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                         cards[card_index].output.reset();
 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         }
 237         card->capture.reset(capture);
 238         card->is_fake_capture = is_fake_capture;
 239         if (card->output.get() != output) {
 240                 card->output.reset(output);
 241         }
 242         card->capture->set_frame_callback(bind(&Mixer::bm_frame, this, card_index, _1, _2, _3, _4, _5, _6, _7));
 243         if (card->frame_allocator == nullptr) {
 244                 card->frame_allocator.reset(new PBOFrameAllocator(8 << 20, global_flags.width, global_flags.height));  // 8 MB.
 245         }
 246         card->capture->set_video_frame_allocator(card->frame_allocator.get());
 247         if (card->surface == nullptr) {
 248                 card->surface = create_surface_with_same_format(mixer_surface);
 249         }
 250         while (!card->new_frames.empty()) card->new_frames.pop();
 251         card->last_timecode = -1;
 252         card->capture->configure_card();
 253
 254         // NOTE: start_bm_capture() happens in thread_func().
 255
 256         DeviceSpec device{InputSourceType::CAPTURE_CARD, card_index};
 257         audio_mixer.reset_resampler(device);
 258         audio_mixer.set_display_name(device, card->capture->get_description());
 259         audio_mixer.trigger_state_changed_callback();
 260 }
 261
 262 void Mixer::set_output_card(int card_index)
 263 {
 264         if (card_index == output_card_index) {
 265                 return;
 266         }
 267         unique_lock<mutex> lock(card_mutex);
 268         if (output_card_index != -1) {
 269                 // Switch the old card from output to input.
 270                 CaptureCard *old_card = &cards[output_card_index];
 271                 old_card->output->end_output();
 272
 273                 // Stop the fake card that we put into place.
 274                 // This needs to _not_ happen under the mutex, to avoid deadlock
 275                 // (delivering the last frame needs to take the mutex).
 276                 bmusb::CaptureInterface *fake_capture = old_card->capture.get();
 277                 lock.unlock();
 278                 fake_capture->stop_dequeue_thread();
 279                 lock.lock();
 280                 old_card->capture = move(old_card->parked_capture);
 281                 old_card->is_fake_capture = false;
 282                 old_card->capture->start_bm_capture();
 283         }
 284
 285         CaptureCard *card = &cards[card_index];
 286         bmusb::CaptureInterface *capture = card->capture.get();
 287         lock.unlock();
 288         capture->stop_dequeue_thread();
 289         lock.lock();
 290         card->parked_capture = move(card->capture);
 291         bmusb::CaptureInterface *fake_capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
 292         configure_card(card_index, fake_capture, /*is_fake_capture=*/true, card->output.release());
 293         card->queue_length_policy.reset(card_index);
 294         card->capture->start_bm_capture();
 295         card->output->start_output(bmdModeHD720p5994, pts_int);  // FIXME
 296         output_card_index = card_index;
 297 }
 298
 299 namespace {
 300
 301 int unwrap_timecode(uint16_t current_wrapped, int last)
 302 {
 303         uint16_t last_wrapped = last & 0xffff;
 304         if (current_wrapped > last_wrapped) {
 305                 return (last & ~0xffff) | current_wrapped;
 306         } else {
 307                 return 0x10000 + ((last & ~0xffff) | current_wrapped);
 308         }
 309 }
 310
 311 }  // namespace
 312
 313 void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
 314                      FrameAllocator::Frame video_frame, size_t video_offset, VideoFormat video_format,
 315                      FrameAllocator::Frame audio_frame, size_t audio_offset, AudioFormat audio_format)
 316 {
 317         DeviceSpec device{InputSourceType::CAPTURE_CARD, card_index};
 318         CaptureCard *card = &cards[card_index];
 319
 320         if (is_mode_scanning[card_index]) {
 321                 if (video_format.has_signal) {
 322                         // Found a stable signal, so stop scanning.
 323                         is_mode_scanning[card_index] = false;
 324                 } else {
 325                         static constexpr double switch_time_s = 0.1;  // Should be enough time for the signal to stabilize.
 326                         steady_clock::time_point now = steady_clock::now();
 327                         double sec_since_last_switch = duration<double>(steady_clock::now() - last_mode_scan_change[card_index]).count();
 328                         if (sec_since_last_switch > switch_time_s) {
 329                                 // It isn't this mode; try the next one.
