Snapcast client for the ESP32. Works on the standard ESP32, does not need versions with extra memory / PSRAM.
Supported codecs:
- PCM
- Flac
- OPUS (builds, but crashes instantly)
Note that you can download the pre-built firmware from CI.
- Install esp-rust
cargo install ldproxy espflash
If you want to build the opus backend, you also need:
export CC=xtensa-esp32-elf-gcc
export CXX=xtensa-esp32-elf-g++To build the project, run make only_build
Note that mDNS (automatic discovery) is not yet implemented, so you must set the IP for the snapcast server on src/main.rs.
Requires espflash.
You need to provide the SSID and PASS environment variables, for your wifi settings:
export SSID=<your wifi name>
export PASS=<your wifi password>These will be embedded into the firmware file with the replacer.py script.
To flash the project into an ESP32 you can run make flashm
I use an UDA1334A module with an ESP32-WROOM-32 (a 320KiB RAM model).
Wire the pins according to this table:
| ESP | I2s board |
|---|---|
| D21 | WSEL |
| D19 | DIN |
| D18 | BCLK |
| GND | GND |
| 3v3 | VIN |
The specific pinout is not required, you only need pins that can output, are not bootstrap pins, and do not output garbage on boot.
If you want to change the wiring, you also need to modify the i2s, dout, ws and bclk variables in main().
A pull-down resistor on WSEL makes for quiet reboots; without this, there's a lot of garbled noise until playback starts.
chunk_ms = 30
buffer = 690
codec = flac
On stereo at 48KHz:
- PCM requires ~1.6Mbit/s
- Flac requires ~1Mbit/s
- Opus requires ~250Kbit/s
All of which seem perfectly fine on the ESP32.
Basic heap analysis:
- On startup, heap low water mark 273KiB
- After setup, heap low water mark 188KiB
Free heap space:
| Buffer Duration | PCM | FLAC | OPUS |
|---|---|---|---|
| 150ms | 167KiB | 173KiB | 146KiB |
| 500ms | 93KiB | 117KiB | ? |
| 700ms | 31KiB* | 53KiB | ? |
* Got a random OOM a few times, investigating
- OPUS does not work
[ ] Host a page with esp tools to provide easy flashing/firmware building