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 <pthread.h>
  14 #include <stdint.h>
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <sys/resource.h>
  18 #include <algorithm>
  19 #include <chrono>
  20 #include <condition_variable>
  21 #include <cstddef>
  22 #include <cstdint>
  23 #include <memory>
  24 #include <mutex>
  25 #include <ratio>
  26 #include <string>
  27 #include <thread>
  28 #include <utility>
  29 #include <vector>
  30
  31 #include "DeckLinkAPI.h"
  32 #include "LinuxCOM.h"
  33 #include "alsa_output.h"
  34 #include "bmusb/bmusb.h"
  35 #include "bmusb/fake_capture.h"
  36 #include "chroma_subsampler.h"
  37 #include "context.h"
  38 #include "decklink_capture.h"
  39 #include "decklink_output.h"
  40 #include "defs.h"
  41 #include "disk_space_estimator.h"
  42 #include "flags.h"
  43 #include "input_mapping.h"
  44 #include "pbo_frame_allocator.h"
  45 #include "ref_counted_gl_sync.h"
  46 #include "resampling_queue.h"
  47 #include "timebase.h"
  48 #include "video_encoder.h"
  49
  50 class IDeckLink;
  51 class QOpenGLContext;
  52
  53 using namespace movit;
  54 using namespace std;
  55 using namespace std::chrono;
  56 using namespace std::placeholders;
  57 using namespace bmusb;
  58
  59 Mixer *global_mixer = nullptr;
  60 bool uses_mlock = false;
  61
  62 namespace {
  63
  64 void insert_new_frame(RefCountedFrame frame, unsigned field_num, bool interlaced, unsigned card_index, InputState *input_state)
  65 {
  66         if (interlaced) {
  67                 for (unsigned frame_num = FRAME_HISTORY_LENGTH; frame_num --> 1; ) {  // :-)
  68                         input_state->buffered_frames[card_index][frame_num] =
  69                                 input_state->buffered_frames[card_index][frame_num - 1];
  70                 }
  71                 input_state->buffered_frames[card_index][0] = { frame, field_num };
  72         } else {
  73                 for (unsigned frame_num = 0; frame_num < FRAME_HISTORY_LENGTH; ++frame_num) {
  74                         input_state->buffered_frames[card_index][frame_num] = { frame, field_num };
  75                 }
  76         }
  77 }
  78
  79 }  // namespace
  80
  81 void QueueLengthPolicy::update_policy(int queue_length)
  82 {
  83         if (queue_length < 0) {  // Starvation.
  84                 if (been_at_safe_point_since_last_starvation && safe_queue_length < 5) {
  85                         ++safe_queue_length;
  86                         fprintf(stderr, "Card %u: Starvation, increasing safe limit to %u frames\n",
  87                                 card_index, safe_queue_length);
  88                 }
  89                 frames_with_at_least_one = 0;
  90                 been_at_safe_point_since_last_starvation = false;
  91                 return;
  92         }
  93         if (queue_length > 0) {
  94                 if (queue_length >= int(safe_queue_length)) {
  95                         been_at_safe_point_since_last_starvation = true;
  96                 }
  97                 if (++frames_with_at_least_one >= 1000 && safe_queue_length > 0) {
  98                         --safe_queue_length;
  99                         fprintf(stderr, "Card %u: Spare frames for more than 1000 frames, reducing safe limit to %u frames\n",
 100                                 card_index, safe_queue_length);
 101                         frames_with_at_least_one = 0;
 102                 }
 103         } else {
 104                 frames_with_at_least_one = 0;
 105         }
 106 }
 107
 108 Mixer::Mixer(const QSurfaceFormat &format, unsigned num_cards)
 109         : httpd(),
 110           num_cards(num_cards),
 111           mixer_surface(create_surface(format)),
 112           h264_encoder_surface(create_surface(format)),
 113           decklink_output_surface(create_surface(format)),
 114           audio_mixer(num_cards)
 115 {
 116         CHECK(init_movit(MOVIT_SHADER_DIR, MOVIT_DEBUG_OFF));
 117         check_error();
 118
 119         // Since we allow non-bouncing 4:2:2 YCbCrInputs, effective subpixel precision
 120         // will be halved when sampling them, and we need to compensate here.
 121         movit_texel_subpixel_precision /= 2.0;
 122
 123         resource_pool.reset(new ResourcePool);
 124         theme.reset(new Theme(global_flags.theme_filename, global_flags.theme_dirs, resource_pool.get(), num_cards));
 125         for (unsigned i = 0; i < NUM_OUTPUTS; ++i) {
 126                 output_channel[i].parent = this;
 127                 output_channel[i].channel = i;
 128         }
 129
 130         ImageFormat inout_format;
 131         inout_format.color_space = COLORSPACE_sRGB;
 132         inout_format.gamma_curve = GAMMA_sRGB;
 133
 134         // Display chain; shows the live output produced by the main chain (its RGBA version).
 135         display_chain.reset(new EffectChain(global_flags.width, global_flags.height, resource_pool.get()));
 136         check_error();
 137         display_input = new FlatInput(inout_format, FORMAT_RGB, GL_UNSIGNED_BYTE, global_flags.width, global_flags.height);  // FIXME: GL_UNSIGNED_BYTE is really wrong.
 138         display_chain->add_input(display_input);
 139         display_chain->add_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED);
 140         display_chain->set_dither_bits(0);  // Don't bother.
 141         display_chain->finalize();
 142
 143         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));
 144
 145         // Start listening for clients only once VideoEncoder has written its header, if any.
 146         httpd.start(9095);
 147
 148         // First try initializing the then PCI devices, then USB, then
 149         // fill up with fake cards until we have the desired number of cards.