 330                                 mode_scanlist_index[card_index]++;
 331                                 mode_scanlist_index[card_index] %= mode_scanlist[card_index].size();
 332                                 cards[card_index].capture->set_video_mode(mode_scanlist[card_index][mode_scanlist_index[card_index]]);
 333                                 last_mode_scan_change[card_index] = now;
 334                         }
 335                 }
 336         }
 337
 338         int64_t frame_length = int64_t(TIMEBASE) * video_format.frame_rate_den / video_format.frame_rate_nom;
 339         assert(frame_length > 0);
 340
 341         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;
 342         if (num_samples > OUTPUT_FREQUENCY / 10) {
 343                 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",
 344                         card_index, int(audio_frame.len), int(audio_offset),
 345                         timecode, int(video_frame.len), int(video_offset), video_format.id);
 346                 if (video_frame.owner) {
 347                         video_frame.owner->release_frame(video_frame);
 348                 }
 349                 if (audio_frame.owner) {
 350                         audio_frame.owner->release_frame(audio_frame);
 351                 }
 352                 return;
 353         }
 354
 355         int dropped_frames = 0;
 356         if (card->last_timecode != -1) {
 357                 dropped_frames = unwrap_timecode(timecode, card->last_timecode) - card->last_timecode - 1;
 358         }
 359
 360         // Number of samples per frame if we need to insert silence.
 361         // (Could be nonintegral, but resampling will save us then.)
 362         const int silence_samples = OUTPUT_FREQUENCY * video_format.frame_rate_den / video_format.frame_rate_nom;
 363
 364         if (dropped_frames > MAX_FPS * 2) {
 365                 fprintf(stderr, "Card %d lost more than two seconds (or time code jumping around; from 0x%04x to 0x%04x), resetting resampler\n",
 366                         card_index, card->last_timecode, timecode);
 367                 audio_mixer.reset_resampler(device);
 368                 dropped_frames = 0;
 369         } else if (dropped_frames > 0) {
 370                 // Insert silence as needed.
 371                 fprintf(stderr, "Card %d dropped %d frame(s) (before timecode 0x%04x), inserting silence.\n",
 372                         card_index, dropped_frames, timecode);
 373
 374                 bool success;
 375                 do {
 376                         success = audio_mixer.add_silence(device, silence_samples, dropped_frames, frame_length);
 377                 } while (!success);
 378         }
 379
 380         audio_mixer.add_audio(device, audio_frame.data + audio_offset, num_samples, audio_format, frame_length);
 381
 382         // Done with the audio, so release it.
 383         if (audio_frame.owner) {
 384                 audio_frame.owner->release_frame(audio_frame);
 385         }
 386
 387         card->last_timecode = timecode;
 388
 389         size_t expected_length = video_format.width * (video_format.height + video_format.extra_lines_top + video_format.extra_lines_bottom) * 2;
 390         if (video_frame.len - video_offset == 0 ||
 391             video_frame.len - video_offset != expected_length) {
 392                 if (video_frame.len != 0) {
 393                         printf("Card %d: Dropping video frame with wrong length (%ld; expected %ld)\n",
 394                                 card_index, video_frame.len - video_offset, expected_length);
 395                 }
 396                 if (video_frame.owner) {
 397                         video_frame.owner->release_frame(video_frame);
 398                 }
 399
 400                 // Still send on the information that we _had_ a frame, even though it's corrupted,
 401                 // so that pts can go up accordingly.
 402                 {
 403                         unique_lock<mutex> lock(card_mutex);
 404                         CaptureCard::NewFrame new_frame;
 405                         new_frame.frame = RefCountedFrame(FrameAllocator::Frame());
 406                         new_frame.length = frame_length;
 407                         new_frame.interlaced = false;
 408                         new_frame.dropped_frames = dropped_frames;
 409                         card->new_frames.push(move(new_frame));
 410                         card->new_frames_changed.notify_all();
 411                 }
 412                 return;
 413         }
 414
 415         PBOFrameAllocator::Userdata *userdata = (PBOFrameAllocator::Userdata *)video_frame.userdata;
 416
 417         unsigned num_fields = video_format.interlaced ? 2 : 1;
 418         steady_clock::time_point frame_upload_start;
 419         bool interlaced_stride = false;
 420         if (video_format.interlaced) {
 421                 // Send the two fields along as separate frames; the other side will need to add
 422                 // a deinterlacer to actually get this right.
 423                 assert(video_format.height % 2 == 0);
 424                 video_format.height /= 2;
 425                 assert(frame_length % 2 == 0);
 426                 frame_length /= 2;
 427                 num_fields = 2;
 428                 if (video_format.second_field_start == 1) {
 429                         interlaced_stride = true;
 430                 }
 431                 frame_upload_start = steady_clock::now();
 432         }
 433         userdata->last_interlaced = video_format.interlaced;
 434         userdata->last_has_signal = video_format.has_signal;
 435         userdata->last_is_connected = video_format.is_connected;
 436         userdata->last_frame_rate_nom = video_format.frame_rate_nom;
 437         userdata->last_frame_rate_den = video_format.frame_rate_den;
 438         RefCountedFrame frame(video_frame);
 439
 440         // Upload the textures.
 441         size_t cbcr_width = video_format.width / 2;
 442         size_t cbcr_offset = video_offset / 2;
 443         size_t y_offset = video_frame.size / 2 + video_offset / 2;
 444
 445         for (unsigned field = 0; field < num_fields; ++field) {
 446                 // Put the actual texture upload in a lambda that is executed in the main thread.
