Thanks again Skekh,
Just to be clear about VDub2:
Quote:
Originally Posted by shekh
Checked what is going on with chroma,
444 -> 422: each pixel is convolved with kernel 0.25, 0.5, 0.25
As I understand this creates some blurring.
422 -> 444: odd pixel is copied as is, even pixel is blended from two neighbor source pixels
This is simple.
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So is the 422 > 444 in VDub2 (by definition) Nearest Neighbor (Point) up-sampling, which is how I first interpreted your description, or Bilinear upsampling ?
Quote:
Originally Posted by WorBry
So, if I understand correctly, its 'nearest neighbour' (point) up-sampling and it's the convolution averaged chroma sub-sampling that brings about the separation of the R/B and G channel plots on the Resolve Parade scope, which manifests as blur ?
Up-sampled in that example to r210, because Resolve wont import v410 |
As regards Resolve; actually prior to 15.1.1 version update, the v210 'round-trip/pass-through' behavior (using the 'Checker-422' clip) was different
The change in behavior seen in 15.1.1 came in response to concern (from BMD forum members) about the quality of the export 422 sub-sampling:
Which is when it became apparent that the 'new' behavior bore a striking similarity to that seen in VDub2 for 422 > 444 > 422.
In fact, referring back to the series I posted earlier....
....when I ran quality metrics (FFMPEG) on the matched v210 exports from the Resolve and VDub2 series, the SSIM scores were 1.000000 (lossless) for Luma and UV chroma.