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

   1 #include "alsa_input.h"
   2
   3 #include <alsa/error.h>
   4 #include <assert.h>
   5 #include <errno.h>
   6 #include <stdio.h>
   7 #include <unistd.h>
   8 #include <cstdint>
   9
  10 #include "alsa_pool.h"
  11 #include "bmusb/bmusb.h"
  12 #include "timebase.h"
  13
  14 using namespace std;
  15 using namespace std::chrono;
  16 using namespace std::placeholders;
  17
  18 #define RETURN_ON_ERROR(msg, expr) do {                                                    \
  19         int err = (expr);                                                                  \
  20         if (err < 0) {                                                                     \
  21                 fprintf(stderr, "[%s] " msg ": %s\n", device.c_str(), snd_strerror(err));  \
  22                 if (err == -ENODEV) return CaptureEndReason::DEVICE_GONE;                  \
  23                 return CaptureEndReason::OTHER_ERROR;                                      \
  24         }                                                                                  \
  25 } while (false)
  26
  27 #define RETURN_FALSE_ON_ERROR(msg, expr) do {                                              \
  28         int err = (expr);                                                                  \
  29         if (err < 0) {                                                                     \
  30                 fprintf(stderr, "[%s] " msg ": %s\n", device.c_str(), snd_strerror(err));  \
  31                 return false;                                                              \
  32         }                                                                                  \
  33 } while (false)
  34
  35 #define WARN_ON_ERROR(msg, expr) do {                                                      \
  36         int err = (expr);                                                                  \
  37         if (err < 0) {                                                                     \
  38                 fprintf(stderr, "[%s] " msg ": %s\n", device.c_str(), snd_strerror(err));  \
  39         }                                                                                  \
  40 } while (false)
  41
  42 ALSAInput::ALSAInput(const char *device, unsigned sample_rate, unsigned num_channels, audio_callback_t audio_callback, ALSAPool *parent_pool, unsigned internal_dev_index)
  43         : device(device),
  44           sample_rate(sample_rate),
  45           num_channels(num_channels),
  46           audio_callback(audio_callback),
  47           parent_pool(parent_pool),
  48           internal_dev_index(internal_dev_index)
  49 {
  50 }
  51
  52 bool ALSAInput::open_device()
  53 {
  54         RETURN_FALSE_ON_ERROR("snd_pcm_open()", snd_pcm_open(&pcm_handle, device.c_str(), SND_PCM_STREAM_CAPTURE, 0));
  55
  56         // Set format.
  57         snd_pcm_hw_params_t *hw_params;
  58         snd_pcm_hw_params_alloca(&hw_params);
  59         if (!set_base_params(device.c_str(), pcm_handle, hw_params, &sample_rate)) {
  60                 return false;
  61         }
  62
  63         RETURN_FALSE_ON_ERROR("snd_pcm_hw_params_set_channels()", snd_pcm_hw_params_set_channels(pcm_handle, hw_params, num_channels));
  64
  65         // Fragment size of 64 samples (about 1 ms at 48 kHz; a frame at 60
  66         // fps/48 kHz is 800 samples.) We ask for 64 such periods in our buffer
  67         // (~85 ms buffer); more than that, and our jitter is probably so high
  68         // that the resampling queue can't keep up anyway.
  69         // The entire thing with periods and such is a bit mysterious to me;
  70         // seemingly I can get 96 frames at a time with no problems even if
  71         // the period size is 64 frames. And if I set num_periods to e.g. 1,
  72         // I can't have a big buffer.
  73         num_periods = 16;
  74         int dir = 0;
  75         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));
  76         period_size = 64;
  77         dir = 0;
  78         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));
  79         buffer_frames = 64 * 64;
  80         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));
  81         RETURN_FALSE_ON_ERROR("snd_pcm_hw_params()", snd_pcm_hw_params(pcm_handle, hw_params));
  82         //snd_pcm_hw_params_free(hw_params);
  83
  84         // Figure out which format the card actually chose.
