1 #include "alsa_input.h"
2 #include "audio_mixer.h"
5 #include <sys/inotify.h>
8 #include <unordered_map>
11 using namespace std::placeholders;
15 bool set_base_params(const char *device_name, snd_pcm_t *pcm_handle, snd_pcm_hw_params_t *hw_params, unsigned *sample_rate)
18 err = snd_pcm_hw_params_any(pcm_handle, hw_params);
20 fprintf(stderr, "[%s] snd_pcm_hw_params_any(): %s\n", device_name, snd_strerror(err));
23 err = snd_pcm_hw_params_set_access(pcm_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
25 fprintf(stderr, "[%s] snd_pcm_hw_params_set_access(): %s\n", device_name, snd_strerror(err));
28 snd_pcm_format_mask_t *format_mask;
29 snd_pcm_format_mask_alloca(&format_mask);
30 snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S16_LE);
31 snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S24_LE);
32 snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S32_LE);
33 err = snd_pcm_hw_params_set_format_mask(pcm_handle, hw_params, format_mask);
35 fprintf(stderr, "[%s] snd_pcm_hw_params_set_format_mask(): %s\n", device_name, snd_strerror(err));
38 err = snd_pcm_hw_params_set_rate_near(pcm_handle, hw_params, sample_rate, 0);
40 fprintf(stderr, "[%s] snd_pcm_hw_params_set_rate_near(): %s\n", device_name, snd_strerror(err));
48 #define RETURN_ON_ERROR(msg, expr) do { \
51 fprintf(stderr, "[%s] " msg ": %s\n", device.c_str(), snd_strerror(err)); \
52 if (err == -ENODEV) return CaptureEndReason::DEVICE_GONE; \
53 return CaptureEndReason::OTHER_ERROR; \
57 #define RETURN_FALSE_ON_ERROR(msg, expr) do { \
60 fprintf(stderr, "[%s] " msg ": %s\n", device.c_str(), snd_strerror(err)); \
65 #define WARN_ON_ERROR(msg, expr) do { \
68 fprintf(stderr, "[%s] " msg ": %s\n", device.c_str(), snd_strerror(err)); \
72 ALSAInput::ALSAInput(const char *device, unsigned sample_rate, unsigned num_channels, audio_callback_t audio_callback, ALSAPool *parent_pool, unsigned internal_dev_index)
74 sample_rate(sample_rate),
75 num_channels(num_channels),
76 audio_callback(audio_callback),
77 parent_pool(parent_pool),
78 internal_dev_index(internal_dev_index)
82 bool ALSAInput::open_device()
84 RETURN_FALSE_ON_ERROR("snd_pcm_open()", snd_pcm_open(&pcm_handle, device.c_str(), SND_PCM_STREAM_CAPTURE, 0));
87 snd_pcm_hw_params_t *hw_params;
88 snd_pcm_hw_params_alloca(&hw_params);
89 if (!set_base_params(device.c_str(), pcm_handle, hw_params, &sample_rate)) {
93 RETURN_FALSE_ON_ERROR("snd_pcm_hw_params_set_channels()", snd_pcm_hw_params_set_channels(pcm_handle, hw_params, num_channels));
95 // Fragment size of 64 samples (about 1 ms at 48 kHz; a frame at 60
96 // fps/48 kHz is 800 samples.) We ask for 64 such periods in our buffer
97 // (~85 ms buffer); more than that, and our jitter is probably so high
98 // that the resampling queue can't keep up anyway.
99 // The entire thing with periods and such is a bit mysterious to me;
100 // seemingly I can get 96 frames at a time with no problems even if
101 // the period size is 64 frames. And if I set num_periods to e.g. 1,
102 // I can't have a big buffer.
105 RETURN_FALSE_ON_ERROR("snd_pcm_hw_params_set_periods_near()", snd_pcm_hw_params_set_periods_near(pcm_handle, hw_params, &num_periods, &dir));
108 RETURN_FALSE_ON_ERROR("snd_pcm_hw_params_set_period_size_near()", snd_pcm_hw_params_set_period_size_near(pcm_handle, hw_params, &period_size, &dir));
109 buffer_frames = 64 * 64;
110 RETURN_FALSE_ON_ERROR("snd_pcm_hw_params_set_buffer_size_near()", snd_pcm_hw_params_set_buffer_size_near(pcm_handle, hw_params, &buffer_frames));
111 RETURN_FALSE_ON_ERROR("snd_pcm_hw_params()", snd_pcm_hw_params(pcm_handle, hw_params));
112 //snd_pcm_hw_params_free(hw_params);
114 // Figure out which format the card actually chose.