 150         unsigned num_pci_devices = 0;
 151         unsigned card_index = 0;
 152
 153         {
 154                 IDeckLinkIterator *decklink_iterator = CreateDeckLinkIteratorInstance();
 155                 if (decklink_iterator != nullptr) {
 156                         for ( ; card_index < num_cards; ++card_index) {
 157                                 IDeckLink *decklink;
 158                                 if (decklink_iterator->Next(&decklink) != S_OK) {
 159                                         break;
 160                                 }
 161
 162                                 DeckLinkCapture *capture = new DeckLinkCapture(decklink, card_index);
 163                                 DeckLinkOutput *output = new DeckLinkOutput(resource_pool.get(), decklink_output_surface, global_flags.width, global_flags.height, card_index);
 164                                 output->set_device(decklink);
 165                                 configure_card(card_index, capture, /*is_fake_capture=*/false, output);
 166                                 ++num_pci_devices;
 167                         }
 168                         decklink_iterator->Release();
 169                         fprintf(stderr, "Found %u DeckLink PCI card(s).\n", num_pci_devices);
 170                 } else {
 171                         fprintf(stderr, "DeckLink drivers not found. Probing for USB cards only.\n");
 172                 }
 173         }
 174
 175         unsigned num_usb_devices = BMUSBCapture::num_cards();
 176         for (unsigned usb_card_index = 0; usb_card_index < num_usb_devices && card_index < num_cards; ++usb_card_index, ++card_index) {
 177                 BMUSBCapture *capture = new BMUSBCapture(usb_card_index);
 178                 capture->set_card_disconnected_callback(bind(&Mixer::bm_hotplug_remove, this, card_index));
 179                 configure_card(card_index, capture, /*is_fake_capture=*/false, /*output=*/nullptr);
 180         }
 181         fprintf(stderr, "Found %u USB card(s).\n", num_usb_devices);
 182
 183         unsigned num_fake_cards = 0;
 184         for ( ; card_index < num_cards; ++card_index, ++num_fake_cards) {
 185                 FakeCapture *capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
 186                 configure_card(card_index, capture, /*is_fake_capture=*/true, /*output=*/nullptr);
 187         }
 188
 189         if (num_fake_cards > 0) {
 190                 fprintf(stderr, "Initialized %u fake cards.\n", num_fake_cards);
 191         }
 192
 193         BMUSBCapture::set_card_connected_callback(bind(&Mixer::bm_hotplug_add, this, _1));
 194         BMUSBCapture::start_bm_thread();
 195
 196         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 197                 cards[card_index].queue_length_policy.reset(card_index);
 198         }
 199
 200         chroma_subsampler.reset(new ChromaSubsampler(resource_pool.get()));
 201
 202         if (global_flags.enable_alsa_output) {
 203                 alsa.reset(new ALSAOutput(OUTPUT_FREQUENCY, /*num_channels=*/2));
 204         }
 205         if (global_flags.output_card != -1) {
 206                 desired_output_card_index = global_flags.output_card;
 207                 set_output_card_internal(global_flags.output_card);
 208         }
 209 }
 210
 211 Mixer::~Mixer()
 212 {
 213         BMUSBCapture::stop_bm_thread();
 214
 215         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 216                 {
 217                         unique_lock<mutex> lock(card_mutex);
 218                         cards[card_index].should_quit = true;  // Unblock thread.
 219                         cards[card_index].new_frames_changed.notify_all();
 220                 }
 221                 cards[card_index].capture->stop_dequeue_thread();
 222                 if (cards[card_index].output) {
 223                         cards[card_index].output->end_output();
 224                         cards[card_index].output.reset();
 225                 }
 226         }
 227
 228         video_encoder.reset(nullptr);
 229 }
 230
 231 void Mixer::configure_card(unsigned card_index, CaptureInterface *capture, bool is_fake_capture, DeckLinkOutput *output)
 232 {
 233         printf("Configuring card %d...\n", card_index);
 234
 235         CaptureCard *card = &cards[card_index];
 236         if (card->capture != nullptr) {
 237                 card->capture->stop_dequeue_thread();
 238         }
 239         card->capture.reset(capture);
 240         card->is_fake_capture = is_fake_capture;
 241         if (card->output.get() != output) {
 242                 card->output.reset(output);
 243         }
 244         card->capture->set_frame_callback(bind(&Mixer::bm_frame, this, card_index, _1, _2, _3, _4, _5, _6, _7));
 245         if (card->frame_allocator == nullptr) {
 246                 card->frame_allocator.reset(new PBOFrameAllocator(8 << 20, global_flags.width, global_flags.height));  // 8 MB.
 247         }
 248         card->capture->set_video_frame_allocator(card->frame_allocator.get());
 249         if (card->surface == nullptr) {
 250                 card->surface = create_surface_with_same_format(mixer_surface);
 251         }
 252         while (!card->new_frames.empty()) card->new_frames.pop();
 253         card->last_timecode = -1;
 254         card->capture->configure_card();
 255
 256         // NOTE: start_bm_capture() happens in thread_func().
 257
 258         DeviceSpec device{InputSourceType::CAPTURE_CARD, card_index};
 259         audio_mixer.reset_resampler(device);
 260         audio_mixer.set_display_name(device, card->capture->get_description());
 261         audio_mixer.trigger_state_changed_callback();
 262 }
 263
 264 void Mixer::set_output_card_internal(int card_index)
 265 {
 266         // We don't really need to take card_mutex, since we're in the mixer
 267         // thread and don't mess with any queues (which is the only thing that happens
 268         // from other threads), but it's probably the safest in the long run.
 269         unique_lock<mutex> lock(card_mutex);
 270         if (output_card_index != -1) {
 271                 // Switch the old card from output to input.
 272                 CaptureCard *old_card = &cards[output_card_index];
 273                 old_card->output->end_output();
 274
 275                 // Stop the fake card that we put into place.
 276                 // This needs to _not_ happen under the mutex, to avoid deadlock
 277                 // (delivering the last frame needs to take the mutex).
 278                 bmusb::CaptureInterface *fake_capture = old_card->capture.get();
 279                 lock.unlock();
 280                 fake_capture->stop_dequeue_thread();
 281                 lock.lock();
 282                 old_card->capture = move(old_card->parked_capture);
 283                 old_card->is_fake_capture = false;
 284                 old_card->capture->start_bm_capture();
 285         }
 286         if (card_index != -1) {
 287                 CaptureCard *card = &cards[card_index];
 288                 bmusb::CaptureInterface *capture = card->capture.get();
 289                 // TODO: DeckLinkCapture::stop_dequeue_thread can actually take
 290                 // several seconds to complete (blocking on DisableVideoInput);
 291                 // see if we can maybe do it asynchronously.
