Any filter for satellite sparkles?

[SatStorm]

I have plenty vhs tapes recorded from analogue satellite sources. Mostly 80s / early 90s MTV stuff & Cartoons

They have the usual black and white sparkles, which use to appear when the reception was weak (remember those days? Before the digital broadcasts, we had to use Low Threshold filters to be able to watch stations when we located out of the official satellite footprint).
Now, which I do some encoding, I wonder what solutions exist regarding that matter, so to "fix" them - if possible.

I know that there is one commercial filter called "SpotRemover 3.55" for virtualdub, but it has years to be updated and AFAIK you can't buy it those days.

Beyond that, what exists out there? Any other Virtualdub or even avisynth ways to fix that?

[PLC401]

AviSynth's 'DeSpot' filter is worth a go, perhaps? You can specify whether to remove white spots, black spots, or both, with a threshold value and other parameters. Not too difficult to use.

Any sort of video plagued with small black or white flecks, it should partially be able to remedy, at the very least.

[SatStorm]

Thanks! Do you have any links / tutorials / etc to read about?

[lordsmurf]

That sounds more like magnetic tape dropouts. I've never found a foolproof way to remove those. The TapeChek device promises to clean them out, but the cost of it is ridiculous, and I find the claim's science to be a bit odd. It insists the dropouts are from debris on the tape, but I don't buy it.

[SatStorm]

No, it's satellite sparkles! I use to receive the channels that way a decade ago! Also they appear mostly on the red colour.

[lordsmurf]

Please upload an image (or 2 or 3 or 4!!!), I want to see it.

[SatStorm]

OK, those are fast screen caps from LP VHS, recorded somewhere late 90s.
Direct capture, without even TBC.

They are from MTV India. C band reception. I use to tune the receiver that way, to have black and not white sparkles mostly. Some times colour ones would appear.

The white on the bottom and on the right, are more thin and they are from tape. But all the blacks are the one I wish to kill them. The thing with the sparkles, is that they appear only on 1 - 2 frames, so a smart temporal solution is needed.

[vhelp]

I can't believe that someone recorded The Archies. I used to watch them in the early 70's. Gosh. Anyway.

1. while reviewing the pics, I couldn't help notice the great amount of mpeg pixelation..it was hard to decirn streaks or sparkles because of this: in mpeg with a lot of pixelation, it gives similar sparkels (gradient lines) and confuses which is which.
2. if you post a two second clip, that might help more. The Archies might be a good clip to post.
3. try and post anther set of pics that have highest bitrate. MJPEG at 20 should do it in terms of near-lossless

I would say that this issue is prob to do with low grade tapes and low speed recordings: ie, EP or LP. I obtained similar issues of these streaking dots or lines when I purchased a 10 pk of 8hr tapes for 5 bucks (I think) so I could record as many hours of the Summer/Winter Olympics, about 4 years ago. And when I realized this during recording and capturing a few (at the time) I stopped recording to the cheap tapes and squeezed a few dollars out my pockets. Anyhow. The streaks I got were white, and they were random, on each frame, though not the heavyness as in yours.

To get rid of them is the other problem.

First, I would analog capture these at the highest bitrate possible. throw out mpeg/dv/etc and go straight to raw yuv or MJPEG at level 20 max. Then..

You could attempt a temporal filter, and that might help, but at the expense of softening the whole frame vs. only the speckles. So there's a compremise that you'll prob make in some of these vids.

But I have a better way of removing them, but it requires more logic and algorithm, not to mention, time to code
I haven't given up on the project because I have lots of these tapes like this, too, to do. So, one day, I'm going to finish the idea. For now, its only a dream.

-vhelp 5144

[mgh]

Think you need frequency domain filters
Neat Video demo

Smart Skating rink-all frequency ranges selected-all sliders at 30-filter available through http://www.thedeemon.com

dfttest (avisynth)
dfttest(tbsize=1,sigma=10)


dfttest(tbsize=1,sigma=50)


dfttest
tbsize is temporal effect, has to be odd integer
tbsize=1, only the frame used
tbsize=3, previous and next frame+frame
tbsize=5, previous two, next two and the frame
etc

[lordsmurf]

Ah yes -- I had those in my cable signal sometimes too.

Not sure what the tech term for those is, not heard them called "sparkles" before. But hey, works for me!

Maybe this would help to clean it up?

[SatStorm]

Hi Vhelp: Actually it is not the Archies: It is a video clip of the Archies! MTV India use to play them a lot a decade ago!

The screen cap here, are simply to show you those "sparkles" or - as the correct term could be - the bad reception analogue satellite noise I wish to "fix" if possible..
I still have those tapes, so when I convert them, I'll do it correct: TBC / hardware adjustments / Canopus ADVC100 to DV / neat video / msu smart sharpening / encode.

@mgh: Thanks! The dfttest(tbsize=1,sigma=50) seems to blur a bit the picture, but it does real great on disapearing that kind of noise!
I'll try to test a bit with this. BTW, is there any virtualdub alike alternative?

@lordsmurf: Hmmm... Could be! Send me one, I'll pay you later!

[kupton]

Unfortunately a lot of programming still comes down satellite to broadcasters via analog transmission. "Sparkles" is exactly what they are called.

[mgh]

you can use avisynth filters inside the ffvdub filter for virtualdub (which is installed in the ffdshow folder when you install ffdshow codec), be sure to use converttoyv12() before and converttorgb32() afterwards

smart skating rink is the virtualdub filter closest to it, you can chain it to improve the cleaning.

[SatStorm]

Thanks mgh.

Meanwhile, I found another nice Russian filter that does some good on those satellite sparkles. It is called «Median filter» and apply a vertical chroma shift according the average nearby when a "sparkle" is detected!

[lordsmurf]

Median actually works pretty well for magnetic dropouts. I used it today for something. The other methods mentioned above were either too damaging to the video, or not strong enough. Median was the winner in my tests.

[SatStorm]

Be careful when you use it. I found out that it mess with interlacing.

I use this filter only on extreme situations - and on those cases it does miracles!

[lordsmurf]

Thanks for the warning. I'll need to test the videos on TV. It may be a filter reserved for deinterlaced work, then.

There's quite a few VirtualDub filters that mess with interlace. ColorMill is another one -- it just randomly reserved field order.

[SatStorm]

Some times a workaround fix the issue: Viewfield / put your filter here / unviewfield. But it is more a "hit or miss" situation.

I end up encoding a small video part, playback it with my popcorn hour, see if it is ok and then do the whole file.

[lordsmurf]

It doesn't just mess with interlacing -- it rapes and violates it. It introduced major distortions.

Maybe the unfold/re-fold of fields will work -- that is one idea.

Another fix is to just go ahead and deinterlace it with a good method, prior to using the median filter. The videos are already so messed up that you're still overall improving it anyway. Deinterlace Area-Based seemed to work okay.

[SatStorm]

The build in unfold/ fold of virtualdub doesn't work. I test it many times with no success.

There are 2 other filter that do the same, but better: View field /unview field. Those filters works sometimes with the Median filter and also always re-arrange the fields to "top field first".

I try to avoid de-interlace when I can.

[lordsmurf]

Doh! Thanks for the notes, saved me some time. I'll give View/unview a try, but it doesn't sound too good either. I hate randomness on computers, especially when it's with time-consuming video work.