  85         RETURN_FALSE_ON_ERROR("snd_pcm_hw_params_current()", snd_pcm_hw_params_current(pcm_handle, hw_params));
  86         snd_pcm_format_t chosen_format;
  87         RETURN_FALSE_ON_ERROR("snd_pcm_hw_params_get_format()", snd_pcm_hw_params_get_format(hw_params, &chosen_format));
  88
  89         audio_format.num_channels = num_channels;
  90         audio_format.bits_per_sample = 0;
  91         switch (chosen_format) {
  92         case SND_PCM_FORMAT_S16_LE:
  93                 audio_format.bits_per_sample = 16;
  94                 break;
  95         case SND_PCM_FORMAT_S24_LE:
  96                 audio_format.bits_per_sample = 24;
  97                 break;
  98         case SND_PCM_FORMAT_S32_LE:
  99                 audio_format.bits_per_sample = 32;
 100                 break;
 101         default:
 102                 assert(false);
 103         }
 104         //printf("num_periods=%u period_size=%u buffer_frames=%u sample_rate=%u bits_per_sample=%d\n",
 105         //      num_periods, unsigned(period_size), unsigned(buffer_frames), sample_rate, audio_format.bits_per_sample);
 106
 107         buffer.reset(new uint8_t[buffer_frames * num_channels * audio_format.bits_per_sample / 8]);
 108
 109         snd_pcm_sw_params_t *sw_params;
 110         snd_pcm_sw_params_alloca(&sw_params);
 111         RETURN_FALSE_ON_ERROR("snd_pcm_sw_params_current()", snd_pcm_sw_params_current(pcm_handle, sw_params));
 112         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));
 113         RETURN_FALSE_ON_ERROR("snd_pcm_sw_params()", snd_pcm_sw_params(pcm_handle, sw_params));
 114
 115         RETURN_FALSE_ON_ERROR("snd_pcm_nonblock()", snd_pcm_nonblock(pcm_handle, 1));
 116         RETURN_FALSE_ON_ERROR("snd_pcm_prepare()", snd_pcm_prepare(pcm_handle));
 117         return true;
 118 }
 119
 120 bool ALSAInput::set_base_params(const char *device_name, snd_pcm_t *pcm_handle, snd_pcm_hw_params_t *hw_params, unsigned *sample_rate)
 121 {
 122         int err;
 123         err = snd_pcm_hw_params_any(pcm_handle, hw_params);
 124         if (err < 0) {
 125                 fprintf(stderr, "[%s] snd_pcm_hw_params_any(): %s\n", device_name, snd_strerror(err));
 126                 return false;
 127         }
 128         err = snd_pcm_hw_params_set_access(pcm_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
 129         if (err < 0) {
 130                 fprintf(stderr, "[%s] snd_pcm_hw_params_set_access(): %s\n", device_name, snd_strerror(err));
 131                 return false;
 132         }
 133         snd_pcm_format_mask_t *format_mask;
 134         snd_pcm_format_mask_alloca(&format_mask);
 135         snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S16_LE);
 136         snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S24_LE);
 137         snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S32_LE);
 138         err = snd_pcm_hw_params_set_format_mask(pcm_handle, hw_params, format_mask);
 139         if (err < 0) {
 140                 fprintf(stderr, "[%s] snd_pcm_hw_params_set_format_mask(): %s\n", device_name, snd_strerror(err));
 141                 return false;
 142         }
 143         err = snd_pcm_hw_params_set_rate_near(pcm_handle, hw_params, sample_rate, 0);
 144         if (err < 0) {
 145                 fprintf(stderr, "[%s] snd_pcm_hw_params_set_rate_near(): %s\n", device_name, snd_strerror(err));
 146                 return false;
 147         }
 148         return true;
 149 }
 150
 151 ALSAInput::~ALSAInput()
 152 {
 153         if (pcm_handle) {
 154                 WARN_ON_ERROR("snd_pcm_close()", snd_pcm_close(pcm_handle));
 155         }
 156 }
 157
 158 void ALSAInput::start_capture_thread()
 159 {
 160         should_quit.unquit();
 161         capture_thread = thread(&ALSAInput::capture_thread_func, this);
 162 }
 163
 164 void ALSAInput::stop_capture_thread()
 165 {
 166         should_quit.quit();
 167         capture_thread.join();
 168 }
 169
 170 void ALSAInput::capture_thread_func()
 171 {
 172         parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::STARTING);
 173
 174         // If the device hasn't been opened already, we need to do so
 175         // before we can capture.
