git.sesse.net Git - nageru/blob - alsa_input.cpp

   1 #include "alsa_input.h"
   2 #include "audio_mixer.h"
   3 #include "defs.h"
   4
   5 #include <sys/inotify.h>
   6
   7 #include <functional>
   8 #include <unordered_map>
   9
  10 using namespace std;
  11 using namespace std::placeholders;
  12
  13 namespace {
  14
  15 bool set_base_params(const char *device_name, snd_pcm_t *pcm_handle, snd_pcm_hw_params_t *hw_params, unsigned *sample_rate)
  16 {
  17         int err;
  18         err = snd_pcm_hw_params_any(pcm_handle, hw_params);
  19         if (err < 0) {
  20                 fprintf(stderr, "[%s] snd_pcm_hw_params_any(): %s\n", device_name, snd_strerror(err));
  21                 return false;
  22         }
  23         err = snd_pcm_hw_params_set_access(pcm_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
  24         if (err < 0) {
  25                 fprintf(stderr, "[%s] snd_pcm_hw_params_set_access(): %s\n", device_name, snd_strerror(err));
  26                 return false;
  27         }
  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);
  34         if (err < 0) {
  35                 fprintf(stderr, "[%s] snd_pcm_hw_params_set_format_mask(): %s\n", device_name, snd_strerror(err));
  36                 return false;
  37         }
  38         err = snd_pcm_hw_params_set_rate_near(pcm_handle, hw_params, sample_rate, 0);
  39         if (err < 0) {
  40                 fprintf(stderr, "[%s] snd_pcm_hw_params_set_rate_near(): %s\n", device_name, snd_strerror(err));
  41                 return false;
  42         }
  43         return true;
  44 }
  45
  46 }  // namespace
  47
  48 ALSAInput::ALSAInput(const char *device, unsigned sample_rate, unsigned num_channels, audio_callback_t audio_callback, ALSAPool *parent_pool, unsigned internal_dev_index)
  49         : device(device),
  50           sample_rate(sample_rate),
  51           num_channels(num_channels),
  52           audio_callback(audio_callback),
  53           parent_pool(parent_pool),
  54           internal_dev_index(internal_dev_index)
  55 {
  56         die_on_error(device, snd_pcm_open(&pcm_handle, device, SND_PCM_STREAM_CAPTURE, 0));
  57
  58         // Set format.
  59         snd_pcm_hw_params_t *hw_params;
  60         snd_pcm_hw_params_alloca(&hw_params);
  61         if (!set_base_params(device, pcm_handle, hw_params, &sample_rate)) {
  62                 exit(1);
  63         }
  64
  65         die_on_error("snd_pcm_hw_params_set_channels()", snd_pcm_hw_params_set_channels(pcm_handle, hw_params, num_channels));
  66
  67         // Fragment size of 64 samples (about 1 ms at 48 kHz; a frame at 60
  68         // fps/48 kHz is 800 samples.) We ask for 64 such periods in our buffer
  69         // (~85 ms buffer); more than that, and our jitter is probably so high
  70         // that the resampling queue can't keep up anyway.
  71         // The entire thing with periods and such is a bit mysterious to me;
  72         // seemingly I can get 96 frames at a time with no problems even if
  73         // the period size is 64 frames. And if I set num_periods to e.g. 1,
  74         // I can't have a big buffer.
  75         num_periods = 16;
  76         int dir = 0;
  77         die_on_error("snd_pcm_hw_params_set_periods_near()", snd_pcm_hw_params_set_periods_near(pcm_handle, hw_params, &num_periods, &dir));
  78         period_size = 64;
  79         dir = 0;
  80         die_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));
  81         buffer_frames = 64 * 64;
  82         die_on_error("snd_pcm_hw_params_set_buffer_size_near()", snd_pcm_hw_params_set_buffer_size_near(pcm_handle, hw_params, &buffer_frames));
  83         die_on_error("snd_pcm_hw_params()", snd_pcm_hw_params(pcm_handle, hw_params));
  84         //snd_pcm_hw_params_free(hw_params);
  85
  86         // Figure out which format the card actually chose.
