General • Re: TFLite micro on RP2040

Code:

void CaptureSamples() {  // This is how many bytes of new data we have each time this is called  const int number_of_samples = DEFAULT_PDM_BUFFER_SIZE/2;  // Calculate what timestamp the last audio sample represents  const int32_t time_in_ms =      g_latest_audio_timestamp +      (number_of_samples / (kAudioSampleFrequency / 1000));  // Determine the index, in the history of all samples, of the last sample  const int32_t start_sample_offset =      g_latest_audio_timestamp * (kAudioSampleFrequency / 1000);  // Determine the index of this sample in our ring buffer  const int capture_index = start_sample_offset % kAudioCaptureBufferSize;  // Read the data to the correct place in our buffer  PDM.read(g_audio_capture_buffer + capture_index, DEFAULT_PDM_BUFFER_SIZE);  // This is how we let the outside world know that new audio data has arrived.  g_latest_audio_timestamp = time_in_ms;}TfLiteStatus InitAudioRecording(tflite::ErrorReporter* error_reporter) {  e = error_reporter;  // Hook up the callback that will be called with each sample  PDM.onReceive(CaptureSamples);  // Start listening for audio: MONO @ 16KHz with gain at 20  PDM.begin(1, kAudioSampleFrequency);  PDM.setGain(20);  // Block until we have our first audio sample  while (!g_latest_audio_timestamp) {  }  return kTfLiteOk;}

Code:

void CaptureSamples() {  // This is how many bytes of new data we have each time this is called  const int number_of_samples = DEFAULT_PDM_BUFFER_SIZE/2;  // Calculate what timestamp the last audio sample represents  const int32_t time_in_ms =      g_latest_audio_timestamp +      (number_of_samples / (kAudioSampleFrequency / 1000));  // Determine the index, in the history of all samples, of the last sample  const int32_t start_sample_offset =      g_latest_audio_timestamp * (kAudioSampleFrequency / 1000);  // Determine the index of this sample in our ring buffer  const int capture_index = start_sample_offset % kAudioCaptureBufferSize;  pdm_microphone_read(g_audio_capture_buffer + capture_index, DEFAULT_PDM_BUFFER_SIZE);  printf("Audio update at time %d from time %d with %d samples\n", time_in_ms, g_latest_audio_timestamp, number_of_samples);  // This is how we let the outside world know that new audio data has arrived.  g_latest_audio_timestamp = time_in_ms;}