info.linkwitz.ha_pcb/Software/UPSoftware/examples/OpusLoopbackEsp32C3/README.md

This sketch is a minimal ESP32-C3 Opus codec smoke test.

What it does:

• Generates a sine wave locally
• Encodes it with Opus
• Decodes it immediately again
• Sends the decoded PCM to I2S

Why this example:

• It tests the raw Opus codec path without Ogg or CAN framing
• It is closer to the later Pi -> CAN -> ESP32 decoder path than MP3
• It keeps CPU load down by using 16 kHz mono and low encoder complexity

Expected hardware:

• ESP32-C3
• I2S DAC / amp on:
  • BCLK = GPIO 6
  • LRCK = GPIO 7
  • DIN = GPIO 5

Required Arduino libraries:

• arduino-audio-tools
• arduino-libopus

If this sketch runs and outputs a stable sine tone, the basic Opus encode/decode chain is working on the ESP32-C3.