  87         die_on_error("snd_pcm_hw_params_current()", snd_pcm_hw_params_current(pcm_handle, hw_params));
  88         snd_pcm_format_t chosen_format;
  89         die_on_error("snd_pcm_hw_params_get_format()", snd_pcm_hw_params_get_format(hw_params, &chosen_format));
  90
  91         audio_format.num_channels = num_channels;
  92         audio_format.bits_per_sample = 0;
  93         switch (chosen_format) {
  94         case SND_PCM_FORMAT_S16_LE:
  95                 audio_format.bits_per_sample = 16;
  96                 break;
  97         case SND_PCM_FORMAT_S24_LE:
  98                 audio_format.bits_per_sample = 24;
  99                 break;
 100         case SND_PCM_FORMAT_S32_LE:
 101                 audio_format.bits_per_sample = 32;
 102                 break;
 103         default:
 104                 assert(false);
 105         }
 106         //printf("num_periods=%u period_size=%u buffer_frames=%u sample_rate=%u bits_per_sample=%d\n",
 107         //      num_periods, unsigned(period_size), unsigned(buffer_frames), sample_rate, audio_format.bits_per_sample);
 108
 109         buffer.reset(new uint8_t[buffer_frames * num_channels * audio_format.bits_per_sample / 8]);
 110
 111         snd_pcm_sw_params_t *sw_params;
 112         snd_pcm_sw_params_alloca(&sw_params);
 113         die_on_error("snd_pcm_sw_params_current()", snd_pcm_sw_params_current(pcm_handle, sw_params));
 114         die_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));
 115         die_on_error("snd_pcm_sw_params()", snd_pcm_sw_params(pcm_handle, sw_params));
 116
 117         die_on_error("snd_pcm_nonblock()", snd_pcm_nonblock(pcm_handle, 1));
 118         die_on_error("snd_pcm_prepare()", snd_pcm_prepare(pcm_handle));
 119 }
 120
 121 ALSAInput::~ALSAInput()
 122 {
 123         die_on_error("snd_pcm_close()", snd_pcm_close(pcm_handle));
 124 }
 125
 126 void ALSAInput::start_capture_thread()
 127 {
 128         should_quit = false;
 129         capture_thread = thread(&ALSAInput::capture_thread_func, this);
 130 }
 131
 132 void ALSAInput::stop_capture_thread()
 133 {
 134         should_quit = true;
 135         capture_thread.join();
 136 }
 137
 138 void ALSAInput::capture_thread_func()
 139 {
 140         parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::STARTING);
 141         die_on_error("snd_pcm_start()", snd_pcm_start(pcm_handle));
 142         parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::RUNNING);
 143
 144         uint64_t num_frames_output = 0;
 145         while (!should_quit) {
 146                 int ret = snd_pcm_wait(pcm_handle, /*timeout=*/100);
 147                 if (ret == 0) continue;  // Timeout.
 148                 if (ret == -EPIPE) {
 149                         fprintf(stderr, "[%s] ALSA overrun\n", device.c_str());
 150                         snd_pcm_prepare(pcm_handle);
 151                         snd_pcm_start(pcm_handle);
 152                         continue;
 153                 }
 154                 die_on_error("snd_pcm_wait()", ret);
 155
 156                 snd_pcm_sframes_t frames = snd_pcm_readi(pcm_handle, buffer.get(), buffer_frames);
 157                 if (frames == -EPIPE) {
 158                         fprintf(stderr, "[%s] ALSA overrun\n", device.c_str());
 159                         snd_pcm_prepare(pcm_handle);
 160                         snd_pcm_start(pcm_handle);
 161                         continue;
 162                 }
 163                 if (frames == 0) {
 164                         fprintf(stderr, "snd_pcm_readi() returned 0\n");
 165                         break;
 166                 }
 167                 die_on_error("snd_pcm_readi()", frames);
 168
 169                 const int64_t prev_pts = frames_to_pts(num_frames_output);
 170                 const int64_t pts = frames_to_pts(num_frames_output + frames);
 171                 bool success;
 172                 do {
 173                         if (should_quit) return;
 174                         success = audio_callback(buffer.get(), frames, audio_format, pts - prev_pts);
 175                 } while (!success);
 176                 num_frames_output += frames;
 177         }
 178         parent_pool->free_card(internal_dev_index);
 179 }
 180
 181 int64_t ALSAInput::frames_to_pts(uint64_t n) const
 182 {
 183         return (n * TIMEBASE) / sample_rate;
 184 }
 185
 186 void ALSAInput::die_on_error(const char *func_name, int err)
 187 {
 188         if (err < 0) {
 189                 fprintf(stderr, "[%s] %s: %s\n", device.c_str(), func_name, snd_strerror(err));
 190                 exit(1);
 191         }
 192 }
 193
 194 ALSAPool::~ALSAPool()
 195 {
 196         for (Device &device : devices) {
 197                 if (device.input != nullptr) {
 198                         device.input->stop_capture_thread();
 199                 }
 200         }
 201 }
 202
 203 std::vector<ALSAPool::Device> ALSAPool::get_devices()
 204 {
 205         lock_guard<mutex> lock(mu);
 206         for (Device &device : devices) {
 207                 device.held = true;
 208         }
 209         return devices;
 210 }
 211
 212 void ALSAPool::hold_device(unsigned index)
 213 {
 214         lock_guard<mutex> lock(mu);
 215         assert(index < devices.size());
 216         devices[index].held = true;
 217 }
 218
 219 void ALSAPool::release_device(unsigned index)
 220 {
 221         lock_guard<mutex> lock(mu);
 222         if (index < devices.size()) {
 223                 devices[index].held = false;
 224         }
 225 }
 226
 227 void ALSAPool::enumerate_devices()
 228 {
 229         // Enumerate all cards.
