[rambus8]

(sorry for my bad english)
I use rtmpdumphelper for capture MFC streaming and works perfect.
I receive the same message (WARNING: ignoring too small audio packet: size 0) but the audio works fine.

maybe your problem is that you are using a video player (like VLC) that dont have the libspexx codec. If this is the problem....you can use a player with libspexx codec built in (like media player classic) or you can convert the audio from libspexx to mp3 with ffmpeg (thai is what I usually do).