Help: removing a fixed white spot on all my videos

[Biddy]

Hi there,

I allready knew while filming that there was dust between my lenses and the result is that a fixed white stain appears in the middle of every video I shot. I tried a lot of different tricks, but so far no luck. At the moment I'm using Avysynth, but I can't figure out how to remove this white stain. Does anybody have an idea how I can fix this?

Thanks!

[poisondeathray]

Have you tried any logo removal or inpainting techniques /filters yet ?

[Biddy]

No, so far I only tried the DeSpot filter (which causes the application to crash) and the RemoveSpot function. How can I use the logo removal or other inpainting techniques/filters?

[jagabo]

A video sample would have been better. You'll have to play around with the ColorYUV adjustments for other shots but try something like this:

src=ImageSource("Video.jpg").ConvertToYV12()
mask=ImageSource("mask.png").ConvertToYV12(matrix="PC.601").ColorYUV(gamma_y=200, gain_y=100)
dark=ColorYUV(src,gain_y=-140,cont_u=100, cont_v=100)

Overlay(src,dark,0,0,mask)
Interleave(src,last,dark) # for comparison

[poisondeathray]

No, so far I only tried the DeSpot filter (which causes the application to crash) and the RemoveSpot function. How can I use the logo removal or other inpainting techniques/filters?

DeSpot , RemoveDirt, RemoveSpots etc... those types of filters only work for non-persistent defects (the spots are sporadic and don't occur on adjacent frames)



There are a bunch of guides and filters, some work better for opaque, some for semi-transparent
http://avisynth.org/mediawiki/External_plugins#Logo_Removal

e.g. delogo , vdub
https://forum.videohelp.com/threads/221665-Removing-Logos-using-DeLogo-vdub-filter#1376335

e.g. msu
http://www.compression.ru/video/logo_removal/index_en.html

e.g xlogo
https://forum.videohelp.com/threads/273109-Remove-an-opaque-logo-using-Xlogo-in-Avisynth

e.g. rm_logo
http://forum.doom9.org/showthread.php?t=134919

[poisondeathray]

You can play with layer blend modes (similar to photoshop layer blend modes) to get slightly better results.

You might have to make adjustments to the mask, as it's hard to tell with a still jpeg. As jagabo said, a video sample would have been better

If it's primarily a "white" spot with some transparency, you shouldn't have to make any major adjustments per scene or when there are lighting and exposure changes- unless you clip, crush, or overexpose in that scene

This is from jagabo, just slightly modified

src=ImageSource("Video.jpg").ConvertToYV12()
mask=ImageSource("mask.png").ConvertToYV12(matrix="pc.601")
dark=src.levels(0,0.4,255,0,255,false)


Overlay(src,dark,0,0,mask, opacity=1, mode="softlight")

You can do this in NLE's or compositing applications like AE, blender. IMO they are easier to use and make adjustments , have better mask tools , feathering, and compositing filters for this sort of thing

[Biddy]

Thanks so far jagabo and poisondeathray! I thought it would be a good idea to give you a video sample And I'm very new to all this video enhancing stuff, so using AVSEdit and Blender is a big challenge for me. If you have any step by step instructions ....you would help me a lot!

[jagabo]

That's not a good choice of clips. As far as the spot is concerned, except for a little camera shake at the start, you've uploaded 100 copies of the same image. A clip where the camera is panning or something is moving past the spot would be much better. Especially different colors and details moving past the spot.

[poisondeathray]

It's probably easier learning basic avisynth than learning how to use blender or after effects . You just copy & paste the code , changing the paths & filenames to match your video

An .avs file is just a text file. You can use notepad copy&paste, and save it, then change the extension from .txt to .avs

Many people use avspmod to preview their scripts (push f5) , but you can use notepad, vdub



For example, instead of ImageSource() , you would use AVISource() with the correct path and filenames . Change "PATH" to C:\folder or wherever the AVI file folder is

I reused jagabo's mask, but resized it to 640x480 (the native clip size). If you spend more time on a better mask you might get better results

e.g.

src=AVISource("PATH\MVI_0110.avi").ConvertToYV12() 
mask=ImageSource("PATH\mask.bmp").BicubicResize(640,480).ConvertToYV12(matrix="pc.601") 
dark=src.levels(0,0.4,255,0,255,false)  

Overlay(src,dark,0,0,mask, opacity=1, mode="softlight")

In addition to jagabo's comments about movement and detail, when you test semi-transparent overlays, you usually want a clip that exhibits a change in exposure (e.g. brighter scene , darker scenes)

[Biddy]

Is this a better video sample?

[jagabo]

That's a much better sample. What I did earlier doesn't work well in some sections. poisondeathray's modification (with a little more modification) works better.

src=AviSource("MVI_0030.AVI") 
mask=ImageSource("mask.png").ConvertToYV12(matrix="pc.601").ColorYUV(gain_y=100)
dark=src.levels(0,0.4,255,0,255,false)

Overlay(src,dark,0,0,mask, opacity=1, mode="softlight")

If you can get the spot with a black background (I noticed there were a few others too) you can build a better mask and it will work better. The spot still showed up a fair amount in some parts of the video. Playing around with the mask and parameters may improve those areas. I built the mask from frame 454.

