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Deinterlacing & "Threshold" Questions

Started by WeBeDazzling, August 09, 2024, 07:37:10 PM

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WeBeDazzling

Regarding deinterlacing.  When using, for example, "dgbob" or "Kernel Deint.", the value input for "threshold", is a lower value more precise, or better, than a higher value?  More specifically, is a higher or lower threshold value going to give better results? 

Same question for different filters.  "Threshold" in other fields, for example, "Luma Stabilizer" (reduce flickering)... for optimal results should a lower or higher threshold value be used?  Generally speaking, I'm sure there are anomalies or outliers depending on the video being edited.   :)

Lastly, does anyone have any recommendation(s) for best deinterlacer available on avidemux?

Thanks for reading & thanks in advance for any feedback.   :)
WbD 

eumagga0x2a

#1
Quote from: WeBeDazzling on August 09, 2024, 07:37:10 PMLastly, does anyone have any recommendation(s) for best deinterlacer available on avidemux?

VDPAU in frame-for-field mode (doubling the frame rate) on Linux with NVIDIA graphics card and proprietary drivers.

On all other operating systems, never used for processing anything other than Yadif.

alexstorm

I don't bother deinterlacing much, because I do not use interlaced media.

For Mp4 you could use Libavedec Deinterlacers.  I would try also Decomb Telecide with No Strategy unless you also have 3:2 pulldown.  The default settings are pretty good.
Field order: top
None but compute
Never
7.00
50.00
10.00
50.00
Turn blend on.

Some things to consider:  Interlaced 640 x 480 is recorded with 0.9 rectangular pixel size.  So you need to pull out the interlace before resizing the height to the correct 4:3.  Ideally, you take the original 640 x 432 and remove the interlace then resize to 640 x 480, not the other way around.  The most important part is using the blend to soften the edges.

Better solution would be to see if the original media is available in a non-interlaced copy.

Hope that helps.


WeBeDazzling

Thank you @alexstorm!   Same, I don't use deinterlace but when I was playing around with it on a video, for eg., this one, 
deinterlace example

   ....there seemed to be better upscale results when I tinkered with deinterlace.  Yet all the various deinterlace options are a bit much to the layperson.   

* "Threshold", does a lower threshold or higher threshold value, when time is not an issue, create more optimal results?   

Thanks for the tips @alexstorm    :)

alexstorm

WeBe,

Finally found info on threshold.
https://ffmpeg.org/ffmpeg-filters.html#vaguedenoiser

===
   threshold
   The filtering strength. The higher, the more filtered the video will be. Hard thresholding can use a higher threshold than soft thresholding before the video looks overfiltered. Default value is 2.
===

Higher you go, apparently is softer.  It probably doesn't take that much more processing time.  The tech underneath of the interlacer, I believe, is with ffmpeg.

Hope that helps.  Have fun with your deinterlacing.