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

   1 #undef Success
   2
   3 #include "mixer.h"
   4
   5 #include <assert.h>
   6 #include <epoxy/egl.h>
   7 #include <movit/effect_chain.h>
   8 #include <movit/effect_util.h>
   9 #include <movit/flat_input.h>
  10 #include <movit/image_format.h>
  11 #include <movit/init.h>
  12 #include <movit/resource_pool.h>
  13 #include <stdint.h>
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <sys/resource.h>
  17 #include <algorithm>
  18 #include <chrono>
  19 #include <condition_variable>
  20 #include <cstddef>
  21 #include <cstdint>
  22 #include <memory>
  23 #include <mutex>
  24 #include <ratio>
  25 #include <string>
  26 #include <thread>
  27 #include <utility>
  28 #include <vector>
  29
  30 #include "DeckLinkAPI.h"
  31 #include "LinuxCOM.h"
  32 #include "alsa_output.h"
  33 #include "bmusb/bmusb.h"
  34 #include "bmusb/fake_capture.h"
  35 #include "chroma_subsampler.h"
  36 #include "context.h"
  37 #include "decklink_capture.h"
  38 #include "decklink_output.h"
  39 #include "defs.h"
  40 #include "disk_space_estimator.h"
  41 #include "flags.h"
  42 #include "input_mapping.h"
  43 #include "pbo_frame_allocator.h"
  44 #include "ref_counted_gl_sync.h"
  45 #include "resampling_queue.h"
  46 #include "timebase.h"
  47 #include "video_encoder.h"
  48
  49 class IDeckLink;
  50 class QOpenGLContext;
  51
  52 using namespace movit;
  53 using namespace std;
  54 using namespace std::chrono;
  55 using namespace std::placeholders;
  56 using namespace bmusb;
  57
  58 Mixer *global_mixer = nullptr;
  59 bool uses_mlock = false;
  60
  61 namespace {
  62
  63 void insert_new_frame(RefCountedFrame frame, unsigned field_num, bool interlaced, unsigned card_index, InputState *input_state)
  64 {
  65         if (interlaced) {
  66                 for (unsigned frame_num = FRAME_HISTORY_LENGTH; frame_num --> 1; ) {  // :-)
  67                         input_state->buffered_frames[card_index][frame_num] =
  68                                 input_state->buffered_frames[card_index][frame_num - 1];
  69                 }
  70                 input_state->buffered_frames[card_index][0] = { frame, field_num };
  71         } else {
  72                 for (unsigned frame_num = 0; frame_num < FRAME_HISTORY_LENGTH; ++frame_num) {
  73                         input_state->buffered_frames[card_index][frame_num] = { frame, field_num };
  74                 }
  75         }
  76 }
  77
  78 }  // namespace
  79
  80 void QueueLengthPolicy::update_policy(int queue_length)
  81 {
  82         if (queue_length < 0) {  // Starvation.
  83                 if (been_at_safe_point_since_last_starvation && safe_queue_length < 5) {
  84                         ++safe_queue_length;
  85                         fprintf(stderr, "Card %u: Starvation, increasing safe limit to %u frames\n",
  86                                 card_index, safe_queue_length);
  87                 }
  88                 frames_with_at_least_one = 0;
  89                 been_at_safe_point_since_last_starvation = false;
  90                 return;
  91         }
  92         if (queue_length > 0) {
  93                 if (queue_length >= int(safe_queue_length)) {
  94                         been_at_safe_point_since_last_starvation = true;
  95                 }
  96                 if (++frames_with_at_least_one >= 1000 && safe_queue_length > 0) {
  97                         --safe_queue_length;
  98                         fprintf(stderr, "Card %u: Spare frames for more than 1000 frames, reducing safe limit to %u frames\n",
  99                                 card_index, safe_queue_length);
 100                         frames_with_at_least_one = 0;
 101                 }
 102         } else {
 103                 frames_with_at_least_one = 0;
 104         }
 105 }
 106
 107 Mixer::Mixer(const QSurfaceFormat &format, unsigned num_cards)
 108         : httpd(),
 109           num_cards(num_cards),
 110           mixer_surface(create_surface(format)),
 111           h264_encoder_surface(create_surface(format)),
 112           decklink_output_surface(create_surface(format)),
 113           audio_mixer(num_cards)
 114 {
 115         CHECK(init_movit(MOVIT_SHADER_DIR, MOVIT_DEBUG_OFF));
 116         check_error();
 117
 118         // Since we allow non-bouncing 4:2:2 YCbCrInputs, effective subpixel precision
 119         // will be halved when sampling them, and we need to compensate here.
 120         movit_texel_subpixel_precision /= 2.0;
 121
 122         resource_pool.reset(new ResourcePool);
 123         theme.reset(new Theme(global_flags.theme_filename, global_flags.theme_dirs, resource_pool.get(), num_cards));
 124         for (unsigned i = 0; i < NUM_OUTPUTS; ++i) {
 125                 output_channel[i].parent = this;
 126                 output_channel[i].channel = i;
 127         }
 128
 129         ImageFormat inout_format;
 130         inout_format.color_space = COLORSPACE_sRGB;
 131         inout_format.gamma_curve = GAMMA_sRGB;
 132
 133         // Display chain; shows the live output produced by the main chain (its RGBA version).
 134         display_chain.reset(new EffectChain(global_flags.width, global_flags.height, resource_pool.get()));
 135         check_error();
 136         display_input = new FlatInput(inout_format, FORMAT_RGB, GL_UNSIGNED_BYTE, global_flags.width, global_flags.height);  // FIXME: GL_UNSIGNED_BYTE is really wrong.
 137         display_chain->add_input(display_input);
 138         display_chain->add_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED);
 139         display_chain->set_dither_bits(0);  // Don't bother.
 140         display_chain->finalize();
 141
 142         video_encoder.reset(new VideoEncoder(resource_pool.get(), h264_encoder_surface, global_flags.va_display, global_flags.width, global_flags.height, &httpd, global_disk_space_estimator));
 143
 144         // Start listening for clients only once VideoEncoder has written its header, if any.
 145         httpd.start(9095);
 146
 147         // First try initializing the then PCI devices, then USB, then
 148         // fill up with fake cards until we have the desired number of cards.
