Hello.
%subj%, there's not much to add here.
The problem has been already discussed here: https://newsgroup.xnview.com/viewtopic. ... 58#p203758
Seems like heif.dll doesn't use dav1d again.
The bug has been already fixed (twice) and re-appeared also twice, the last time it was fixed in 1.8.6 and re-appeared in 1.9.0.
AVIF decoding slowdown (again)
Moderators: helmut, XnTriq, xnview, Dreamer
Re: AVIF decoding slowdown (again)

Pierre.
Re: AVIF decoding slowdown (again)
This problem is supposed to be fixed in XnView MP 1.9.3. Please check and confirm the bug fix here.
Pierre.
Re: AVIF decoding slowdown (again)
I think I am noticing considerable speed up with AVIF, especially when pic is fully zoomed out and browsing through them.xnview wrote: Mon Aug 11, 2025 6:05 am This problem is supposed to be fixed in XnView MP 1.9.3. Please check and confirm the bug fix here.
AVIF and HEIC rendering appeared to behave pretty similarly (avif was a bit faster). Now AVIF is much faster but HEIC is still slow. Could the same issue (dav1d or something..?) be bothering HEIC rendering as well?
HEIC issues are not disturbing me anymore as much as in spring as I have converted all of them to something else but anyhow it is a common format.
Re: AVIF decoding slowdown (again)
Can confirm, AVIF decoding speed is fixed now.xnview wrote: Mon Aug 11, 2025 6:05 am This problem is supposed to be fixed in XnView MP 1.9.3. Please check and confirm the bug fix here.
I think HEIC requires more CPU resources than AVIF, but currently the speed difference in decoding is weirdly big.golemus wrote: Tue Aug 12, 2025 1:16 am AVIF and HEIC rendering appeared to behave pretty similarly (avif was a bit faster). Now AVIF is much faster but HEIC is still slow. Could the same issue (dav1d or something..?) be bothering HEIC rendering as well?
HEIC issues are not disturbing me anymore as much as in spring as I have converted all of them to something else but anyhow it is a common format.
For example it takes ~ 25 sec. to decode this .HEIC file on i7 14700k:
https://krakenfiles.com/view/e2v5IpAWks/file.html
Decoding of the same image in AVIF format takes ~2 sec.