View source for Template:RK3399SelectALSAAudioDevice

===Select the system default audio device===
You can set the system default audio device by following the steps below. <br />
Use the following command to view all the sound card devices in the system (Note: different development boards will have different results):
<syntaxhighlight lang="bash">
pi@NanoPi:~$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: realtekrt5651co [realtek,rt5651-codec], device 0: ff880000.i2s-rt5651-aif1 rt5651-aif1-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: rockchiphdmi [rockchip,hdmi], device 0: ff8a0000.i2s-i2s-hifi i2s-hifi-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 2: ROCKCHIPSPDIF [ROCKCHIP,SPDIF], device 0: ff870000.spdif-dit-hifi dit-hifi-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0
</syntaxhighlight>
As you can see, the following sound card devices are available on the hardware:
::{| class="wikitable"
|-
|Sound card device || Sound card  number || Description
|-
|  realtekrt5651co || 0 || Realtek sound card's default output interface (through 3.5mm jack interface)
|-
|  rockchiphdmi || 1 || HDMI
|-
|  ROCKCHIPSPDIF || 2 || SPDIF (Note: temporarily unavailable, because the hardware is not exported)...
|}
To configure the audio output to the 3.5mm jack, modify the configuration file /etc/asound.conf and modify it to the following: 
<syntaxhighlight lang="bash">
defaults.pcm.card 0
defaults.pcm.device 0
</syntaxhighlight>
To configure to output audio to HDMI, change the defaults.pcm.card above to 1.<br />
Note that some boards do not have a Realtek sound card (no 3.5mm jack interface), so the card number of the HDMI device will be 0, so the configuration should be based on the result of the aplay -l command.