 149         unsigned num_pci_devices = 0;
 150         unsigned card_index = 0;
 151
 152         {
 153                 IDeckLinkIterator *decklink_iterator = CreateDeckLinkIteratorInstance();
 154                 if (decklink_iterator != nullptr) {
 155                         for ( ; card_index < num_cards; ++card_index) {
 156                                 IDeckLink *decklink;
 157                                 if (decklink_iterator->Next(&decklink) != S_OK) {
 158                                         break;
 159                                 }
 160
 161                                 DeckLinkCapture *capture = new DeckLinkCapture(decklink, card_index);
 162                                 DeckLinkOutput *output = new DeckLinkOutput(resource_pool.get(), decklink_output_surface, global_flags.width, global_flags.height, card_index);
 163                                 output->set_device(decklink);
 164                                 configure_card(card_index, capture, /*is_fake_capture=*/false, output);
 165                                 ++num_pci_devices;
 166                         }
 167                         decklink_iterator->Release();
 168                         fprintf(stderr, "Found %u DeckLink PCI card(s).\n", num_pci_devices);
 169                 } else {
 170                         fprintf(stderr, "DeckLink drivers not found. Probing for USB cards only.\n");
 171                 }
 172         }
 173
 174         unsigned num_usb_devices = BMUSBCapture::num_cards();
 175         for (unsigned usb_card_index = 0; usb_card_index < num_usb_devices && card_index < num_cards; ++usb_card_index, ++card_index) {
 176                 BMUSBCapture *capture = new BMUSBCapture(usb_card_index);
 177                 capture->set_card_disconnected_callback(bind(&Mixer::bm_hotplug_remove, this, card_index));
 178                 configure_card(card_index, capture, /*is_fake_capture=*/false, /*output=*/nullptr);
 179         }
 180         fprintf(stderr, "Found %u USB card(s).\n", num_usb_devices);
 181
 182         unsigned num_fake_cards = 0;
 183         for ( ; card_index < num_cards; ++card_index, ++num_fake_cards) {
 184                 FakeCapture *capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
 185                 configure_card(card_index, capture, /*is_fake_capture=*/true, /*output=*/nullptr);
 186         }
 187
 188         if (num_fake_cards > 0) {
 189                 fprintf(stderr, "Initialized %u fake cards.\n", num_fake_cards);
 190         }
 191
 192         BMUSBCapture::set_card_connected_callback(bind(&Mixer::bm_hotplug_add, this, _1));
 193         BMUSBCapture::start_bm_thread();
 194
 195         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 196                 cards[card_index].queue_length_policy.reset(card_index);
 197         }
 198
 199         chroma_subsampler.reset(new ChromaSubsampler(resource_pool.get()));
 200
 201         if (global_flags.enable_alsa_output) {
 202                 alsa.reset(new ALSAOutput(OUTPUT_FREQUENCY, /*num_channels=*/2));
 203         }
 204         if (global_flags.output_card != -1) {
 205                 set_output_card(global_flags.output_card);
 206         }
 207 }
 208
 209 Mixer::~Mixer()
 210 {
 211         BMUSBCapture::stop_bm_thread();
 212
 213         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 214                 {
 215                         unique_lock<mutex> lock(card_mutex);
 216                         cards[card_index].should_quit = true;  // Unblock thread.
 217                         cards[card_index].new_frames_changed.notify_all();
 218                 }
 219                 cards[card_index].capture->stop_dequeue_thread();
 220                 if (cards[card_index].output) {
 221                         cards[card_index].output->end_output();
 222                         delete cards[card_index].output;
 223                 }
 224         }
 225
 226         video_encoder.reset(nullptr);
 227 }
 228
 229 void Mixer::configure_card(unsigned card_index, CaptureInterface *capture, bool is_fake_capture, DeckLinkOutput *output)
 230 {
 231         printf("Configuring card %d...\n", card_index);
 232
 233         CaptureCard *card = &cards[card_index];
 234         if (card->capture != nullptr) {
 235                 card->capture->stop_dequeue_thread();
 236                 delete card->capture;
 237         }
 238         card->capture = capture;
 239         card->is_fake_capture = is_fake_capture;
 240         card->output = output;
 241         card->capture->set_frame_callback(bind(&Mixer::bm_frame, this, card_index, _1, _2, _3, _4, _5, _6, _7));
 242         if (card->frame_allocator == nullptr) {
 243                 card->frame_allocator.reset(new PBOFrameAllocator(8 << 20, global_flags.width, global_flags.height));  // 8 MB.
 244         }
 245         card->capture->set_video_frame_allocator(card->frame_allocator.get());
 246         if (card->surface == nullptr) {
 247                 card->surface = create_surface_with_same_format(mixer_surface);
 248         }
 249         while (!card->new_frames.empty()) card->new_frames.pop();
 250         card->last_timecode = -1;
 251         card->capture->configure_card();
 252
 253         // NOTE: start_bm_capture() happens in thread_func().
 254
 255         DeviceSpec device{InputSourceType::CAPTURE_CARD, card_index};
 256         audio_mixer.reset_resampler(device);
 257         audio_mixer.set_display_name(device, card->capture->get_description());
 258         audio_mixer.trigger_state_changed_callback();
 259 }
 260
 261 void Mixer::set_output_card(int card_index)
 262 {
 263         if (card_index == output_card_index) {
 264                 return;
 265         }
 266         unique_lock<mutex> lock(card_mutex);
 267         if (output_card_index != -1) {
 268                 // Switch the old card from output to input.
