Selecting a Decoder

Define the Decoder on the Server

First you need to define the codec or audio format that snapcast is using in /etc/snapserver.conf. Supported values are flac, ogg, opus and pcm. My recommendation would be to use opus!

codec = pcm

is selecting pcm the data will be provided as pcm.

The default sample rate of 48000 is a bit high for pcm, so I suggest to adjust it as well e.g. with

sampleformat = 44100:16:2

Define the Decoder for the Arduino Client

You need to install the necessary decoder library first! (See the urls below). Then you can use them in your Arduino sketch as follows:

PCM (WAV)

// codecs
WAVDecoder pcm;
// setup client
WiFiClient wifi;
I2SStream out;
SnapClient client(wifi, out, opus);

The WAVDecoder is part of the AudioTools.

Opus

#include "AudioCodecs/CodecOpus.h"   // https://github.com/pschatzmann/arduino-libopus.git

// codecs
OpusAudioDecoder opus;
// setup client
WiFiClient wifi;
I2SStream out;
SnapClient client(wifi, out, opus);

You need to install libopus

FLAC

#include "AudioCodecs/CodecFLAC.h"   // https://github.com/pschatzmann/arduino-libflac.git

// codecs
FLACDecoder flac;
// setup client
WiFiClient wifi;
I2SStream out;
SnapClient client(wifi, out, flac);

You need to install libflac

OGG (Vorbis)

#include "AudioCodecs/CodecVorbis.h" //https://github.com/pschatzmann/arduino-libvorbis-tremor

// codecs
VorbisDecoder ogg;
// setup client
WiFiClient wifi;
I2SStream out;
SnapClient client(wifi, out, ogg);

You need to install libvorbis-tremor. Currently it is only working with the low memory branch.