Quote:
Originally Posted by poisondeathray
I'm not sure how valid that test would be. EXR is usually sRGB linear , and 16bit half float .
For any metric you usually need a common ground to compare. This means same pixel format (same colorspace, same bit depth, same chroma subsampling) . Otherwise you introduce other variables that are not controlled for. e.g. if one run uses one algorithm to scale (e.g. bicubic vs. bilinear, vs...) , or another dithers down using one algorithm, but another does not... or if you convert to RGB using different matrix, etc... there are many factors that invalidate your testing
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EXR contains whatever you put into it (has nothing to do with sRGB) - there are no assumptions here: this is the master of the movie in HD in lossless 16 bit EXR, I took 400 frames as a test sequence
for streaming the movie was encoded via ffmpeg and x265 from EXR (rgb48le) to x265 12bit 444 (yuv444p12le) - final result looks very good, we're using VMAF to compare various encodes (presets/CRF/etc) against each other... exact same as NF does it w/ VMAF... the master one delivers to NF is obviosly also not 8bit 420, they encode from that (high quality) master for NF streaming...
so the "common ground" you state is the
same movie in the
same resolution, which is the only thing that NF states in their VMAF instructions...
the whole reason for comparison is different output bit depth w/ different output chroma subsampling, on top of different encoding settings, so I do not understand your point...