 447                 // It is entirely possible to do this in the same thread (and it might even be
 448                 // faster, depending on the GPU and driver), but it appears to be trickling
 449                 // driver bugs very easily.
 450                 //
 451                 // Note that this means we must hold on to the actual frame data in <userdata>
 452                 // until the upload command is run, but we hold on to <frame> much longer than that
 453                 // (in fact, all the way until we no longer use the texture in rendering).
 454                 auto upload_func = [field, video_format, y_offset, cbcr_offset, cbcr_width, interlaced_stride, userdata]() {
 455                         unsigned field_start_line;
 456                         if (field == 1) {
 457                                 field_start_line = video_format.second_field_start;
 458                         } else {
 459                                 field_start_line = video_format.extra_lines_top;
 460                         }
 461
 462                         if (userdata->tex_y[field] == 0 ||
 463                             userdata->tex_cbcr[field] == 0 ||
 464                             video_format.width != userdata->last_width[field] ||
 465                             video_format.height != userdata->last_height[field]) {
 466                                 // We changed resolution since last use of this texture, so we need to create
 467                                 // a new object. Note that this each card has its own PBOFrameAllocator,
 468                                 // we don't need to worry about these flip-flopping between resolutions.
 469                                 glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr[field]);
 470                                 check_error();
 471                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_RG8, cbcr_width, video_format.height, 0, GL_RG, GL_UNSIGNED_BYTE, nullptr);
 472                                 check_error();
 473                                 glBindTexture(GL_TEXTURE_2D, userdata->tex_y[field]);
 474                                 check_error();
 475                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, video_format.width, video_format.height, 0, GL_RED, GL_UNSIGNED_BYTE, nullptr);
 476                                 check_error();
 477                                 userdata->last_width[field] = video_format.width;
 478                                 userdata->last_height[field] = video_format.height;
 479                         }
 480
 481                         GLuint pbo = userdata->pbo;
 482                         check_error();
 483                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER, pbo);
 484                         check_error();
 485
 486                         size_t field_y_start = y_offset + video_format.width * field_start_line;
 487                         size_t field_cbcr_start = cbcr_offset + cbcr_width * field_start_line * sizeof(uint16_t);
 488
 489                         if (global_flags.flush_pbos) {
 490                                 glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, field_y_start, video_format.width * video_format.height);
 491                                 check_error();
 492                                 glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, field_cbcr_start, cbcr_width * video_format.height * sizeof(uint16_t));
 493                                 check_error();
 494                         }
 495
 496                         glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr[field]);
 497                         check_error();
 498                         if (interlaced_stride) {
 499                                 glPixelStorei(GL_UNPACK_ROW_LENGTH, cbcr_width * 2);
 500                                 check_error();
 501                         } else {
 502                                 glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 503                                 check_error();
 504                         }
 505                         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, cbcr_width, video_format.height, GL_RG, GL_UNSIGNED_BYTE, BUFFER_OFFSET(field_cbcr_start));
 506                         check_error();
 507                         glBindTexture(GL_TEXTURE_2D, userdata->tex_y[field]);
 508                         check_error();
 509                         if (interlaced_stride) {
 510                                 glPixelStorei(GL_UNPACK_ROW_LENGTH, video_format.width * 2);
 511                                 check_error();
 512                         } else {
 513                                 glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 514                                 check_error();
 515                         }
 516                         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, video_format.width, video_format.height, GL_RED, GL_UNSIGNED_BYTE, BUFFER_OFFSET(field_y_start));
 517                         check_error();
 518                         glBindTexture(GL_TEXTURE_2D, 0);
 519                         check_error();
 520                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
 521                         check_error();
 522                         glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 523                         check_error();
 524                 };
 525
 526                 if (field == 1) {
 527                         // Don't upload the second field as fast as we can; wait until
 528                         // the field time has approximately passed. (Otherwise, we could
 529                         // get timing jitter against the other sources, and possibly also
 530                         // against the video display, although the latter is not as critical.)
 531                         // This requires our system clock to be reasonably close to the
 532                         // video clock, but that's not an unreasonable assumption.
 533                         steady_clock::time_point second_field_start = frame_upload_start +
 534                                 nanoseconds(frame_length * 1000000000 / TIMEBASE);
 535                         this_thread::sleep_until(second_field_start);
 536                 }
 537
 538                 {
 539                         unique_lock<mutex> lock(card_mutex);
 540                         CaptureCard::NewFrame new_frame;
 541                         new_frame.frame = frame;
 542                         new_frame.length = frame_length;
 543                         new_frame.field = field;
 544                         new_frame.interlaced = video_format.interlaced;
 545                         new_frame.upload_func = upload_func;
 546                         new_frame.dropped_frames = dropped_frames;
 547                         new_frame.received_timestamp = video_frame.received_timestamp;  // Ignore the audio timestamp.
