Traceback (most recent call last):
  File "/usr/share/arista/arista/transcoder.py", line 143, in _got_info
    self._setup_pass()
  File "/usr/share/arista/arista/transcoder.py", line 437, in _setup_pass
    self._build_pipeline(cmd)
  File "/usr/share/arista/arista/transcoder.py", line 456, in _build_pipeline
    str(e))
PipelineException: Unable to construct pipeline! could not link lame1 to mux