 269                 CaptureCard *old_card = &cards[output_card_index];
 270                 old_card->output->end_output();
 271
 272                 old_card->capture->stop_dequeue_thread();
 273                 delete old_card->capture;
 274
 275                 old_card->capture = old_card->parked_capture;
 276                 old_card->is_fake_capture = false;
 277                 old_card->parked_capture = nullptr;
 278                 old_card->capture->start_bm_capture();
 279         }
 280
 281         CaptureCard *card = &cards[card_index];
 282         card->capture->stop_dequeue_thread();
 283         card->parked_capture = card->capture;
 284         FakeCapture *capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
 285         configure_card(card_index, capture, /*is_fake_capture=*/true, card->output);
 286         card->queue_length_policy.reset(card_index);
 287         card->capture->start_bm_capture();
 288         card->output->start_output(bmdModeHD720p5994, pts_int);  // FIXME
 289         output_card_index = card_index;
 290 }
 291
 292 namespace {
 293
 294 int unwrap_timecode(uint16_t current_wrapped, int last)
 295 {
 296         uint16_t last_wrapped = last & 0xffff;
 297         if (current_wrapped > last_wrapped) {
 298                 return (last & ~0xffff) | current_wrapped;
 299         } else {
 300                 return 0x10000 + ((last & ~0xffff) | current_wrapped);
 301         }
 302 }
 303
 304 }  // namespace
 305
 306 void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
 307                      FrameAllocator::Frame video_frame, size_t video_offset, VideoFormat video_format,
 308                      FrameAllocator::Frame audio_frame, size_t audio_offset, AudioFormat audio_format)
 309 {
 310         DeviceSpec device{InputSourceType::CAPTURE_CARD, card_index};
 311         CaptureCard *card = &cards[card_index];
 312
 313         if (is_mode_scanning[card_index]) {
 314                 if (video_format.has_signal) {
 315                         // Found a stable signal, so stop scanning.
 316                         is_mode_scanning[card_index] = false;
 317                 } else {
 318                         static constexpr double switch_time_s = 0.1;  // Should be enough time for the signal to stabilize.
 319                         steady_clock::time_point now = steady_clock::now();
 320                         double sec_since_last_switch = duration<double>(steady_clock::now() - last_mode_scan_change[card_index]).count();
 321                         if (sec_since_last_switch > switch_time_s) {
 322                                 // It isn't this mode; try the next one.
 323                                 mode_scanlist_index[card_index]++;
 324                                 mode_scanlist_index[card_index] %= mode_scanlist[card_index].size();
 325                                 cards[card_index].capture->set_video_mode(mode_scanlist[card_index][mode_scanlist_index[card_index]]);
 326                                 last_mode_scan_change[card_index] = now;
 327                         }
 328                 }
 329         }
 330
 331         int64_t frame_length = int64_t(TIMEBASE) * video_format.frame_rate_den / video_format.frame_rate_nom;
 332         assert(frame_length > 0);
 333
 334         size_t num_samples = (audio_frame.len > audio_offset) ? (audio_frame.len - audio_offset) / audio_format.num_channels / (audio_format.bits_per_sample / 8) : 0;
 335         if (num_samples > OUTPUT_FREQUENCY / 10) {
 336                 printf("Card %d: Dropping frame with implausible audio length (len=%d, offset=%d) [timecode=0x%04x video_len=%d video_offset=%d video_format=%x)\n",
 337                         card_index, int(audio_frame.len), int(audio_offset),
 338                         timecode, int(video_frame.len), int(video_offset), video_format.id);
 339                 if (video_frame.owner) {
 340                         video_frame.owner->release_frame(video_frame);
 341                 }
 342                 if (audio_frame.owner) {
 343                         audio_frame.owner->release_frame(audio_frame);
 344                 }
 345                 return;
 346         }
 347
 348         int dropped_frames = 0;
 349         if (card->last_timecode != -1) {
 350                 dropped_frames = unwrap_timecode(timecode, card->last_timecode) - card->last_timecode - 1;
 351         }
 352
 353         // Number of samples per frame if we need to insert silence.
 354         // (Could be nonintegral, but resampling will save us then.)
 355         const int silence_samples = OUTPUT_FREQUENCY * video_format.frame_rate_den / video_format.frame_rate_nom;
 356
 357         if (dropped_frames > MAX_FPS * 2) {
 358                 fprintf(stderr, "Card %d lost more than two seconds (or time code jumping around; from 0x%04x to 0x%04x), resetting resampler\n",
 359                         card_index, card->last_timecode, timecode);
 360                 audio_mixer.reset_resampler(device);
 361                 dropped_frames = 0;
 362         } else if (dropped_frames > 0) {
 363                 // Insert silence as needed.
 364                 fprintf(stderr, "Card %d dropped %d frame(s) (before timecode 0x%04x), inserting silence.\n",
 365                         card_index, dropped_frames, timecode);
 366
 367                 bool success;
 368                 do {
 369                         success = audio_mixer.add_silence(device, silence_samples, dropped_frames, frame_length);
 370                 } while (!success);
 371         }
 372
 373         audio_mixer.add_audio(device, audio_frame.data + audio_offset, num_samples, audio_format, frame_length);
 374
 375         // Done with the audio, so release it.
 376         if (audio_frame.owner) {
 377                 audio_frame.owner->release_frame(audio_frame);
 378         }
 379
 380         card->last_timecode = timecode;
 381
 382         size_t expected_length = video_format.width * (video_format.height + video_format.extra_lines_top + video_format.extra_lines_bottom) * 2;
 383         if (video_frame.len - video_offset == 0 ||
 384             video_frame.len - video_offset != expected_length) {
 385                 if (video_frame.len != 0) {
 386                         printf("Card %d: Dropping video frame with wrong length (%ld; expected %ld)\n",
 387                                 card_index, video_frame.len - video_offset, expected_length);
 388                 }
 389                 if (video_frame.owner) {
 390                         video_frame.owner->release_frame(video_frame);
 391                 }
 392
 393                 // Still send on the information that we _had_ a frame, even though it's corrupted,
 394                 // so that pts can go up accordingly.
 395                 {
 396                         unique_lock<mutex> lock(card_mutex);
 397                         CaptureCard::NewFrame new_frame;
 398                         new_frame.frame = RefCountedFrame(FrameAllocator::Frame());
 399                         new_frame.length = frame_length;
 400                         new_frame.interlaced = false;
 401                         new_frame.dropped_frames = dropped_frames;
 402                         card->new_frames.push(move(new_frame));
 403                         card->new_frames_changed.notify_all();
 404                 }
 405                 return;
 406         }
 407
 408         PBOFrameAllocator::Userdata *userdata = (PBOFrameAllocator::Userdata *)video_frame.userdata;
 409
 410         unsigned num_fields = video_format.interlaced ? 2 : 1;
 411         steady_clock::time_point frame_upload_start;
 412         bool interlaced_stride = false;
 413         if (video_format.interlaced) {
 414                 // Send the two fields along as separate frames; the other side will need to add
 415                 // a deinterlacer to actually get this right.
