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 <movit/util.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 "context.h"
  37 #include "decklink_capture.h"
  38 #include "defs.h"
  39 #include "disk_space_estimator.h"
  40 #include "flags.h"
  41 #include "input_mapping.h"
  42 #include "pbo_frame_allocator.h"
  43 #include "ref_counted_gl_sync.h"
  44 #include "resampling_queue.h"
  45 #include "timebase.h"
  46 #include "video_encoder.h"
  47
  48 class IDeckLink;
  49 class QOpenGLContext;
  50
  51 using namespace movit;
  52 using namespace std;
  53 using namespace std::chrono;
  54 using namespace std::placeholders;
  55 using namespace bmusb;
  56
  57 Mixer *global_mixer = nullptr;
  58 bool uses_mlock = false;
  59
  60 namespace {
  61
  62 void insert_new_frame(RefCountedFrame frame, unsigned field_num, bool interlaced, unsigned card_index, InputState *input_state)
  63 {
  64         if (interlaced) {
  65                 for (unsigned frame_num = FRAME_HISTORY_LENGTH; frame_num --> 1; ) {  // :-)
  66                         input_state->buffered_frames[card_index][frame_num] =
  67                                 input_state->buffered_frames[card_index][frame_num - 1];
  68                 }
  69                 input_state->buffered_frames[card_index][0] = { frame, field_num };
  70         } else {
  71                 for (unsigned frame_num = 0; frame_num < FRAME_HISTORY_LENGTH; ++frame_num) {
  72                         input_state->buffered_frames[card_index][frame_num] = { frame, field_num };
  73                 }
  74         }
  75 }
  76
  77 }  // namespace
  78
  79 void QueueLengthPolicy::update_policy(int queue_length)
  80 {
  81         if (queue_length < 0) {  // Starvation.
  82                 if (been_at_safe_point_since_last_starvation && safe_queue_length < 5) {
  83                         ++safe_queue_length;
  84                         fprintf(stderr, "Card %u: Starvation, increasing safe limit to %u frames\n",
  85                                 card_index, safe_queue_length);
  86                 }
  87                 frames_with_at_least_one = 0;
  88                 been_at_safe_point_since_last_starvation = false;
  89                 return;
  90         }
  91         if (queue_length > 0) {
  92                 if (queue_length >= int(safe_queue_length)) {
  93                         been_at_safe_point_since_last_starvation = true;
  94                 }
  95                 if (++frames_with_at_least_one >= 1000 && safe_queue_length > 0) {
  96                         --safe_queue_length;
  97                         fprintf(stderr, "Card %u: Spare frames for more than 1000 frames, reducing safe limit to %u frames\n",
  98                                 card_index, safe_queue_length);
  99                         frames_with_at_least_one = 0;
 100                 }
 101         } else {
 102                 frames_with_at_least_one = 0;
 103         }
 104 }
 105
 106 Mixer::Mixer(const QSurfaceFormat &format, unsigned num_cards)
 107         : httpd(),
 108           num_cards(num_cards),
 109           mixer_surface(create_surface(format)),
 110           h264_encoder_surface(create_surface(format)),
 111           audio_mixer(num_cards)
 112 {
 113         CHECK(init_movit(MOVIT_SHADER_DIR, MOVIT_DEBUG_OFF));
 114         check_error();
 115
 116         // Since we allow non-bouncing 4:2:2 YCbCrInputs, effective subpixel precision
 117         // will be halved when sampling them, and we need to compensate here.
 118         movit_texel_subpixel_precision /= 2.0;
 119
 120         resource_pool.reset(new ResourcePool);
 121         theme.reset(new Theme(global_flags.theme_filename, global_flags.theme_dirs, resource_pool.get(), num_cards));
 122         for (unsigned i = 0; i < NUM_OUTPUTS; ++i) {
 123                 output_channel[i].parent = this;
 124                 output_channel[i].channel = i;
 125         }
 126
 127         ImageFormat inout_format;
 128         inout_format.color_space = COLORSPACE_sRGB;
 129         inout_format.gamma_curve = GAMMA_sRGB;
 130
 131         // Display chain; shows the live output produced by the main chain (its RGBA version).