 230         for (int card_index = -1; snd_card_next(&card_index) == 0 && card_index >= 0; ) {
 231                 char address[256];
 232                 snprintf(address, sizeof(address), "hw:%d", card_index);
 233
 234                 snd_ctl_t *ctl;
 235                 int err = snd_ctl_open(&ctl, address, 0);
 236                 if (err < 0) {
 237                         printf("%s: %s\n", address, snd_strerror(err));
 238                         continue;
 239                 }
 240                 unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
 241
 242                 // Enumerate all devices on this card.
 243                 for (int dev_index = -1; snd_ctl_pcm_next_device(ctl, &dev_index) == 0 && dev_index >= 0; ) {
 244                         probe_device_with_retry(card_index, dev_index);
 245                 }
 246         }
 247 }
 248
 249 void ALSAPool::probe_device_with_retry(unsigned card_index, unsigned dev_index)
 250 {
 251         char address[256];
 252         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 253
 254         lock_guard<mutex> lock(add_device_mutex);
 255         if (add_device_tries_left.count(address)) {
 256                 // Some thread is already busy retrying this,
 257                 // so just reset its count.
 258                 add_device_tries_left[address] = num_retries;
 259                 return;
 260         }
 261
 262         // Try (while still holding the lock) to add the device synchronously.
 263         ProbeResult result = probe_device_once(card_index, dev_index);
 264         if (result == ProbeResult::SUCCESS) {
 265                 return;
 266         } else if (result == ProbeResult::FAILURE) {
 267                 return;
 268         }
 269         assert(result == ProbeResult::DEFER);
 270
 271         // Add failed for whatever reason (probably just that the device
 272         // isn't up yet. Set up a count so that nobody else starts a thread,
 273         // then start it ourselves.
 274         fprintf(stderr, "Trying %s again in one second...\n", address);
 275         add_device_tries_left[address] = num_retries;
 276         thread(&ALSAPool::probe_device_retry_thread_func, this, card_index, dev_index).detach();
 277 }
 278
 279 void ALSAPool::probe_device_retry_thread_func(unsigned card_index, unsigned dev_index)
 280 {
 281         char address[256];
 282         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 283
 284         for ( ;; ) {  // Termination condition within the loop.
 285                 sleep(1);
 286
 287                 // See if there are any retries left.
 288                 lock_guard<mutex> lock(add_device_mutex);
 289                 if (!add_device_tries_left.count(address) ||
 290                     add_device_tries_left[address] == 0) {
 291                         add_device_tries_left.erase(address);
 292                         fprintf(stderr, "Giving up probe of %s.\n", address);
 293                         return;
 294                 }
 295
 296                 // Seemingly there were. Give it a try (we still hold the mutex).
 297                 ProbeResult result = probe_device_once(card_index, dev_index);
 298                 if (result == ProbeResult::SUCCESS) {
 299                         add_device_tries_left.erase(address);
 300                         fprintf(stderr, "Probe of %s succeeded.\n", address);
 301                         return;
 302                 } else if (result == ProbeResult::FAILURE || --add_device_tries_left[address] == 0) {
 303                         add_device_tries_left.erase(address);
 304                         fprintf(stderr, "Giving up probe of %s.\n", address);
 305                         return;
 306                 }
 307
 308                 // Failed again.