 416                 assert(video_format.height % 2 == 0);
 417                 video_format.height /= 2;
 418                 assert(frame_length % 2 == 0);
 419                 frame_length /= 2;
 420                 num_fields = 2;
 421                 if (video_format.second_field_start == 1) {
 422                         interlaced_stride = true;
 423                 }
 424                 frame_upload_start = steady_clock::now();
 425         }
 426         userdata->last_interlaced = video_format.interlaced;
 427         userdata->last_has_signal = video_format.has_signal;
 428         userdata->last_is_connected = video_format.is_connected;
 429         userdata->last_frame_rate_nom = video_format.frame_rate_nom;
 430         userdata->last_frame_rate_den = video_format.frame_rate_den;
 431         RefCountedFrame frame(video_frame);
 432
 433         // Upload the textures.
 434         size_t cbcr_width = video_format.width / 2;
 435         size_t cbcr_offset = video_offset / 2;
 436         size_t y_offset = video_frame.size / 2 + video_offset / 2;
 437
 438         for (unsigned field = 0; field < num_fields; ++field) {
 439                 // Put the actual texture upload in a lambda that is executed in the main thread.
 440                 // It is entirely possible to do this in the same thread (and it might even be
 441                 // faster, depending on the GPU and driver), but it appears to be trickling
 442                 // driver bugs very easily.
 443                 //
 444                 // Note that this means we must hold on to the actual frame data in <userdata>
 445                 // until the upload command is run, but we hold on to <frame> much longer than that
 446                 // (in fact, all the way until we no longer use the texture in rendering).
 447                 auto upload_func = [field, video_format, y_offset, cbcr_offset, cbcr_width, interlaced_stride, userdata]() {
 448                         unsigned field_start_line;
 449                         if (field == 1) {
 450                                 field_start_line = video_format.second_field_start;
 451                         } else {
 452                                 field_start_line = video_format.extra_lines_top;
 453                         }
 454
 455                         if (userdata->tex_y[field] == 0 ||
 456                             userdata->tex_cbcr[field] == 0 ||
 457                             video_format.width != userdata->last_width[field] ||
 458                             video_format.height != userdata->last_height[field]) {
 459                                 // We changed resolution since last use of this texture, so we need to create
 460                                 // a new object. Note that this each card has its own PBOFrameAllocator,
 461                                 // we don't need to worry about these flip-flopping between resolutions.
 462                                 glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr[field]);
 463                                 check_error();
 464                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_RG8, cbcr_width, video_format.height, 0, GL_RG, GL_UNSIGNED_BYTE, nullptr);
 465                                 check_error();
 466                                 glBindTexture(GL_TEXTURE_2D, userdata->tex_y[field]);
 467                                 check_error();
 468                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, video_format.width, video_format.height, 0, GL_RED, GL_UNSIGNED_BYTE, nullptr);
 469                                 check_error();
 470                                 userdata->last_width[field] = video_format.width;
 471                                 userdata->last_height[field] = video_format.height;
 472                         }
 473
 474                         GLuint pbo = userdata->pbo;
 475                         check_error();
 476                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER, pbo);
 477                         check_error();
 478
 479                         size_t field_y_start = y_offset + video_format.width * field_start_line;
 480                         size_t field_cbcr_start = cbcr_offset + cbcr_width * field_start_line * sizeof(uint16_t);
 481
 482                         if (global_flags.flush_pbos) {
 483                                 glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, field_y_start, video_format.width * video_format.height);
 484                                 check_error();
 485                                 glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, field_cbcr_start, cbcr_width * video_format.height * sizeof(uint16_t));
 486                                 check_error();
 487                         }
 488
 489                         glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr[field]);
 490                         check_error();
 491                         if (interlaced_stride) {
 492                                 glPixelStorei(GL_UNPACK_ROW_LENGTH, cbcr_width * 2);
 493                                 check_error();
 494                         } else {
 495                                 glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 496                                 check_error();
 497                         }
 498                         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, cbcr_width, video_format.height, GL_RG, GL_UNSIGNED_BYTE, BUFFER_OFFSET(field_cbcr_start));
 499                         check_error();
 500                         glBindTexture(GL_TEXTURE_2D, userdata->tex_y[field]);
 501                         check_error();
 502                         if (interlaced_stride) {
 503                                 glPixelStorei(GL_UNPACK_ROW_LENGTH, video_format.width * 2);
 504                                 check_error();
 505                         } else {
 506                                 glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 507                                 check_error();
 508                         }
 509                         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, video_format.width, video_format.height, GL_RED, GL_UNSIGNED_BYTE, BUFFER_OFFSET(field_y_start));
 510                         check_error();
 511                         glBindTexture(GL_TEXTURE_2D, 0);
 512                         check_error();
 513                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
 514                         check_error();
 515                         glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 516                         check_error();
 517                 };
 518
 519                 if (field == 1) {
 520                         // Don't upload the second field as fast as we can; wait until
 521                         // the field time has approximately passed. (Otherwise, we could
 522                         // get timing jitter against the other sources, and possibly also
 523                         // against the video display, although the latter is not as critical.)
 524                         // This requires our system clock to be reasonably close to the
 525                         // video clock, but that's not an unreasonable assumption.
 526                         steady_clock::time_point second_field_start = frame_upload_start +
 527                                 nanoseconds(frame_length * 1000000000 / TIMEBASE);
 528                         this_thread::sleep_until(second_field_start);
 529                 }
 530
 531                 {
 532                         unique_lock<mutex> lock(card_mutex);
 533                         CaptureCard::NewFrame new_frame;
 534                         new_frame.frame = frame;
 535                         new_frame.length = frame_length;
 536                         new_frame.field = field;
 537                         new_frame.interlaced = video_format.interlaced;
 538                         new_frame.upload_func = upload_func;
 539                         new_frame.dropped_frames = dropped_frames;
 540                         new_frame.received_timestamp = video_frame.received_timestamp;  // Ignore the audio timestamp.
