Quote:
Originally Posted by TheSkiller
It's not the same, I am not talking about chroma placement (like DV vs MPEG2).
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Neither was I—I was pointing out that if we assume that we can just Weave() together fields and have correct chroma siting (this is true of the "standard" 4:2:0 interlaced chroma siting), then there's nothing special that needs to be done if we can assume the playback setup isn't completely broken.
Okay, that's actually a huge bunch of "if"s chained together and we all know playback setups can be broken in very creative ways, but honestly I think the solution should be to fix them (or at least get people to stop buying shitty DVD players etc.) rather than messing with things on the mastering side.
Quote:
Originally Posted by TheSkiller
It's about how the chroma was downsampled from (usually) 4:2:2 to 4:2:0 for DVD encoding. [snip] Now that will result in the CUE (chroma upsampling error) if you used ConvertToYV12(interlaced=false) rather than ConvertToYV12(interlaced=true) for downsampling to 4:2:0.
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My ten minutes of Googling led me to believe that the term "CUE" is meant specifically for the problem of upscaling the chroma fields with the wrong offsets, not for a mismatch of interlaced/progressive resampling. The latter's not as big a problem and can be worked around on the mastering end just by using a low-pass filter prior to interlacing (or widening the support of the downscaling filter when converting from 4:2:2/4:4:4/RGB to 4:2:0).
A playback setup is not required to be able to detect and reverse pulldown, so this application of a low-pass filter is the only way to guarantee that the chroma will correctly render on playback, regardless of whether the content is really interlaced (50/60 temporally distinct fields) or pulled-down. In practice it's probably safe to assume some sort of field matching will be used and that progressive chroma upsampling is done after all the deinterlacing and field matching nonsense, so you could just ignore this issue entirely. If it still uses interlaced chroma upsampling after deinterlacing or field matching, then that obviously falls under the category of "your setup is broken so we won't support it".