James Almer (12022-03-20):
> Same as the AVCodecContext option.
> 
> Signed-off-by: James Almer <jamrial@gmail.com>
> ---
>  fftools/ffmpeg.h     | 2 ++
>  fftools/ffmpeg_opt.c | 8 ++++++++
>  2 files changed, 10 insertions(+)

I do not like this: it requires more typing from the user, even with the
"short" alias in the previous patch.

Also, there are many occurrences of "-ac" in the documentation, they
need to be updated too.

Regards,

-- 
  Nicolas George