 292                 lock.unlock();
 293                 capture->stop_dequeue_thread();
 294                 lock.lock();
 295                 card->parked_capture = move(card->capture);
 296                 bmusb::CaptureInterface *fake_capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
 297                 configure_card(card_index, fake_capture, /*is_fake_capture=*/true, card->output.release());
 298                 card->queue_length_policy.reset(card_index);
 299                 card->capture->start_bm_capture();
 300                 card->output->start_output(bmdModeHD720p5994, pts_int);  // FIXME
 301         }
 302         output_card_index = card_index;
 303 }
 304
 305 namespace {
 306
 307 int unwrap_timecode(uint16_t current_wrapped, int last)
 308 {
 309         uint16_t last_wrapped = last & 0xffff;
 310         if (current_wrapped > last_wrapped) {
 311                 return (last & ~0xffff) | current_wrapped;
 312         } else {
 313                 return 0x10000 + ((last & ~0xffff) | current_wrapped);
 314         }
 315 }
 316
 317 }  // namespace
 318
 319 void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
 320                      FrameAllocator::Frame video_frame, size_t video_offset, VideoFormat video_format,
 321                      FrameAllocator::Frame audio_frame, size_t audio_offset, AudioFormat audio_format)
 322 {
 323         DeviceSpec device{InputSourceType::CAPTURE_CARD, card_index};
 324         CaptureCard *card = &cards[card_index];
 325
 326         if (is_mode_scanning[card_index]) {
 327                 if (video_format.has_signal) {
 328                         // Found a stable signal, so stop scanning.
 329                         is_mode_scanning[card_index] = false;
 330                 } else {
 331                         static constexpr double switch_time_s = 0.1;  // Should be enough time for the signal to stabilize.
 332                         steady_clock::time_point now = steady_clock::now();
 333                         double sec_since_last_switch = duration<double>(steady_clock::now() - last_mode_scan_change[card_index]).count();
 334                         if (sec_since_last_switch > switch_time_s) {
 335                                 // It isn't this mode; try the next one.
 336                                 mode_scanlist_index[card_index]++;
 337                                 mode_scanlist_index[card_index] %= mode_scanlist[card_index].size();
 338                                 cards[card_index].capture->set_video_mode(mode_scanlist[card_index][mode_scanlist_index[card_index]]);
 339                                 last_mode_scan_change[card_index] = now;
 340                         }
 341                 }
 342         }
 343
 344         int64_t frame_length = int64_t(TIMEBASE) * video_format.frame_rate_den / video_format.frame_rate_nom;
 345         assert(frame_length > 0);
 346
 347         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;
 348         if (num_samples > OUTPUT_FREQUENCY / 10) {
 349                 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",
 350                         card_index, int(audio_frame.len), int(audio_offset),
 351                         timecode, int(video_frame.len), int(video_offset), video_format.id);
 352                 if (video_frame.owner) {
 353                         video_frame.owner->release_frame(video_frame);
 354                 }
 355                 if (audio_frame.owner) {
 356                         audio_frame.owner->release_frame(audio_frame);
 357                 }
 358                 return;
 359         }
 360
 361         int dropped_frames = 0;
 362         if (card->last_timecode != -1) {
 363                 dropped_frames = unwrap_timecode(timecode, card->last_timecode) - card->last_timecode - 1;
 364         }
 365
 366         // Number of samples per frame if we need to insert silence.
 367         // (Could be nonintegral, but resampling will save us then.)
 368         const int silence_samples = OUTPUT_FREQUENCY * video_format.frame_rate_den / video_format.frame_rate_nom;
 369
 370         if (dropped_frames > MAX_FPS * 2) {
 371                 fprintf(stderr, "Card %d lost more than two seconds (or time code jumping around; from 0x%04x to 0x%04x), resetting resampler\n",
 372                         card_index, card->last_timecode, timecode);
 373                 audio_mixer.reset_resampler(device);
 374                 dropped_frames = 0;
 375         } else if (dropped_frames > 0) {
 376                 // Insert silence as needed.
 377                 fprintf(stderr, "Card %d dropped %d frame(s) (before timecode 0x%04x), inserting silence.\n",
 378                         card_index, dropped_frames, timecode);
 379
 380                 bool success;
 381                 do {
 382                         success = audio_mixer.add_silence(device, silence_samples, dropped_frames, frame_length);
 383                 } while (!success);
 384         }
 385
 386         audio_mixer.add_audio(device, audio_frame.data + audio_offset, num_samples, audio_format, frame_length);
 387
 388         // Done with the audio, so release it.
 389         if (audio_frame.owner) {
 390                 audio_frame.owner->release_frame(audio_frame);
 391         }
 392
 393         card->last_timecode = timecode;
 394
 395         size_t expected_length = video_format.width * (video_format.height + video_format.extra_lines_top + video_format.extra_lines_bottom) * 2;
 396         if (video_frame.len - video_offset == 0 ||
 397             video_frame.len - video_offset != expected_length) {
 398                 if (video_frame.len != 0) {
 399                         printf("Card %d: Dropping video frame with wrong length (%ld; expected %ld)\n",
 400                                 card_index, video_frame.len - video_offset, expected_length);
 401                 }
 402                 if (video_frame.owner) {
 403                         video_frame.owner->release_frame(video_frame);
 404                 }
 405
 406                 // Still send on the information that we _had_ a frame, even though it's corrupted,
 407                 // so that pts can go up accordingly.
 408                 {
 409                         unique_lock<mutex> lock(card_mutex);
 410                         CaptureCard::NewFrame new_frame;
 411                         new_frame.frame = RefCountedFrame(FrameAllocator::Frame());
 412                         new_frame.length = frame_length;
 413                         new_frame.interlaced = false;
 414                         new_frame.dropped_frames = dropped_frames;
 415                         card->new_frames.push(move(new_frame));
 416                         card->new_frames_changed.notify_all();
 417                 }
 418                 return;
 419         }
 420
 421         PBOFrameAllocator::Userdata *userdata = (PBOFrameAllocator::Userdata *)video_frame.userdata;
 422
 423         unsigned num_fields = video_format.interlaced ? 2 : 1;
 424         steady_clock::time_point frame_upload_start;
 425         bool interlaced_stride = false;
 426         if (video_format.interlaced) {
 427                 // Send the two fields along as separate frames; the other side will need to add
 428                 // a deinterlacer to actually get this right.
