The example records 10 seconds AMR-NB or AMR-WB audio file to microSD Card. The AMR audio compression format is optimized for speech coding and produces much smaller output files comparing to other popular codecs.

This demo makes use of callback function instead of Message Queue for events. For instance, pipeline_amr_sdcard example uses Message Queue for events.

This example is will run on boards marked with green checkbox. Please remember to select the board in menuconfig as discussed is section Usage below.

Board Name	Getting Started	Chip	Compatible
ESP32-LyraT
ESP32-LyraTD-MSC
ESP32-LyraT-Mini
ESP32-Korvo-DU1906
ESP32-S2-Kaluga-1 Kit

Prepare the audio board:

• Insert a microSD card into board's slot.

Configure the example:

• Select compatible audio board in menuconfig > Audio HAL.
• You may change between AMR-NB and AMR-WB encoder in menuconfig > Example configuration > Audio encoder file type.

Load and run the example:

• Speak to the board once prompted on the serial monitor.
• After finish, you can open /sdcard/rec.amr or /sdcard/rec.Wamr to hear the recorded file.