 132         display_chain.reset(new EffectChain(global_flags.width, global_flags.height, resource_pool.get()));
 133         check_error();
 134         display_input = new FlatInput(inout_format, FORMAT_RGB, GL_UNSIGNED_BYTE, global_flags.width, global_flags.height);  // FIXME: GL_UNSIGNED_BYTE is really wrong.
 135         display_chain->add_input(display_input);
 136         display_chain->add_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED);
 137         display_chain->set_dither_bits(0);  // Don't bother.
 138         display_chain->finalize();
 139
 140         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));
 141
 142         // Start listening for clients only once VideoEncoder has written its header, if any.
 143         httpd.start(9095);
 144
 145         // First try initializing the then PCI devices, then USB, then
 146         // fill up with fake cards until we have the desired number of cards.
 147         unsigned num_pci_devices = 0;
 148         unsigned card_index = 0;
 149
 150         {
 151                 IDeckLinkIterator *decklink_iterator = CreateDeckLinkIteratorInstance();
 152                 if (decklink_iterator != nullptr) {
 153                         for ( ; card_index < num_cards; ++card_index) {
 154                                 IDeckLink *decklink;
 155                                 if (decklink_iterator->Next(&decklink) != S_OK) {
 156                                         break;
 157                                 }
 158
 159                                 configure_card(card_index, new DeckLinkCapture(decklink, card_index), /*is_fake_capture=*/false);
 160                                 ++num_pci_devices;
 161                         }
 162                         decklink_iterator->Release();
 163                         fprintf(stderr, "Found %u DeckLink PCI card(s).\n", num_pci_devices);
 164                 } else {
 165                         fprintf(stderr, "DeckLink drivers not found. Probing for USB cards only.\n");
 166                 }
 167         }
 168         unsigned num_usb_devices = BMUSBCapture::num_cards();
 169         for (unsigned usb_card_index = 0; usb_card_index < num_usb_devices && card_index < num_cards; ++usb_card_index, ++card_index) {
 170                 BMUSBCapture *capture = new BMUSBCapture(usb_card_index);
 171                 capture->set_card_disconnected_callback(bind(&Mixer::bm_hotplug_remove, this, card_index));
 172                 configure_card(card_index, capture, /*is_fake_capture=*/false);
 173         }
 174         fprintf(stderr, "Found %u USB card(s).\n", num_usb_devices);
 175
 176         unsigned num_fake_cards = 0;
 177         for ( ; card_index < num_cards; ++card_index, ++num_fake_cards) {
 178                 FakeCapture *capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
 179                 configure_card(card_index, capture, /*is_fake_capture=*/true);
 180         }
 181
 182         if (num_fake_cards > 0) {
 183                 fprintf(stderr, "Initialized %u fake cards.\n", num_fake_cards);
 184         }
 185
 186         BMUSBCapture::set_card_connected_callback(bind(&Mixer::bm_hotplug_add, this, _1));
 187         BMUSBCapture::start_bm_thread();
 188
 189         for (card_index = 0; card_index < num_cards; ++card_index) {
 190                 cards[card_index].queue_length_policy.reset(card_index);
 191                 cards[card_index].capture->start_bm_capture();
 192         }
 193
 194         // Set up stuff for NV12 conversion.
 195
 196         // Cb/Cr shader.
