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         audio_format.sample_rate = sample_rate;
 105         //printf("num_periods=%u period_size=%u buffer_frames=%u sample_rate=%u bits_per_sample=%d\n",
 106         //      num_periods, unsigned(period_size), unsigned(buffer_frames), sample_rate, audio_format.bits_per_sample);
 107
 108         buffer.reset(new uint8_t[buffer_frames * num_channels * audio_format.bits_per_sample / 8]);
 109
 110         snd_pcm_sw_params_t *sw_params;
 111         snd_pcm_sw_params_alloca(&sw_params);
 112         RETURN_FALSE_ON_ERROR("snd_pcm_sw_params_current()", snd_pcm_sw_params_current(pcm_handle, sw_params));
 113         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));
 114         RETURN_FALSE_ON_ERROR("snd_pcm_sw_params()", snd_pcm_sw_params(pcm_handle, sw_params));
 115
 116         RETURN_FALSE_ON_ERROR("snd_pcm_nonblock()", snd_pcm_nonblock(pcm_handle, 1));
 117         RETURN_FALSE_ON_ERROR("snd_pcm_prepare()", snd_pcm_prepare(pcm_handle));
 118         return true;
 119 }
 120
 121 bool ALSAInput::set_base_params(const char *device_name, snd_pcm_t *pcm_handle, snd_pcm_hw_params_t *hw_params, unsigned *sample_rate)
 122 {
 123         int err;
 124         err = snd_pcm_hw_params_any(pcm_handle, hw_params);
 125         if (err < 0) {
 126                 fprintf(stderr, "[%s] snd_pcm_hw_params_any(): %s\n", device_name, snd_strerror(err));
 127                 return false;
 128         }
 129         err = snd_pcm_hw_params_set_access(pcm_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
 130         if (err < 0) {
 131                 fprintf(stderr, "[%s] snd_pcm_hw_params_set_access(): %s\n", device_name, snd_strerror(err));
 132                 return false;
 133         }
 134         snd_pcm_format_mask_t *format_mask;
 135         snd_pcm_format_mask_alloca(&format_mask);
 136         snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S16_LE);
 137         snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S24_LE);
 138         snd_pcm_format_mask_set(format_mask, SND_PCM_FORMAT_S32_LE);
 139         err = snd_pcm_hw_params_set_format_mask(pcm_handle, hw_params, format_mask);
 140         if (err < 0) {
 141                 fprintf(stderr, "[%s] snd_pcm_hw_params_set_format_mask(): %s\n", device_name, snd_strerror(err));
 142                 return false;
 143         }
 144         err = snd_pcm_hw_params_set_rate_near(pcm_handle, hw_params, sample_rate, 0);
 145         if (err < 0) {
 146                 fprintf(stderr, "[%s] snd_pcm_hw_params_set_rate_near(): %s\n", device_name, snd_strerror(err));
 147                 return false;
 148         }
 149         return true;
 150 }
 151
 152 ALSAInput::~ALSAInput()
 153 {
 154         if (pcm_handle) {
 155                 WARN_ON_ERROR("snd_pcm_close()", snd_pcm_close(pcm_handle));
 156         }
 157 }
 158
 159 void ALSAInput::start_capture_thread()
 160 {
 161         assert(!device.empty());
 162         should_quit.unquit();
 163         capture_thread = thread(&ALSAInput::capture_thread_func, this);
 164 }
 165
 166 void ALSAInput::stop_capture_thread()
 167 {
 168         should_quit.quit();
 169         capture_thread.join();
 170 }
 171
 172 void ALSAInput::capture_thread_func()
 173 {
 174         parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::STARTING);
 175
 176         // If the device hasn't been opened already, we need to do so
 177         // before we can capture.
