Bug#787764: libvpx2: vp9 encoding is significantly slower in 1.4.0 than in 1.3.0

[Fabio Pedretti]

Hi Matt, can you check if the performance regression you noticed with
1.4.0 was resolved with a newer libvpx release?
You may also eventually check the upstream issues report at
https://bugs.chromium.org/p/webm/issues/list
Thanks.