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  1. Member
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    Most deinterlacers I've worked with do clever things like adaptive motion-based deinterlacing, edge-directed interpolation and so on. Sometimes these things cause side-effects like video artifacts and/or frame rate changes that require dealing with afterwards.

    I understand Deshaker works better with an external deinterlacer. However, any video artifacts annoyingly tend to get amplified and/or cause crawling effects.

    At this point in the workflow I'm (perhaps naively) more interested in merely providing accurate progressive input, rather than further improving the subjective quality of the video during interlacing.

    Would a simplistic field-combining deinterlacer work in such a case, and is one available for Avisynth or VirtualDub?

    Would feeding Deshaker with interlaced input and telling it it's progressive achieve the same effect?

    Thanks!
    Francois
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    Sorry. Dual post.
    Last edited by sanlyn; 23rd Mar 2014 at 07:10.
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    I hink this question was answered earlier. Is this the same video posted here: https://forum.videohelp.com/threads/348114-Best-VirtualDub-or-Avisynth-deshaker-for-thi...=1#post2177554
    Last edited by sanlyn; 23rd Mar 2014 at 07:10.
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  4. Bob() in AviSynth, Bob Doubler in VirtualDub.
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    That's the one, yes.

    Originally Posted by fvisagie View Post
    Would feeding Deshaker with interlaced input and telling it it's progressive achieve the same effect?
    I can confirm that doesn't work very well, whatever the theory behind it!

    Originally Posted by jagabo View Post
    Bob() in AviSynth, Bob Doubler in VirtualDub.
    Thanks, but they still split each frame into two, one per field, and then interpolate the missing one as far as I can tell. This would be useful for reinterlacing later, but if one WANTS to end up with progressive output merely combining each frame's two fields should suffice?

    Anyway, I've started testing with QTGMC () as you suggested at https://forum.videohelp.com/threads/338334-Deinterlacing-before-deshaking?p=2102505&vie...=1#post2102505 and after being bowled over by Deshaker the other day I'm left in awe all over again. QTGMC's results are so clean and quiet - even after Deshaker - that I see no reason not to continue this way.

    Except to also try out DePan () as 2Bdecided suggested https://forum.videohelp.com/threads/348114-Best-VirtualDub-or-Avisynth-deshaker-for-thi...=1#post2177549.

    Thanks for all the help, much appreciated.
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  6. Originally Posted by fvisagie View Post
    but if one WANTS to end up with progressive output merely combining each frame's two fields should suffice?
    No, that's what you already have, interlaced frames, two fields in each frame. If you want to turn those two half-pictures into a two full pictures, or a single full picture, you need to deinterlace somehow.

    Originally Posted by fvisagie View Post
    QTGMC's results are so clean and quiet
    That's your best bet. Use SelectEven() or SelectOdd() if you need the original frame rate.
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    Originally Posted by jagabo View Post
    If you want to turn those two half-pictures into a two full pictures, or a single full picture, you need to deinterlace somehow.
    That's what I don't get. If you already have two half-pictures per frame, why all this need for interpolation, blending etc. during deinterlacing - why is it not good enough to simply combine the two half-pictures into a single full picture? Could it be that sometimes there's a temporal difference between the two? Or some other issue?

    But thanks, even though I don't grasp the fundamentals here, advice taken and I'll happily live with QTGMC for now, forever decimating its output .
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    Originally Posted by fvisagie View Post
    why is it not good enough to simply combine the two half-pictures into a single full picture? Could it be that sometimes there's a temporal difference between the two?
    Exactly for that reason: they are halves of 2 different pictures - one from previous moment in time and the other one from next moment.
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    Originally Posted by Alex_ander View Post
    they are halves of 2 different pictures - one from previous moment in time and the other one from next moment.
    Somewhere I must have made the erroneous assumption that the two fields in a frame (usually the case with the DV files I work with) were two halves of the same picture.

    Your confirmation cleared up a LOT... including the way that Avisynth treats interlaced content .

    Now I can happily commit myself to QTGMC ().
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  10. Originally Posted by fvisagie View Post
    Somewhere I must have made the erroneous assumption that the two fields in a frame (usually the case with the DV files I work with) were two halves of the same picture.
    DV video from a live camcorder is usually fully interlaced -- ie, every half-pictures is from a different point in time (unless your camcorder offers a progressive mode). Recordings from film sources may contain pairs of fields from the same frame. Those can be treated as progressive.
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    Thanks, that's good to know. At least I already know that when there's a rule/standard in video, there will be exceptions .
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