I have a huge collection of video files that are in the range of CRF 16-20 taking up TB's of space. The only need I have for these originals is that I have to encode them from time to time but the CRF of these final encodes is very low (CRF 26-28).

I understand that a lossy to lossy conversion ALWAYS results in some quality loss but my question is what if the intermediate file is almost visually lossless compared to the final output.

So to sum up, what quality difference should I expect from the following routes?

CRF 18 (original) -----> CRF 28 (final)
CRF 18 (original) -----> CRF 22 (long-term storage) -----> Lossy  CRF 28 (final)

1 Answer 1


We could do test runs, show comparison screenshots, VMAF scores, bitrate to quality charts, etc, but there is no other way to answer that doesn't essentially say "it will look worse".

  • I would love to see quality charts like that! It's something I've been interested before, but research never turned up anything. Notably, there would presumably be a threshold where the source file is large enough that it doesn't really look worse, right? That's why ProRes is a common intermediate format, even though it's still lossy. Jan 13, 2021 at 19:17

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