115 RETURN_FALSE_ON_ERROR("snd_pcm_hw_params_current()", snd_pcm_hw_params_current(pcm_handle, hw_params));
116 snd_pcm_format_t chosen_format;
117 RETURN_FALSE_ON_ERROR("snd_pcm_hw_params_get_format()", snd_pcm_hw_params_get_format(hw_params, &chosen_format));
119 audio_format.num_channels = num_channels;
120 audio_format.bits_per_sample = 0;
121 switch (chosen_format) {
122 case SND_PCM_FORMAT_S16_LE:
123 audio_format.bits_per_sample = 16;
125 case SND_PCM_FORMAT_S24_LE:
126 audio_format.bits_per_sample = 24;
128 case SND_PCM_FORMAT_S32_LE:
129 audio_format.bits_per_sample = 32;
134 //printf("num_periods=%u period_size=%u buffer_frames=%u sample_rate=%u bits_per_sample=%d\n",
135 // num_periods, unsigned(period_size), unsigned(buffer_frames), sample_rate, audio_format.bits_per_sample);
137 buffer.reset(new uint8_t[buffer_frames * num_channels * audio_format.bits_per_sample / 8]);
139 snd_pcm_sw_params_t *sw_params;
140 snd_pcm_sw_params_alloca(&sw_params);
141 RETURN_FALSE_ON_ERROR("snd_pcm_sw_params_current()", snd_pcm_sw_params_current(pcm_handle, sw_params));
142 RETURN_FALSE_ON_ERROR("snd_pcm_sw_params_set_start_threshold", snd_pcm_sw_params_set_start_threshold(pcm_handle, sw_params, num_periods * period_size / 2));
143 RETURN_FALSE_ON_ERROR("snd_pcm_sw_params()", snd_pcm_sw_params(pcm_handle, sw_params));
145 RETURN_FALSE_ON_ERROR("snd_pcm_nonblock()", snd_pcm_nonblock(pcm_handle, 1));
146 RETURN_FALSE_ON_ERROR("snd_pcm_prepare()", snd_pcm_prepare(pcm_handle));
150 ALSAInput::~ALSAInput()
153 WARN_ON_ERROR("snd_pcm_close()", snd_pcm_close(pcm_handle));
157 void ALSAInput::start_capture_thread()
160 capture_thread = thread(&ALSAInput::capture_thread_func, this);
163 void ALSAInput::stop_capture_thread()
166 capture_thread.join();
169 void ALSAInput::capture_thread_func()
171 parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::STARTING);
173 // If the device hasn't been opened already, we need to do so
174 // before we can capture.
175 while (!should_quit && pcm_handle == nullptr) {
176 if (!open_device()) {
177 fprintf(stderr, "[%s] Waiting one second and trying again...\n",
184 // Don't call free_card(); that would be a deadlock.
185 WARN_ON_ERROR("snd_pcm_close()", snd_pcm_close(pcm_handle));
186 pcm_handle = nullptr;
190 // Do the actual capture. (Termination condition within loop.)
192 switch (do_capture()) {
193 case CaptureEndReason::REQUESTED_QUIT:
194 // Don't call free_card(); that would be a deadlock.
195 WARN_ON_ERROR("snd_pcm_close()", snd_pcm_close(pcm_handle));
196 pcm_handle = nullptr;
198 case CaptureEndReason::DEVICE_GONE:
199 parent_pool->free_card(internal_dev_index);
200 WARN_ON_ERROR("snd_pcm_close()", snd_pcm_close(pcm_handle));
201 pcm_handle = nullptr;
203 case CaptureEndReason::OTHER_ERROR:
204 parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::STARTING);
205 fprintf(stderr, "[%s] Sleeping one second and restarting capture...\n",
213 ALSAInput::CaptureEndReason ALSAInput::do_capture()
215 parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::STARTING);
216 RETURN_ON_ERROR("snd_pcm_start()", snd_pcm_start(pcm_handle));
217 parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::RUNNING);
219 uint64_t num_frames_output = 0;
220 while (!should_quit) {
221 int ret = snd_pcm_wait(pcm_handle, /*timeout=*/100);
222 if (ret == 0) continue; // Timeout.