 429                 assert(video_format.height % 2 == 0);
 430                 video_format.height /= 2;
 431                 assert(frame_length % 2 == 0);
 432                 frame_length /= 2;
 433                 num_fields = 2;
 434                 if (video_format.second_field_start == 1) {
 435                         interlaced_stride = true;
 436                 }
 437                 frame_upload_start = steady_clock::now();
 438         }
 439         userdata->last_interlaced = video_format.interlaced;
 440         userdata->last_has_signal = video_format.has_signal;
 441         userdata->last_is_connected = video_format.is_connected;
 442         userdata->last_frame_rate_nom = video_format.frame_rate_nom;
 443         userdata->last_frame_rate_den = video_format.frame_rate_den;
 444         RefCountedFrame frame(video_frame);
 445
 446         // Upload the textures.
 447         size_t cbcr_width = video_format.width / 2;
 448         size_t cbcr_offset = video_offset / 2;
 449         size_t y_offset = video_frame.size / 2 + video_offset / 2;
 450
 451         for (unsigned field = 0; field < num_fields; ++field) {
 452                 // Put the actual texture upload in a lambda that is executed in the main thread.
 453                 // It is entirely possible to do this in the same thread (and it might even be
 454                 // faster, depending on the GPU and driver), but it appears to be trickling
 455                 // driver bugs very easily.
 456                 //
 457                 // Note that this means we must hold on to the actual frame data in <userdata>
 458                 // until the upload command is run, but we hold on to <frame> much longer than that
 459                 // (in fact, all the way until we no longer use the texture in rendering).
 460                 auto upload_func = [field, video_format, y_offset, cbcr_offset, cbcr_width, interlaced_stride, userdata]() {
 461                         unsigned field_start_line;
 462                         if (field == 1) {
 463                                 field_start_line = video_format.second_field_start;
 464                         } else {
 465                                 field_start_line = video_format.extra_lines_top;
 466                         }
 467
 468                         if (userdata->tex_y[field] == 0 ||
 469                             userdata->tex_cbcr[field] == 0 ||
 470                             video_format.width != userdata->last_width[field] ||
 471                             video_format.height != userdata->last_height[field]) {
 472                                 // We changed resolution since last use of this texture, so we need to create
 473                                 // a new object. Note that this each card has its own PBOFrameAllocator,
 474                                 // we don't need to worry about these flip-flopping between resolutions.
 475                                 glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr[field]);
 476                                 check_error();
 477                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_RG8, cbcr_width, video_format.height, 0, GL_RG, GL_UNSIGNED_BYTE, nullptr);
 478                                 check_error();
 479                                 glBindTexture(GL_TEXTURE_2D, userdata->tex_y[field]);
 480                                 check_error();
 481                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, video_format.width, video_format.height, 0, GL_RED, GL_UNSIGNED_BYTE, nullptr);
 482                                 check_error();
 483                                 userdata->last_width[field] = video_format.width;
 484                                 userdata->last_height[field] = video_format.height;
 485                         }
 486
 487                         GLuint pbo = userdata->pbo;
 488                         check_error();
 489                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER, pbo);
 490                         check_error();
 491
 492                         size_t field_y_start = y_offset + video_format.width * field_start_line;
 493                         size_t field_cbcr_start = cbcr_offset + cbcr_width * field_start_line * sizeof(uint16_t);
 494
 495                         if (global_flags.flush_pbos) {
 496                                 glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, field_y_start, video_format.width * video_format.height);
 497                                 check_error();
 498                                 glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, field_cbcr_start, cbcr_width * video_format.height * sizeof(uint16_t));
 499                                 check_error();
 500                         }
 501
 502                         glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr[field]);
 503                         check_error();
 504                         if (interlaced_stride) {
 505                                 glPixelStorei(GL_UNPACK_ROW_LENGTH, cbcr_width * 2);
 506                                 check_error();
 507                         } else {
 508                                 glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 509                                 check_error();
 510                         }
 511                         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, cbcr_width, video_format.height, GL_RG, GL_UNSIGNED_BYTE, BUFFER_OFFSET(field_cbcr_start));
 512                         check_error();
 513                         glBindTexture(GL_TEXTURE_2D, userdata->tex_y[field]);
 514                         check_error();
 515                         if (interlaced_stride) {
 516                                 glPixelStorei(GL_UNPACK_ROW_LENGTH, video_format.width * 2);
 517                                 check_error();
 518                         } else {
 519                                 glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 520                                 check_error();
 521                         }
 522                         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, video_format.width, video_format.height, GL_RED, GL_UNSIGNED_BYTE, BUFFER_OFFSET(field_y_start));
 523                         check_error();
 524                         glBindTexture(GL_TEXTURE_2D, 0);
 525                         check_error();
 526                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
 527                         check_error();
 528                         glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
 529                         check_error();
 530                 };
 531
 532                 if (field == 1) {
 533                         // Don't upload the second field as fast as we can; wait until
 534                         // the field time has approximately passed. (Otherwise, we could
 535                         // get timing jitter against the other sources, and possibly also
 536                         // against the video display, although the latter is not as critical.)
 537                         // This requires our system clock to be reasonably close to the
 538                         // video clock, but that's not an unreasonable assumption.
 539                         steady_clock::time_point second_field_start = frame_upload_start +
 540                                 nanoseconds(frame_length * 1000000000 / TIMEBASE);
 541                         this_thread::sleep_until(second_field_start);
 542                 }
 543
 544                 {
 545                         unique_lock<mutex> lock(card_mutex);
 546                         CaptureCard::NewFrame new_frame;
 547                         new_frame.frame = frame;
 548                         new_frame.length = frame_length;
 549                         new_frame.field = field;
 550                         new_frame.interlaced = video_format.interlaced;
 551                         new_frame.upload_func = upload_func;
 552                         new_frame.dropped_frames = dropped_frames;
 553                         new_frame.received_timestamp = video_frame.received_timestamp;  // Ignore the audio timestamp.
