Quote:
Originally posted by trbarry
Well, it was easier to just write a quickie filter and see what it does. It seems to help, at least for the horizontal dup problem.
I've only tested with the MainConcept decoder so far, with Fred's data. But it does seem that even chroma pixels are just being duplicated in that codec. The new filter will help that by discarding the odd chroma pixels and recreating them as the average of the 2 adjacent even pixels.
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Tom,
The Canopus and Mainconcept DV decoders appear very similar in that they both produce the chroma bug for 4:1:1.
Have now tried ReInterpolate411() on a Canopus software DV decode of the material I sent to Fred Thompson and it does seem to fix the chroma bug.
However, when comparing the Canopus decode and the reinterpolated version of the Star Wars laser blast space scene as bmp enlarged to 1600% (to make the pixels visible) and flipping between the two, the laser blast seems to move left by 2 pixels even though the white rocket engines remain more or less in the same positions.
I have noticed a similar effect when comparing the Panasonic and Canopus decoders: one will have a slippage of a few pixels compared to the other.
Could this be a result of the different decoders (and your interpolation) applying interpolation in opposite directions (if that makes any sense)?
Anyway, ReInterpolate411() at least removes the obvious chroma bug problem and brings the decode back to a quality similar to the Sony decoder (which doesn't have the chroma bug but which shifts the brightness upwards).
Each decoder seems to do something different to the original DV image.
So far I haven't found a way to view the original DV source without the influence of decoder peculiarities. Even using Directshowsource in Avisynth (to make use of the inbuilt DV decoder in windows as comparison) seems to return only a 320x240 image and I can't find an option to supply the full 720x480.
Ian