224 fprintf(stderr, "[%s] ALSA overrun\n", device.c_str());
225 snd_pcm_prepare(pcm_handle);
226 snd_pcm_start(pcm_handle);
229 RETURN_ON_ERROR("snd_pcm_wait()", ret);
231 snd_pcm_sframes_t frames = snd_pcm_readi(pcm_handle, buffer.get(), buffer_frames);
232 if (frames == -EPIPE) {
233 fprintf(stderr, "[%s] ALSA overrun\n", device.c_str());
234 snd_pcm_prepare(pcm_handle);
235 snd_pcm_start(pcm_handle);
239 fprintf(stderr, "snd_pcm_readi() returned 0\n");
242 RETURN_ON_ERROR("snd_pcm_readi()", frames);
244 const int64_t prev_pts = frames_to_pts(num_frames_output);
245 const int64_t pts = frames_to_pts(num_frames_output + frames);
248 if (should_quit) return CaptureEndReason::REQUESTED_QUIT;
249 success = audio_callback(buffer.get(), frames, audio_format, pts - prev_pts);
251 num_frames_output += frames;
253 return CaptureEndReason::REQUESTED_QUIT;
256 int64_t ALSAInput::frames_to_pts(uint64_t n) const
258 return (n * TIMEBASE) / sample_rate;
261 ALSAPool::~ALSAPool()
263 for (Device &device : devices) {
264 if (device.input != nullptr) {
265 device.input->stop_capture_thread();
270 std::vector<ALSAPool::Device> ALSAPool::get_devices()
272 lock_guard<mutex> lock(mu);
273 for (Device &device : devices) {
279 void ALSAPool::hold_device(unsigned index)
281 lock_guard<mutex> lock(mu);
282 assert(index < devices.size());
283 devices[index].held = true;
286 void ALSAPool::release_device(unsigned index)
288 lock_guard<mutex> lock(mu);
289 if (index < devices.size()) {
290 devices[index].held = false;
294 void ALSAPool::enumerate_devices()
296 // Enumerate all cards.
297 for (int card_index = -1; snd_card_next(&card_index) == 0 && card_index >= 0; ) {
299 snprintf(address, sizeof(address), "hw:%d", card_index);
302 int err = snd_ctl_open(&ctl, address, 0);
304 printf("%s: %s\n", address, snd_strerror(err));
307 unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
309 // Enumerate all devices on this card.
310 for (int dev_index = -1; snd_ctl_pcm_next_device(ctl, &dev_index) == 0 && dev_index >= 0; ) {
311 probe_device_with_retry(card_index, dev_index);
316 void ALSAPool::probe_device_with_retry(unsigned card_index, unsigned dev_index)
319 snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
321 lock_guard<mutex> lock(add_device_mutex);
322 if (add_device_tries_left.count(address)) {
323 // Some thread is already busy retrying this,
324 // so just reset its count.
325 add_device_tries_left[address] = num_retries;
329 // Try (while still holding the lock) to add the device synchronously.
330 ProbeResult result = probe_device_once(card_index, dev_index);
331 if (result == ProbeResult::SUCCESS) {
333 } else if (result == ProbeResult::FAILURE) {
336 assert(result == ProbeResult::DEFER);
338 // Add failed for whatever reason (probably just that the device
339 // isn't up yet. Set up a count so that nobody else starts a thread,
340 // then start it ourselves.
341 fprintf(stderr, "Trying %s again in one second...\n", address);
342 add_device_tries_left[address] = num_retries;
343 thread(&ALSAPool::probe_device_retry_thread_func, this, card_index, dev_index).detach();
346 void ALSAPool::probe_device_retry_thread_func(unsigned card_index, unsigned dev_index)
349 snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
351 for ( ;; ) { // Termination condition within the loop.
354 // See if there are any retries left.
355 lock_guard<mutex> lock(add_device_mutex);
356 if (!add_device_tries_left.count(address) ||
357 add_device_tries_left[address] == 0) {
358 add_device_tries_left.erase(address);
359 fprintf(stderr, "Giving up probe of %s.\n", address);
363 // Seemingly there were. Give it a try (we still hold the mutex).
364 ProbeResult result = probe_device_once(card_index, dev_index);
365 if (result == ProbeResult::SUCCESS) {
366 add_device_tries_left.erase(address);
367 fprintf(stderr, "Probe of %s succeeded.\n", address);
369 } else if (result == ProbeResult::FAILURE || --add_device_tries_left[address] == 0) {
370 add_device_tries_left.erase(address);
371 fprintf(stderr, "Giving up probe of %s.\n", address);
376 assert(result == ProbeResult::DEFER);
377 fprintf(stderr, "Trying %s again in one second (%d tries left)...\n",
378 address, add_device_tries_left[address]);
382 ALSAPool::ProbeResult ALSAPool::probe_device_once(unsigned card_index, unsigned dev_index)
385 snprintf(address, sizeof(address), "hw:%d", card_index);
387 int err = snd_ctl_open(&ctl, address, 0);
389 printf("%s: %s\n", address, snd_strerror(err));
390 return ALSAPool::ProbeResult::DEFER;
392 unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
394 snd_pcm_info_t *pcm_info;
395 snd_pcm_info_alloca(&pcm_info);
396 snd_pcm_info_set_device(pcm_info, dev_index);
397 snd_pcm_info_set_subdevice(pcm_info, 0);
398 snd_pcm_info_set_stream(pcm_info, SND_PCM_STREAM_CAPTURE);
399 if (snd_ctl_pcm_info(ctl, pcm_info) < 0) {
400 // Not available for capture.