 309                 assert(result == ProbeResult::DEFER);
 310                 fprintf(stderr, "Trying %s again in one second (%d tries left)...\n",
 311                         address, add_device_tries_left[address]);
 312         }
 313 }
 314
 315 ALSAPool::ProbeResult ALSAPool::probe_device_once(unsigned card_index, unsigned dev_index)
 316 {
 317         char address[256];
 318         snprintf(address, sizeof(address), "hw:%d", card_index);
 319         snd_ctl_t *ctl;
 320         int err = snd_ctl_open(&ctl, address, 0);
 321         if (err < 0) {
 322                 printf("%s: %s\n", address, snd_strerror(err));
 323                 return ALSAPool::ProbeResult::DEFER;
 324         }
 325         unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
 326
 327         snd_pcm_info_t *pcm_info;
 328         snd_pcm_info_alloca(&pcm_info);
 329         snd_pcm_info_set_device(pcm_info, dev_index);
 330         snd_pcm_info_set_subdevice(pcm_info, 0);
 331         snd_pcm_info_set_stream(pcm_info, SND_PCM_STREAM_CAPTURE);
 332         if (snd_ctl_pcm_info(ctl, pcm_info) < 0) {
 333                 // Not available for capture.
 334                 printf("%s: Not available for capture.\n", address);
 335                 return ALSAPool::ProbeResult::DEFER;
 336         }
 337
 338         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 339
 340         unsigned num_channels = 0;
 341
 342         // Find all channel maps for this device, and pick out the one
 343         // with the most channels.
 344         snd_pcm_chmap_query_t **cmaps = snd_pcm_query_chmaps_from_hw(card_index, dev_index, 0, SND_PCM_STREAM_CAPTURE);
 345         if (cmaps != nullptr) {
 346                 for (snd_pcm_chmap_query_t **ptr = cmaps; *ptr; ++ptr) {
 347                         num_channels = max(num_channels, (*ptr)->map.channels);
 348                 }
 349                 snd_pcm_free_chmaps(cmaps);
 350         }
 351         if (num_channels == 0) {
 352                 // Device had no channel maps. We need to open it to query.
 353                 // TODO: Do this asynchronously.
 354                 snd_pcm_t *pcm_handle;
 355                 int err = snd_pcm_open(&pcm_handle, address, SND_PCM_STREAM_CAPTURE, 0);
 356                 if (err < 0) {
 357                         printf("%s: %s\n", address, snd_strerror(err));
 358                         return ALSAPool::ProbeResult::DEFER;
 359                 }
 360                 snd_pcm_hw_params_t *hw_params;
 361                 snd_pcm_hw_params_alloca(&hw_params);
 362                 unsigned sample_rate;
 363                 if (!set_base_params(address, pcm_handle, hw_params, &sample_rate)) {
 364                         snd_pcm_close(pcm_handle);
 365                         return ALSAPool::ProbeResult::DEFER;
 366                 }
 367                 err = snd_pcm_hw_params_get_channels_max(hw_params, &num_channels);
 368                 if (err < 0) {
 369                         fprintf(stderr, "[%s] snd_pcm_hw_params_get_channels_max(): %s\n",
 370                                 address, snd_strerror(err));
 371                         snd_pcm_close(pcm_handle);
 372                         return ALSAPool::ProbeResult::DEFER;
 373                 }
 374                 snd_pcm_close(pcm_handle);
 375         }
 376
 377         if (num_channels == 0) {
 378                 printf("%s: No channel maps with channels\n", address);
 379                 return ALSAPool::ProbeResult::FAILURE;
 380         }
 381
 382         snd_ctl_card_info_t *card_info;
 383         snd_ctl_card_info_alloca(&card_info);
 384         snd_ctl_card_info(ctl, card_info);
 385
 386         lock_guard<mutex> lock(mu);
 387         unsigned internal_dev_index = find_free_device_index();
 388         devices[internal_dev_index].address = address;
 389         devices[internal_dev_index].name = snd_ctl_card_info_get_name(card_info);
 390         devices[internal_dev_index].info = snd_pcm_info_get_name(pcm_info);
 391         devices[internal_dev_index].num_channels = num_channels;
 392         devices[internal_dev_index].state = Device::State::READY;
 393
 394         fprintf(stderr, "%s: Probed successfully.\n", address);
 395
 396         return ALSAPool::ProbeResult::SUCCESS;
 397 }
 398
 399 void ALSAPool::init()
 400 {
 401         thread(&ALSAPool::inotify_thread_func, this).detach();
 402         enumerate_devices();
 403 }
 404
 405 void ALSAPool::inotify_thread_func()
 406 {
 407         int inotify_fd = inotify_init();
 408         if (inotify_fd == -1) {
 409                 perror("inotify_init()");
 410                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 411                 return;
 412         }
 413
 414         int watch_fd = inotify_add_watch(inotify_fd, "/dev/snd", IN_MOVE | IN_CREATE | IN_DELETE);
 415         if (watch_fd == -1) {
