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audio_duplex: support stereo input

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This commit is contained in:
Matthias Ringwald 2020-06-01 22:53:36 +02:00
parent 5d23aae8c9
commit a7996a1da5
1 changed files with 30 additions and 13 deletions
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43
example/audio_duplex.c
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@ -48,6 +48,11 @@
// uncomment to test start/stop of loopback / audio driver
// #define TEST_START_STOP_INTERVAL 5000
// change to 1 for mono input and 2 for stereo input
#define NUM_INPUT_CHANNELS 1
#define BYTES_PER_SAMPLE (NUM_INPUT_CHANNELS * 2)
#ifdef TEST_START_STOP_INTERVAL
static void stop_loopback(btstack_timer_source_t * ts);
#endif
@ -62,9 +67,9 @@ const uint32_t samplerate = 16000;
static uint16_t audio_buffer_storage[BUFFER_SAMPLES];
static btstack_ring_buffer_t audio_buffer;
// mono buffer
#define MONO_BUFFER_LEN 128
static int16_t mono_buffer[MONO_BUFFER_LEN];
// transfer buffer
#define TRANSFER_BUFFER_LEN 128
static int16_t transfer_buffer[TRANSFER_BUFFER_LEN];
// playback starts after audio_buffer is half full
static int playback_started;
@ -75,34 +80,46 @@ static int count_playback;
static void audio_recording(const int16_t * pcm_buffer, uint16_t num_samples_to_write){
count_recording += num_samples_to_write;
int err = btstack_ring_buffer_write(&audio_buffer, (uint8_t *) pcm_buffer, num_samples_to_write * 2);
int err = btstack_ring_buffer_write(&audio_buffer, (uint8_t *) pcm_buffer, num_samples_to_write * BYTES_PER_SAMPLE);
if (err){
printf("Failed to store %u samples\n", num_samples_to_write);
}
}
static void audio_playback(int16_t * pcm_buffer, uint16_t num_samples_to_write){
int num_samples_in_buffer = btstack_ring_buffer_bytes_available(&audio_buffer) / 2;
int num_samples_in_buffer = btstack_ring_buffer_bytes_available(&audio_buffer) / BYTES_PER_SAMPLE;
if (playback_started == 0){
if ( num_samples_in_buffer < (BUFFER_SAMPLES / 2)) return;
playback_started = 1;
}
count_playback += num_samples_to_write;
while (num_samples_to_write){
num_samples_in_buffer = btstack_ring_buffer_bytes_available(&audio_buffer) / 2;
num_samples_in_buffer = btstack_ring_buffer_bytes_available(&audio_buffer) / BYTES_PER_SAMPLE;
int num_samples_ready = btstack_min(num_samples_in_buffer, num_samples_to_write);
// limit by mono_buffer
int num_samples_from_buffer = btstack_min(num_samples_ready, MONO_BUFFER_LEN);
// limit by transfer_buffer
int num_samples_from_buffer = btstack_min(num_samples_ready, TRANSFER_BUFFER_LEN);
if (!num_samples_from_buffer) break;
uint32_t bytes_read;
btstack_ring_buffer_read(&audio_buffer, (uint8_t *) mono_buffer, num_samples_from_buffer * 2, &bytes_read);
btstack_ring_buffer_read(&audio_buffer, (uint8_t *) transfer_buffer, num_samples_from_buffer * BYTES_PER_SAMPLE, &bytes_read);
#if (NUM_INPUT_CHANNELS == 1)
// duplicate samples for stereo output
int i;
for (i=0; i < num_samples_from_buffer;i++){
*pcm_buffer++ = mono_buffer[i];
*pcm_buffer++ = mono_buffer[i];
for (i=0; i < num_samples_from_buffer;i++) {
*pcm_buffer++ = transfer_buffer[i];
*pcm_buffer++ = transfer_buffer[i];
num_samples_to_write--;
}
#endif
#if (NUM_INPUT_CHANNELS == 2)
// copy samples
int i;
int j = 0;
for (i=0; i < num_samples_from_buffer;i++) {
*pcm_buffer++ = transfer_buffer[j++];
*pcm_buffer++ = transfer_buffer[j++];
num_samples_to_write--;
}
#endif
}
// warn about underrun
@ -127,7 +144,7 @@ static void start_loopback(btstack_timer_source_t * ts){
// setup audio: mono input -> stereo output
audio_sink->init(2, samplerate, &audio_playback);
audio_source->init(1, samplerate, &audio_recording);
audio_source->init(NUM_INPUT_CHANNELS, samplerate, &audio_recording);
// start duplex
audio_sink->start_stream();