Please see Multimedia chapter of the Digi Embedded Linux help. it has many examples of what you are trying to do.
Gplay is a command line application provided by Freescale that accepts a filename as parameter and will automatically chose the best codecs to play it with. For this, it uses the playbin element introduced in the next section. Gplay is the recommended way to reproduce media, although on occasions it can fail to play specific files. In such cases the gstreamer pipeline has to be manually created using gst-launch as explained in .
# gplay big_buck_bunny_480p_h264.mov
If you need more control you can use the gst-launch application directly which allows to create flexible pipelines using all available elements. Some examples follow.
The playbin2 element will automatically select elements for your pipeline:
# gst-launch playbin2 uri=file:///root/big_buck_bunny_480p_h264.mov
complete audio and video playback pipeline:
# gst-launch filesrc location=big_buck_bunny_480p_h264.mov ! 'video/quicktime' ! aiurdemux
name=demux demux. ! queue max-size-buffers=0 max-size-time=0 ! mfw_vpudecoder ! mfw_v4lsink demux. !
queue max-size-buffers=0 max-size-time=0 ! faad ! audioconvert ! 'audio/x-raw-int, channels=2' !
This is all copy & paste from online help, please take a look for more info and example directly in to the multimedia chapter or even gstreamer documentation: