Audio

IQ9 currently supports the following audio interfaces:

• 3.5mm headphone (No. 4 in the following figure)
• HDMI OUT (No. 9 in the following figure)
• USB Audio (No. 5, 6, 7 in the following figure)

This section describes how to perform audio playback, recording, and input/output interface switching when a UAC device is connected.

Sound card

• The mounting order of the onboard sound card and the UAC device sound card mainly depends on the following factors:

1. The connection interface of the UAC device. 2. Whether the UAC device is connected before or after device boot-up.

• On IQ9, run the following command to check the mounted sound cards:

``shell cat /proc/asound/cards ``

:::warning 1. The following instructions assume that the onboard sound card is mounted as card 0, and the UAC device is mounted as card 1. 2. The actual name and supported formats of UAC devices may vary. Please adjust commands accordingly based on your specific device. :::

• On IQ9, run the following command to check the allocated PCM stream list:

ALSA

• On IQ9, run the following commands to install the ALSA utilities.

``shell sudo apt update sudo apt install alsa-utils ``

Playback

:::warning 1. Run the following command to ensure the /opt path has read/write permissions. 2. Make sure the WAV test file (<FileName>.wav) has been pushed to the /opt directory before running the command. :::

``shell sudo chmod 777 -R /opt paplay /opt/<FileName>.mp3 ``

• 3.5mm headphone playback

``shell amixer -c 0 cset "name=DAC Playback Volume" 192 amixer -c 0 cset "name=PRIMARY_MI2S_RX Audio Mixer MultiMedia1" 1 aplay -Dplughw:0,0 /opt/<FileName>.wav ``

• HDMI OUT playback

``shell amixer -c 0 cset "name=QUATERNARY_MI2S_RX Audio Mixer MultiMedia2" 1 aplay -Dplughw:0,1 /opt/<FileName>.wav ``

• UAC playback

``shell aplay -Dplughw:1,0 /opt/<FileName>.wav ``

Recording

:::warning Run the following command to ensure the /opt path has read/write permissions. :::

``shell sudo chmod 777 -R /opt ``

• 3.5mm headphone recording

``shell amixer -c 0 cset "name=MultiMedia3 Mixer PRIMARY_MI2S_TX" 1 arecord -Dplughw:0,2 -f S16_LE -r 48000 -c 1 -d 10 -t wav /opt/<FileName>.wav ``

• UAC recording

:::warning Adjust the command parameters based on the formats actually supported by the UAC device. :::

``shell arecord -Dplughw:1,0 -f S16_LE -r 48000 -c 1 -d 10 -t wav /opt/<FileName>.wav ``

PulseAudio

• On IQ9, run the following commands to install the PulseAudio utilities:

``shell sudo apt update sudo apt install pulseaudio pulseaudio-utils ` :::note Please run the Pulseaudio command under a non-root user. For example, use the su ubuntu` command to switch to the ubuntu user. :::

Set the audio output interface

:::warning 1. PulseAudio automatically switches audio output based on sink priority: UAC > 3.5mm headphone > HDMI OUT. 2. Users can manually switch using the set-default-sink command. Once switched manually, the automatic strategy will be overridden until the sink is manually set back to the one with the highest priority. :::

• On IQ9, use the following command to view sink names and their priorities:

``shell pactl list sinks | grep -A5 -B1 -E 'Sink #|priority' ``

Switch the audio output interface

``shell pactl set-default-sink <Sink-Name> ` Examples - Switch output to 3.5mm headphone: `shell pactl set-default-sink alsa_output.platform-sound.HiFi__hw_qcs6490IQ93_0__sink ` - Switch output to HDMI OUT: `shell pactl set-default-sink alsa_output.platform-sound.HiFi__hw_qcs6490IQ93_1__sink ` - Switch output to UAC device: :::warning Adjust the command according to the actual sink name of your UAC device. ::: `shell pactl set-default-sink alsa_output.usb-GeneralPlus_USB_Audio_Device-00.analog-stereo ``

Set the audio input interface

• On IQ9, run the following command to list available sources and their priorities:

``shell pactl list sources | grep -A5 -B1 -E 'Source #|priority' ``

Switch the audio input interface

pactl set-default-source <Source-Name>

Examples: - Switch input to 3.5mm headphone: ``shell pactl set-default-source alsa_input.platform-sound.HiFi__hw_qcs6490IQ93_2__source ` - Switch input to UAC device: :::warning Adjust the command according to the actual source name of your UAC device. ::: `shell pactl set-default-source alsa_input.usb-GeneralPlus_USB_Audio_Device-00.mono-fallback ``

Playback

:::warning 1. Run the following command to make sure the /opt directory has read/write permissions. 2. Before running the command, ensure the MP3 test file (<FileName>.wav) has been pushed to the /opt directory. :::

``shell sudo chmod 777 -R /opt ``

Recording

:::waring Run the following command to make sure the /opt directory has read/write permissions. ::: ``shell sudo chmod 777 -R /opt ` - On IQ9, run the following command to start recording: `shell parecord /opt/<FileName>.mp3 ``