 541                         card->new_frames.push(move(new_frame));
 542                         card->new_frames_changed.notify_all();
 543                 }
 544         }
 545 }
 546
 547 void Mixer::bm_hotplug_add(libusb_device *dev)
 548 {
 549         lock_guard<mutex> lock(hotplug_mutex);
 550         hotplugged_cards.push_back(dev);
 551 }
 552
 553 void Mixer::bm_hotplug_remove(unsigned card_index)
 554 {
 555         cards[card_index].new_frames_changed.notify_all();
 556 }
 557
 558 void Mixer::thread_func()
 559 {
 560         eglBindAPI(EGL_OPENGL_API);
 561         QOpenGLContext *context = create_context(mixer_surface);
 562         if (!make_current(context, mixer_surface)) {
 563                 printf("oops\n");
 564                 exit(1);
 565         }
 566
 567         // Start the actual capture. (We don't want to do it before we're actually ready
 568         // to process output frames.)
 569         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 570                 if (int(card_index) != output_card_index) {
 571                         cards[card_index].capture->start_bm_capture();
 572                 }
 573         }
 574
 575         steady_clock::time_point start, now;
 576         start = steady_clock::now();
 577
 578         int frame = 0;
 579         int stats_dropped_frames = 0;
 580
 581         while (!should_quit) {
 582                 CaptureCard::NewFrame new_frames[MAX_VIDEO_CARDS];
 583                 bool has_new_frame[MAX_VIDEO_CARDS] = { false };
 584
 585                 bool master_card_is_output;
 586                 unsigned master_card_index;
 587                 if (output_card_index != -1) {
 588                         master_card_is_output = true;
 589                         master_card_index = output_card_index;
 590                 } else {
 591                         master_card_is_output = false;
 592                         master_card_index = theme->map_signal(master_clock_channel);
 593                         assert(master_card_index < num_cards);
 594                 }
 595
 596                 OutputFrameInfo output_frame_info = get_one_frame_from_each_card(master_card_index, master_card_is_output, new_frames, has_new_frame);
 597                 schedule_audio_resampling_tasks(output_frame_info.dropped_frames, output_frame_info.num_samples, output_frame_info.frame_duration);
 598                 stats_dropped_frames += output_frame_info.dropped_frames;
 599
 600                 handle_hotplugged_cards();
 601
 602                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 603                         if (card_index == master_card_index || !has_new_frame[card_index]) {
 604                                 continue;
 605                         }
 606                         if (new_frames[card_index].frame->len == 0) {
 607                                 ++new_frames[card_index].dropped_frames;
 608                         }
 609                         if (new_frames[card_index].dropped_frames > 0) {
 610                                 printf("Card %u dropped %d frames before this\n",
 611                                         card_index, int(new_frames[card_index].dropped_frames));
 612                         }
 613                 }
 614
 615                 // If the first card is reporting a corrupted or otherwise dropped frame,
 616                 // just increase the pts (skipping over this frame) and don't try to compute anything new.
 617                 if (!master_card_is_output && new_frames[master_card_index].frame->len == 0) {
 618                         ++stats_dropped_frames;
 619                         pts_int += new_frames[master_card_index].length;
 620                         continue;
 621                 }
 622
 623                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 624                         if (!has_new_frame[card_index] || new_frames[card_index].frame->len == 0)
 625                                 continue;
 626
 627                         CaptureCard::NewFrame *new_frame = &new_frames[card_index];
 628                         assert(new_frame->frame != nullptr);
 629                         insert_new_frame(new_frame->frame, new_frame->field, new_frame->interlaced, card_index, &input_state);
 630                         check_error();
 631
 632                         // The new texture might need uploading before use.
 633                         if (new_frame->upload_func) {
 634                                 new_frame->upload_func();
 635                                 new_frame->upload_func = nullptr;
 636                         }
 637                 }
 638
 639                 int64_t frame_duration = output_frame_info.frame_duration;
 640                 render_one_frame(frame_duration);
 641                 ++frame;
 642                 pts_int += frame_duration;
 643
 644                 now = steady_clock::now();
 645                 double elapsed = duration<double>(now - start).count();
 646                 if (frame % 100 == 0) {
 647                         printf("%d frames (%d dropped) in %.3f seconds = %.1f fps (%.1f ms/frame)",
 648                                 frame, stats_dropped_frames, elapsed, frame / elapsed,
 649                                 1e3 * elapsed / frame);
 650                 //      chain->print_phase_timing();
 651
 652                         // Check our memory usage, to see if we are close to our mlockall()
 653                         // limit (if at all set).
 654                         rusage used;
 655                         if (getrusage(RUSAGE_SELF, &used) == -1) {
 656                                 perror("getrusage(RUSAGE_SELF)");
 657                                 assert(false);
 658                         }
 659
 660                         if (uses_mlock) {
 661                                 rlimit limit;
 662                                 if (getrlimit(RLIMIT_MEMLOCK, &limit) == -1) {
 663                                         perror("getrlimit(RLIMIT_MEMLOCK)");
 664                                         assert(false);
 665                                 }
 666
 667                                 if (limit.rlim_cur == 0) {
 668                                         printf(", using %ld MB memory (locked)",
 669                                                 long(used.ru_maxrss / 1024));
 670                                 } else {
 671                                         printf(", using %ld / %ld MB lockable memory (%.1f%%)",
 672                                                 long(used.ru_maxrss / 1024),
 673                                                 long(limit.rlim_cur / 1048576),
 674                                                 float(100.0 * (used.ru_maxrss * 1024.0) / limit.rlim_cur));
 675                                 }
 676                         } else {
 677                                 printf(", using %ld MB memory (not locked)",
 678                                         long(used.ru_maxrss / 1024));
 679                         }
 680
 681                         printf("\n");
 682                 }
 683
 684
 685                 if (should_cut.exchange(false)) {  // Test and clear.
 686                         video_encoder->do_cut(frame);
 687                 }
 688
 689 #if 0
 690                 // Reset every 100 frames, so that local variations in frame times
 691                 // (especially for the first few frames, when the shaders are
 692                 // compiled etc.) don't make it hard to measure for the entire
 693                 // remaining duration of the program.
