I’m genuinely curious about upload formats now, as in effort versus results. You seem to be very familiar with test procedures, so maybe you can give some insight on the best method here.
Let’s say I have a Shotcut project which I export to both Ut Video and DNxHR. (I could have chosen ProRes, but DNxHR is easier to go cross-platform and also has an 8-bit option which should require less disk space than ProRes which is always at least 10-bit.)
Now let’s say I upload both videos to YouTube, then download them at highest quality using www.ClipConverter.cc or some other ripping service. Once I have the YouTube transcoded versions, what is the best procedure to determine whether the lossless upload retained higher quality (edge sharpness, color accuracy, fewest artefacts) versus the visually lossless upload?
If we use SSIM, what percentage would be necessary to say “I’m willing to accept that loss to get the radically smaller upload and storage size”? Same question for PSNR, VMAF, or anything else. For my purposes, if my eye can’t tell a difference, that’s good enough for me. But I’m wondering how to put some science on this in case my eyes aren’t as good as everyone else’s.
I would also assume that the content of the video would play a part in testing too. I would assume that a static shot of a test card would be the worst possible video to upload. VP9 and H.264/265 have frame buffers and are smart enough to realize that no change is happening, and can therefore devote more bitrate to getting a really good first I-frame, knowing that the following P/B “frames” will have very little difference to encode. This will make the video look better than it really is, as the quality would quickly fall apart once motion starts happening and not as much bitrate can be devoted to a single frame anymore. So what would the appropriate amount of motion be to test the lossless upload versus the visually lossless upload?
If I could archive DNxHR rather than Ut Video or FFV1 and have an imperceptible quality difference, that would be a good day in my book. Now how to test it…