 416                 perror("inotify_add_watch()");
 417                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 418                 close(inotify_fd);
 419                 return;
 420         }
 421
 422         int size = sizeof(inotify_event) + NAME_MAX + 1;
 423         unique_ptr<char[]> buf(new char[size]);
 424         for ( ;; ) {
 425                 int ret = read(inotify_fd, buf.get(), size);
 426                 if (ret < int(sizeof(inotify_event))) {
 427                         fprintf(stderr, "inotify read unexpectedly returned %d, giving up hotplug of ALSA devices.\n",
 428                                 int(ret));
 429                         close(watch_fd);
 430                         close(inotify_fd);
 431                         return;
 432                 }
 433
 434                 for (int i = 0; i < ret; ) {
 435                         const inotify_event *event = reinterpret_cast<const inotify_event *>(&buf[i]);
 436                         i += sizeof(inotify_event) + event->len;
 437
 438                         if (event->mask & IN_Q_OVERFLOW) {
 439                                 fprintf(stderr, "WARNING: inotify overflowed, may lose ALSA hotplug events.\n");
 440                                 continue;
 441                         }
 442                         unsigned card, device;
 443                         char type;
 444                         if (sscanf(event->name, "pcmC%uD%u%c", &card, &device, &type) == 3 && type == 'c') {
 445                                 if (event->mask & (IN_MOVED_FROM | IN_DELETE)) {
 446                                         printf("Deleted capture device: Card %u, device %u\n", card, device);
 447                                         // TODO: Unplug.
 448                                 }
 449                                 if (event->mask & (IN_MOVED_TO | IN_CREATE)) {
 450                                         printf("Adding capture device: Card %u, device %u\n", card, device);
 451                                         probe_device_with_retry(card, device);
 452                                 }
 453                         }
 454                 }
 455         }
 456 }
 457
 458 void ALSAPool::reset_device(unsigned index)
 459 {
 460         lock_guard<mutex> lock(mu);
 461         Device *device = &devices[index];
 462         if (inputs[index] != nullptr) {
 463                 inputs[index]->stop_capture_thread();
 464         }
 465         if (!device->held) {
 466                 inputs[index].reset();
 467         } else {
 468                 // TODO: Put on a background thread instead of locking?
 469                 auto callback = bind(&AudioMixer::add_audio, global_audio_mixer, DeviceSpec{InputSourceType::ALSA_INPUT, index}, _1, _2, _3, _4);
 470                 inputs[index].reset(new ALSAInput(device->address.c_str(), OUTPUT_FREQUENCY, device->num_channels, callback, this, index));
 471                 inputs[index]->start_capture_thread();
 472         }
 473         device->input = inputs[index].get();
 474 }
 475
 476 unsigned ALSAPool::get_capture_frequency(unsigned index)
 477 {
 478         lock_guard<mutex> lock(mu);
 479         assert(devices[index].held);
 480         if (devices[index].input)
 481                 return devices[index].input->get_sample_rate();
 482         else
 483                 return OUTPUT_FREQUENCY;
 484 }
 485
 486 ALSAPool::Device::State ALSAPool::get_card_state(unsigned index)
 487 {
 488         lock_guard<mutex> lock(mu);
 489         assert(devices[index].held);
 490         return devices[index].state;
 491 }
 492
 493 void ALSAPool::set_card_state(unsigned index, ALSAPool::Device::State state)
 494 {
 495         lock_guard<mutex> lock(mu);
 496         devices[index].state = state;
 497 }
 498
 499 unsigned ALSAPool::find_free_device_index()
 500 {
 501         for (unsigned i = 0; i < devices.size(); ++i) {
 502                 if (devices[i].state == Device::State::EMPTY) {
 503                         devices[i].state = Device::State::READY;
 504                         return i;
 505                 }
 506         }
 507         Device new_dev;
 508         new_dev.state = Device::State::READY;
 509         devices.push_back(new_dev);
 510         inputs.emplace_back(nullptr);
 511         return devices.size() - 1;
 512 }
 513
 514 void ALSAPool::free_card(unsigned index)
 515 {
 516         lock_guard<mutex> lock(mu);
 517         if (devices[index].held) {
 518                 devices[index].state = Device::State::DEAD;
 519         } else {
 520                 devices[index].state = Device::State::EMPTY;
 521                 inputs[index].reset();
 522         }
 523         while (!devices.empty() && devices.back().state == Device::State::EMPTY) {
 524                 devices.pop_back();
 525                 inputs.pop_back();
 526         }
 527 }