 694                 if (frame == 10000) {
 695                         frame = 0;
 696                         start = now;
 697                 }
 698 #endif
 699                 check_error();
 700         }
 701
 702         resource_pool->clean_context();
 703 }
 704
 705 bool Mixer::input_card_is_master_clock(unsigned card_index, unsigned master_card_index) const
 706 {
 707         if (output_card_index != -1) {
 708                 // The output card (ie., cards[output_card_index].output) is the master clock,
 709                 // so no input card (ie., cards[card_index].capture) is.
 710                 return false;
 711         }
 712         return (card_index == master_card_index);
 713 }
 714
 715 Mixer::OutputFrameInfo Mixer::get_one_frame_from_each_card(unsigned master_card_index, bool master_card_is_output, CaptureCard::NewFrame new_frames[MAX_VIDEO_CARDS], bool has_new_frame[MAX_VIDEO_CARDS])
 716 {
 717         OutputFrameInfo output_frame_info;
 718 start:
 719         unique_lock<mutex> lock(card_mutex, defer_lock);
 720         if (master_card_is_output) {
 721                 // Clocked to the output, so wait for it to be ready for the next frame.
 722                 cards[master_card_index].output->wait_for_frame(pts_int, &output_frame_info.dropped_frames, &output_frame_info.frame_duration);
 723                 lock.lock();
 724         } else {
 725                 // Wait for the master card to have a new frame.
 726                 // TODO: Add a timeout.
 727                 lock.lock();
 728                 cards[master_card_index].new_frames_changed.wait(lock, [this, master_card_index]{ return !cards[master_card_index].new_frames.empty() || cards[master_card_index].capture->get_disconnected(); });
 729         }
 730
 731         if (master_card_is_output) {
 732                 handle_hotplugged_cards();
 733         } else if (cards[master_card_index].new_frames.empty()) {
 734                 // We were woken up, but not due to a new frame. Deal with it
 735                 // and then restart.
 736                 assert(cards[master_card_index].capture->get_disconnected());
 737                 handle_hotplugged_cards();
 738                 goto start;
 739         }
 740
 741         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 742                 CaptureCard *card = &cards[card_index];
 743                 if (card->new_frames.empty()) {
 744                         assert(!input_card_is_master_clock(card_index, master_card_index));
 745                         card->queue_length_policy.update_policy(-1);
 746                         continue;
 747                 }
 748                 new_frames[card_index] = move(card->new_frames.front());
 749                 has_new_frame[card_index] = true;
 750                 card->new_frames.pop();
 751                 card->new_frames_changed.notify_all();
 752
 753                 if (input_card_is_master_clock(card_index, master_card_index)) {
 754                         // We don't use the queue length policy for the master card,
 755                         // but we will if it stops being the master. Thus, clear out
 756                         // the policy in case we switch in the future.
 757                         card->queue_length_policy.reset(card_index);
 758                 } else {
 759                         // If we have excess frames compared to the policy for this card,
 760                         // drop frames from the head.
 761                         card->queue_length_policy.update_policy(card->new_frames.size());
 762                         while (card->new_frames.size() > card->queue_length_policy.get_safe_queue_length()) {
 763                                 card->new_frames.pop();
 764                         }
 765                 }
 766         }
 767
 768         if (!master_card_is_output) {
 769                 output_frame_info.dropped_frames = new_frames[master_card_index].dropped_frames;
 770                 output_frame_info.frame_duration = new_frames[master_card_index].length;
 771         }
 772
 773         // This might get off by a fractional sample when changing master card
 774         // between ones with different frame rates, but that's fine.
 775         int num_samples_times_timebase = OUTPUT_FREQUENCY * output_frame_info.frame_duration + fractional_samples;
 776         output_frame_info.num_samples = num_samples_times_timebase / TIMEBASE;
 777         fractional_samples = num_samples_times_timebase % TIMEBASE;
 778         assert(output_frame_info.num_samples >= 0);
 779
 780         return output_frame_info;
 781 }
 782
 783 void Mixer::handle_hotplugged_cards()
 784 {
 785         // Check for cards that have been disconnected since last frame.
 786         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 787                 CaptureCard *card = &cards[card_index];
 788                 if (card->capture->get_disconnected()) {
 789                         fprintf(stderr, "Card %u went away, replacing with a fake card.\n", card_index);
 790                         FakeCapture *capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
 791                         configure_card(card_index, capture, /*is_fake_capture=*/true, /*output=*/nullptr);
 792                         card->queue_length_policy.reset(card_index);
 793                         card->capture->start_bm_capture();
 794                 }
 795         }
 796
 797         // Check for cards that have been connected since last frame.
 798         vector<libusb_device *> hotplugged_cards_copy;
 799         {
 800                 lock_guard<mutex> lock(hotplug_mutex);
 801                 swap(hotplugged_cards, hotplugged_cards_copy);
 802         }
 803         for (libusb_device *new_dev : hotplugged_cards_copy) {
 804                 // Look for a fake capture card where we can stick this in.
 805                 int free_card_index = -1;
 806                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 807                         if (cards[card_index].is_fake_capture) {
 808                                 free_card_index = card_index;
 809                                 break;
 810                         }
 811                 }
 812
 813                 if (free_card_index == -1) {
 814                         fprintf(stderr, "New card plugged in, but no free slots -- ignoring.\n");
 815                         libusb_unref_device(new_dev);
 816                 } else {
 817                         // BMUSBCapture takes ownership.
 818                         fprintf(stderr, "New card plugged in, choosing slot %d.\n", free_card_index);
 819                         CaptureCard *card = &cards[free_card_index];
 820                         BMUSBCapture *capture = new BMUSBCapture(free_card_index, new_dev);
 821                         configure_card(free_card_index, capture, /*is_fake_capture=*/false, /*output=*/nullptr);
 822                         card->queue_length_policy.reset(free_card_index);
 823                         capture->set_card_disconnected_callback(bind(&Mixer::bm_hotplug_remove, this, free_card_index));
 824                         capture->start_bm_capture();
 825                 }
 826         }
 827 }
 828
 829
 830 void Mixer::schedule_audio_resampling_tasks(unsigned dropped_frames, int num_samples_per_frame, int length_per_frame)
 831 {
 832         // Resample the audio as needed, including from previously dropped frames.