 197         string cbcr_vert_shader =
 198                 "#version 130 \n"
 199                 " \n"
 200                 "in vec2 position; \n"
 201                 "in vec2 texcoord; \n"
 202                 "out vec2 tc0; \n"
 203                 "uniform vec2 foo_chroma_offset_0; \n"
 204                 " \n"
 205                 "void main() \n"
 206                 "{ \n"
 207                 "    // The result of glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0) is: \n"
 208                 "    // \n"
 209                 "    //   2.000  0.000  0.000 -1.000 \n"
 210                 "    //   0.000  2.000  0.000 -1.000 \n"
 211                 "    //   0.000  0.000 -2.000 -1.000 \n"
 212                 "    //   0.000  0.000  0.000  1.000 \n"
 213                 "    gl_Position = vec4(2.0 * position.x - 1.0, 2.0 * position.y - 1.0, -1.0, 1.0); \n"
 214                 "    vec2 flipped_tc = texcoord; \n"
 215                 "    tc0 = flipped_tc + foo_chroma_offset_0; \n"
 216                 "} \n";
 217         string cbcr_frag_shader =
 218                 "#version 130 \n"
 219                 "in vec2 tc0; \n"
 220                 "uniform sampler2D cbcr_tex; \n"
 221                 "out vec4 FragColor; \n"
 222                 "void main() { \n"
 223                 "    FragColor = texture(cbcr_tex, tc0); \n"
 224                 "} \n";
 225         vector<string> frag_shader_outputs;
 226         cbcr_program_num = resource_pool->compile_glsl_program(cbcr_vert_shader, cbcr_frag_shader, frag_shader_outputs);
 227
 228         float vertices[] = {
 229                 0.0f, 2.0f,
 230                 0.0f, 0.0f,
 231                 2.0f, 0.0f
 232         };
 233         cbcr_vbo = generate_vbo(2, GL_FLOAT, sizeof(vertices), vertices);
 234         cbcr_position_attribute_index = glGetAttribLocation(cbcr_program_num, "position");
 235         cbcr_texcoord_attribute_index = glGetAttribLocation(cbcr_program_num, "texcoord");
 236
 237         if (global_flags.enable_alsa_output) {
 238                 alsa.reset(new ALSAOutput(OUTPUT_FREQUENCY, /*num_channels=*/2));
 239         }
 240 }
 241
 242 Mixer::~Mixer()
 243 {
 244         resource_pool->release_glsl_program(cbcr_program_num);
 245         glDeleteBuffers(1, &cbcr_vbo);
 246         BMUSBCapture::stop_bm_thread();
 247
 248         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 249                 {
 250                         unique_lock<mutex> lock(bmusb_mutex);
 251                         cards[card_index].should_quit = true;  // Unblock thread.
 252                         cards[card_index].new_frames_changed.notify_all();
 253                 }
 254                 cards[card_index].capture->stop_dequeue_thread();
 255         }
 256
 257         video_encoder.reset(nullptr);
 258 }
 259
 260 void Mixer::configure_card(unsigned card_index, CaptureInterface *capture, bool is_fake_capture)
 261 {
 262         printf("Configuring card %d...\n", card_index);
 263
 264         CaptureCard *card = &cards[card_index];
 265         if (card->capture != nullptr) {
 266                 card->capture->stop_dequeue_thread();
 267                 delete card->capture;
 268         }
 269         card->capture = capture;
 270         card->is_fake_capture = is_fake_capture;
 271         card->capture->set_frame_callback(bind(&Mixer::bm_frame, this, card_index, _1, _2, _3, _4, _5, _6, _7));
 272         if (card->frame_allocator == nullptr) {
 273                 card->frame_allocator.reset(new PBOFrameAllocator(8 << 20, global_flags.width, global_flags.height));  // 8 MB.
 274         }
 275         card->capture->set_video_frame_allocator(card->frame_allocator.get());
 276         if (card->surface == nullptr) {
 277                 card->surface = create_surface_with_same_format(mixer_surface);
 278         }
 279         while (!card->new_frames.empty()) card->new_frames.pop();
 280         card->fractional_samples = 0;
 281         card->last_timecode = -1;
 282         card->capture->configure_card();
 283
 284         DeviceSpec device{InputSourceType::CAPTURE_CARD, card_index};
 285         audio_mixer.reset_resampler(device);
 286         audio_mixer.set_display_name(device, card->capture->get_description());
 287         audio_mixer.trigger_state_changed_callback();
 288 }
 289
 290
 291 namespace {
 292
 293 int unwrap_timecode(uint16_t current_wrapped, int last)
 294 {
 295         uint16_t last_wrapped = last & 0xffff;
 296         if (current_wrapped > last_wrapped) {
 297                 return (last & ~0xffff) | current_wrapped;
 298         } else {
 299                 return 0x10000 + ((last & ~0xffff) | current_wrapped);
 300         }
 301 }
 302
 303 }  // namespace
 304
 305 void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
 306                      FrameAllocator::Frame video_frame, size_t video_offset, VideoFormat video_format,
 307                      FrameAllocator::Frame audio_frame, size_t audio_offset, AudioFormat audio_format)
 308 {
 309         DeviceSpec device{InputSourceType::CAPTURE_CARD, card_index};
 310         CaptureCard *card = &cards[card_index];
 311
 312         if (is_mode_scanning[card_index]) {
 313                 if (video_format.has_signal) {
 314                         // Found a stable signal, so stop scanning.
