As a side effect, this workaround the AAC decoding problem after pause/seek
when going through our packetizer (eg: pause/seek with vlc VOD).

But the bug is still there : faad will stop decoding audio forever after
receiving a buffer full of 0 (at least with faad2-2.5 from
audiocoding.com, faad2 from mplayer svn does not show this problem)