DCTFilter
 

here i go again...

simple script:

xxxResize(352, 176, 0, 0.6, 0, 0, 720, 480) # no matter if bicubic,lanczos,bilinear!
# with or without other filters here or in other positions
DCTFilter(1,1,1,1,1,1,0.5,0)
AddBorders(0, 32, 0, 32) # the borders was used only to realce the problem
trim (xx1000,xx2000) # choose the scene to encode ( ~41 seconds )

:roll:
i see thin light lines from top to bottom next to left and right blackborders,
removing the DCTFilter(1,1,1,1,1,1,0.5,0) from the script,
the thin light lines disappear!

i see easily in 352X240 (ntsc) but is hard to see in 7??X480 !
can someone do samples with each situation and post the result please?

if you want to test to see the "light lines", you need to encode and play, ok?
:arrow: don't wait to see it loading the script in vdub,
encode a sample and see in a player like powerdvd !


thanks in advance!
:)

DCTFilter bug 8O

yes.....it's like "ghosts" in tvs with bad antenas....!

I have never experienced the phenomenon you're describing but on the other hand I almost never use DCT filter - I think it removes far too much of the fine details in the video.
But - it's good to be informed about bugs :wink: .

audioslave wrote:
"I have never experienced the phenomenon you're describing but on the other hand I almost never use DCT filter"
8O
:roll: ...of course....!
:lol:
audioslave my friend...you're a joker.... :rotf:
cool... 8)
:wink:

Jorel,

I've also seen this effect. It's like DCT filter adds some "ringing" (gibbs) around the borders.

Kwag,

I'd not call this a "bug"... it's a direct result of how the filter works (you cut off high frequencies, Gibbs has to appear).

Jorel you should post a pic (cause now I only can assume), as I never noticed a "bug" in DCT Filter.

As GFR said, ... DCTFilter does exactly the same as when applying a very high frequency cutting matrix. Now Jorel just change DCTFilter from ...

DctFilter(1,1,1,1,1,1,0.5,0)

to ...

DctFilter(1,1,1,0.5,0,0,0,0)

you see what happens? The horizontal resolution wont be touched effectively BUT the horizontal frequenzies will be dropped more and more the higher the frequencies get :arrow: Seems like a Movie pic scaled to half width and afterwars rescaled to full width just pointResize() used :lol:

And thats why when applying a DCTfilter using strong highfreq. settings on a stream where that one gots for exmple only 352 as width, ... the high frequencies at that width are very importand as they will be scaled 2x for watching on a full size res. TV. .... And therefore 352x288(240) could appear more blurry as a rescaling to full resolution on a TV is much more softer as for example a more precise Bicubic resize ..... which for example is a very importand advantage WHY we got that benefit of Notch matrixes etc.

GFR,
you wrote the "right words" !
:D

ink,
i did using DctFilter(1,1,1,0.5,0,0,0,0)....
is really worse!...the "light lines" (ghosts) are big....i need a exorcist priest .
8O
then is better don't use DctFilter in 302X240 or change the parameters?
send recomendations please ink !
:wink:

<edited>
sorry ink, i don't know how post the pictures here, (i need to learn) :oops:
...i can send by mail if you want it!
:)

@ Joel

the(dot)incredible(at)gmx(dot)net


Well I actually do not use DCTfilter at 352x288 encodings as the Notch already filters enough on that resolution ... but thats only IMHO.

But I do not have that much continously experience on 352x288(240) as they do only take 1% of all my encodings :wink:

Outside Germany I don't know but it seems that lycos.com does offer webspace easyely where you also can point to pic.jpg from a forum like in here.

And it's about 0.5% of my encodings :lol:

-kwag

8O
and 90% of my encodes!
i got a dvd burner but still doing (cartoons) kvcd 320X240 for my kids!
8) or lame :?:

do i still use DctFilter changing some parameters for kvcds (320X240)
or "trash it" for this resolution ?!? :?

ink,
thanks for the webspace links...you have pm!
:wink:

Trash it.

I did the same last week, after having read a thread from Inc on that subject :-). I tested, and he is right !

ok Phil !
:wink:

thanks you all !

:wink:

That's fine :D

-kwag