 315                         is_mode_scanning[card_index] = false;
 316                 } else {
 317                         static constexpr double switch_time_s = 0.5;  // Should be enough time for the signal to stabilize.
 318                         steady_clock::time_point now = steady_clock::now();
 319                         double sec_since_last_switch = duration<double>(steady_clock::now() - last_mode_scan_change[card_index]).count();
 320                         if (sec_since_last_switch > switch_time_s) {
 321                                 // It isn't this mode; try the next one.
 322                                 mode_scanlist_index[card_index]++;
 323                                 mode_scanlist_index[card_index] %= mode_scanlist[card_index].size();
 324                                 cards[card_index].capture->set_video_mode(mode_scanlist[card_index][mode_scanlist_index[card_index]]);
 325                                 last_mode_scan_change[card_index] = now;
 326                         }
 327                 }
 328         }
 329
 330         int64_t frame_length = int64_t(TIMEBASE) * video_format.frame_rate_den / video_format.frame_rate_nom;
 331         assert(frame_length > 0);
 332
 333         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;
 334         if (num_samples > OUTPUT_FREQUENCY / 10) {
 335                 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",
 336                         card_index, int(audio_frame.len), int(audio_offset),
 337                         timecode, int(video_frame.len), int(video_offset), video_format.id);
 338                 if (video_frame.owner) {
 339                         video_frame.owner->release_frame(video_frame);
 340                 }
 341                 if (audio_frame.owner) {
 342                         audio_frame.owner->release_frame(audio_frame);
 343                 }
 344                 return;
 345         }
 346
 347         int dropped_frames = 0;
 348         if (card->last_timecode != -1) {
 349                 dropped_frames = unwrap_timecode(timecode, card->last_timecode) - card->last_timecode - 1;
 350         }
 351
 352         // Number of samples per frame if we need to insert silence.
 353         // (Could be nonintegral, but resampling will save us then.)
 354         const int silence_samples = OUTPUT_FREQUENCY * video_format.frame_rate_den / video_format.frame_rate_nom;
 355
 356         if (dropped_frames > MAX_FPS * 2) {
 357                 fprintf(stderr, "Card %d lost more than two seconds (or time code jumping around; from 0x%04x to 0x%04x), resetting resampler\n",
 358                         card_index, card->last_timecode, timecode);
 359                 audio_mixer.reset_resampler(device);
 360                 dropped_frames = 0;
 361         } else if (dropped_frames > 0) {
 362                 // Insert silence as needed.
 363                 fprintf(stderr, "Card %d dropped %d frame(s) (before timecode 0x%04x), inserting silence.\n",
 364                         card_index, dropped_frames, timecode);
 365
 366                 bool success;
 367                 do {
 368                         success = audio_mixer.add_silence(device, silence_samples, dropped_frames, frame_length);
 369                 } while (!success);
 370         }
 371
 372         audio_mixer.add_audio(device, audio_frame.data + audio_offset, num_samples, audio_format, frame_length);
 373
 374         // Done with the audio, so release it.
 375         if (audio_frame.owner) {
 376                 audio_frame.owner->release_frame(audio_frame);
 377         }
 378
 379         card->last_timecode = timecode;
 380
 381         size_t expected_length = video_format.width * (video_format.height + video_format.extra_lines_top + video_format.extra_lines_bottom) * 2;
 382         if (video_frame.len - video_offset == 0 ||
 383             video_frame.len - video_offset != expected_length) {
 384                 if (video_frame.len != 0) {
 385                         printf("Card %d: Dropping video frame with wrong length (%ld; expected %ld)\n",
 386                                 card_index, video_frame.len - video_offset, expected_length);
 387                 }
 388                 if (video_frame.owner) {
 389                         video_frame.owner->release_frame(video_frame);
 390                 }
 391
 392                 // Still send on the information that we _had_ a frame, even though it's corrupted,
 393                 // so that pts can go up accordingly.
