write_xing options seems to be only available for mp3 convertion, cf: https://manpages.debian.org/jessie/libav-tools/avconv.1.en.html
write_xing options seems to be only available for mp3 convertion, cf: https://manpages.debian.org/jessie/libav-tools/avconv.1.en.html

jiaaro/pydub