ESP32 Audio by Phil Schatzmann leads to Watchdog Reboot and other issues

Question

like the title suggests, I am using an esp32 and want to output a mp3 file from an SD-card via the i2s-Amp MAX98357a.

To begin with, I was trying to get an example from the library running, but it just doesn't work.

This is the example sketch:

/**
 * @file player-sdfat-i2s.ino
 * @brief see https://github.com/pschatzmann/arduino-audio-tools/blob/main/examples/examples-player/player-sdfat-i2s/README.md
 * 
 * @author Phil Schatzmann
 * @copyright GPLv3
 */


#include "AudioTools.h"
#include "AudioTools/AudioLibs/AudioSourceSDFAT.h"
#include "AudioTools/AudioCodecs/CodecMP3Helix.h"


const char *startFilePath="/";
const char* ext="mp3";
AudioSourceSDFAT source(startFilePath, ext);
I2SStream i2s;
MP3DecoderHelix decoder;
AudioPlayer player(source, i2s, decoder);


void printMetaData(MetaDataType type, const char* str, int len){
  Serial.print("==> ");
  Serial.print(toStr(type));
  Serial.print(": ");
  Serial.println(str);
}

void setup() {
  Serial.begin(115200);
  AudioToolsLogger.begin(Serial, AudioToolsLogLevel::Debug);

  // setup output
  auto cfg = i2s.defaultConfig(TX_MODE);
  /*cfg.pin_bck = 4;
  cfg.pin_ws = 2;
  cfg.pin_data = 15;*/
  i2s.begin(cfg);

  // setup player
  //source.setFileFilter("*Bob Dylan*");
  player.setMetadataCallback(printMetaData);
  player.begin();
}

void loop() {
  player.copy();
}

I have tried "player-sdfat-i2s", "player-sd-i2s" and "streams-sd_mp3-i2s". I do not get any audio output, so I switched the AudioToolsLogger to "Debug" rather than "Info", and it seems that the watchdog is resetting the ESP32. The title is read correctly from the sd-card, so the SPI-connections are correct, and I have triple checked the i2s connections and tried different power sources. This is an excerpt from the Debugging text via serial:

==> Title: test_track_1
[I] StreamCopy.h : 169 - StreamCopy::copy  1024 -> 1024 -> 1024 bytes - in 1 hops
[D] AudioPlayer.h : 363 - virtual size_t audio_tools::AudioPlayer::copy(size_t)
[D] StreamCopy.h : 106 - copy 1024 bytes 
[D] StreamCopy.h : 249 - available: 1898066
[D] StreamCopy.h : 394 - write: 1024
[D] AudioEncoded.h : 188 - EncodedAudioOutput::write: 1024
[D] CodecMP3Helix.h : 108 - virtual size_t audio_tools::MP3DecoderHelix::write(const uint8_t*, size_t): 1024
ets Jul 29 2019 12:21:46

rst:0x8 (TG1WDT_SYS_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff0030,len:4688

With other examples, I have had errors regarding "Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled."

I have tried for days to get it working and would be greatful for suggestions!