 833         assert(num_cards > 0);
 834         for (unsigned frame_num = 0; frame_num < dropped_frames + 1; ++frame_num) {
 835                 const bool dropped_frame = (frame_num != dropped_frames);
 836                 {
 837                         // Signal to the audio thread to process this frame.
 838                         // Note that if the frame is a dropped frame, we signal that
 839                         // we don't want to use this frame as base for adjusting
 840                         // the resampler rate. The reason for this is that the timing
 841                         // of these frames is often way too late; they typically don't
 842                         // “arrive” before we synthesize them. Thus, we could end up
 843                         // in a situation where we have inserted e.g. five audio frames
 844                         // into the queue before we then start pulling five of them
 845                         // back out. This makes ResamplingQueue overestimate the delay,
 846                         // causing undue resampler changes. (We _do_ use the last,
 847                         // non-dropped frame; perhaps we should just discard that as well,
 848                         // since dropped frames are expected to be rare, and it might be
 849                         // better to just wait until we have a slightly more normal situation).
 850                         unique_lock<mutex> lock(audio_mutex);
 851                         bool adjust_rate = !dropped_frame;
 852                         audio_task_queue.push(AudioTask{pts_int, num_samples_per_frame, adjust_rate});
 853                         audio_task_queue_changed.notify_one();
 854                 }
 855                 if (dropped_frame) {
 856                         // For dropped frames, increase the pts. Note that if the format changed
 857                         // in the meantime, we have no way of detecting that; we just have to
 858                         // assume the frame length is always the same.
 859                         pts_int += length_per_frame;
 860                 }
 861         }
 862 }
 863
 864 void Mixer::render_one_frame(int64_t duration)
 865 {
 866         // Get the main chain from the theme, and set its state immediately.
 867         Theme::Chain theme_main_chain = theme->get_chain(0, pts(), global_flags.width, global_flags.height, input_state);
 868         EffectChain *chain = theme_main_chain.chain;
 869         theme_main_chain.setup_chain();
 870         //theme_main_chain.chain->enable_phase_timing(true);
 871
 872         GLuint y_tex, cbcr_tex;
 873         bool got_frame = video_encoder->begin_frame(&y_tex, &cbcr_tex);
 874         assert(got_frame);
 875
 876         // Render main chain.
 877         GLuint cbcr_full_tex = resource_pool->create_2d_texture(GL_RG8, global_flags.width, global_flags.height);
 878         GLuint rgba_tex = resource_pool->create_2d_texture(GL_RGB565, global_flags.width, global_flags.height);  // Saves texture bandwidth, although dithering gets messed up.
 879         GLuint fbo = resource_pool->create_fbo(y_tex, cbcr_full_tex, rgba_tex);
 880         check_error();
 881         chain->render_to_fbo(fbo, global_flags.width, global_flags.height);
 882         resource_pool->release_fbo(fbo);
 883
 884         chroma_subsampler->subsample_chroma(cbcr_full_tex, global_flags.width, global_flags.height, cbcr_tex);
 885         if (output_card_index != -1) {
 886                 cards[output_card_index].output->send_frame(y_tex, cbcr_full_tex, theme_main_chain.input_frames, pts_int, duration);
 887         }
 888         resource_pool->release_2d_texture(cbcr_full_tex);
 889
 890         // Set the right state for rgba_tex.
 891         glBindFramebuffer(GL_FRAMEBUFFER, 0);
 892         glBindTexture(GL_TEXTURE_2D, rgba_tex);
 893         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 894         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 895         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 896
 897         const int64_t av_delay = lrint(global_flags.audio_queue_length_ms * 0.001 * TIMEBASE);  // Corresponds to the delay in ResamplingQueue.
 898         RefCountedGLsync fence = video_encoder->end_frame(pts_int + av_delay, duration, theme_main_chain.input_frames);
 899
 900         // The live frame just shows the RGBA texture we just rendered.
 901         // It owns rgba_tex now.
 902         DisplayFrame live_frame;
 903         live_frame.chain = display_chain.get();
 904         live_frame.setup_chain = [this, rgba_tex]{
 905                 display_input->set_texture_num(rgba_tex);
 906         };
 907         live_frame.ready_fence = fence;
 908         live_frame.input_frames = {};
 909         live_frame.temp_textures = { rgba_tex };
 910         output_channel[OUTPUT_LIVE].output_frame(live_frame);
 911
 912         // Set up preview and any additional channels.
 913         for (int i = 1; i < theme->get_num_channels() + 2; ++i) {
 914                 DisplayFrame display_frame;
 915                 Theme::Chain chain = theme->get_chain(i, pts(), global_flags.width, global_flags.height, input_state);  // FIXME: dimensions
 916                 display_frame.chain = chain.chain;
 917                 display_frame.setup_chain = chain.setup_chain;
 918                 display_frame.ready_fence = fence;
 919                 display_frame.input_frames = chain.input_frames;
 920                 display_frame.temp_textures = {};
 921                 output_channel[i].output_frame(display_frame);
 922         }
 923 }
 924
 925 void Mixer::audio_thread_func()
 926 {
 927         while (!should_quit) {
 928                 AudioTask task;
 929
 930                 {
 931                         unique_lock<mutex> lock(audio_mutex);
 932                         audio_task_queue_changed.wait(lock, [this]{ return should_quit || !audio_task_queue.empty(); });
 933                         if (should_quit) {
 934                                 return;
 935                         }
 936                         task = audio_task_queue.front();
 937                         audio_task_queue.pop();
 938                 }
 939
 940                 ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy =
 941                         task.adjust_rate ? ResamplingQueue::ADJUST_RATE : ResamplingQueue::DO_NOT_ADJUST_RATE;
 942                 vector<float> samples_out = audio_mixer.get_output(
 943                         double(task.pts_int) / TIMEBASE,
 944                         task.num_samples,
 945                         rate_adjustment_policy);
 946
 947                 // Send the samples to the sound card, then add them to the output.
