Restoration Challenge

[guns1inger]

I am trying to bring a VHS tape back to life on the way to DVD. It is in a pretty sorry state, as it has been used as a teaching aid for about 12 years, and was a copy of a TV recording that had been well watched before that. So far, I have been able to do a pretty decent cleanup job using Convolution3D and Fulcilives' tutorial (many thanks, this is my first step into the AVS world). The settings were pretty agressive, the but the results are good.

The problem is that there is damage embedded in this copy of the tape that come from the original tape. It is the type of disturbance you normally see from a tape with a kink or surface damage. Are there any filters that can deal with this type of fleeting (i.e. generally 1 or 2 frames only) problem ? While I want to give them the best job possible, it is a freebie, so painting out noise frame by frame in this instance is a no-no.

Just to speed things along, I have tried a number of setting in Convolution3d, as well as peachsmoother. As I said - great results for the general noise and chroma issues from the original dub - but neither touched the tape damage.

Many thanks in advance.

/edit (sometime later that night)

I have been playing around with DeSpot and DeScratch with little success. If anyone has some tips (especially on DeScratch), give a yell.

/end edit

[Soopafresh]

Consider asking this question on Doom9's AVISynth board. Quite a few of the plugin authors hang out there and might be able to point you to an AVIsynth or VirtualDub plugin that might help. I know there is a virtualdub plugin that allows you to apply an effect on only certain sections of your file, based on frame ranges. That might make your restoration process easier.

Bottom line though, you're probably entering the arena of diminishing returns. You might end up spending more time fixing these last little glitches than you did capturing and doing your initial clean up.

[lordsmurf]

I'm a visual person.
I need to see an error too to give advice.

[LSchafroth]

I'm a visual person.
I need to see an error too to give advice.

Try this one then.

https://www.videohelp.com/forum/viewtopic.php?t=266991

[vhelp]

@ guns1inger

Wait. Before you start going nuts (well, you already have) anyways.

When you take on a specific project like this, the first thing
you should consider as a rule, is to use the highest bitrate
possible. You are talking "restoration", so why defeat this
with a low bitrate method, and then archive it (as if it were
the last, to be an original) so..
.
My recommendedation, in these situations, are to use the highest
bitrate per dvd disk. I preference 9000 CBR. Why ? Because it
gives me the closest match to the original, whereas the tipicle
bitrate method (VBR) normally does not because of the way it
distributes (calculates) the bitrate across a wide time-line.
.
You want your source to look as exact as the original.. noise
and all. First make sure you can acomplish this. You should be
able to with the above bitrate. (Don't count on a 2-pass vbr
to equal the same, because of its "bitrate distribution method",
etc)
.
Then, you want to assign certain tasks to (not improve) but
help eliminate certain anamilies.. (ie, noise, lines, etc)
.
But, the problem with this, is that "removing" anamilies (above)
in most cases, changes the image originality. for instance, they
make things looks pastic or masky (as in DS9's Odo's face)
.
When I (did) use noise removers (of all sorts) I found my images
looked like the above description. But, using *very little*
param values helps sligtly. But, there are thresholds that crush
this, and you have a masky looking source. This is always the
case when dealing with Filtering a video source. That's why I
suggested to use *very little* param values in your Filtering
functions.. whatever they are.

Below are processes that other users may or may not agree with.
Feel free to use at your own trails for optimum transfer reproduction

Things I might filterize ...

* VHS & Bitrate
{

part A

Always use highest resolutions, ( ie, 720x480 ) *not* 352x480
and bitrate method, 9000 CBR. You want to maintain the maximum
detail. Applying a multi-pass VBR method is not always enough
for VHS sources.. especially for aged or signs of ware cases.

If you want to maintain closest match to the source, then you must
use a high bitrate, and use the CBR method because it will not
fluctuate the bitrate during "quiet" scenes. Everything will be
as close to constant as possible (pending which Encoder you use,
your mileage will vary)

part B

Break up your source into 1hr disks. Using the above bitrate
method, you should be able to match very closely, that of your
original source.

Then, when you apply (debug) Filters, you can do so, knowing that
your source will have enough bitrate to maintain a certain stability
during the Filtering applications. (If too low a bitrate, pixelation
occurs, which means lesser (poorer) effectivenss in your filters)

}


* edges - ie, boarders (top/bot/left/rt)
{

For edges and MPEG-1, use 8 pixel black masks
For edges and MPEG-2, use 16 pixel black masks

}


* Resolutions - ie, 704x480 vs. 720x480
{

Keeping the (to maintain aspect ratio) 704, add 8 pixles to the
source (left/right) only.

.. if you add the 8 pixels to the top/bot, you'll throw off the
.. apsect of it, because the horizontal looses its visual stage.
.. The only thing that is missing is the left/right apsects, during
.. the tv's resizing through sampling. The height "480" does not
.. change, and here is where we are missing a small piece of the
.. aspect ratio of things, when we change from 704 to 720 pixels.
..
.. ( ..does not change.. ) I was talking about the source AVI, and
.. *NOT* the TV resizing
..
.. The above is my personal opinion about mainting aspect ratio with
.. 704 -to- 720 sources.

The other add'l option (using the above steps) is to continue with your
adding the 8 pixels (left/right) *but* for the top/bot, mask
it with 8 pixles to match the left and right sides, so that things
look more balanced

It's ok to cover (mask) with black, your top/bottom video area because
of the tv's overscan (what you do not see, during tv viewing) anyways.
Plus, it has an added advantage (if you insist on using VBR) with the
bitrate distribution because of the black areas to encode = less bitrate.

(be sure to note the different pixels to use when dealing with
either MPEG-1 vs. MPEG-2 (above))

}

I may have a few more possible suggestions, but I'll stop here.

Good luck,
-vhelp 3311

EDITED - by vhelp