401 printf("%s: Not available for capture.\n", address);
402 return ALSAPool::ProbeResult::DEFER;
405 snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
407 unsigned num_channels = 0;
409 // Find all channel maps for this device, and pick out the one
410 // with the most channels.
411 snd_pcm_chmap_query_t **cmaps = snd_pcm_query_chmaps_from_hw(card_index, dev_index, 0, SND_PCM_STREAM_CAPTURE);
412 if (cmaps != nullptr) {
413 for (snd_pcm_chmap_query_t **ptr = cmaps; *ptr; ++ptr) {
414 num_channels = max(num_channels, (*ptr)->map.channels);
416 snd_pcm_free_chmaps(cmaps);
418 if (num_channels == 0) {
419 // Device had no channel maps. We need to open it to query.
420 // TODO: Do this asynchronously.
421 snd_pcm_t *pcm_handle;
422 int err = snd_pcm_open(&pcm_handle, address, SND_PCM_STREAM_CAPTURE, 0);
424 printf("%s: %s\n", address, snd_strerror(err));
425 return ALSAPool::ProbeResult::DEFER;
427 snd_pcm_hw_params_t *hw_params;
428 snd_pcm_hw_params_alloca(&hw_params);
429 unsigned sample_rate;
430 if (!set_base_params(address, pcm_handle, hw_params, &sample_rate)) {
431 snd_pcm_close(pcm_handle);
432 return ALSAPool::ProbeResult::DEFER;
434 err = snd_pcm_hw_params_get_channels_max(hw_params, &num_channels);
436 fprintf(stderr, "[%s] snd_pcm_hw_params_get_channels_max(): %s\n",
437 address, snd_strerror(err));
438 snd_pcm_close(pcm_handle);
439 return ALSAPool::ProbeResult::DEFER;
441 snd_pcm_close(pcm_handle);
444 if (num_channels == 0) {
445 printf("%s: No channel maps with channels\n", address);
446 return ALSAPool::ProbeResult::FAILURE;
449 snd_ctl_card_info_t *card_info;
450 snd_ctl_card_info_alloca(&card_info);
451 snd_ctl_card_info(ctl, card_info);
453 string name = snd_ctl_card_info_get_name(card_info);
454 string info = snd_pcm_info_get_name(pcm_info);
456 unsigned internal_dev_index;
458 lock_guard<mutex> lock(mu);
459 internal_dev_index = find_free_device_index(name, info, num_channels, address);
460 devices[internal_dev_index].address = address;
461 devices[internal_dev_index].name = name;
462 devices[internal_dev_index].info = info;
463 devices[internal_dev_index].num_channels = num_channels;
464 // Note: Purposefully does not overwrite held.
467 fprintf(stderr, "%s: Probed successfully.\n", address);
469 reset_device(internal_dev_index); // Restarts it if it is held (ie., we just replaced a dead card).