 394                 {
 395                         unique_lock<mutex> lock(bmusb_mutex);
 396                         CaptureCard::NewFrame new_frame;
 397                         new_frame.frame = RefCountedFrame(FrameAllocator::Frame());
 398                         new_frame.length = frame_length;
 399                         new_frame.interlaced = false;
 400                         new_frame.dropped_frames = dropped_frames;
 401                         card->new_frames.push(move(new_frame));
 402                         card->new_frames_changed.notify_all();
 403                 }
 404                 return;
 405         }
 406
 407         PBOFrameAllocator::Userdata *userdata = (PBOFrameAllocator::Userdata *)video_frame.userdata;
 408
 409         unsigned num_fields = video_format.interlaced ? 2 : 1;
 410         steady_clock::time_point frame_upload_start;
 411         if (video_format.interlaced) {
 412                 // Send the two fields along as separate frames; the other side will need to add
 413                 // a deinterlacer to actually get this right.
 414                 assert(video_format.height % 2 == 0);
 415                 video_format.height /= 2;
 416                 assert(frame_length % 2 == 0);
 417                 frame_length /= 2;
 418                 num_fields = 2;
 419                 frame_upload_start = steady_clock::now();
 420         }
 421         userdata->last_interlaced = video_format.interlaced;
 422         userdata->last_has_signal = video_format.has_signal;
 423         userdata->last_is_connected = video_format.is_connected;
 424         userdata->last_frame_rate_nom = video_format.frame_rate_nom;
 425         userdata->last_frame_rate_den = video_format.frame_rate_den;
 426         RefCountedFrame frame(video_frame);
 427
 428         // Upload the textures.
 429         size_t cbcr_width = video_format.width / 2;
 430         size_t cbcr_offset = video_offset / 2;
 431         size_t y_offset = video_frame.size / 2 + video_offset / 2;
 432
 433         for (unsigned field = 0; field < num_fields; ++field) {
 434                 // Put the actual texture upload in a lambda that is executed in the main thread.
 435                 // It is entirely possible to do this in the same thread (and it might even be
 436                 // faster, depending on the GPU and driver), but it appears to be trickling
 437                 // driver bugs very easily.
 438                 //
 439                 // Note that this means we must hold on to the actual frame data in <userdata>
 440                 // until the upload command is run, but we hold on to <frame> much longer than that
 441                 // (in fact, all the way until we no longer use the texture in rendering).
 442                 auto upload_func = [field, video_format, y_offset, cbcr_offset, cbcr_width, userdata]() {
 443                         unsigned field_start_line = (field == 1) ? video_format.second_field_start : video_format.extra_lines_top + field * (video_format.height + 22);
 444
 445                         if (userdata->tex_y[field] == 0 ||
 446                             userdata->tex_cbcr[field] == 0 ||
 447                             video_format.width != userdata->last_width[field] ||
 448                             video_format.height != userdata->last_height[field]) {
 449                                 // We changed resolution since last use of this texture, so we need to create
 450                                 // a new object. Note that this each card has its own PBOFrameAllocator,
 451                                 // we don't need to worry about these flip-flopping between resolutions.
 452                                 glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr[field]);
 453                                 check_error();
 454                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_RG8, cbcr_width, video_format.height, 0, GL_RG, GL_UNSIGNED_BYTE, nullptr);
 455                                 check_error();
 456                                 glBindTexture(GL_TEXTURE_2D, userdata->tex_y[field]);
 457                                 check_error();
 458                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, video_format.width, video_format.height, 0, GL_RED, GL_UNSIGNED_BYTE, nullptr);
 459                                 check_error();
 460                                 userdata->last_width[field] = video_format.width;
 461                                 userdata->last_height[field] = video_format.height;
 462                         }
 463
 464                         GLuint pbo = userdata->pbo;
 465                         check_error();
 466                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER, pbo);
 467                         check_error();
 468
 469                         size_t field_y_start = y_offset + video_format.width * field_start_line;
 470                         size_t field_cbcr_start = cbcr_offset + cbcr_width * field_start_line * sizeof(uint16_t);
 471
 472                         if (global_flags.flush_pbos) {
 473                                 glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, field_y_start, video_format.width * video_format.height);
 474                                 check_error();
 475                                 glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, field_cbcr_start, cbcr_width * video_format.height * sizeof(uint16_t));
 476                                 check_error();
 477                         }
 478
 479                         glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr[field]);
 480                         check_error();
 481                         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, cbcr_width, video_format.height, GL_RG, GL_UNSIGNED_BYTE, BUFFER_OFFSET(field_cbcr_start));
 482                         check_error();
 483                         glBindTexture(GL_TEXTURE_2D, userdata->tex_y[field]);
 484                         check_error();
 485                         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, video_format.width, video_format.height, GL_RED, GL_UNSIGNED_BYTE, BUFFER_OFFSET(field_y_start));
 486                         check_error();
 487                         glBindTexture(GL_TEXTURE_2D, 0);
 488                         check_error();
 489                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
 490                         check_error();
 491                 };
 492
 493                 if (field == 1) {
 494                         // Don't upload the second field as fast as we can; wait until
 495                         // the field time has approximately passed. (Otherwise, we could
 496                         // get timing jitter against the other sources, and possibly also
 497                         // against the video display, although the latter is not as critical.)
