Using libavformat under Debian Jessie, I get the following:
$ ~/usr/bin/fmfconv -p youtube out.fmf out.avi *INF open_out(): Output file (out.avi) opened as FFMPEG - ffmpeg file format file. *INF open_inp(): Input file (out.fmf) opened as FMF file. *ERR FFMPEG: Encoder aac does not support sample format s16
Diff:
Thank you. I have dropped FFmpeg API support in [r5351], so this bug is no longer reproducible.
The man page has some examples for using ffmeg and the aac audio encoder:
Related
Commit: [r5351]