 548                         card->new_frames.push(move(new_frame));
 549                         card->new_frames_changed.notify_all();
 550                 }
 551         }
 552 }
 553
 554 void Mixer::bm_hotplug_add(libusb_device *dev)
 555 {
 556         lock_guard<mutex> lock(hotplug_mutex);
 557         hotplugged_cards.push_back(dev);
 558 }
 559
 560 void Mixer::bm_hotplug_remove(unsigned card_index)
 561 {
 562         cards[card_index].new_frames_changed.notify_all();
 563 }
 564
 565 void Mixer::thread_func()
 566 {
 567         eglBindAPI(EGL_OPENGL_API);
 568         QOpenGLContext *context = create_context(mixer_surface);
 569         if (!make_current(context, mixer_surface)) {
 570                 printf("oops\n");
 571                 exit(1);
 572         }
 573
 574         // Start the actual capture. (We don't want to do it before we're actually ready
 575         // to process output frames.)
 576         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 577                 if (int(card_index) != output_card_index) {
 578                         cards[card_index].capture->start_bm_capture();
 579                 }
 580         }
 581
 582         steady_clock::time_point start, now;
 583         start = steady_clock::now();
 584
 585         int frame = 0;
 586         int stats_dropped_frames = 0;
 587
 588         while (!should_quit) {
 589                 CaptureCard::NewFrame new_frames[MAX_VIDEO_CARDS];
 590                 bool has_new_frame[MAX_VIDEO_CARDS] = { false };
 591
 592                 bool master_card_is_output;
 593                 unsigned master_card_index;
 594                 if (output_card_index != -1) {
 595                         master_card_is_output = true;
 596                         master_card_index = output_card_index;
 597                 } else {
 598                         master_card_is_output = false;
 599                         master_card_index = theme->map_signal(master_clock_channel);
 600                         assert(master_card_index < num_cards);
 601                 }
 602
 603                 OutputFrameInfo output_frame_info = get_one_frame_from_each_card(master_card_index, master_card_is_output, new_frames, has_new_frame);
 604                 schedule_audio_resampling_tasks(output_frame_info.dropped_frames, output_frame_info.num_samples, output_frame_info.frame_duration);
 605                 stats_dropped_frames += output_frame_info.dropped_frames;
 606
 607                 handle_hotplugged_cards();
 608
 609                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 610                         if (card_index == master_card_index || !has_new_frame[card_index]) {
 611                                 continue;
 612                         }
 613                         if (new_frames[card_index].frame->len == 0) {
 614                                 ++new_frames[card_index].dropped_frames;
 615                         }
 616                         if (new_frames[card_index].dropped_frames > 0) {
 617                                 printf("Card %u dropped %d frames before this\n",
 618                                         card_index, int(new_frames[card_index].dropped_frames));
 619                         }
 620                 }
 621
 622                 // If the first card is reporting a corrupted or otherwise dropped frame,
 623                 // just increase the pts (skipping over this frame) and don't try to compute anything new.
 624                 if (!master_card_is_output && new_frames[master_card_index].frame->len == 0) {
 625                         ++stats_dropped_frames;
 626                         pts_int += new_frames[master_card_index].length;
 627                         continue;
 628                 }
 629
 630                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 631                         if (!has_new_frame[card_index] || new_frames[card_index].frame->len == 0)
 632                                 continue;
 633
 634                         CaptureCard::NewFrame *new_frame = &new_frames[card_index];
 635                         assert(new_frame->frame != nullptr);
 636                         insert_new_frame(new_frame->frame, new_frame->field, new_frame->interlaced, card_index, &input_state);
 637                         check_error();
 638
 639                         // The new texture might need uploading before use.
 640                         if (new_frame->upload_func) {
 641                                 new_frame->upload_func();
 642                                 new_frame->upload_func = nullptr;
 643                         }
 644                 }
 645
 646                 int64_t frame_duration = output_frame_info.frame_duration;
 647                 render_one_frame(frame_duration);
 648                 ++frame;
 649                 pts_int += frame_duration;
 650
 651                 now = steady_clock::now();
 652                 double elapsed = duration<double>(now - start).count();
 653                 if (frame % 100 == 0) {
 654                         printf("%d frames (%d dropped) in %.3f seconds = %.1f fps (%.1f ms/frame)",
 655                                 frame, stats_dropped_frames, elapsed, frame / elapsed,
 656                                 1e3 * elapsed / frame);
 657                 //      chain->print_phase_timing();
 658
 659                         // Check our memory usage, to see if we are close to our mlockall()
 660                         // limit (if at all set).