 554                         card->new_frames.push(move(new_frame));
 555                         card->new_frames_changed.notify_all();
 556                 }
 557         }
 558 }
 559
 560 void Mixer::bm_hotplug_add(libusb_device *dev)
 561 {
 562         lock_guard<mutex> lock(hotplug_mutex);
 563         hotplugged_cards.push_back(dev);
 564 }
 565
 566 void Mixer::bm_hotplug_remove(unsigned card_index)
 567 {
 568         cards[card_index].new_frames_changed.notify_all();
 569 }
 570
 571 void Mixer::thread_func()
 572 {
 573         pthread_setname_np(pthread_self(), "Mixer_OpenGL");
 574
 575         eglBindAPI(EGL_OPENGL_API);
 576         QOpenGLContext *context = create_context(mixer_surface);
 577         if (!make_current(context, mixer_surface)) {
 578                 printf("oops\n");
 579                 exit(1);
 580         }
 581
 582         // Start the actual capture. (We don't want to do it before we're actually ready
 583         // to process output frames.)
 584         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 585                 if (int(card_index) != output_card_index) {
 586                         cards[card_index].capture->start_bm_capture();
 587                 }
 588         }
 589
 590         steady_clock::time_point start, now;
 591         start = steady_clock::now();
 592
 593         int frame = 0;
 594         int stats_dropped_frames = 0;
 595
 596         while (!should_quit) {
 597                 if (desired_output_card_index != output_card_index) {
 598                         set_output_card_internal(desired_output_card_index);
 599                 }
 600
 601                 CaptureCard::NewFrame new_frames[MAX_VIDEO_CARDS];
 602                 bool has_new_frame[MAX_VIDEO_CARDS] = { false };
 603
 604                 bool master_card_is_output;
 605                 unsigned master_card_index;
 606                 if (output_card_index != -1) {
 607                         master_card_is_output = true;
 608                         master_card_index = output_card_index;
 609                 } else {
 610                         master_card_is_output = false;
 611                         master_card_index = theme->map_signal(master_clock_channel);
 612                         assert(master_card_index < num_cards);
 613                 }
 614
 615                 OutputFrameInfo output_frame_info = get_one_frame_from_each_card(master_card_index, master_card_is_output, new_frames, has_new_frame);
 616                 schedule_audio_resampling_tasks(output_frame_info.dropped_frames, output_frame_info.num_samples, output_frame_info.frame_duration, output_frame_info.is_preroll);
 617                 stats_dropped_frames += output_frame_info.dropped_frames;
 618
 619                 handle_hotplugged_cards();
 620
 621                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 622                         if (card_index == master_card_index || !has_new_frame[card_index]) {
 623                                 continue;
 624                         }
 625                         if (new_frames[card_index].frame->len == 0) {
 626                                 ++new_frames[card_index].dropped_frames;
 627                         }
 628                         if (new_frames[card_index].dropped_frames > 0) {
 629                                 printf("Card %u dropped %d frames before this\n",
 630                                         card_index, int(new_frames[card_index].dropped_frames));
 631                         }
 632                 }
 633
 634                 // If the first card is reporting a corrupted or otherwise dropped frame,
 635                 // just increase the pts (skipping over this frame) and don't try to compute anything new.
 636                 if (!master_card_is_output && new_frames[master_card_index].frame->len == 0) {
 637                         ++stats_dropped_frames;
 638                         pts_int += new_frames[master_card_index].length;
 639                         continue;
 640                 }
 641
 642                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 643                         if (!has_new_frame[card_index] || new_frames[card_index].frame->len == 0)
 644                                 continue;
 645
 646                         CaptureCard::NewFrame *new_frame = &new_frames[card_index];
 647                         assert(new_frame->frame != nullptr);
 648                         insert_new_frame(new_frame->frame, new_frame->field, new_frame->interlaced, card_index, &input_state);
 649                         check_error();
 650
 651                         // The new texture might need uploading before use.
 652                         if (new_frame->upload_func) {
 653                                 new_frame->upload_func();
 654                                 new_frame->upload_func = nullptr;
 655                         }
 656                 }
 657
 658                 int64_t frame_duration = output_frame_info.frame_duration;
 659                 render_one_frame(frame_duration);
 660                 ++frame;
 661                 pts_int += frame_duration;
 662
 663                 now = steady_clock::now();
 664                 double elapsed = duration<double>(now - start).count();
 665                 if (frame % 100 == 0) {
 666                         printf("%d frames (%d dropped) in %.3f seconds = %.1f fps (%.1f ms/frame)",
 667                                 frame, stats_dropped_frames, elapsed, frame / elapsed,
 668                                 1e3 * elapsed / frame);
 669                 //      chain->print_phase_timing();
 670
 671                         // Check our memory usage, to see if we are close to our mlockall()
 672                         // limit (if at all set).
 673                         rusage used;
 674                         if (getrusage(RUSAGE_SELF, &used) == -1) {
 675                                 perror("getrusage(RUSAGE_SELF)");
 676                                 assert(false);
 677                         }
 678
 679                         if (uses_mlock) {
 680                                 rlimit limit;
 681                                 if (getrlimit(RLIMIT_MEMLOCK, &limit) == -1) {
 682                                         perror("getrlimit(RLIMIT_MEMLOCK)");
 683                                         assert(false);
 684                                 }
 685
 686                                 if (limit.rlim_cur == 0) {
 687                                         printf(", using %ld MB memory (locked)",
 688                                                 long(used.ru_maxrss / 1024));
 689                                 } else {
 690                                         printf(", using %ld / %ld MB lockable memory (%.1f%%)",
 691                                                 long(used.ru_maxrss / 1024),
 692                                                 long(limit.rlim_cur / 1048576),
 693                                                 float(100.0 * (used.ru_maxrss * 1024.0) / limit.rlim_cur));
 694                                 }
 695                         } else {
 696                                 printf(", using %ld MB memory (not locked)",
 697                                         long(used.ru_maxrss / 1024));
 698                         }
 699
 700                         printf("\n");
 701                 }
 702
 703
 704                 if (should_cut.exchange(false)) {  // Test and clear.
