ref: 2dfc08f6b27c796f1b2b140f1e3b37d137cd260c
parent: 050366e484a2302927f9d537eea79250d30fa867
author: Sigrid Solveig Haflínudóttir <ftrvxmtrx@gmail.com>
date: Wed Feb 17 10:40:46 EST 2021
matroska: use OutputSamplingFrequency if defined, set default audio parameters