[HELP] Telecine Settings->Analyse

[Miranda]

Detected interlaced Material with 29,../59,.. fps, but didn't detect the material to be telecine. You might want to run 'Filtering->(De-)Interlace/Telecine->Deinterlace/Telecine Settings->Analyse'.

I'm unable to locate this particular setting. Can anyone help?

[Selur]

It's the magnifying glass with the question mark under 'Filtering->(De-)Interlace/Telecine->Deinterlace/Telecine Settings'.
Note that this analysis is just a heuristic which might also be wrong.

Cu Selur

[Miranda]

It's the magnifying glass with the question mark under  'Filtering->(De-)Interlace/Telecine->Deinterlace/Telecine Settings'.
Note that this analysis is just a heuristic which might also be wrong.

Cu Selur

Thanks - is there a more accurate way of analysing the video? I currently use MediaInfo, but I find that can also be wrong.

[Selur]

Sure, look at the content.
If you overwrite the scanorder to 'progressive' and the Vapoursynth Preview shows no combing the content is progressive.
If you leave the scan order (tff or bff) and bob deinterlace the content (in example using QTGMC + Bob) and look a the frames:
If each frame is different then the content is interlaced.
If you see a 3 different and 2 identical frames the content is telecined.
If you see another pattern of different and identical frames the content is mixed.

-----
found some old list I once wrote:

Typical interlace patterns:

1. content is progressive:
   • applying AssumeTFF().Bob()* you will see: stop -> forward_movment -> stop -> forward_movement **
     
   • applying AssumeBFF().Bob()* you will see: stop -> forward_movment -> stop -> forward_movement **
     
   
   
2. content is field shifted:
   • applying AssumeTFF().Bob()* you will see: backwards_movment -> forward_movment -> backwards_movment -> forward_movment **, ***
     
   • applying AssumeBFF().Bob()* you will see: forward_movment -> stop -> forward_movement -> stop **, ***
     
   
   
3. content is interlaced TFF:
   • applying AssumeTFF().Bob()* you will see: forward_movment -> forward_movment -> forward_movment -> forward_movement **
     
   • applying AssumeBFF().Bob()* you will see: forward_movment -> backwards_movment -> forward_movement -> backwards_movment **
     
   
   
4. content is interlaced BFF:
   • applying AssumeTFF().Bob()* you will see: forward_movment -> backwards_movment -> forward_movement -> backwards_movment **
     
   • applying AssumeVFF().Bob()* you will see: forward_movment -> forward_movment -> forward_movment -> forward_movement **
     
   
   
5. content is interlaced XFF with blending:
   • same as the corresponding interlaced pattern, but you will also see some blended (= ghosted) frames in-between
     
   
   
6. content is telecine:
   • applying AssumeVFF().Bob()* you will see 3 times forward_movement 2 still frames
     
7. content is mixed:
   • applying AssumeVFF().Bob()* you will see a mix of any of the above
     

* in Hybrid you would use QTGMC+Bob
** then moving through the content
*** or vice versa

which might help.

Cu Selur

[shijan]

I can also add another very common type used in DVDs - Progressive content placed inside Interlaced container. This is usually used for 25fps PAL videos.

Container auto detected as interlaced, but if change input type to Progressive video will look like 25fps progressive.

If Change to input interlaced and set QTGMC tff or bff - it will show normal 25 fps framerate, QTGMC will act like noise reduction, may slightly improve quality.

Changing between tff or bff  usually makes no any difference because frames are almost the same, but you can experiment and look which version visually look best for you.

If Change to QTGMC bob - it will output 50fps but show two almost identical repeated progressive frames instead of one. QTGMC will also act like noise reduction here.

[Selur]

That's simply wrong flagged content.
If you have progressive input you should not use QTGMC as deinterlacer.
(better use Filtering->Vapoursynth->DeNoise->QTGMC, if you want to use QTGMC)

Cu Selur

[shijan]

It is not a simply wrong flagged video. DVDs just can't be progressive by specification, so it was a common trick (used in last years of DVDs i guess) to fit better quality progressive content inside interlaced DVD. If look really deep under magnification it is possible to see very tiny near invisible unusual interlaced artifacts in some local places that still need some tiny amount of filtering or deinterlacing.

So for those types videos i experiment with Input type: Interlaced, and use QTGMC with top or bottom field first. There is a little side effect of usind QTGMC like this. It may produce new artifacts because QTGMC may detect some fine patterns as interlaced fields, but in reality they are simply real life details.

So there is also another probably better way to deal with this footage - Instead of QTGMC, set input type to Progressive and use AntiAliasing filter before Resize to remove those tiny jagged/interlaced  artifacts.

By the way, i guess similar trick sometimes used in BluRays. It named "fake interlace" or something like this. Progressive content flagged as interlaced to fit 1920x1080 high framerate videos to BluRay specification.

[Selur]

I think deinterlacing is in such cases wrong.
I think changing the scan order to progressive and using vinverse would be the right choice an if one want some of QTGMCs filtering using DeNoise->QTGMC it the right choice.

Cu Selur