Basic Audio Playback

#include <M5Unified.h> #include <SPI.h> #include <SD.h> #define SD_SPI_CS_PIN 4 #define SD_SPI_SCK_PIN 18 #define SD_SPI_MISO_PIN 19 #define SD_SPI_MOSI_PIN 23 bool playWAVFromSD(const char* filename, uint32_t repeat = 1, int channel = -1, bool stop_current = true); bool playWAVMemory(File& wavFile, size_t fileSize, uint32_t repeat, int channel, bool stop_current); bool playWAVSegmented(const char* filename, uint32_t repeat, int channel, bool stop_current); void printf_log(const char *format, ...); void println_log(const char *str); void setup() { M5.begin(); Serial.begin(115200); M5.Display.fillRect(0, 0, 320, 240, WHITE); M5.Display.setTextColor(BLACK); M5.Display.setFont(&fonts::FreeMonoBold9pt7b); M5.Display.setCursor(0, 0); // SD Card Initialization SPI.begin(SD_SPI_SCK_PIN, SD_SPI_MISO_PIN, SD_SPI_MOSI_PIN, SD_SPI_CS_PIN); if (!SD.begin(SD_SPI_CS_PIN, SPI, 25000000)) { println_log("Card failed, or not present"); while (1) delay(1000); } uint64_t cardSize = SD.cardSize() / (1024 * 1024); printf_log("SD Card Size: %lluMB\n", cardSize); println_log("Starting audio playback..."); playWAVFromSD("/sample-6s.wav", 1, -1, true); } void loop() { } bool playWAVFromSD(const char* filename, uint32_t repeat, int channel, bool stop_current) { if (!SD.exists(filename)) { println_log("File does not exist!"); return false; } File wavFile = SD.open(filename, FILE_READ); if (!wavFile) { println_log("Failed to open file!"); return false; } size_t fileSize = wavFile.size(); printf_log("File size: %d Byte (%.2f KB)\n", fileSize, fileSize/1024.0); size_t freeHeap = ESP.getFreeHeap(); printf_log("Free heap: %d bytes\n", freeHeap); if (fileSize < freeHeap / 2) { return playWAVMemory(wavFile, fileSize, repeat, channel, stop_current); } // File too large, use segmented playback wavFile.close(); return playWAVSegmented(filename, repeat, channel, stop_current); } bool playWAVMemory(File& wavFile, size_t fileSize, uint32_t repeat, int channel, bool stop_current) { uint8_t* wavData = (uint8_t*)malloc(fileSize); if (!wavData) { println_log("Memory allocation failed!"); wavFile.close(); return false; } println_log("Loading file to memory..."); size_t bytesRead = wavFile.read(wavData, fileSize); wavFile.close(); if (bytesRead != fileSize) { printf_log("Read error: %d/%d bytes\n", bytesRead, fileSize); free(wavData); return false; } println_log("Starting playback..."); bool result = M5.Speaker.playWav(wavData, fileSize, repeat, channel, stop_current); if (result) { while (M5.Speaker.isPlaying()) { delay(100); } println_log("Playback completed!"); } free(wavData); return result; } // Segment playback (large file) - optimize memory usage bool playWAVSegmented(const char* filename, uint32_t repeat, int channel, bool stop_current) { File wavFile = SD.open(filename, FILE_READ); if (!wavFile) return false; uint8_t header[44]; if (wavFile.read(header, 44) != 44) { wavFile.close(); return false; } if (strncmp((char*)header, "RIFF", 4) != 0 || strncmp((char*)header + 8, "WAVE", 4) != 0) { println_log("Invalid WAV format"); wavFile.close(); return false; } uint32_t totalFileSize = *(uint32_t*)(header + 4) + 8; uint32_t sampleRate = *(uint32_t*)(header + 24); uint16_t channels = *(uint16_t*)(header + 22); uint16_t bitsPerSample = *(uint16_t*)(header + 34); printf_log("WAV: %dHz, %dch, %dbit\n", sampleRate, channels, bitsPerSample); size_t dataSize = totalFileSize - 44; size_t bytesPerSample = (bitsPerSample / 8) * channels; size_t chunkSizeInSamples = 16384 / bytesPerSample; size_t chunkSize = chunkSizeInSamples * bytesPerSample; printf_log("Chunk size: %d bytes (%d samples)\n", chunkSize, chunkSizeInSamples); uint8_t* chunkBuffer = nullptr; size_t actualChunkSize = chunkSize; while (actualChunkSize >= 4096 && !chunkBuffer) { // Minimum 4KB chunkBuffer = (uint8_t*)malloc(actualChunkSize + 44); if (!chunkBuffer) { actualChunkSize /= 2; chunkSizeInSamples = actualChunkSize / bytesPerSample; actualChunkSize = chunkSizeInSamples * bytesPerSample; printf_log("Retrying with smaller chunk: %d bytes\n", actualChunkSize); } } if (!chunkBuffer) { println_log("Buffer allocation failed even with small chunks!"); wavFile.close(); return false; } printf_log("Using chunk size: %d bytes\n", actualChunkSize); println_log("Starting segmented playback..."); for (uint32_t rep = 0; rep < repeat; rep++) { size_t totalRead = 0; int segmentNum = 0; wavFile.seek(44); while (totalRead < dataSize) { size_t bytesToRead = min(actualChunkSize, dataSize - totalRead); memcpy(chunkBuffer, header, 44); uint32_t chunkFileSize = bytesToRead + 36; memcpy(chunkBuffer + 4, &chunkFileSize, 4); memcpy(chunkBuffer + 40, &bytesToRead, 4); size_t bytesRead = wavFile.read(chunkBuffer + 44, bytesToRead); if (bytesRead == 0) break; totalRead += bytesRead; segmentNum++; if (segmentNum % 5 == 1) { printf_log("Segment %d (%.1f%%)\n", segmentNum, (float)totalRead / dataSize * 100.0); } bool playResult = M5.Speaker.playWav(chunkBuffer, bytesRead + 44, 1, channel, stop_current); if (!playResult) { printf_log("Segment %d failed\n", segmentNum); break; } while (M5.Speaker.isPlaying()) { delay(5); } delay(10); } if (rep < repeat - 1) { delay(1000); } } free(chunkBuffer); wavFile.close(); println_log("Segmented playback completed!"); return true; } void printf_log(const char *format, ...) { char buf[256]; va_list args; va_start(args, format); vsnprintf(buf, 256, format, args); va_end(args); Serial.print(buf); M5.Display.printf(buf); } void println_log(const char *str) { Serial.println(str); M5.Display.println(str); }