On 3/31/26 21:45, Richard Bartczak via ffmpeg-user wrote:
breathe a sigh of relief, if yes. I did use AV01 encoding, with
libaom. Not usable on my system, speedx leads to <= 0.002 (hints to
improve it ?).
Therefore libsvtav1 I use. The first results lead me to do further
tests, I compare it with libx265 encoding.
Different parameter, crf, tune (further parameter ?)-
Further hints to make the comparison complete (tune 1-3, crf < 13,
..., 780p, 50fps, an example I can upload).
My intention, compression without visible less.
Regards
Richard
average crf equality I found out testing by encoding the same sources
with both libx265 and libsvtav1 using standard encoder settings for the
given preset settings and calculating vmaf score of the encoded video.
This is with libx265 on preset slow and libsvtav1 on preset 3 (The
presets that are a good tradeoff beween speed/size on my system)
libx265 crf 30 == libsvtav1 crf 42 vmaf score > 75
libx265 crf 24 == libsvtav1 crf 36 vmaf score > 80
libx265 crf 20 == libsvtav1 crf 30 vmaf score > 95
libx265 crf 16 == libsvtav1 crf 24 vmaf score > 99
A vmaf score above 95 is for most people indistinguishable from the
source video.
You have to make a tradeoff however between presets (encoded
filesize/speed) and crf (quality/speed) to find out which settings work
best for you. Low preset = low speed but high compression, low crf =
high quality but slow speed. Depending on the source material you might
need different settings for optimal results with different sources.
generally with libsvtav1 presets below 3 take (very) much more time for
very little gain in compression, presets above 8 are fast but file size
increases rapidly as compression declines to keep the quality constant.
Often it is wise to make a fast encodes of a relevant part of the source
video with a high preset on different crf levels to find the crf quality
that fits your source best and then use a low preset to encode the
entire source on that crf level to get the desired compression. Usually
a fast paced action video needs lower crf values compared to a simple
animated video for delivering >95 vmaf scores.
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