 705                         video_encoder->do_cut(frame);
 706                 }
 707
 708 #if 0
 709                 // Reset every 100 frames, so that local variations in frame times
 710                 // (especially for the first few frames, when the shaders are
 711                 // compiled etc.) don't make it hard to measure for the entire
 712                 // remaining duration of the program.
 713                 if (frame == 10000) {
 714                         frame = 0;
 715                         start = now;
 716                 }
 717 #endif
 718                 check_error();
 719         }
 720
 721         resource_pool->clean_context();
 722 }
 723
 724 bool Mixer::input_card_is_master_clock(unsigned card_index, unsigned master_card_index) const
 725 {
 726         if (output_card_index != -1) {
 727                 // The output card (ie., cards[output_card_index].output) is the master clock,
 728                 // so no input card (ie., cards[card_index].capture) is.
 729                 return false;
 730         }
 731         return (card_index == master_card_index);
 732 }
 733
 734 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])
 735 {
 736         OutputFrameInfo output_frame_info;
 737 start:
 738         unique_lock<mutex> lock(card_mutex, defer_lock);
 739         if (master_card_is_output) {
 740                 // Clocked to the output, so wait for it to be ready for the next frame.
 741                 cards[master_card_index].output->wait_for_frame(pts_int, &output_frame_info.dropped_frames, &output_frame_info.frame_duration, &output_frame_info.is_preroll);
 742                 lock.lock();
 743         } else {
 744                 // Wait for the master card to have a new frame.
 745                 // TODO: Add a timeout.
 746                 output_frame_info.is_preroll = false;
 747                 lock.lock();
 748                 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(); });
 749         }
 750
 751         if (master_card_is_output) {
 752                 handle_hotplugged_cards();
 753         } else if (cards[master_card_index].new_frames.empty()) {
 754                 // We were woken up, but not due to a new frame. Deal with it
 755                 // and then restart.
 756                 assert(cards[master_card_index].capture->get_disconnected());
 757                 handle_hotplugged_cards();
 758                 goto start;
 759         }
 760
 761         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 762                 CaptureCard *card = &cards[card_index];
 763                 if (card->new_frames.empty()) {
 764                         assert(!input_card_is_master_clock(card_index, master_card_index));
 765                         card->queue_length_policy.update_policy(-1);
 766                         continue;
 767                 }
 768                 new_frames[card_index] = move(card->new_frames.front());
 769                 has_new_frame[card_index] = true;
 770                 card->new_frames.pop();
 771                 card->new_frames_changed.notify_all();
 772
 773                 if (input_card_is_master_clock(card_index, master_card_index)) {
 774                         // We don't use the queue length policy for the master card,
 775                         // but we will if it stops being the master. Thus, clear out
 776                         // the policy in case we switch in the future.
 777                         card->queue_length_policy.reset(card_index);
 778                 } else {
 779                         // If we have excess frames compared to the policy for this card,
 780                         // drop frames from the head.
 781                         card->queue_length_policy.update_policy(card->new_frames.size());
 782                         while (card->new_frames.size() > card->queue_length_policy.get_safe_queue_length()) {
 783                                 card->new_frames.pop();
 784                         }
 785                 }
 786         }
 787
 788         if (!master_card_is_output) {
 789                 output_frame_info.dropped_frames = new_frames[master_card_index].dropped_frames;
 790                 output_frame_info.frame_duration = new_frames[master_card_index].length;
 791         }
 792
 793         // This might get off by a fractional sample when changing master card
 794         // between ones with different frame rates, but that's fine.
 795         int num_samples_times_timebase = OUTPUT_FREQUENCY * output_frame_info.frame_duration + fractional_samples;
 796         output_frame_info.num_samples = num_samples_times_timebase / TIMEBASE;
 797         fractional_samples = num_samples_times_timebase % TIMEBASE;
 798         assert(output_frame_info.num_samples >= 0);
 799
 800         return output_frame_info;
 801 }
 802
 803 void Mixer::handle_hotplugged_cards()
 804 {
 805         // Check for cards that have been disconnected since last frame.
 806         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 807                 CaptureCard *card = &cards[card_index];
 808                 if (card->capture->get_disconnected()) {
 809                         fprintf(stderr, "Card %u went away, replacing with a fake card.\n", card_index);
 810                         FakeCapture *capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
 811                         configure_card(card_index, capture, /*is_fake_capture=*/true, /*output=*/nullptr);
 812                         card->queue_length_policy.reset(card_index);
 813                         card->capture->start_bm_capture();
 814                 }
 815         }
 816
 817         // Check for cards that have been connected since last frame.
 818         vector<libusb_device *> hotplugged_cards_copy;
 819         {
 820                 lock_guard<mutex> lock(hotplug_mutex);
 821                 swap(hotplugged_cards, hotplugged_cards_copy);
 822         }
 823         for (libusb_device *new_dev : hotplugged_cards_copy) {
 824                 // Look for a fake capture card where we can stick this in.
 825                 int free_card_index = -1;
 826                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 827                         if (cards[card_index].is_fake_capture) {
 828                                 free_card_index = card_index;
 829                                 break;
 830                         }
 831                 }
 832
 833                 if (free_card_index == -1) {
 834                         fprintf(stderr, "New card plugged in, but no free slots -- ignoring.\n");
 835                         libusb_unref_device(new_dev);
 836                 } else {
 837                         // BMUSBCapture takes ownership.
 838                         fprintf(stderr, "New card plugged in, choosing slot %d.\n", free_card_index);
 839                         CaptureCard *card = &cards[free_card_index];
 840                         BMUSBCapture *capture = new BMUSBCapture(free_card_index, new_dev);
 841                         configure_card(free_card_index, capture, /*is_fake_capture=*/false, /*output=*/nullptr);
 842                         card->queue_length_policy.reset(free_card_index);
 843                         capture->set_card_disconnected_callback(bind(&Mixer::bm_hotplug_remove, this, free_card_index));
 844                         capture->start_bm_capture();
 845                 }
 846         }
 847 }
 848
 849
 850 void Mixer::schedule_audio_resampling_tasks(unsigned dropped_frames, int num_samples_per_frame, int length_per_frame, bool is_preroll)
 851 {
 852         // Resample the audio as needed, including from previously dropped frames.
