To test aac encoder:
  - currently use input wav files is c:/temp/pcm_s16le_48000_2ch.wav (override with "--in <filepath>" command-line parameter)
  - copy media_codecs.xml to sdcard:/media_codecs.xml from Externals/multimedia/nnMedia/android5_1/frameworks/av/media/libstagefirght/data
  - output MP4 is c:/temp/MediaOutAudioOnly.mp4 (override with "--out <filepath>" command-line parameter)
  - output can be suppressed with "--no-output-files" command-line parameter
