Automate interlace detection?

[Mr_Odwin]

Is there an AVIsynth plugin/function that can tell if the source is interlaced or progressive? Not worrying about telecined vs. true interlaced, just whether it's interlaced, or not. I think DGIndex does this for mpeg2 but is there anything out there for a general source as part of an avisynth script?

[Mug Funky]

scriptclip("iscombed==true? subtitle(''interlaced''): subtitle(''progressive'')")

i'm not sure if that will work - i forget how avs deals with escaping the " character.

[foxyshadis]

scriptclip("""iscombed==true? subtitle(''interlaced''): subtitle(''progressive'')"""), but right idea.

Oh, and iscombed is in the decomb package fyi.

[scharfis_brain]

iscobed alone is NOT reliable enough!

One will need a combination of several instances of iscombed with different thresholds.

those instances of iscombed will need to be applied to different 'timestamps' related to the actual timestamps in order to reliably detect 3:2, 2:2, and pure interlace.
No-Motion scenes need to be treated as pure interlace, just be be safe not to create mouth-combing.

That is only a idea. I currently have no time to implement this into AVISynth.

[Guest]

scharfi is correct. IsCombed() will tell you only if a given frame shows combing (strictly, whether the amount of the picture area that contains vertical detail at the spatial frequency of combing exceeds a threshold amount). Combing can arise from real interlaced video, from pulldown, from a field phase shift, etc. A more intelligent algorithm is required if one is trying to automatically determine the nature of a given clip.

Also note that DGIndex's indication is not a reliable indication of whether the content is actually interlaced! It indicates only how the MPEG picture was encoded.

[Mr_Odwin]

Thanks everyone. This can all be so confusing sometimes! :D