Easiest way to interpolate defective/stuck pixel?

[Lyris]

Actually, it's not a stuck pixel, it's what I think is a blemish on the telecine's CRT (yes, CRT). In any case, the result is the same: a 'rogue pixel' in a fixed position over the video.

Is there a plugin to knock the pixel out and replace it with an average of its neighbours? I guess I could do it with a median filter and a bunch of Crop and Stack commands, but has anyone made a more elegant solution?

[johnmeyer]

Delogo. Use it directly in VirtualDub, or load it in AVISynth.

I did a very quick & dirty "tutorial," showing how to remove a fixed spot from a video, exactly what you are trying to do. Here it is:

Delogo Spot Removal Tutorial (http://www.youtube.com/watch?v=Z12TutFSg8c&feature=channel_video_title)

[Lyris]

Works brilliantly - why didn't I think of DeLogo... Thanks!

[johnmeyer]

Glad it worked! This problem comes up often in various forums and I finally decided to do that crude tutorial to quickly show you how to use the plug-in. The two most important tips are to make sure not to feather the mask (i.e., turn of anti-aliasing, blending, and feathering in your photo-editor's paint tool); and make the mask a little too large rather than a little too small. Scrub through quite a bit of footage before choosing the frame to use as a mask, and pick a frame which reveals whether there is any "ghosting" around the defect you are trying to remove. With analog captures of off-the-air television, where you are trying to remove a "bug" logo, it is not uncommon to have quite a bit of ringing/ghosting around the logo, some of which doesn't easily show up on every frame. You have to make sure the mask is large enough to cover these additional, more subtle, regions around the defect or else you will still see some residual.

The delogo filter works fairly well for its original intended purpose (removing station ID "bugs"), but it works exceptionally well for removing small dust defects, dead pixel defects, spots on the lens, dirt on a window when shooting on a tripod through that window, etc.

Of course, if the spot moves, all bets are off.

[Lyris]

Yes, I made sure to only cover the 2 affected pixels (what seems like one defect + some analogue haloing) without any feather. The repair is invisible.

[Mug Funky]

would it be possible to see a sample?

blemishes on a CRT will be massively out of focus, and will cover much more than 1 pixel. defects in the electronics may be 1 pixel high, but several pixels wide. after all, the optics are focussed on the film, not on the CRT which is quite a distance away.

also, it can be fixed with a ~1 min auto-align operation (of course the film would have to be transferred again).

maybe something in the chain was buggered - like the noise reducer or some other digital component. the haloing you mention suggests it happens before the "aperture correction" (sharpening), so maybe something's messed up in the primaries.

i miss this stuff, but not really :)

[johnmeyer]

would it be possible to see a sample?Did you want a sample of the OP's video, or just a sample of the fix using Delog? I did post above a short "tutorial" showing how Delogo can be used to fix this sort of problem. As was just posted above, the fix often is pretty close to perfect, if the spot is small enough and doesn't move.

I don't think the nature of the spot matters much, as long as it is small.

[Lyris]

Ah, so it's not a blemish on the CRT then - my bad. I'm 99.99% sure this is a CRT transfer though: it has high frequency electronic noise mixed in with the grain in a way that I don't associate with CCD telecine. A slight horizontal softening helps blend it in a bit better without affecting the resolution. Temporal filtering would just bulldoze the grain as well as the noise.

I can't imagine there would be any problem with me posting a non-identifiable image:

http://www.imgplace.com/viewimg694/5925/44unled1.jpg

It doesn't appear on all scenes, oddly.