IMX8 Android Audio

From Variscite Wiki
DART-MX8M - Android Oreo Android O8.1.0_r14 - Audio

1 Android Audio

To give you overview we recommend you go through the https://source.android.com/devices/audio documents.

1.1 Android Provides

  1. Audio HAL from NXP
  2. Variscite adds EVK hardware support such as codec, DMIC support to the HAL.
  3. Once you program the images, it comes with the required HAL support to verify the Audio input / Output Functionality.

1.2 Hardware Setup

1.2.1 DART-MX8M

- Line IN: J21 - Audio Jack 3.5 mm
- Headphone Out: J22 - Audio Jack 3.5mm
- DMIC: On board

1.2.2 Audio In

- Connect 3.5 mm jack to Audio In: Ref:https://www.amazon.ca/AmazonBasics-3-5mm-Stereo-Audio-Cable/dp/B00NO73MUQ
- One end to Audio Output of the source you wish to record, one end to Audio In Jack of the DART-MX8M see above

1.2.3 Audio Output

- Connect 3.5 mm headphone jack to headphone / speaker

2 Audio In test

- Run below commands on adb shell

# tinymix 'Headphone Volume' 35;tinymix  'Capture Input' ADC;tinymix 'DMIC Mux' DMIC2;

- Start Sound Record as per below screen shot
- If app asks for permissions click on allow for microphone and internal stroage dialoge
- Make sure you have audio line in source is playing some music
- Click on the record button and you should see below screen
Imx8 Audio In.png

3 Audio Out test

- To review recorded audio, you may click on play button
Imx8 Audio Review.png
- Click on music player app (Cactus Player)
Imx8 Audio Out Cactus Player.png
- Click on music / recorded audio you captured
Imx8 Audio Out Cactus Playing Audio.png


4 DMIC test

By default if you don't connect the audio input is selcted via on board DMIC

Use above recording application to record via the application.