 176         while (!should_quit.should_quit() && pcm_handle == nullptr) {
 177                 if (!open_device()) {
 178                         fprintf(stderr, "[%s] Waiting one second and trying again...\n",
 179                                 device.c_str());
 180                         should_quit.sleep_for(seconds(1));
 181                 }
 182         }
 183
 184         if (should_quit.should_quit()) {
 185                 // Don't call free_card(); that would be a deadlock.
 186                 WARN_ON_ERROR("snd_pcm_close()", snd_pcm_close(pcm_handle));
 187                 pcm_handle = nullptr;
 188                 return;
 189         }
 190
 191         // Do the actual capture. (Termination condition within loop.)
 192         for ( ;; ) {
 193                 switch (do_capture()) {
 194                 case CaptureEndReason::REQUESTED_QUIT:
 195                         // Don't call free_card(); that would be a deadlock.
 196                         WARN_ON_ERROR("snd_pcm_close()", snd_pcm_close(pcm_handle));
 197                         pcm_handle = nullptr;
 198                         return;
 199                 case CaptureEndReason::DEVICE_GONE:
 200                         parent_pool->free_card(internal_dev_index);
 201                         WARN_ON_ERROR("snd_pcm_close()", snd_pcm_close(pcm_handle));
 202                         pcm_handle = nullptr;
 203                         return;
 204                 case CaptureEndReason::OTHER_ERROR:
 205                         parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::STARTING);
 206                         fprintf(stderr, "[%s] Sleeping one second and restarting capture...\n",
 207                                 device.c_str());
 208                         should_quit.sleep_for(seconds(1));
 209                         break;
 210                 }
 211         }
 212 }
 213
 214 ALSAInput::CaptureEndReason ALSAInput::do_capture()
 215 {
 216         parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::STARTING);
 217         RETURN_ON_ERROR("snd_pcm_start()", snd_pcm_start(pcm_handle));
 218         parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::RUNNING);
 219
 220         uint64_t num_frames_output = 0;
 221         while (!should_quit.should_quit()) {
 222                 int ret = snd_pcm_wait(pcm_handle, /*timeout=*/100);
 223                 if (ret == 0) continue;  // Timeout.
 224                 if (ret == -EPIPE) {
 225                         fprintf(stderr, "[%s] ALSA overrun\n", device.c_str());
 226                         snd_pcm_prepare(pcm_handle);
 227                         snd_pcm_start(pcm_handle);
 228                         continue;
 229                 }
 230                 RETURN_ON_ERROR("snd_pcm_wait()", ret);
 231
 232                 snd_pcm_sframes_t frames = snd_pcm_readi(pcm_handle, buffer.get(), buffer_frames);
 233                 if (frames == -EPIPE) {
 234                         fprintf(stderr, "[%s] ALSA overrun\n", device.c_str());
 235                         snd_pcm_prepare(pcm_handle);
 236                         snd_pcm_start(pcm_handle);
 237                         continue;
 238                 }
 239                 if (frames == 0) {
 240                         fprintf(stderr, "snd_pcm_readi() returned 0\n");
 241                         break;
 242                 }
 243                 RETURN_ON_ERROR("snd_pcm_readi()", frames);
 244
 245                 const int64_t prev_pts = frames_to_pts(num_frames_output);
 246                 const int64_t pts = frames_to_pts(num_frames_output + frames);
 247                 const steady_clock::time_point now = steady_clock::now();
 248                 bool success;
 249                 do {
 250                         if (should_quit.should_quit()) return CaptureEndReason::REQUESTED_QUIT;
 251                         success = audio_callback(buffer.get(), frames, audio_format, pts - prev_pts, now);
 252                 } while (!success);
 253                 num_frames_output += frames;
 254         }
 255         return CaptureEndReason::REQUESTED_QUIT;
 256 }
 257
 258 int64_t ALSAInput::frames_to_pts(uint64_t n) const
 259 {
 260         return (n * TIMEBASE) / sample_rate;
 261 }
 262