Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.

 

Go Back   Doom9's Forum > Capturing and Editing Video > Avisynth Usage

Reply
 
Thread Tools Search this Thread Display Modes
Old 19th June 2015, 23:54   #1  |  Link
MysteryX
Soul Architect
 
MysteryX's Avatar
 
Join Date: Apr 2014
Posts: 2,173
When Are Debancing and Dithering Needed?

I'm still confused about the whole Debanding/Dithering thing.

I wrote a software that contains a Media Encoder that allows upscaling SD content into HD with just a few clicks; GREATLY simplifying the process, especially if you need to convert 50 videos.

Here's a sample video before and after.

Now my question is: would this video benefit from any debanding and/or dithering? What difference do they make? When are those needed?

Last edited by MysteryX; 24th June 2015 at 06:59.
MysteryX is offline   Reply With Quote
Old 20th June 2015, 00:08   #2  |  Link
creaothceann
Registered User
 
Join Date: Jul 2010
Location: Germany
Posts: 360
Quote:
Originally Posted by MysteryX View Post
When are those needed?
Recent example I did on a wallpaper (possibly nsfw)...

original: http://i.imgur.com/gQVFk5W.jpg
fixed: http://i.imgur.com/UwRFR8K.jpg

script:
Code:
ImageSource("source.png", 0, 0)
ConvertToYV12
GradFun3(smode=2, thr=0.35*2, thrc=0.35*2, radius=16, radiusc=16)
creaothceann is offline   Reply With Quote
Old 20th June 2015, 00:31   #3  |  Link
MysteryX
Soul Architect
 
MysteryX's Avatar
 
Join Date: Apr 2014
Posts: 2,173
Yes I know what debanding is, but I honestly don't notice any of it in most videos.

Last edited by MysteryX; 24th June 2015 at 07:00.
MysteryX is offline   Reply With Quote
Old 20th June 2015, 00:53   #4  |  Link
wonkey_monkey
Formerly davidh*****
 
wonkey_monkey's Avatar
 
Join Date: Jan 2004
Posts: 1,843
Quote:
Originally Posted by creaothceann View Post
Recent example I did on a wallpaper (possibly nsfw)...
I'm truly shocked by those images. She's not wearing a crash helmet!
__________________
My AviSynth filters / I'm the Doctor
wonkey_monkey is offline   Reply With Quote
Old 20th June 2015, 07:46   #5  |  Link
vivan
/人 ◕ ‿‿ ◕ 人\
 
Join Date: May 2011
Location: Russia
Posts: 649
Debanding is the process of removing banding. Usually it's performed by reconstructing gradients to a higher bitdepth.
Imagine having a gradient that goes from 0 to 10 in 20 pixels - you need a >8 bit colorspace to store it.

Dithering is the process of lowering bitdepth. Just dithering makes on sense - you can't lower 8 bits to 8 bits.
After debanding you have 16-bit image - so you have to lower bitdepth at some point. Most debanding filters (if not all) have built-in dithering. Some have an option to output 16-bit image, so you can process it further (read about dither tools) and dither it down to 8/10 only at the end.

Will your video benefit from debanding? Probably just a bit. But you'll need way higher bitrate to encode all noise it adds. Or 10 bits.
vivan is offline   Reply With Quote
Old 20th June 2015, 09:56   #6  |  Link
foxyshadis
ангел смерти
 
foxyshadis's Avatar
 
Join Date: Nov 2004
Location: Lost
Posts: 9,420
You left enough grain in these videos that there's no appreciable banding -- banding noticeably occurs when a video is too clean, not when it's dirty. Of course you won't get any use out of debanding.

There's a much bigger problem though: The after video exhibits severe judder, so something about your 25->60 frame rate conversion is incorrect. It's producing very jerky video that appears to skip frames several times a second or double up frames too many times, I'm not sure.
__________________
There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order.
foxyshadis is offline   Reply With Quote
Old 20th June 2015, 19:31   #7  |  Link
MysteryX
Soul Architect
 
MysteryX's Avatar
 
Join Date: Apr 2014
Posts: 2,173
Quote:
Originally Posted by foxyshadis View Post
You left enough grain in these videos that there's no appreciable banding -- banding noticeably occurs when a video is too clean, not when it's dirty. Of course you won't get any use out of debanding.

There's a much bigger problem though: The after video exhibits severe judder, so something about your 25->60 frame rate conversion is incorrect. It's producing very jerky video that appears to skip frames several times a second or double up frames too many times, I'm not sure.
I'm using the "Smooth" preset, could that be it? It can cause artifacts.
MysteryX is offline   Reply With Quote
Old 21st June 2015, 05:02   #8  |  Link
MysteryX
Soul Architect
 
MysteryX's Avatar
 
Join Date: Apr 2014
Posts: 2,173
I looked again more carefully at the clip frame by frame and don't see what you're referring to. The only thing I see is "1 frame repeat every 16 seconds"
MysteryX is offline   Reply With Quote
Old 23rd June 2015, 08:48   #9  |  Link
osgZach
Registered User
 
Join Date: Feb 2009
Location: USA
Posts: 662
Quote:
Originally Posted by foxyshadis View Post
You left enough grain in these videos that there's no appreciable banding -- banding noticeably occurs when a video is too clean, not when it's dirty. Of course you won't get any use out of debanding.

There's a much bigger problem though: The after video exhibits severe judder, so something about your 25->60 frame rate conversion is incorrect. It's producing very jerky video that appears to skip frames several times a second or double up frames too many times, I'm not sure.

I'm not really seeing the judder either. Maybe my eyes are getting crap with age, all I see is ocassional crap camera-work

I did see one slight jerk in the beginning but that was about it. Couldn't tell after that if it was frame repeats / or shitty camera man when watching in real-time.
osgZach is offline   Reply With Quote
Old 24th June 2015, 01:35   #10  |  Link
foxyshadis
ангел смерти
 
foxyshadis's Avatar
 
Join Date: Nov 2004
Location: Lost
Posts: 9,420
My bad, I watched one with MPC and one with MPDN. The new one looks smooth on MPC. I'm not sure why MPDN failed with this when it's fine with 1080p, but I'll have to remember that from now on....
__________________
There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order.
foxyshadis is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 01:32.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.