 661                         rusage used;
 662                         if (getrusage(RUSAGE_SELF, &used) == -1) {
 663                                 perror("getrusage(RUSAGE_SELF)");
 664                                 assert(false);
 665                         }
 666
 667                         if (uses_mlock) {
 668                                 rlimit limit;
 669                                 if (getrlimit(RLIMIT_MEMLOCK, &limit) == -1) {
 670                                         perror("getrlimit(RLIMIT_MEMLOCK)");
 671                                         assert(false);
 672                                 }
 673
 674                                 if (limit.rlim_cur == 0) {
 675                                         printf(", using %ld MB memory (locked)",
 676                                                 long(used.ru_maxrss / 1024));
 677                                 } else {
 678                                         printf(", using %ld / %ld MB lockable memory (%.1f%%)",
 679                                                 long(used.ru_maxrss / 1024),
 680                                                 long(limit.rlim_cur / 1048576),
 681                                                 float(100.0 * (used.ru_maxrss * 1024.0) / limit.rlim_cur));
 682                                 }
 683                         } else {
 684                                 printf(", using %ld MB memory (not locked)",
 685                                         long(used.ru_maxrss / 1024));
 686                         }
 687
 688                         printf("\n");
 689                 }
 690
 691
 692                 if (should_cut.exchange(false)) {  // Test and clear.
 693                         video_encoder->do_cut(frame);
 694                 }
 695
 696 #if 0
 697                 // Reset every 100 frames, so that local variations in frame times
 698                 // (especially for the first few frames, when the shaders are
 699                 // compiled etc.) don't make it hard to measure for the entire
 700                 // remaining duration of the program.
 701                 if (frame == 10000) {
 702                         frame = 0;
 703                         start = now;
 704                 }
 705 #endif
 706                 check_error();
 707         }
 708
 709         resource_pool->clean_context();
 710 }
 711
 712 bool Mixer::input_card_is_master_clock(unsigned card_index, unsigned master_card_index) const
 713 {
 714         if (output_card_index != -1) {
 715                 // The output card (ie., cards[output_card_index].output) is the master clock,
 716                 // so no input card (ie., cards[card_index].capture) is.
 717                 return false;
 718         }
 719         return (card_index == master_card_index);
 720 }
 721
 722 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])
 723 {
 724         OutputFrameInfo output_frame_info;
 725 start:
 726         unique_lock<mutex> lock(card_mutex, defer_lock);
 727         if (master_card_is_output) {
 728                 // Clocked to the output, so wait for it to be ready for the next frame.
 729                 cards[master_card_index].output->wait_for_frame(pts_int, &output_frame_info.dropped_frames, &output_frame_info.frame_duration);
 730                 lock.lock();
 731         } else {
 732                 // Wait for the master card to have a new frame.
 733                 // TODO: Add a timeout.
 734                 lock.lock();
 735                 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(); });
 736         }
 737
 738         if (master_card_is_output) {
 739                 handle_hotplugged_cards();
 740         } else if (cards[master_card_index].new_frames.empty()) {
 741                 // We were woken up, but not due to a new frame. Deal with it
 742                 // and then restart.
 743                 assert(cards[master_card_index].capture->get_disconnected());
 744                 handle_hotplugged_cards();
 745                 goto start;
 746         }
 747
 748         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 749                 CaptureCard *card = &cards[card_index];
 750                 if (card->new_frames.empty()) {
 751                         assert(!input_card_is_master_clock(card_index, master_card_index));
 752                         card->queue_length_policy.update_policy(-1);
 753                         continue;
 754                 }
 755                 new_frames[card_index] = move(card->new_frames.front());
 756                 has_new_frame[card_index] = true;
 757                 card->new_frames.pop();
 758                 card->new_frames_changed.notify_all();
 759
 760                 if (input_card_is_master_clock(card_index, master_card_index)) {
 761                         // We don't use the queue length policy for the master card,
 762                         // but we will if it stops being the master. Thus, clear out
 763                         // the policy in case we switch in the future.
 764                         card->queue_length_policy.reset(card_index);
 765                 } else {
 766                         // If we have excess frames compared to the policy for this card,
 767                         // drop frames from the head.
 768                         card->queue_length_policy.update_policy(card->new_frames.size());
 769                         while (card->new_frames.size() > card->queue_length_policy.get_safe_queue_length()) {
 770                                 card->new_frames.pop();
 771                         }
 772                 }
 773         }
 774
 775         if (!master_card_is_output) {
 776                 output_frame_info.dropped_frames = new_frames[master_card_index].dropped_frames;
 777                 output_frame_info.frame_duration = new_frames[master_card_index].length;
 778         }
 779
 780         // This might get off by a fractional sample when changing master card
 781         // between ones with different frame rates, but that's fine.
 782         int num_samples_times_timebase = OUTPUT_FREQUENCY * output_frame_info.frame_duration + fractional_samples;
 783         output_frame_info.num_samples = num_samples_times_timebase / TIMEBASE;
 784         fractional_samples = num_samples_times_timebase % TIMEBASE;
 785         assert(output_frame_info.num_samples >= 0);
 786
 787         return output_frame_info;
 788 }
 789
 790 void Mixer::handle_hotplugged_cards()
 791 {
 792         // Check for cards that have been disconnected since last frame.