[Biddy]

Thanks for that! Finally, I get the drift how to work with these masks and it does help a lot! Just an odd question, but how do you build a mask based on a frame?
And is it possible to use different parameters for different frames within the same video, as in some parts the spot is hardly notable (so I don't need a mask in does areas, right?) and in other parts it is disturbingly there?

[poisondeathray]

Thanks for that! Finally, I get the drift how to work with these masks and it does help a lot! Just an odd question, but how do you build a mask based on a frame?
And is it possible to use different parameters for different frames within the same video, as in some parts the spot is hardly notable (so I don't need a mask in does areas, right?) and in other parts it is disturbingly there?

You can build a mask in any paint or graphics program (photoshop, gimp etc...) e.g. take a screenshot a frame where the defect is visible (e.g againt a black background would be easier, but any frame where defect is visible) , then paint it in

To use different settings & parameters, it's harder to do in avisynth (you can cut it up with trims() and use different settings then join) , or it's easier to use a NLE or compositing application (you keyframe the settings), you also have other tools to modify masks and composite things right at hand

I think jagabo made his mask a bit small - there is a halo or ring around the defect. Instead of going back & forth in your graphics program, one way is use mask tools modifiers to expand the mask . You can do this right in avspmod (so you can see the mask and get feedback by pushing f5) . e.g. I added mt_expand to "grow" the mask, and use a blur to feather it a bit (to make edges more soft, so there is less abrupt transition) . Also I'm not sure why he didn't use a black/white/greyscale mask ?

src=AviSource("MVI_0030.AVI") 

mask=ImageSource("mask.png").ConvertToYV12(matrix="pc.601").ColorYUV(gain_y=100).tweak(sat=0.2, coring=false).mt_expand(24,u=3,v=3).binomialblur(5) 

dark=src.levels(0,0.4,255,0,255,false)
Overlay(src,dark,0,0,mask, opacity=1, mode="softlight")

This sample clip shows problems that can occur with clipping(overexposure) and color cast - this will impair up the channel calculation of any "fix" as the response is no longer linear. It's more difficult to fix with 1 setting or "automatic" process - to get a better repair you would need adjust the settings and use other masks but this requires some manual work

[jagabo]

I think jagabo made his mask a bit small - there is a halo or ring around the defect.

Yes, there was no frame with a nice black background behind the entire spot. I used the best I could find in the clip but ended up losing some of spot. Ie, I took frame 454 and painted everything around the spot black, including a little bit of the spot because there were image elements there.

[Biddy]

I'm trying to get the code running, but can't get around the message that there is no function named binomialblur. I put VariableBlur.dll in my plugins, but it doesn't seem to work. What can I do about that?
For the rest: I'm very thankful for your help jagabo and poisondeathray! It's allready so much better than before!

[poisondeathray]

Try loading it manually with LoadPlugin("PATH\variableblur.dll")

Or you can use another blur e.g. blur(1.5).blur(1.5).blur(1.5)

[Biddy]

LoadPlugin doesn't work either: If I search through the Avisynth functions in AvsPmod, it doesn't seem to appear in the list. Can there be something wrong with the dll I downloaded (I tried two different downloads).

[poisondeathray]

0.5 is the latest
http://avisynth.org/mediawiki/Variableblur
http://bengal.missouri.edu/~kes25c/variableblur.zip

0.4 is here , I think this is the one I'm using on this computer
http://www.tsp.person.dk/VariableBlur040.zip


The type of blur isn't important for this, any will do

One reason why this 2nd clip won't be fixed/solved properly with 1 set of settings is the blue channel is almost non-existent in sections - so you will get a disparity with any repair . The yellow cast is so strong that the camera recorded almost nothing in the blue channel (ie. there is almost no data when looking at the blue channel in RGB) . To "solve" the equation you need at least 2 sets of settings, one for when B=0 and when B doesn't = 0 over the defect . This means keyframing or applying different settings to different sections

The 1st clip is more balanced (no color cast) , so it possible to get a decent repair with 1 setting

(Or another approach might be to color correct the clip first - if you desaturate yellows & some red it will be more balanced)

[Biddy]

Thanks for your reply, I go for the Blur, Blur, Blur because VariableBlur just isn't working.

I'll try the keyframing (as soon as I know what that means) or the different settings for sections wherever I can. The second clip is shot in a yellow tent, so that's why there is hardly any blue. But it's good to see that at least the spot 'disappears' while seeing a face (2nd clip) or if a motorcycle is passing by (1st clip). They have the main focus in these video's, so all the surroundings (with their smaller spots) are less import for me at this point.

[poisondeathray]

Some of the other "spots" look like lens flares .

You probably want to bring down the yellow and red saturation in the tent shot - there some of hidden detail that is obscured by it (the video has "illegal" non broadcast safe colors) .