Examples problems with multimedia

On a new installation, trying audio-visualizer example.
First thing is it ask if I want to compile it in place or copy it. I decided to copy it.
When building it it couldn't find examples.pri
I had to modify the pro file to
/opt/Qt/Examples/Qt-5.7/qt3d/examples.pri

Once it compiled, running the example gave a number of errors complaining of plugin's missing from GStreamer. I'm not sure what it's talking about since clicking of the mpg plays it just fine.

Starting /home/chris/qtworkspace/build-audio-visualizer-qml-Desktop_Qt_5_7_0_GCC_64bit-Debug/audio-visualizer-qml...
QML debugging is enabled. Only use this in a safe environment.
qml: error with audio 2
Warning: "No decoder available for type 'audio/mpeg, mpegversion=(int)1, mpegaudioversion=(int)1, layer=(int)3, rate=(int)44100, channels=(int)2, parsed=(boolean)true'."
qml: error with audio 1
Error: "Your GStreamer installation is missing a plug-in."
No Input Settings found, keyboard and mouse events won't be handled
qml: error with audio 2
Warning: "No decoder available for type 'audio/mpeg, mpegversion=(int)1, mpegaudioversion=(int)1, layer=(int)3, rate=(int)44100, channels=(int)2, parsed=(boolean)true'."
qml: error with audio 1
Error: "Your GStreamer installation is missing a plug-in."
/home/chris/qtworkspace/build-audio-visualizer-qml-Desktop_Qt_5_7_0_GCC_64bit-Debug/audio-visualizer-qml exited with code 0