:
http://www5e.biglobe.ne.jp/~hoe/dv-and-movie/tipsxxx/index.html

[Mounir]

Thanks Cobo , in the meantime i found one good filter for dropouts called DeVCR, see Here (http://avisynth.org/mediawiki/DeVCR) ; it does a similar work but temporally and with greater accuracy as far as i can judge, see this picture (before/after) (http://imageshack.us/f/585/89679629.jpg/)

[jmac698]

I've tested all the plugins and depulse (jp) worked best. Don't think I tried deVCR *script* though. I used removedirtMC as well. Observe the white lines here:
http://screenshotcomparison.com/comparison/84395/picture:3
mouse over to see them disappear! I should work backwords and find statistics of the white lines.
I removed them with a capturing technique, so it probably won't help you.