use command from codinho

# gst-launch-0.10 filesrc location="/bin/audio_src_48k_le.wav" ! audio/x-raw-int, rate=48000,channels=2,width=16,signed=true,endianness=1234 ! alsasink
Setting pipeline to PAUSED ...
Pipeline is PREROLLING ...
ERROR: from element /GstPipeline:pipeline0/GstCapsFilter:capsfilter0: Filter caps do not completely specif
y the output format
Additional debug info:
gstcapsfilter.c(393): gst_capsfilter_prepare_buf (): /GstPipeline:pipeline0/GstCapsFilter:capsfilter0:
Output caps are unfixed: EMPTY
ERROR: pipeline doesn't want to preroll.
Setting pipeline to NULL ...
Freeing pipeline ...
#