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19th June 2015, 22:54 | #1 | Link |
Soul Architect
Join Date: Apr 2014
Posts: 2,559
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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?
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FrameRateConverter | AvisynthShader | AvsFilterNet | Natural Grounding Player with Yin Media Encoder, 432hz Player, Powerliminals Player and Audio Video Muxer Last edited by MysteryX; 24th June 2015 at 05:59. |
19th June 2015, 23:08 | #2 | Link |
Registered User
Join Date: Jul 2010
Location: Germany
Posts: 357
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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) |
19th June 2015, 23:31 | #3 | Link |
Soul Architect
Join Date: Apr 2014
Posts: 2,559
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Yes I know what debanding is, but I honestly don't notice any of it in most videos.
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FrameRateConverter | AvisynthShader | AvsFilterNet | Natural Grounding Player with Yin Media Encoder, 432hz Player, Powerliminals Player and Audio Video Muxer Last edited by MysteryX; 24th June 2015 at 06:00. |
20th June 2015, 06:46 | #5 | Link |
/人 ◕ ‿‿ ◕ 人\
Join Date: May 2011
Location: Russia
Posts: 643
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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. |
20th June 2015, 08:56 | #6 | Link |
Angel of Night
Join Date: Nov 2004
Location: Tangled in the silks
Posts: 9,559
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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. |
20th June 2015, 18:31 | #7 | Link | |
Soul Architect
Join Date: Apr 2014
Posts: 2,559
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Quote:
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23rd June 2015, 07:48 | #9 | Link | |
Registered User
Join Date: Feb 2009
Location: USA
Posts: 676
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Quote:
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. |
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24th June 2015, 00:35 | #10 | Link |
Angel of Night
Join Date: Nov 2004
Location: Tangled in the silks
Posts: 9,559
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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....
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