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/* Copyright 2018 The TensorFlow Authors. All Rights Reserved. | ||
Licensed under the Apache License, Version 2.0 (the "License"); | ||
you may not use this file except in compliance with the License. | ||
You may obtain a copy of the License at | ||
http://www.apache.org/licenses/LICENSE-2.0 | ||
Unless required by applicable law or agreed to in writing, software | ||
distributed under the License is distributed on an "AS IS" BASIS, | ||
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
See the License for the specific language governing permissions and | ||
limitations under the License. | ||
==============================================================================*/ | ||
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#include <stdio.h> | ||
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#include "audio_provider.h" | ||
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extern "C" { | ||
#include "pico/pdm_microphone.h" | ||
} | ||
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#include "micro_features/micro_model_settings.h" | ||
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#define DEFAULT_PDM_BUFFER_SIZE 256 | ||
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namespace { | ||
bool g_is_audio_initialized = false; | ||
// An internal buffer able to fit 16x our sample size | ||
constexpr int kAudioCaptureBufferSize = DEFAULT_PDM_BUFFER_SIZE * 16; | ||
int16_t g_audio_capture_buffer[kAudioCaptureBufferSize]; | ||
// A buffer that holds our output | ||
int16_t g_audio_output_buffer[kMaxAudioSampleSize]; | ||
// Mark as volatile so we can check in a while loop to see if | ||
// any samples have arrived yet. | ||
volatile int32_t g_latest_audio_timestamp = 0; | ||
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struct pdm_microphone_config pdm_config = { | ||
.gpio_data = 2, | ||
.gpio_clk = 3, | ||
.pio = pio0, | ||
.pio_sm = 0, | ||
.sample_rate = 16000, | ||
.sample_buffer_size = 256, | ||
}; | ||
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// struct analog_microphone_config config = { | ||
// .gpio = 26, | ||
// .bias_voltage = 1.25, | ||
// .sample_rate = 16000, | ||
// .sample_buffer_size = 256, | ||
// }; | ||
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} // namespace | ||
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#include "pico/stdlib.h" | ||
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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; | ||
// 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_microphone_read(g_audio_capture_buffer + capture_index, DEFAULT_PDM_BUFFER_SIZE); | ||
// analog_microphone_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; | ||
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// uint32_t now = to_ms_since_boot(get_absolute_time()); | ||
// printf("now = %u\n", now); | ||
} | ||
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TfLiteStatus InitAudioRecording(tflite::ErrorReporter* error_reporter) { | ||
pdm_microphone_init(&pdm_config); | ||
// pdm_microphone_set_filter_gain(20); | ||
// pdm_microphone_set_filter_max_volume(128); | ||
pdm_microphone_set_samples_ready_handler(CaptureSamples); | ||
pdm_microphone_start(); | ||
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// analog_microphone_init(&config); | ||
// analog_microphone_set_samples_ready_handler(CaptureSamples); | ||
// analog_microphone_start(); | ||
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// Block until we have our first audio sample | ||
while (!g_latest_audio_timestamp) { | ||
} | ||
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return kTfLiteOk; | ||
} | ||
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TfLiteStatus GetAudioSamples(tflite::ErrorReporter* error_reporter, | ||
int start_ms, int duration_ms, | ||
int* audio_samples_size, int16_t** audio_samples) { | ||
// Set everything up to start receiving audio | ||
if (!g_is_audio_initialized) { | ||
TfLiteStatus init_status = InitAudioRecording(error_reporter); | ||
if (init_status != kTfLiteOk) { | ||
return init_status; | ||
} | ||
g_is_audio_initialized = true; | ||
} | ||
// This next part should only be called when the main thread notices that the | ||
// latest audio sample data timestamp has changed, so that there's new data | ||
// in the capture ring buffer. The ring buffer will eventually wrap around and | ||
// overwrite the data, but the assumption is that the main thread is checking | ||
// often enough and the buffer is large enough that this call will be made | ||
// before that happens. | ||
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// Determine the index, in the history of all samples, of the first | ||
// sample we want | ||
const int start_offset = start_ms * (kAudioSampleFrequency / 1000); | ||
// Determine how many samples we want in total | ||
const int duration_sample_count = | ||
duration_ms * (kAudioSampleFrequency / 1000); | ||
for (int i = 0; i < duration_sample_count; ++i) { | ||
// For each sample, transform its index in the history of all samples into | ||
// its index in g_audio_capture_buffer | ||
const int capture_index = (start_offset + i) % kAudioCaptureBufferSize; | ||
// Write the sample to the output buffer | ||
g_audio_output_buffer[i] = g_audio_capture_buffer[capture_index]; | ||
} | ||
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// Set pointers to provide access to the audio | ||
*audio_samples_size = kMaxAudioSampleSize; | ||
*audio_samples = g_audio_output_buffer; | ||
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return kTfLiteOk; | ||
} | ||
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int32_t LatestAudioTimestamp() { return g_latest_audio_timestamp; } |