 948                 if (alsa) {
 949                         alsa->write(samples_out);
 950                 }
 951                 if (output_card_index != -1) {
 952                         const int64_t av_delay = lrint(global_flags.audio_queue_length_ms * 0.001 * TIMEBASE);  // Corresponds to the delay in ResamplingQueue.
 953                         cards[output_card_index].output->send_audio(task.pts_int + av_delay, samples_out);
 954                 }
 955                 video_encoder->add_audio(task.pts_int, move(samples_out));
 956         }
 957 }
 958
 959 void Mixer::release_display_frame(DisplayFrame *frame)
 960 {
 961         for (GLuint texnum : frame->temp_textures) {
 962                 resource_pool->release_2d_texture(texnum);
 963         }
 964         frame->temp_textures.clear();
 965         frame->ready_fence.reset();
 966         frame->input_frames.clear();
 967 }
 968
 969 void Mixer::start()
 970 {
 971         mixer_thread = thread(&Mixer::thread_func, this);
 972         audio_thread = thread(&Mixer::audio_thread_func, this);
 973 }
 974
 975 void Mixer::quit()
 976 {
 977         should_quit = true;
 978         audio_task_queue_changed.notify_one();
 979         mixer_thread.join();
 980         audio_thread.join();
 981 }
 982
 983 void Mixer::transition_clicked(int transition_num)
 984 {
 985         theme->transition_clicked(transition_num, pts());
 986 }
 987
 988 void Mixer::channel_clicked(int preview_num)
 989 {
 990         theme->channel_clicked(preview_num);
 991 }
 992
 993 void Mixer::start_mode_scanning(unsigned card_index)
 994 {
 995         assert(card_index < num_cards);
 996         if (is_mode_scanning[card_index]) {
 997                 return;
 998         }
 999         is_mode_scanning[card_index] = true;
1000         mode_scanlist[card_index].clear();
1001         for (const auto &mode : cards[card_index].capture->get_available_video_modes()) {
1002                 mode_scanlist[card_index].push_back(mode.first);
1003         }
1004         assert(!mode_scanlist[card_index].empty());
1005         mode_scanlist_index[card_index] = 0;
1006         cards[card_index].capture->set_video_mode(mode_scanlist[card_index][0]);
1007         last_mode_scan_change[card_index] = steady_clock::now();
1008 }
1009
1010 Mixer::OutputChannel::~OutputChannel()
1011 {
1012         if (has_current_frame) {
1013                 parent->release_display_frame(&current_frame);
1014         }
1015         if (has_ready_frame) {
1016                 parent->release_display_frame(&ready_frame);
1017         }
1018 }
1019
1020 void Mixer::OutputChannel::output_frame(DisplayFrame frame)
1021 {
1022         // Store this frame for display. Remove the ready frame if any
1023         // (it was seemingly never used).
1024         {
1025                 unique_lock<mutex> lock(frame_mutex);
1026                 if (has_ready_frame) {
1027                         parent->release_display_frame(&ready_frame);
1028                 }
1029                 ready_frame = frame;
1030                 has_ready_frame = true;
1031         }
1032
1033         if (new_frame_ready_callback) {
1034                 new_frame_ready_callback();
1035         }
1036
1037         // Reduce the number of callbacks by filtering duplicates. The reason
1038         // why we bother doing this is that Qt seemingly can get into a state
1039         // where its builds up an essentially unbounded queue of signals,
1040         // consuming more and more memory, and there's no good way of collapsing
1041         // user-defined signals or limiting the length of the queue.
1042         if (transition_names_updated_callback) {
1043                 vector<string> transition_names = global_mixer->get_transition_names();
1044                 bool changed = false;
1045                 if (transition_names.size() != last_transition_names.size()) {
1046                         changed = true;
1047                 } else {
1048                         for (unsigned i = 0; i < transition_names.size(); ++i) {
1049                                 if (transition_names[i] != last_transition_names[i]) {
1050                                         changed = true;
1051                                         break;
1052                                 }
1053                         }
1054                 }
1055                 if (changed) {
1056                         transition_names_updated_callback(transition_names);
1057                         last_transition_names = transition_names;
1058                 }
1059         }
1060         if (name_updated_callback) {
1061                 string name = global_mixer->get_channel_name(channel);
1062                 if (name != last_name) {
1063                         name_updated_callback(name);
1064                         last_name = name;
1065                 }
1066         }
1067         if (color_updated_callback) {
1068                 string color = global_mixer->get_channel_color(channel);
1069                 if (color != last_color) {
1070                         color_updated_callback(color);
1071                         last_color = color;
1072                 }
1073         }
1074 }
1075
1076 bool Mixer::OutputChannel::get_display_frame(DisplayFrame *frame)
1077 {
1078         unique_lock<mutex> lock(frame_mutex);
1079         if (!has_current_frame && !has_ready_frame) {
1080                 return false;
1081         }
1082
1083         if (has_current_frame && has_ready_frame) {
1084                 // We have a new ready frame. Toss the current one.
1085                 parent->release_display_frame(&current_frame);
1086                 has_current_frame = false;
1087         }
1088         if (has_ready_frame) {
1089                 assert(!has_current_frame);
1090                 current_frame = ready_frame;
1091                 ready_frame.ready_fence.reset();  // Drop the refcount.
1092                 ready_frame.input_frames.clear();  // Drop the refcounts.
1093                 has_current_frame = true;
1094                 has_ready_frame = false;
1095         }
1096
1097         *frame = current_frame;
1098         return true;
1099 }
1100
1101 void Mixer::OutputChannel::set_frame_ready_callback(Mixer::new_frame_ready_callback_t callback)
1102 {
1103         new_frame_ready_callback = callback;
1104 }
1105
1106 void Mixer::OutputChannel::set_transition_names_updated_callback(Mixer::transition_names_updated_callback_t callback)
1107 {
1108         transition_names_updated_callback = callback;
1109 }
1110
1111 void Mixer::OutputChannel::set_name_updated_callback(Mixer::name_updated_callback_t callback)
1112 {
1113         name_updated_callback = callback;
1114 }
1115
1116 void Mixer::OutputChannel::set_color_updated_callback(Mixer::color_updated_callback_t callback)
1117 {
1118         color_updated_callback = callback;
1119 }
1120
1121 mutex RefCountedGLsync::fence_lock;