 853         assert(num_cards > 0);
 854         for (unsigned frame_num = 0; frame_num < dropped_frames + 1; ++frame_num) {
 855                 const bool dropped_frame = (frame_num != dropped_frames);
 856                 {
 857                         // Signal to the audio thread to process this frame.
 858                         // Note that if the frame is a dropped frame, we signal that
 859                         // we don't want to use this frame as base for adjusting
 860                         // the resampler rate. The reason for this is that the timing
 861                         // of these frames is often way too late; they typically don't
 862                         // “arrive” before we synthesize them. Thus, we could end up
 863                         // in a situation where we have inserted e.g. five audio frames
 864                         // into the queue before we then start pulling five of them
 865                         // back out. This makes ResamplingQueue overestimate the delay,
 866                         // causing undue resampler changes. (We _do_ use the last,
 867                         // non-dropped frame; perhaps we should just discard that as well,
 868                         // since dropped frames are expected to be rare, and it might be
 869                         // better to just wait until we have a slightly more normal situation).
 870                         unique_lock<mutex> lock(audio_mutex);
 871                         bool adjust_rate = !dropped_frame && !is_preroll;
 872                         audio_task_queue.push(AudioTask{pts_int, num_samples_per_frame, adjust_rate});
 873                         audio_task_queue_changed.notify_one();
 874                 }
 875                 if (dropped_frame) {
 876                         // For dropped frames, increase the pts. Note that if the format changed
 877                         // in the meantime, we have no way of detecting that; we just have to
 878                         // assume the frame length is always the same.
 879                         pts_int += length_per_frame;
 880                 }
 881         }
 882 }
 883
 884 void Mixer::render_one_frame(int64_t duration)
 885 {
 886         // Get the main chain from the theme, and set its state immediately.
 887         Theme::Chain theme_main_chain = theme->get_chain(0, pts(), global_flags.width, global_flags.height, input_state);
 888         EffectChain *chain = theme_main_chain.chain;
 889         theme_main_chain.setup_chain();
 890         //theme_main_chain.chain->enable_phase_timing(true);
 891
 892         GLuint y_tex, cbcr_tex;
 893         bool got_frame = video_encoder->begin_frame(&y_tex, &cbcr_tex);
 894         assert(got_frame);
 895
 896         // Render main chain.
 897         GLuint cbcr_full_tex = resource_pool->create_2d_texture(GL_RG8, global_flags.width, global_flags.height);
 898         GLuint rgba_tex = resource_pool->create_2d_texture(GL_RGB565, global_flags.width, global_flags.height);  // Saves texture bandwidth, although dithering gets messed up.
 899         GLuint fbo = resource_pool->create_fbo(y_tex, cbcr_full_tex, rgba_tex);
 900         check_error();
 901         chain->render_to_fbo(fbo, global_flags.width, global_flags.height);
 902         resource_pool->release_fbo(fbo);
 903
 904         chroma_subsampler->subsample_chroma(cbcr_full_tex, global_flags.width, global_flags.height, cbcr_tex);
 905         if (output_card_index != -1) {
 906                 cards[output_card_index].output->send_frame(y_tex, cbcr_full_tex, theme_main_chain.input_frames, pts_int, duration);
 907         }
 908         resource_pool->release_2d_texture(cbcr_full_tex);
 909
 910         // Set the right state for rgba_tex.
 911         glBindFramebuffer(GL_FRAMEBUFFER, 0);
 912         glBindTexture(GL_TEXTURE_2D, rgba_tex);
 913         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 914         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 915         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 916
 917         const int64_t av_delay = lrint(global_flags.audio_queue_length_ms * 0.001 * TIMEBASE);  // Corresponds to the delay in ResamplingQueue.
 918         RefCountedGLsync fence = video_encoder->end_frame(pts_int + av_delay, duration, theme_main_chain.input_frames);
 919
 920         // The live frame just shows the RGBA texture we just rendered.
 921         // It owns rgba_tex now.
 922         DisplayFrame live_frame;
 923         live_frame.chain = display_chain.get();
 924         live_frame.setup_chain = [this, rgba_tex]{
 925                 display_input->set_texture_num(rgba_tex);
 926         };
 927         live_frame.ready_fence = fence;
 928         live_frame.input_frames = {};
 929         live_frame.temp_textures = { rgba_tex };
 930         output_channel[OUTPUT_LIVE].output_frame(live_frame);
 931
 932         // Set up preview and any additional channels.
 933         for (int i = 1; i < theme->get_num_channels() + 2; ++i) {
 934                 DisplayFrame display_frame;
 935                 Theme::Chain chain = theme->get_chain(i, pts(), global_flags.width, global_flags.height, input_state);  // FIXME: dimensions
 936                 display_frame.chain = chain.chain;
 937                 display_frame.setup_chain = chain.setup_chain;
 938                 display_frame.ready_fence = fence;
 939                 display_frame.input_frames = chain.input_frames;
 940                 display_frame.temp_textures = {};
 941                 output_channel[i].output_frame(display_frame);
 942         }
 943 }
 944
 945 void Mixer::audio_thread_func()
 946 {
 947         pthread_setname_np(pthread_self(), "Mixer_Audio");
 948
 949         while (!should_quit) {
 950                 AudioTask task;
 951
 952                 {
 953                         unique_lock<mutex> lock(audio_mutex);
 954                         audio_task_queue_changed.wait(lock, [this]{ return should_quit || !audio_task_queue.empty(); });
 955                         if (should_quit) {
 956                                 return;
 957                         }
 958                         task = audio_task_queue.front();
 959                         audio_task_queue.pop();
 960                 }
 961
 962                 ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy =
 963                         task.adjust_rate ? ResamplingQueue::ADJUST_RATE : ResamplingQueue::DO_NOT_ADJUST_RATE;
 964                 vector<float> samples_out = audio_mixer.get_output(
 965                         double(task.pts_int) / TIMEBASE,
 966                         task.num_samples,
 967                         rate_adjustment_policy);
 968
 969                 // Send the samples to the sound card, then add them to the output.
