VHS tape dropout fixes? TBC, software?

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If the TBC doesn't take care of your drop-outs entirely, there are some software methods that work to further fix that situation. It's not without its quality drawbacks, however.

what program do you use on the computer for dropouts?

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[lordsmurf]

^ We'd been discussing hardware restoration methods, with most talking centering around the Digital Processing Systems DPS-200 timebase corrector (TBC) that comes with dropout compensation built into the unit.

However, from my tests, that wasn't always enough. It really depends on the tape and the age.

Quote:

If the TBC doesn't take care of your drop-outs entirely, there are some software methods that work to further fix that situation. It's not without its quality drawbacks, however.

And of course, I was asked for some details on this.

Quote:

what program do you use on the computer for dropouts?

It's not so much a program as a method.

One of the easier methods is to load a lossless/uncompressed AVI into VirtualDub. Now you can pre-deinterlace it in Avisynth, or you can use Yadif or Deinterlace Area-based in VirtualDub. You have to convert the video to progressive. This is where the loss comes in -- in motion, resolution/detail, and odd digital artifacting. But sometimes that is the lesser evil than dropouts.

Once the footage is progressive, play with the VirtualDub Median filter.

Median averages a span of pixels, and determines if something is "amiss" and replaces the dropout with pixels from neighboring frames -- pretty much the same thing that the TBC does. However, the TBC operated in an interlaced analog domain. Then again, the software filter is much stronger. You lose strength either way.

It takes time and experiments, and I hope you have faster computers, too. At least a dual-core, preferably a quad-core, to encode with any sort of speed. Some of the best work comes from mixing in NeatVideo (pro pay version).

[deter]

In the market for one of these machines. Not really interested in progressive video or software fixes at this time.

The VHS stuff doesn't really have this drop out problem, however some of the old betamax tapes do.

This would be for a betamax drops...(The machine doesn't have s-video)

My current method on fixing the drop outs is to pull the frames out of the video and re-paint them.

I was told the Sony EVO-9500 (Betamax) has a drop out suppression circuitry.

However these machines are hard to find and usually cost a few grand. The question I ask myself is it worth it to just test it out and see if it works.

[lordsmurf]

Re-visiting this post -- saw your post at VH -- there may be a way to use some advanced Avisynth filtering. I don't know what filters would do it, or if it would work on interlaced footage either.

Technically, there may be a way to separate the fields in VirtualDub, and process with median, then re-merge, but satstorm at VH says he's already tried this (and he's no dummy). I believe him that it doesn't work well --- I've run into the same issue trying to use Color Mill in VirtualDub, and it mangled interlacing. Worth some experiments, however, as there are several ways to separate fields, both in VirtualDub filters, or with Avisynth filters (and load the avs script into VirtualDub for the median work -- or even just to preview the script in a GUI).

What I can't help with is the Avisynth scripting. I've never been fond of it, so I try to avoid it when possible. And usually, it's quite possible.

Avisynth also is NOT the magic cure all "best method" that some die-hard scripters want to believe (and want others to believe). Don't fall into that quicksand trap. But it's worth a shot when VirtualDub and other software leaves you wanting. Like now.

The only place to find good Avisynth info is at the Doom9 Avisyth forum: http://forum.doom9.org/forumdisplay.php?f=33

DOOM9 NOTE: That's a good site for certain things, this being one of them, but be aware that it comes with very techie (sometimes needlessly techie) information, and there are a number of purists and theory sticklers. Just wanted to prep you before throwing you into a shark pen, as I know you're still fairly new to video and all that goes with it. It's also the home of Avisynth developer neuron2. I sometimes participate there too, although it's mostly confined to capturing forum topics.

As these forums expand, there will eventually be more Avisynth info in the restoration forums here -- but that doesn't help you right now. Should you find some good answers, however, come back here and share them!