Audio Capture/Playback Demo User Guide¶

1. Feature Overview¶

1.1 Program Overview¶

sgs_demo_audio_alsa_ai_ao_demo is a sample program that demonstrates ALSA audio capture and playback functionality. It supports recording, playback, DMIC testing, and ECHO echo testing, and provides recording gain and playback volume settings.

1.2 Key Features¶

Audio Capture: Supports input sources such as AMIC, DMIC, and ECHO
Audio Playback: Supports DAC/speaker output
Echo Capture (pass_echo): Captures speaker echo while playing audio
AI-to-AO Passthrough: Hardware direct connection from AI to AO
Hardware Mixing (pass_mix): Play music and AI-to-AO passthrough simultaneously
Recording Gain Adjustment (0~100%)
Playback Volume Adjustment (0~100%)

1.3 Use Case and Interface Mapping¶

usecase	interface
capture	adc_a / adc_b / dmic / echo_rx / i2s_a_rx / i2s_b_rx / i2s_c_rx
playback	dac / echo_tx / i2s_a_tx / i2s_b_tx / i2s_c_tx
passthrough	adc_a-dac / adc_b-dac
pass_mix	adc_a/adc_b-dac hardware mixing (playback + AI-to-AO passthrough)
pass_echo	echo_tx-echo_rx echo capture

2. Build Environment¶

2.1 Build Environment Setup¶

Set up the arm64 build environment in the project root directory:

export PATH=/tools/toolchain/aarch64-unknown-linux-gcc-12.4.0-glibc-2.37-gnu/bin:$PATH
export CROSS_COMPILE=aarch64-unknown-linux-gnu-12.4.0-
export ARCH=arm64
cd project
make linux-comake_mhera.emmc.glibc-12.4.0-arm64-ext4.d3.4096.fccsp16_lpddr4x_defconfig

If using 2GB DDR, the defconfig can use linux-comake_mhera.emmc.glibc-12.4.0-arm64-ext4.d3.2048.fccsp16_lpddr4x_defconfig

2.2 Build Commands¶

# Build the entire project
cd project
make clean;make image -j16

# Build the audio demo
cd sdk/verify/sample_code
make demo/audio/alsa_ai_ao_demo

2.3 Build Output¶

The generated executable is located at: sdk/verify/sample_code/out/arm64/app/sgs_demo_audio_alsa_ai_ao_demo

3. Runtime Environment¶

3.1 Hardware Environment¶

Comake PI D3 development board
Power supply and Ethernet cable
AMIC and DMIC
Speaker

Hardware connections as shown below:

Front	Back

Note: When connecting the DMIC to the DMIC port on the board, the metal surface faces downward and the blue side faces upward, as shown in the backside wiring diagram above.

3.2 DTS Configuration¶

No special requirements.

3.3 Command-line Parameter Reference¶

3.3.1 General Parameters¶

Option	Description	Option	Description
-A	Audio card number for capture	-F	File path for captured audio (WAV)
-a	Audio card number for playback	-f	Audio file path for playback (WAV)
-D	Device number for capture	-T	Capture duration (seconds)
-d	Playback device number	-t	Playback duration (seconds)
-C	Number of capture channels	-V	Capture gain (0~100)
-c	Number of playback channels	-v	Playback volume (0~100)
-R	Capture sample rate	-r	Playback sample rate
-i	Capture input source

4. Running Instructions¶

4.1 Prerequisites¶

Hardware: Comake PI D3 development board, power supply, Ethernet cable, AMIC, DMIC, speaker
Software: Flashing tool, image already flashed
Dependencies: ALSA environment variables correctly configured

4.2 Installation and Deployment¶

Copy the compiled executable sgs_demo_audio_alsa_ai_ao_demo to /customer/sample_code/ on the board and set permissions to 777:

chmod 777 /customer/sample_code/sgs_demo_audio_alsa_ai_ao_demo

Log in to the board and set the ALSA environment variables:

export ALSA_CONFIG_DIR=/customer/alsalib/res/alsa
export ALSA_PLUGIN_DIR=/customer/alsalib/
export LD_LIBRARY_PATH=/customer/alsalib/:$LD_LIBRARY_PATH

Navigate to the program directory:

cd /customer/sample_code/

4.3 Test Cases¶

Command-line usage format: ./sgs_demo_audio_alsa_ai_ao_demo [usecase] -i [interface] [options]

D3 board supported use cases: capture, playback, pass_echo

D3 board supported interfaces: capture supports dmic and echo_rx only; playback supports dac and echo_tx only

Test Objective	Steps	Command	Expected Result
AMIC Recording Test	Record 10 seconds of audio using AMIC with gain set to 60%	`./sgs_demo_audio_alsa_ai_ao_demo capture -i adc_a -F test.wav -A 0 -D 0 -R 8000 -C 1 -T 10 -V 60`	1. App does not crash 2. Recording completes successfully 3. test.wav file is generated 4. Recording audio is clear and audible
DMIC Recording Test	Record 10 seconds of audio using DMIC with gain set to 60%	`./sgs_demo_audio_alsa_ai_ao_demo capture -i dmic -F test.wav -A 0 -D 0 -R 8000 -C 1 -T 10 -V 60`	1. App runs without issues 2. Recording completes successfully 3. test.wav file is generated 4. Recording audio is clear and audible
DAC Playback Test	Play 10 seconds of audio through DAC/speaker with volume at 40%	`./sgs_demo_audio_alsa_ai_ao_demo playback -i dac -f ./test.wav -a 0 -d 0 -c 2 -t 10 -v 40`	1. App runs without issues 2. Playback starts successfully 3. Sound is clear and normal 4. Playback completes without interruption
ECHO Capture Test	Play audio and capture speaker echo simultaneously, recording gain 50%, playback volume 40%, duration 10s	`./sgs_demo_audio_alsa_ai_ao_demo pass_echo -i echo_tx-echo_rx -f ./resource/input/48K_16bit_STERO_30s.wav -F echorx.wav -a 0 -d 0 -r 48000 -t 10 -v 40 -A 0 -D 0 -R 48000 -T 10 -C 2 -V 50`	1. App runs without issues 2. Playback and echo capture run simultaneously 3. echorx.wav file is generated 4. Echo audio matches the playback content

5. Results¶

5.1 Functional Results¶

5.1.1 AMIC Recording¶

Program starts and records audio normally
Audio data is captured via AMIC and saved as a WAV file
Recording duration and gain are adjustable via parameters

5.1.2 DMIC Recording¶

Program starts and records audio normally
Audio data is captured via DMIC and saved as a WAV file
Recording duration and gain are adjustable via parameters

5.1.3 DAC Playback¶

Reads WAV audio file and outputs to speaker via DAC
Playback volume and duration are adjustable via parameters
Program exits automatically upon completion

5.1.4 ECHO Capture¶

Captures speaker echo while playing audio
Generates an echo recording file (echorx.wav)
Can be used for echo cancellation algorithm debugging

5.2 FAQ¶

If the app behaves abnormally, check hardware connections and driver status
ALSA environment variables (ALSA_CONFIG_DIR) must be correctly set before running
The 48K_16bit_STERO_30s.wav test file can be obtained from demo/resource/input/
If the board lacks required libraries, verify that libs have been copied to /config/lib