 970                 if (alsa) {
 971                         alsa->write(samples_out);
 972                 }
 973                 if (output_card_index != -1) {
 974                         const int64_t av_delay = lrint(global_flags.audio_queue_length_ms * 0.001 * TIMEBASE);  // Corresponds to the delay in ResamplingQueue.
 975                         cards[output_card_index].output->send_audio(task.pts_int + av_delay, samples_out);
 976                 }
 977                 video_encoder->add_audio(task.pts_int, move(samples_out));
 978         }
 979 }
 980
 981 void Mixer::release_display_frame(DisplayFrame *frame)
 982 {
 983         for (GLuint texnum : frame->temp_textures) {
 984                 resource_pool->release_2d_texture(texnum);
 985         }
 986         frame->temp_textures.clear();
 987         frame->ready_fence.reset();
 988         frame->input_frames.clear();
 989 }
 990
 991 void Mixer::start()
 992 {
 993         mixer_thread = thread(&Mixer::thread_func, this);
 994         audio_thread = thread(&Mixer::audio_thread_func, this);
 995 }
 996
 997 void Mixer::quit()
 998 {
 999         should_quit = true;
1000         audio_task_queue_changed.notify_one();
1001         mixer_thread.join();
1002         audio_thread.join();
1003 }
1004
1005 void Mixer::transition_clicked(int transition_num)
1006 {
1007         theme->transition_clicked(transition_num, pts());
1008 }
1009
1010 void Mixer::channel_clicked(int preview_num)
1011 {
1012         theme->channel_clicked(preview_num);
1013 }
1014
1015 void Mixer::start_mode_scanning(unsigned card_index)
1016 {
1017         assert(card_index < num_cards);
1018         if (is_mode_scanning[card_index]) {
1019                 return;
1020         }
1021         is_mode_scanning[card_index] = true;
1022         mode_scanlist[card_index].clear();
1023         for (const auto &mode : cards[card_index].capture->get_available_video_modes()) {
1024                 mode_scanlist[card_index].push_back(mode.first);
1025         }
1026         assert(!mode_scanlist[card_index].empty());
1027         mode_scanlist_index[card_index] = 0;
1028         cards[card_index].capture->set_video_mode(mode_scanlist[card_index][0]);
1029         last_mode_scan_change[card_index] = steady_clock::now();
1030 }
1031
1032 Mixer::OutputChannel::~OutputChannel()
1033 {
1034         if (has_current_frame) {
1035                 parent->release_display_frame(&current_frame);
1036         }
1037         if (has_ready_frame) {
1038                 parent->release_display_frame(&ready_frame);
1039         }
1040 }
1041
1042 void Mixer::OutputChannel::output_frame(DisplayFrame frame)
1043 {
1044         // Store this frame for display. Remove the ready frame if any
1045         // (it was seemingly never used).
1046         {
1047                 unique_lock<mutex> lock(frame_mutex);
1048                 if (has_ready_frame) {
1049                         parent->release_display_frame(&ready_frame);
1050                 }
1051                 ready_frame = frame;
1052                 has_ready_frame = true;
1053         }
1054
1055         if (new_frame_ready_callback) {
1056                 new_frame_ready_callback();
1057         }
1058
1059         // Reduce the number of callbacks by filtering duplicates. The reason
1060         // why we bother doing this is that Qt seemingly can get into a state
1061         // where its builds up an essentially unbounded queue of signals,
1062         // consuming more and more memory, and there's no good way of collapsing
1063         // user-defined signals or limiting the length of the queue.
1064         if (transition_names_updated_callback) {
1065                 vector<string> transition_names = global_mixer->get_transition_names();
1066                 bool changed = false;
1067                 if (transition_names.size() != last_transition_names.size()) {
1068                         changed = true;
1069                 } else {
1070                         for (unsigned i = 0; i < transition_names.size(); ++i) {
1071                                 if (transition_names[i] != last_transition_names[i]) {
1072                                         changed = true;
1073                                         break;
1074                                 }
1075                         }
1076                 }
1077                 if (changed) {
1078                         transition_names_updated_callback(transition_names);
1079                         last_transition_names = transition_names;
1080                 }
1081         }
1082         if (name_updated_callback) {
1083                 string name = global_mixer->get_channel_name(channel);
1084                 if (name != last_name) {
1085                         name_updated_callback(name);
1086                         last_name = name;
1087                 }
1088         }
1089         if (color_updated_callback) {
1090                 string color = global_mixer->get_channel_color(channel);
1091                 if (color != last_color) {
1092                         color_updated_callback(color);
1093                         last_color = color;
1094                 }
1095         }
1096 }
1097
1098 bool Mixer::OutputChannel::get_display_frame(DisplayFrame *frame)
1099 {
1100         unique_lock<mutex> lock(frame_mutex);
1101         if (!has_current_frame && !has_ready_frame) {
1102                 return false;
1103         }
1104
1105         if (has_current_frame && has_ready_frame) {
1106                 // We have a new ready frame. Toss the current one.
1107                 parent->release_display_frame(&current_frame);
1108                 has_current_frame = false;
1109         }
1110         if (has_ready_frame) {
1111                 assert(!has_current_frame);
1112                 current_frame = ready_frame;
1113                 ready_frame.ready_fence.reset();  // Drop the refcount.
1114                 ready_frame.input_frames.clear();  // Drop the refcounts.
1115                 has_current_frame = true;
1116                 has_ready_frame = false;
1117         }
1118
1119         *frame = current_frame;
1120         return true;
1121 }
1122
1123 void Mixer::OutputChannel::set_frame_ready_callback(Mixer::new_frame_ready_callback_t callback)
1124 {
1125         new_frame_ready_callback = callback;
1126 }
1127
1128 void Mixer::OutputChannel::set_transition_names_updated_callback(Mixer::transition_names_updated_callback_t callback)
1129 {
1130         transition_names_updated_callback = callback;
1131 }
1132
1133 void Mixer::OutputChannel::set_name_updated_callback(Mixer::name_updated_callback_t callback)
1134 {
1135         name_updated_callback = callback;
1136 }
1137
1138 void Mixer::OutputChannel::set_color_updated_callback(Mixer::color_updated_callback_t callback)
1139 {
1140         color_updated_callback = callback;
1141 }
1142
1143 mutex RefCountedGLsync::fence_lock;