Mono AAC with channel pairing is broken with AAC
This file decodes fine with --codec avcodec
but not with --codec faad
which is the default decoder used.
http://streams.videolan.org/misc/test-files-ccc/lagrange_breaks_libav_and_faad2.mka
There seems to be gaps in the output stream.
There's a log of Unexpected channel configuration change
at the beginning of the stream. It doesn't detect the second channel as a copy of the first one and returns an error "21".
On top of that, faad doesn't decode the first 3 packets, losing audio data/sync at the beginning.