 793         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 794                 CaptureCard *card = &cards[card_index];
 795                 if (card->capture->get_disconnected()) {
 796                         fprintf(stderr, "Card %u went away, replacing with a fake card.\n", card_index);
 797                         FakeCapture *capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
 798                         configure_card(card_index, capture, /*is_fake_capture=*/true, /*output=*/nullptr);
 799                         card->queue_length_policy.reset(card_index);
 800                         card->capture->start_bm_capture();
 801                 }
 802         }
 803
 804         // Check for cards that have been connected since last frame.
 805         vector<libusb_device *> hotplugged_cards_copy;
 806         {
 807                 lock_guard<mutex> lock(hotplug_mutex);
 808                 swap(hotplugged_cards, hotplugged_cards_copy);
 809         }
 810         for (libusb_device *new_dev : hotplugged_cards_copy) {
 811                 // Look for a fake capture card where we can stick this in.
 812                 int free_card_index = -1;
 813                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 814                         if (cards[card_index].is_fake_capture) {
 815                                 free_card_index = card_index;
 816                                 break;
 817                         }
 818                 }
 819
 820                 if (free_card_index == -1) {
 821                         fprintf(stderr, "New card plugged in, but no free slots -- ignoring.\n");
 822                         libusb_unref_device(new_dev);
 823                 } else {
 824                         // BMUSBCapture takes ownership.
 825                         fprintf(stderr, "New card plugged in, choosing slot %d.\n", free_card_index);
 826                         CaptureCard *card = &cards[free_card_index];
 827                         BMUSBCapture *capture = new BMUSBCapture(free_card_index, new_dev);
 828                         configure_card(free_card_index, capture, /*is_fake_capture=*/false, /*output=*/nullptr);
 829                         card->queue_length_policy.reset(free_card_index);
 830                         capture->set_card_disconnected_callback(bind(&Mixer::bm_hotplug_remove, this, free_card_index));
 831                         capture->start_bm_capture();
 832                 }
 833         }
 834 }
 835
 836
 837 void Mixer::schedule_audio_resampling_tasks(unsigned dropped_frames, int num_samples_per_frame, int length_per_frame)
 838 {
 839         // Resample the audio as needed, including from previously dropped frames.
 840         assert(num_cards > 0);
 841         for (unsigned frame_num = 0; frame_num < dropped_frames + 1; ++frame_num) {
 842                 const bool dropped_frame = (frame_num != dropped_frames);
 843                 {
 844                         // Signal to the audio thread to process this frame.
 845                         // Note that if the frame is a dropped frame, we signal that
 846                         // we don't want to use this frame as base for adjusting
 847                         // the resampler rate. The reason for this is that the timing
 848                         // of these frames is often way too late; they typically don't
 849                         // “arrive” before we synthesize them. Thus, we could end up
 850                         // in a situation where we have inserted e.g. five audio frames
 851                         // into the queue before we then start pulling five of them
 852                         // back out. This makes ResamplingQueue overestimate the delay,
 853                         // causing undue resampler changes. (We _do_ use the last,
 854                         // non-dropped frame; perhaps we should just discard that as well,
 855                         // since dropped frames are expected to be rare, and it might be
 856                         // better to just wait until we have a slightly more normal situation).
 857                         unique_lock<mutex> lock(audio_mutex);
 858                         bool adjust_rate = !dropped_frame;
 859                         audio_task_queue.push(AudioTask{pts_int, num_samples_per_frame, adjust_rate});
 860                         audio_task_queue_changed.notify_one();
 861                 }
 862                 if (dropped_frame) {
 863                         // For dropped frames, increase the pts. Note that if the format changed
 864                         // in the meantime, we have no way of detecting that; we just have to
 865                         // assume the frame length is always the same.
 866                         pts_int += length_per_frame;
 867                 }
 868         }
 869 }
 870
 871 void Mixer::render_one_frame(int64_t duration)
 872 {
 873         // Get the main chain from the theme, and set its state immediately.
 874         Theme::Chain theme_main_chain = theme->get_chain(0, pts(), global_flags.width, global_flags.height, input_state);
 875         EffectChain *chain = theme_main_chain.chain;
 876         theme_main_chain.setup_chain();
 877         //theme_main_chain.chain->enable_phase_timing(true);
 878
 879         GLuint y_tex, cbcr_tex;
 880         bool got_frame = video_encoder->begin_frame(&y_tex, &cbcr_tex);
 881         assert(got_frame);
 882
 883         // Render main chain.
 884         GLuint cbcr_full_tex = resource_pool->create_2d_texture(GL_RG8, global_flags.width, global_flags.height);
 885         GLuint rgba_tex = resource_pool->create_2d_texture(GL_RGB565, global_flags.width, global_flags.height);  // Saves texture bandwidth, although dithering gets messed up.
