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    Last edited by owlmoon; 16th Mar 2014 at 22:40.
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  2. Member
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    Originally Posted by owlmoon View Post
    Do you have to use Decomb Telecine WITH Decomb Decimate? Can Decomb Decimate be used just by itself? Tried researching but there's not much literature on this and its poorly explained. Using Avidemux btw.



    If you want to read the literature, look up avisynth decomb from neuron2, because that's where they were ported from
    http://neuron2.net/decomb/decombnew.html
    http://neuron2.net/decomb/DecombTutorial.html
    http://avisynth.org.ru/docs/english/externalfilters/decombreferencemanual.htm

    In short, telecide is for field matching, decimate is for removing duplicates

    e.g. if it's progressive source (maybe a telecined source was improperly deinterlaced), you can use decimate by itself to remove the duplicates

    if it's a telecined film source NTSC dvd, you usually use both

    But there are dozens of other combinations that avidemux and decomb might not be able to handle appropriately (e.g. field blending, field shifting, PAL<=>NTSC normconversions,etc....)

    If you have no clue, post an unprocessed sample with steady motion , like a panning shot
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    Last edited by owlmoon; 16th Mar 2014 at 22:40.
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    Say if a file looks like its just a normal file (i.e. no obvious combing artifacts) but has 29.97fps and plays in a stuttering motion, and there's a 'pause' on the 6th frame (from reading around this indicates a pal source, as the 6th frame looks like a duplicate from the frame that came before it) and you JUST use Decomb Decimate cycle 6 to sort out the frame to get it to playback at 24.975fps, and it works perfectly, is that enough?
    Yes, decimate cycle 6 should return 24.975 (essentially the original 25fps)

    I assume you wouldn't need Decomb Telecide if you don't have combing artifacts/those jagged lines that look ugly on screen etc, is this correct?
    Yes, telecide might not be necessary if fields are no longer separate (there are no combing)


    And if you did have both combing artifacts and bad stutter with 29.97fps, then you'd need both Decomb Telecide and Decombe Decimate right? (to sort out the interlacing issue as well as frame rates).
    It depends what is causing the "combing", and what is causing the "stutter". There are many causes, some of them not treatable with avidemux or decomb . One accurate way to examine is to look at separate fields and note the pattern (you can also see field blends if they are present)
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    Last edited by owlmoon; 16th Mar 2014 at 22:40.
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    I can't tell you why unless I look at the video. There might be other, better ways to treat it

    There can be many reasons . e.g. sometimes "duplicates" are not detected as duplicates because variances in compression artifacts and noise between frames . Some sources are supposed to have mixed frame rates. E.g. some sequences might be 30p, others 24p. This is common in CG sequences mixed with live action. Some sources have intended duplicates. This is common in animation - some cel renders are 12p while others are 24p. Sometimes you have a messed up source because it has gone through several conversions. Sometimes the video is edited while still in fields, and there are orphan fields or cadence disruptions in several scenes. There are dozens of other scenarios - I can't list them all
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  7. Originally Posted by owlmoon View Post
    Say if a file looks like its just a normal file (i.e. no obvious combing artifacts) but has 29.97fps and plays in a stuttering motion, and there's a 'pause' on the 6th frame (from reading around this indicates a pal source, as the 6th frame looks like a duplicate from the frame that came before it) and you JUST use Decomb Decimate cycle 6 to sort out the frame to get it to playback at 24.975fps, and it works perfectly, is that enough?
    Maybe, maybe not. How do you know every 6th frame is a duplicate in a progressive video? Just by playing it in a software player? If so the player could be deinterlacing it. You have to look at the unfiltered frames to be sure of what you have. There's every chance you'll need both Telecide and Decimate. While I've seen DVDs with that kind of a cadence, it's fairly rare because it's the wrong way (of several very wrong ways) to convert PAL to NTSC. I don't use AviDemux and maybe it does show you the unfiltered frames.

    And as pdr suggests, post a sample of something you're not sure about. 10 seconds of steady movement is usually enough.
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    Last edited by owlmoon; 16th Mar 2014 at 22:40.
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    Originally Posted by owlmoon View Post
    Ok thanks anyway poisondeathray. Just one more question (last one): I tried adding Decomb Telecide to 3 already normal (had no combing artifacts) files just for experimental reasons, and found 2 were no different yet the 3rd looked like it had combing AFTER adding the Decomb Telecide filter. I'm wondering if adding Decomb Telecide is a bad idea and can cause combing artifacts or other errors if the file does not even need that particular filter. Just want your opinion on that, if thats ok? Sorry if I am asking too many questions this is the last one
    Yes Telecide can cause problems if you use it incorrectly. Any field matching filter can degrade the video because they have post processing. Unless you disable it in the settings, it can apply deinterlacing according to the comb detection threshold. That can cause aliasing on a progressive source
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    Last edited by owlmoon; 16th Mar 2014 at 22:40.
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  12. Originally Posted by owlmoon View Post
    Hi manono, well basically I played the file through vlc and went through each individual frame one-by-one and could manually check the pause on each 6th frame. I did this several times in different places of the file.
    If VLC is deinterlacing it then your analysis is wrong.

    As suggested several times now, please post a sample from the source. By the way, what is your source, DVD, MKV download, what?
    As far as I know from reading around, it seems like Decomb Decimate is needed without Decomb Telecide if the file does not look interlaced..
    If the file is really progressive, yes, Telecide isn't needed and could conceivably cause adverse effects. It might deinterlace what doesn't need deinterlacing.
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    Last edited by owlmoon; 16th Mar 2014 at 22:40.
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  14. Member DB83's Avatar
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    This is, for all intents and purposes, your second topic on the same issue.

    In both of the topics you have been asked to provide a short sample of the source video. You have ignored all these requests.

    Whilst your analysis of the issue may be correct, it may also be wrong and the advice you have been given has been thrown by your mis-analysis.

    PAL is NOT 24.975 fps it is 25 fps. In your other topic you implied 23.976 fps which is IVTC'd from NTSC.

    One or other is incorrect. Without the sample we simply can not tell. IMHO frame by frame advance/inspection using vlc is not an ideal method.
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