On Sun, Jun 17, 2018 at 12:30 PM Brian Wolff <bawolff(a)gmail.com> wrote:
Good to see us moving forward to newer codecs.
What is the expected impact on transcode time/memory
usage? (As in, will
large videos still transcode fine or would they potentially hit limits
Using the same CPU thread count, typical files take about 3-4 times longer
with the configuration we've got ready. This doesn't seem to be a major
problem at low resolutions, but higher resolutions may need to have the
limits raised for very long videos like conference talks. Memory usage may
be higher but I've not specifically noticed a major difference between VP8
and VP9 there.
This could be improved significantly by updating to libvpx 1.7 and a
matching version of ffmpeg that supports macroblock row multithreading:
this means that we'll be able to use more than 4 threads for HD videos,
which should allow using all cores on a 20-core/40-thread machine if it's
not loaded up with other files.
The necessary libraries are released; we just need to backport the newer
packages to Debian 9 I believe. Don't yet know whether this will be an easy
or hard task.
Now that you mention it I am concerned about the time limit on very long
videos, so I'll take another look at the packaging backport and see if we
can knock that out quickly. :)