Combing in VHS

[xiaNaix]

I'm doing some VHS encodes and, using filters, am able to remove most of the noise. I notice quite a bit of noise around the edges of (mostly white) objects and, based on inspecting the source AVI in VirtualDub, suspect it is being caused by combing. I really don't want to deinterlace unless I have to. Is there a way to remove combs without deinterlacing?

[scharfis_brain]

please post a sample image, or video!

[xiaNaix]

This is old Halloween footage. In the encode, there is noise around the edges of objects such as the tombstones. As you can see in the screenshot, there is quite a bit of what I think are combs around them. Obviously, the camerawork isn't exactly steady. ;)

I've got an encode running now with GreedyHMA to see if it looks any better.

[sh0dan]

Originally posted by xiaNaix
Is there a way to remove combs without deinterlacing?
Removing combs without deinterlacing is a contradiction of terms. When you are removing combs you are deinterlacing (IVTC is just an intelligent form of deinterlacing).

Anyway - try KernelDeint it's the best deinterlacer out there IMO.

[xiaNaix]

I don't like the way the deinterlaced version looks. It doesn't seem as smooth as the interlaced version. :( Is it just me or is transferring VHS to DVD a big pain in the arse?

[Si]

Its you :p

You didn't mention you were encoding to DVD.

Just encode your footage as interlaced MPEG-2.

If you want to pre-filter, then you have to separate the fields, do your filtering and then weave them back together again.

regards
Simon

[xiaNaix]

Actually... I think I may have cured it! :eek: I added this to my avisynth script...


luma=Blur(1.0) #
MergeLuma(luma)


I don't see the combing effect when viewing in VirtualDubMod anymore! We'll see what happens after the encode.

[scharfis_brain]

We'll see what happens after the encode.

ghosting!

when encoding to DVD DO NOT deinterlace, combs are not visible on TV since TV works interlaced!

A PC monitor is NOT suitable for interlaced Video playback!

[xiaNaix]

The combs don't show up on the TV after the encode but, instead, there is noise around all of the objects that appeared combed in VirtualDub. I'm looking at it on my 27" \/\/ega so maybe on a regular TV it won't be as noticable. I guess I should live with it, eh? ;)

[morsa]

you're really making a big mistake man!
That combing you see in your PC monitor doesn't show up on a TV screen.

[xiaNaix]

Arrrrgh! I know that! The combs don't show on the TV screen but noise does! Wherever that combing appears in VirtualDub is where the noise appears in the final encode. Blurring the luma created ghosting, just as scharfis_brain said. I did some reading and found out that CCE is prone to this type of mosquito noise. I did another encode, this time using the latest MainConcept, and it reduced the problem quite alot. :D

[Boulder]

You can use the quantization characteristics (flat part priority) setting in CCE to alter the way it allocated bits in the image.

[Mug Funky]

you're encoding as progressive frame in your mpeg-2 encoder.

i don't know which encoder you're using, but any of these will mitigate the mosquito-noise you're getting (of course a higher bitrate will do nicely as well... DVD goes up to 9.8mbps, which is more than adequate for lo-fi vhs, esp. with the noise removed)

look for any and all of these options in your encoder:

"interlace", "alternate scan (or "not zig-zag scan")", "field pictures", etc.

one thing you'll have to worry about as well is what field order the video is in. you'll REALLY notice problems if you get the field order wrong... (you'll know when you see it :))

[edit]... oh, you're using CCE. i'd stick to it (don't think mainconcept is up to CCE's standard, but to me TMPGenc is the nicest). just un-click "zig zag scan" and it should be peachy. if not, increase the bitrate.

[Si]

you're encoding as progressive frame in your mpeg-2 encoder.

I already told him that :)

He think he understands interlacing but unfortunately he doesn't :)

Eventually it'll click ;)

regards
Simon

[xiaNaix]

Originally posted by siwalters
I already told him that :)

He think he understands interlacing but unfortunately he doesn't :)

Eventually it'll click ;)

regards
Simon

Thanks for the compliment. :rolleyes:

[Si]

We've all been there at the beginning :)

regards
Simon