Add flag for Darwin systems to address ffmpeg bug #2697
Add flag for Darwin systems to address ffmpeg bug #2697

This command-line flag addresses an issue with ffmpeg on Mac/
Darwin systems which incorrectly doubles the reported duration
of audio files exported to .mp3 format with ffmpeg
(see https://trac.ffmpeg.org/ticket/2697).

This fix has been tested on Mac OS 10.7.X (Lion) and 10.11.X
(Yosemite) with fresh installs of ffmpeg via Homebrew.

jiaaro/pydub