I have the same issue as described in this post from 2013. There were several other similar posts:
http://www.avidemux.org/smf/index.php/topic,11709.msg61168.html#msg61168
Also, the volume control bar doesn't do anything.
I have 2.6.8 installed on Devuan 3.16.0-4-686-pae. Please tell me that there is a way to get this working with alsa. I have never installed pulseaudio on any of my systems and really want to keep it that way.
golinux
PS I really miss the gtk interface though I understand why you switched. It had a much cleaner look IMO. Dropping frame count is also going to make life less pleasant every time positioning info needs to be entered in a filter. :((