Opus Example

Source: example/multimedia/audio/opus

Supported Platforms

eh-lb525

Overview

This example demonstrates how to use the Opus audio codec library to record, encode, decode, and play audio. The example includes:

Recording PCM audio from a microphone at 16 kHz sample rate
Encoding: compressing PCM frames with the Opus encoder (10 ms frames, ~16 kbps)
Decoding: decompressing Opus-encoded audio with the Opus decoder
Playback: outputting decoded PCM to the speaker

Usage

Hardware Requirements

Before running the example, prepare:

A supported development board (see quick_start)
A speaker

menuconfig Settings

This example reads and writes files, so enable the FAT filesystem:

Note: the root partition is mounted in mnt_init.
Enable AUDIO CODEC and AUDIO PROC:
Enable AUDIO (AUDIO):
Enable the Audio Manager (AUDIO_USING_MANAGER):

Notes

If opus_test() calls opus_encoder_ctl(encoder, OPUS_SET_FORCE_MODE(MODE_SILK_ONLY));, set OPUS_STACK_SIZE to 20k. If it does not call that function, set OPUS_STACK_SIZE to 200k.

Build and Flash

From the example project directory, build with scons:

scons --board=eh-lb525 -j32

Then go to the example project/build_xx directory and run uart_download.bat. Choose the serial port when prompted to flash:

./uart_download.bat

Uart Download
please input the serial port num:5

For detailed build and flash steps, see quick_start.

Expected Behavior

Automatic: On startup the program records 10 seconds from the microphone, encodes and decodes the audio, then plays it back.

Manual commands:

opus — record 10 seconds to /mic16k.pcm, then encode/decode and play
opus /mic16k.pcm — read PCM from the specified file, then encode/decode and play
opus xxxxx — if the file does not exist, record and loopback in real time for 10 seconds (record and play simultaneously)

Troubleshooting

(No specific diagnostics provided.)

References

For RT-Thread device examples, refer to the RT-Thread documentation (for example, see the RTC documentation on the RT-Thread website).

Revision History

Version	Date	Notes
0.0.1	12/2025	Initial release