 886         GLuint fbo = resource_pool->create_fbo(y_tex, cbcr_full_tex, rgba_tex);
 887         check_error();
 888         chain->render_to_fbo(fbo, global_flags.width, global_flags.height);
 889         resource_pool->release_fbo(fbo);
 890
 891         chroma_subsampler->subsample_chroma(cbcr_full_tex, global_flags.width, global_flags.height, cbcr_tex);
 892         if (output_card_index != -1) {
 893                 cards[output_card_index].output->send_frame(y_tex, cbcr_full_tex, theme_main_chain.input_frames, pts_int, duration);
 894         }
 895         resource_pool->release_2d_texture(cbcr_full_tex);
 896
 897         // Set the right state for rgba_tex.
 898         glBindFramebuffer(GL_FRAMEBUFFER, 0);
 899         glBindTexture(GL_TEXTURE_2D, rgba_tex);
 900         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 901         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 902         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 903
 904         const int64_t av_delay = lrint(global_flags.audio_queue_length_ms * 0.001 * TIMEBASE);  // Corresponds to the delay in ResamplingQueue.
 905         RefCountedGLsync fence = video_encoder->end_frame(pts_int + av_delay, duration, theme_main_chain.input_frames);
 906
 907         // The live frame just shows the RGBA texture we just rendered.
 908         // It owns rgba_tex now.
 909         DisplayFrame live_frame;
 910         live_frame.chain = display_chain.get();
 911         live_frame.setup_chain = [this, rgba_tex]{
 912                 display_input->set_texture_num(rgba_tex);
 913         };
 914         live_frame.ready_fence = fence;
 915         live_frame.input_frames = {};
 916         live_frame.temp_textures = { rgba_tex };
 917         output_channel[OUTPUT_LIVE].output_frame(live_frame);
 918
 919         // Set up preview and any additional channels.
 920         for (int i = 1; i < theme->get_num_channels() + 2; ++i) {
 921                 DisplayFrame display_frame;
 922                 Theme::Chain chain = theme->get_chain(i, pts(), global_flags.width, global_flags.height, input_state);  // FIXME: dimensions
 923                 display_frame.chain = chain.chain;
 924                 display_frame.setup_chain = chain.setup_chain;
 925                 display_frame.ready_fence = fence;
 926                 display_frame.input_frames = chain.input_frames;
 927                 display_frame.temp_textures = {};
 928                 output_channel[i].output_frame(display_frame);
 929         }
 930 }
 931
 932 void Mixer::audio_thread_func()
 933 {
 934         while (!should_quit) {
 935                 AudioTask task;
 936
 937                 {
 938                         unique_lock<mutex> lock(audio_mutex);
 939                         audio_task_queue_changed.wait(lock, [this]{ return should_quit || !audio_task_queue.empty(); });
 940                         if (should_quit) {
 941                                 return;
 942                         }
 943                         task = audio_task_queue.front();
 944                         audio_task_queue.pop();
 945                 }
 946
 947                 ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy =
 948                         task.adjust_rate ? ResamplingQueue::ADJUST_RATE : ResamplingQueue::DO_NOT_ADJUST_RATE;
 949                 vector<float> samples_out = audio_mixer.get_output(
 950                         double(task.pts_int) / TIMEBASE,
 951                         task.num_samples,
 952                         rate_adjustment_policy);
 953
 954                 // Send the samples to the sound card, then add them to the output.
 955                 if (alsa) {
 956                         alsa->write(samples_out);
 957                 }
 958                 if (output_card_index != -1) {
 959                         const int64_t av_delay = lrint(global_flags.audio_queue_length_ms * 0.001 * TIMEBASE);  // Corresponds to the delay in ResamplingQueue.