470 if (global_audio_mixer) {
471 global_audio_mixer->trigger_state_changed_callback();
474 return ALSAPool::ProbeResult::SUCCESS;
477 void ALSAPool::unplug_device(unsigned card_index, unsigned dev_index)
480 snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
481 for (unsigned i = 0; i < devices.size(); ++i) {
482 if (devices[i].state != Device::State::EMPTY &&
483 devices[i].state != Device::State::DEAD &&
484 devices[i].address == address) {
490 void ALSAPool::init()
492 thread(&ALSAPool::inotify_thread_func, this).detach();
496 void ALSAPool::inotify_thread_func()
498 int inotify_fd = inotify_init();
499 if (inotify_fd == -1) {
500 perror("inotify_init()");
501 fprintf(stderr, "No hotplug of ALSA devices available.\n");
505 int watch_fd = inotify_add_watch(inotify_fd, "/dev/snd", IN_MOVE | IN_CREATE | IN_DELETE);
506 if (watch_fd == -1) {
507 perror("inotify_add_watch()");
508 fprintf(stderr, "No hotplug of ALSA devices available.\n");
513 int size = sizeof(inotify_event) + NAME_MAX + 1;
514 unique_ptr<char[]> buf(new char[size]);
516 int ret = read(inotify_fd, buf.get(), size);
517 if (ret < int(sizeof(inotify_event))) {
518 fprintf(stderr, "inotify read unexpectedly returned %d, giving up hotplug of ALSA devices.\n",
525 for (int i = 0; i < ret; ) {
526 const inotify_event *event = reinterpret_cast<const inotify_event *>(&buf[i]);
527 i += sizeof(inotify_event) + event->len;
529 if (event->mask & IN_Q_OVERFLOW) {
530 fprintf(stderr, "WARNING: inotify overflowed, may lose ALSA hotplug events.\n");
533 unsigned card, device;
535 if (sscanf(event->name, "pcmC%uD%u%c", &card, &device, &type) == 3 && type == 'c') {
536 if (event->mask & (IN_MOVED_FROM | IN_DELETE)) {
537 printf("Deleted capture device: Card %u, device %u\n", card, device);
538 unplug_device(card, device);
540 if (event->mask & (IN_MOVED_TO | IN_CREATE)) {
541 printf("Adding capture device: Card %u, device %u\n", card, device);
542 probe_device_with_retry(card, device);
549 void ALSAPool::reset_device(unsigned index)
551 lock_guard<mutex> lock(mu);
552 Device *device = &devices[index];
553 if (inputs[index] != nullptr) {
554 inputs[index]->stop_capture_thread();
557 inputs[index].reset();
559 // TODO: Put on a background thread instead of locking?
560 auto callback = bind(&AudioMixer::add_audio, global_audio_mixer, DeviceSpec{InputSourceType::ALSA_INPUT, index}, _1, _2, _3, _4);
561 inputs[index].reset(new ALSAInput(device->address.c_str(), OUTPUT_FREQUENCY, device->num_channels, callback, this, index));
562 inputs[index]->start_capture_thread();
564 device->input = inputs[index].get();
567 unsigned ALSAPool::get_capture_frequency(unsigned index)
569 lock_guard<mutex> lock(mu);
570 assert(devices[index].held);
571 if (devices[index].input)
572 return devices[index].input->get_sample_rate();
574 return OUTPUT_FREQUENCY;
577 ALSAPool::Device::State ALSAPool::get_card_state(unsigned index)
579 lock_guard<mutex> lock(mu);
580 assert(devices[index].held);
581 return devices[index].state;
584 void ALSAPool::set_card_state(unsigned index, ALSAPool::Device::State state)
587 lock_guard<mutex> lock(mu);
588 devices[index].state = state;
591 DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
592 bool silence = (state != ALSAPool::Device::State::RUNNING);
593 while (!global_audio_mixer->silence_card(spec, silence))
595 global_audio_mixer->trigger_state_changed_callback();
598 unsigned ALSAPool::find_free_device_index(const string &name, const string &info, unsigned num_channels, const string &address)
600 // First try to find an exact match on a dead card.
601 for (unsigned i = 0; i < devices.size(); ++i) {
602 if (devices[i].state == Device::State::DEAD &&
603 devices[i].address == address &&
604 devices[i].name == name &&
605 devices[i].info == info &&
606 devices[i].num_channels == num_channels) {
607 devices[i].state = Device::State::READY;
612 // Then try to find a match on everything but the address
613 // (probably that devices were plugged back in a different order).
614 // If we have two cards that are equal, this might get them mixed up,
615 // but we don't have anything better.
616 for (unsigned i = 0; i < devices.size(); ++i) {
617 if (devices[i].state == Device::State::DEAD &&
618 devices[i].name == name &&
619 devices[i].info == info &&
620 devices[i].num_channels == num_channels) {
621 devices[i].state = Device::State::READY;
626 // OK, so we didn't find a match; see if there are any empty slots.
627 for (unsigned i = 0; i < devices.size(); ++i) {
628 if (devices[i].state == Device::State::EMPTY) {
629 devices[i].state = Device::State::READY;
630 devices[i].held = false;
635 // Failing that, we just insert the new device at the end.
637 new_dev.state = Device::State::READY;
638 new_dev.held = false;
639 devices.push_back(new_dev);
640 inputs.emplace_back(nullptr);
641 return devices.size() - 1;
644 void ALSAPool::free_card(unsigned index)
646 DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
647 while (!global_audio_mixer->silence_card(spec, true))
651 lock_guard<mutex> lock(mu);
652 if (devices[index].held) {
653 devices[index].state = Device::State::DEAD;
655 devices[index].state = Device::State::EMPTY;
656 inputs[index].reset();
658 while (!devices.empty() && devices.back().state == Device::State::EMPTY) {
664 global_audio_mixer->trigger_state_changed_callback();