 178         while (!should_quit.should_quit() && pcm_handle == nullptr) {
 179                 if (!open_device()) {
 180                         fprintf(stderr, "[%s] Waiting one second and trying again...\n",
 181                                 device.c_str());
 182                         should_quit.sleep_for(seconds(1));
 183                 }
 184         }
 185
 186         if (should_quit.should_quit()) {
 187                 // Don't call free_card(); that would be a deadlock.
 188                 if (pcm_handle) {
 189                         WARN_ON_ERROR("snd_pcm_close()", snd_pcm_close(pcm_handle));
 190                 }
 191                 pcm_handle = nullptr;
 192                 return;
 193         }
 194
 195         // Do the actual capture. (Termination condition within loop.)
 196         for ( ;; ) {
 197                 switch (do_capture()) {
 198                 case CaptureEndReason::REQUESTED_QUIT:
 199                         // Don't call free_card(); that would be a deadlock.
 200                         WARN_ON_ERROR("snd_pcm_close()", snd_pcm_close(pcm_handle));
 201                         pcm_handle = nullptr;
 202                         return;
 203                 case CaptureEndReason::DEVICE_GONE:
 204                         parent_pool->free_card(internal_dev_index);
 205                         WARN_ON_ERROR("snd_pcm_close()", snd_pcm_close(pcm_handle));
 206                         pcm_handle = nullptr;
 207                         return;
 208                 case CaptureEndReason::OTHER_ERROR:
 209                         parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::STARTING);
 210                         fprintf(stderr, "[%s] Sleeping one second and restarting capture...\n",
 211                                 device.c_str());
 212                         should_quit.sleep_for(seconds(1));
 213                         break;
 214                 }
 215         }
 216 }
 217
 218 ALSAInput::CaptureEndReason ALSAInput::do_capture()
 219 {
 220         parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::STARTING);
 221         RETURN_ON_ERROR("snd_pcm_start()", snd_pcm_start(pcm_handle));
 222         parent_pool->set_card_state(internal_dev_index, ALSAPool::Device::State::RUNNING);
 223
 224         uint64_t num_frames_output = 0;
 225         while (!should_quit.should_quit()) {
 226                 int ret = snd_pcm_wait(pcm_handle, /*timeout=*/100);
 227                 if (ret == 0) continue;  // Timeout.
 228                 if (ret == -EPIPE) {
 229                         fprintf(stderr, "[%s] ALSA overrun\n", device.c_str());
 230                         snd_pcm_prepare(pcm_handle);
 231                         snd_pcm_start(pcm_handle);
 232                         continue;
 233                 }
 234                 RETURN_ON_ERROR("snd_pcm_wait()", ret);
 235
 236                 snd_pcm_sframes_t frames = snd_pcm_readi(pcm_handle, buffer.get(), buffer_frames);
 237                 if (frames == -EPIPE) {
 238                         fprintf(stderr, "[%s] ALSA overrun\n", device.c_str());
 239                         snd_pcm_prepare(pcm_handle);
 240                         snd_pcm_start(pcm_handle);
 241                         continue;
 242                 }
 243                 if (frames == 0) {
 244                         fprintf(stderr, "snd_pcm_readi() returned 0\n");
 245                         break;
 246                 }
 247                 RETURN_ON_ERROR("snd_pcm_readi()", frames);
 248
 249                 const int64_t prev_pts = frames_to_pts(num_frames_output);
 250                 const int64_t pts = frames_to_pts(num_frames_output + frames);
 251                 const steady_clock::time_point now = steady_clock::now();
 252                 bool success;
 253                 do {
 254                         if (should_quit.should_quit()) return CaptureEndReason::REQUESTED_QUIT;
 255                         success = audio_callback(buffer.get(), frames, audio_format, pts - prev_pts, now);
 256                 } while (!success);
 257                 num_frames_output += frames;
 258         }
 259         return CaptureEndReason::REQUESTED_QUIT;
 260 }
 261
 262 int64_t ALSAInput::frames_to_pts(uint64_t n) const
 263 {
 264         return (n * TIMEBASE) / sample_rate;
 265 }
 266