Audio
======

This guide will show you how to connect and use a headset/microphone in order to exercise some of the available audio interfaces supported on the development kit.

.. image:: ../../images/phycore-imx8x/pcm-065_audio_callout.webp
    :width: 600px
    :alt: Audio
.. image:: ../../images/phycore-imx8x/pcm-065_audio_profile__callout.webp
    :width: 600px
    :alt: Audio Profile

Requirements
--------------

* Ethernet Cable (Included in development kit)

* Headphone/Microphone device with a standard 2.5mm Audio Jack connection (individual or combo)

Playing Audio
---------------

* For this example, you'll need the phyCORE-i.MX8X development kit connected to the internet. Checkout the :ref:`ethernet-8x` guide first!

* Next, plug your headphones into the "Headphone (Default)" port (the black headphone jack).

* Use the "wget" command to download a sample .wav file from the music science web server at the University of Helsinki directly to the development kit.

  .. code-block:: none
    :caption: Target (Linux)

    wget http://www.music.helsinki.fi/tmt/opetus/uusmedia/esim/a2002011001-e02.wav

  .. code-block:: none
    :caption: Expected Output

    a2002011001-e02.wav  100% |********************************| 9356k  0:00:00 ETA
    'a2002011001-e02.wav' saved

* Use the "aplay" command to play the audio

  .. code-block:: none
    :caption: Target (Linux)

    aplay a2002011001-e02.wav

  .. code-block:: none
    :caption: Expected Output

    Playing WAVE 'a2002011001-e02.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

Capturing Sound
----------------

* Connect the microphone into the Pink jack.

* Use the "arecord" command to capture audio at this interface. The command below will record sound for 10 seconds and save it to the file testrecord.wav.

  .. code-block:: none
    :caption: Target (Linux)

    arecord -d 10 -f cd -t wav testrecord.wav

 .. code-block:: none
   :caption: Expected Output

   Recording WAVE 'testrecord.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

* Use the following to playback the file you just recorded:

  .. code-block:: none
    :caption: Target (Linux)

    aplay testrecord.wav

 .. code-block:: none
   :caption: Expected Output

   Playing WAVE 'testrecord.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

Adjusting Playback and Capture Settings
-----------------------------------------

The alsamixer program can be used to configure sound devices and do things such as change volume or mute particular interfaces.

.. tip:: More information about alsamixer can be found here: https://linux.die.net/man/1/alsamixer

* Launch alsamixer in the target console:

  .. code-block:: none
    :caption: Target (Linux)

    alsamixer

  A GUI interface will pop up which can be navigated using arrow keys and the hotkeys.

  .. image:: ../../images/phycore-imx8x/pcm-065_audio-alsamixer-gui.webp
    :width: 500px
    :alt: Alsamixer Settings GUI