 960                         cards[output_card_index].output->send_audio(task.pts_int + av_delay, samples_out);
 961                 }
 962                 video_encoder->add_audio(task.pts_int, move(samples_out));
 963         }
 964 }
 965
 966 void Mixer::release_display_frame(DisplayFrame *frame)
 967 {
 968         for (GLuint texnum : frame->temp_textures) {
 969                 resource_pool->release_2d_texture(texnum);
 970         }
 971         frame->temp_textures.clear();
 972         frame->ready_fence.reset();
 973         frame->input_frames.clear();
 974 }
 975
 976 void Mixer::start()
 977 {
 978         mixer_thread = thread(&Mixer::thread_func, this);
 979         audio_thread = thread(&Mixer::audio_thread_func, this);
 980 }
 981
 982 void Mixer::quit()
 983 {
 984         should_quit = true;
 985         audio_task_queue_changed.notify_one();
 986         mixer_thread.join();
 987         audio_thread.join();
 988 }
 989
 990 void Mixer::transition_clicked(int transition_num)
 991 {
 992         theme->transition_clicked(transition_num, pts());
 993 }
 994
 995 void Mixer::channel_clicked(int preview_num)
 996 {
 997         theme->channel_clicked(preview_num);
 998 }
 999
1000 void Mixer::start_mode_scanning(unsigned card_index)
1001 {
1002         assert(card_index < num_cards);
1003         if (is_mode_scanning[card_index]) {
1004                 return;
1005         }
1006         is_mode_scanning[card_index] = true;
1007         mode_scanlist[card_index].clear();
1008         for (const auto &mode : cards[card_index].capture->get_available_video_modes()) {
1009                 mode_scanlist[card_index].push_back(mode.first);
1010         }
1011         assert(!mode_scanlist[card_index].empty());
1012         mode_scanlist_index[card_index] = 0;
1013         cards[card_index].capture->set_video_mode(mode_scanlist[card_index][0]);
1014         last_mode_scan_change[card_index] = steady_clock::now();
1015 }
1016
1017 Mixer::OutputChannel::~OutputChannel()
1018 {
1019         if (has_current_frame) {
1020                 parent->release_display_frame(&current_frame);
1021         }
1022         if (has_ready_frame) {
1023                 parent->release_display_frame(&ready_frame);
1024         }
1025 }
1026
1027 void Mixer::OutputChannel::output_frame(DisplayFrame frame)
1028 {
1029         // Store this frame for display. Remove the ready frame if any
1030         // (it was seemingly never used).
1031         {
1032                 unique_lock<mutex> lock(frame_mutex);
1033                 if (has_ready_frame) {
1034                         parent->release_display_frame(&ready_frame);
1035                 }
1036                 ready_frame = frame;
1037                 has_ready_frame = true;
1038         }
1039
1040         if (new_frame_ready_callback) {
1041                 new_frame_ready_callback();
1042         }
1043
1044         // Reduce the number of callbacks by filtering duplicates. The reason
1045         // why we bother doing this is that Qt seemingly can get into a state
1046         // where its builds up an essentially unbounded queue of signals,
1047         // consuming more and more memory, and there's no good way of collapsing
1048         // user-defined signals or limiting the length of the queue.
1049         if (transition_names_updated_callback) {
1050                 vector<string> transition_names = global_mixer->get_transition_names();
1051                 bool changed = false;
1052                 if (transition_names.size() != last_transition_names.size()) {
1053                         changed = true;
1054                 } else {
1055                         for (unsigned i = 0; i < transition_names.size(); ++i) {
1056                                 if (transition_names[i] != last_transition_names[i]) {
1057                                         changed = true;
1058                                         break;
1059                                 }
1060                         }
1061                 }
1062                 if (changed) {
1063                         transition_names_updated_callback(transition_names);
1064                         last_transition_names = transition_names;
1065                 }
1066         }
1067         if (name_updated_callback) {
1068                 string name = global_mixer->get_channel_name(channel);
1069                 if (name != last_name) {
1070                         name_updated_callback(name);
1071                         last_name = name;
1072                 }
1073         }
1074         if (color_updated_callback) {
1075                 string color = global_mixer->get_channel_color(channel);
1076                 if (color != last_color) {
1077                         color_updated_callback(color);
1078                         last_color = color;
1079                 }
1080         }
1081 }
1082
1083 bool Mixer::OutputChannel::get_display_frame(DisplayFrame *frame)
1084 {
1085         unique_lock<mutex> lock(frame_mutex);
1086         if (!has_current_frame && !has_ready_frame) {
1087                 return false;
1088         }
1089
1090         if (has_current_frame && has_ready_frame) {
1091                 // We have a new ready frame. Toss the current one.
1092                 parent->release_display_frame(&current_frame);
1093                 has_current_frame = false;
1094         }
1095         if (has_ready_frame) {
1096                 assert(!has_current_frame);
1097                 current_frame = ready_frame;
1098                 ready_frame.ready_fence.reset();  // Drop the refcount.
1099                 ready_frame.input_frames.clear();  // Drop the refcounts.
1100                 has_current_frame = true;
1101                 has_ready_frame = false;
1102         }
1103
1104         *frame = current_frame;
1105         return true;
1106 }
1107
1108 void Mixer::OutputChannel::set_frame_ready_callback(Mixer::new_frame_ready_callback_t callback)
1109 {
1110         new_frame_ready_callback = callback;
1111 }
1112
1113 void Mixer::OutputChannel::set_transition_names_updated_callback(Mixer::transition_names_updated_callback_t callback)
1114 {
1115         transition_names_updated_callback = callback;
1116 }
1117
1118 void Mixer::OutputChannel::set_name_updated_callback(Mixer::name_updated_callback_t callback)
1119 {
1120         name_updated_callback = callback;
1121 }
1122
1123 void Mixer::OutputChannel::set_color_updated_callback(Mixer::color_updated_callback_t callback)
1124 {
1125         color_updated_callback = callback;
1126 }
1127
1128 mutex RefCountedGLsync::fence_lock;