Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.

 

Go Back   Doom9's Forum > Announcements and Chat > General Discussion

Reply
 
Thread Tools Search this Thread Display Modes
Old 18th March 2023, 03:48   #21  |  Link
poisondeathray
Registered User
 
Join Date: Sep 2007
Posts: 5,412
Quote:
Originally Posted by VictiniSter View Post
I'm curious, how does BWDIF compare with yadifmod2? For some stuff I'm working on, QTGMC results in static elements like logos move up and down from one frame to the next when doubling the frame rate. I was recommended yadifmod2 because it handles static elements better.
In general, BWDIF produces sharper results, but sometimes the aliasing artifacts are worse (sharper , so more pronounced)

QTGMC shouldn't have issues with static overlay elements , unless the objects underneath the logo were moving in such a way that confused the algorithm, or you have some other problems with your video

Yadif(mod)(2) and bwdif should be ok too - unless you have some other problems with your video. Both avisynth versions have edeint options , so you can use nnedi3 or others for interpolation

Another approach is combining a mask overlay with a deinterlacer to cover those elements
poisondeathray is offline   Reply With Quote
Old 19th May 2024, 16:26   #22  |  Link
Sneals2000
Registered User
 
Join Date: May 2007
Location: UK
Posts: 18
Quote:
Originally Posted by kolak View Post
Alchemist box is not as good (as it has to work in realtime and it's old) as new Alchemist File sold by Grass Valley now. Price is acceptable for pro market (way better than old box) and offers much more. Old box is not sold anymore, is it?
The hardware model is not sold because GV closed the only factory they had left (Newbury) that could make it in their mad dash to pivot to the cloud... Their ex-Quantel server products suffered the same fate, as has the former-Snell Kahuna vision mixer range (though I believe the latter could be made elsewhere - but were too much competition for their North American-designed K-Frame switchers). The Kahuna Maverik control surface lives on as an AMPP control surface, as does the Quantel LiveTouch control panel for the cloud-based LiveTouch X.

I believe there is also an Alchemist Live box based on COTS hardware - though I don't know how it compares in performance terms to the custom hardware boxes.

Last edited by Sneals2000; 19th May 2024 at 16:34.
Sneals2000 is offline   Reply With Quote
Old 19th May 2024, 16:32   #23  |  Link
Sneals2000
Registered User
 
Join Date: May 2007
Location: UK
Posts: 18
Quote:
Originally Posted by kolak View Post
BWDIF is ok, but nothing crazy good. Better than w3fdif, YADIF, but not really on pair with motion adaptive ones.
Motion Compensative is a step up from Motion Adaptive isn't it?

Motion Adaptive deinterlacers change their deinterlacing mode based on whether there is intra-frame motion (i.e. motion difference between the two fields in a frame) - either globally or on a block-by-block basis.

Motion Compensative deinterlacers go a step further and try to detect the speed and direction of motion of picture elements to assist in interpolating the missing fields from the fields that are present (not dissimilar to the way LongGOP codecs use motion vectors for compression).

Phase Correlation - as used by Alchemist frame rate converters and Quasar SD-HD upconverters - improves on just basic block matching because the phase correlation surface indcates rotational motion in addition to linear translation (most block matching algorithms only try to match in linear directions - Phase Correlation-assisted block matching can also detect rotation)

It'll be interesting to see what happens if/when the patents for Phase Correlation use in this area lapse. (If they haven't already - Alchemist is based on the early 90s Gazelle Phase Correlation slow motion interpolator)
Sneals2000 is offline   Reply With Quote
Old 19th May 2024, 20:26   #24  |  Link
richardpl
Registered User
 
Join Date: Jan 2012
Posts: 297
Wouldn't this phase correlation be also slow to do on CPU?
richardpl is offline   Reply With Quote
Old 13th June 2024, 08:40   #25  |  Link
DTL
Registered User
 
Join Date: Jul 2018
Posts: 1,176
Quote:
Originally Posted by Sneals2000 View Post
Motion Compensative is a step up from Motion Adaptive isn't it?
As you see with M_QTGMC example - the motion estimation is still very poor at the high and complex motion areas. And moving pictures like sports or action scenes are about realy fast and complex motion.
Some shows are too - good example is Brazilian Carnival. And with unstable and unreliable motion extimation the performance of simple QTGMC is poor too - it lost many details. And attempt to make higher quality motion estimation by combining several runs of ME engine with different params sets and also making statistical averaging of MVs from several searches around current block's position quickly degrades performance to 10x or even 100x times slower and close to unusable.
The only recommended solution may be with combined processing if possible to cut total movie to scenes with low and high complexity of motion and apply different ME engine to mostly static and complex motion scenes. But it is not valid to totally complex footages.
Though as the interlaced scan footage production is going to end so we have limited size of footage to deinterlace with (in theory) infitine time to process and it can be solved with finite time even with slow deinterlace engines.

"improves on just basic block matching because the phase correlation surface indcates rotational motion in addition to linear translation (most block matching algorithms only try to match in linear directions"

Rotation with a not very small radius and not very fast speed can be close to translation of the small enough blocks. So with decreasing of blocksize the error of rotation compensation also decreases. But with decreasing blocksize typical general motion estimation errors become higher. Some solution is progressive decreasing of blocksize (also takes more time to run). So the translation is the most important and main transform to estimate and compensate in most of ME/MC engines like deinterlace/denoise/FRC/MPEG.
Skipping rotation compensation makes more and more error only with 'large' temporal radius engines like denoisers and with typical deinterlace and FRC engines with a very small temporal radius like +-1 frame/field the rotation errors are very small at most footages.

Quote:
Originally Posted by kolak View Post
There is also an important detail- do we need deinterlacing to single or double fps?
It's very important as single one is way simpler and way easier to achieve (with simpler/faster deinterlacers).
Double-fps is natural for interlaced video by design. The storage in the form of a 'frame of 2 fields' was simply to make it more viewable at the progressive screens without deinterlacing. With correct proportions.

In the scan way it may better named field-based footage as a sequence of fields (and with double-frames rate).

The real analog and SDI transmission also performed in the field-stream. Not in the form of full-height 'frame'. CRT also displays as field sequence.

Last edited by DTL; 13th June 2024 at 09:07.
DTL is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 05:12.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.