Pipeline with aacparse fails to play stream

Submitted by Jan Alexander Steffens @heftig

Link to original bug (#750989)

Description

I've got a live stream here that plays fine in FFplay/MPV but fails to play in GStreamer if aacparse is present.

Recording: http://pkgbuild.com/~heftig/foob.flv (Created via rtmpsrc ! filesink)

Failing pipeline: GST_DEBUG='*:WARNING,aacparse:LOG' gst-launch-1.0 filesrc location='foob.flv' ! flvdemux name=demux multiqueue name=mq demux.video ! mq.sink_0 demux.audio ! mq.sink_1 mq.src_0 ! h264parse ! avdec_h264 ! queue ! videoconvert ! xvimagesink mq.src_1 ! aacparse ! faad ! queue ! audioconvert ! pulsesink

Working pipeline (aacparse removed): GST_DEBUG='*:WARNING,aacparse:LOG' gst-launch-1.0 filesrc location='foob.flv' ! flvdemux name=demux multiqueue name=mq demux.video ! mq.sink_0 demux.audio ! mq.sink_1 mq.src_0 ! h264parse ! avdec_h264 ! queue ! videoconvert ! xvimagesink mq.src_1 ! faad ! queue ! audioconvert ! pulsesink

The only interesting debug message seems to be

0:00:00.021212666 14233 0x7f91cc003000 DEBUG aacparse gstaacparse.c:290:gst_aac_parse_sink_setcaps:<aacparse0> setcaps: audio/mpeg, mpegversion=(int)4, framed=(boolean)true, stream-format=(string)raw, rate=(int)44100, channel
s=(int)2

It reports the caps with channels=(int)2, even though the stream is mono.

Version: 1.4.5