[tsdemux] report audio stream type (for visually impaired audio-description, receiver-mixed supplementary channel, ...)

Submitted by Tvrtko Ursulin

Link to original bug (#657809)

Description

Playing a MPEG transport stream from disk with a simplest gst-launch invocation like gst-launch-0.10 playbin2=file://... and playback starts without sound in a certain percentage of invocations.

Test stream (~35Mb) available on request.

If sync=false on the output alsasink then sound always work but with a sync issue.

May be a core issue and not specific to MPEG TS since I am seeing similar problem when playing V4L2 video with ALSA sound.