Just to add some perspective:
root@theon:~ # ls -l /usr/sbin/asterisk
-rwxr-xr-x 1 root root 3549992 Feb 12 08:53 /usr/sbin/asterisk
(That’s Asterisk 22 on Debian Unstable.) Admittedly, its dependencies seem a bit fewer:
root@theon:~ # ls -l /usr/sbin/asterisk
-rwxr-xr-x 1 root root 3549992 Feb 12 08:53 /usr/sbin/asterisk
root@theon:~ # ldd /usr/sbin/asterisk | wc -l
27
root@theon:~ # ldd /usr/local/bin/ffmpeg | wc -l
293
(That’s my custom FFmpeg build, of course.)
But remember what you get functionality-wise: FFmpeg is not limited to audio-only formats, it can also extract audio from video files, or insert audio into video files. And it can directly read from and write to real-time audio/video streams.
And then there’s the whole “filtergraph” architecture …