 498                         // This requires our system clock to be reasonably close to the
 499                         // video clock, but that's not an unreasonable assumption.
 500                         steady_clock::time_point second_field_start = frame_upload_start +
 501                                 nanoseconds(frame_length * 1000000000 / TIMEBASE);
 502                         this_thread::sleep_until(second_field_start);
 503                 }
 504
 505                 {
 506                         unique_lock<mutex> lock(bmusb_mutex);
 507                         CaptureCard::NewFrame new_frame;
 508                         new_frame.frame = frame;
 509                         new_frame.length = frame_length;
 510                         new_frame.field = field;
 511                         new_frame.interlaced = video_format.interlaced;
 512                         new_frame.upload_func = upload_func;
 513                         new_frame.dropped_frames = dropped_frames;
 514                         new_frame.received_timestamp = video_frame.received_timestamp;  // Ignore the audio timestamp.
 515                         card->new_frames.push(move(new_frame));
 516                         card->new_frames_changed.notify_all();
 517                 }
 518         }
 519 }
 520
 521 void Mixer::bm_hotplug_add(libusb_device *dev)
 522 {
 523         lock_guard<mutex> lock(hotplug_mutex);
 524         hotplugged_cards.push_back(dev);
 525 }
 526
 527 void Mixer::bm_hotplug_remove(unsigned card_index)
 528 {
 529         cards[card_index].new_frames_changed.notify_all();
 530 }
 531
 532 void Mixer::thread_func()
 533 {
 534         eglBindAPI(EGL_OPENGL_API);
 535         QOpenGLContext *context = create_context(mixer_surface);
 536         if (!make_current(context, mixer_surface)) {
 537                 printf("oops\n");
 538                 exit(1);
 539         }
 540
 541         steady_clock::time_point start, now;
 542         start = steady_clock::now();
 543
 544         int frame = 0;
 545         int stats_dropped_frames = 0;
 546
 547         while (!should_quit) {
 548                 CaptureCard::NewFrame new_frames[MAX_VIDEO_CARDS];
 549                 bool has_new_frame[MAX_VIDEO_CARDS] = { false };
 550                 int num_samples[MAX_VIDEO_CARDS] = { 0 };
 551
 552                 unsigned master_card_index = theme->map_signal(master_clock_channel);
 553                 assert(master_card_index < num_cards);
 554
 555                 get_one_frame_from_each_card(master_card_index, new_frames, has_new_frame, num_samples);
 556                 schedule_audio_resampling_tasks(new_frames[master_card_index].dropped_frames, num_samples[master_card_index], new_frames[master_card_index].length);
 557                 stats_dropped_frames += new_frames[master_card_index].dropped_frames;
 558
 559                 handle_hotplugged_cards();
 560
 561                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 562                         if (card_index == master_card_index || !has_new_frame[card_index]) {
 563                                 continue;
 564                         }
 565                         if (new_frames[card_index].frame->len == 0) {
 566                                 ++new_frames[card_index].dropped_frames;
 567                         }
 568                         if (new_frames[card_index].dropped_frames > 0) {
 569                                 printf("Card %u dropped %d frames before this\n",
 570                                         card_index, int(new_frames[card_index].dropped_frames));
 571                         }
 572                 }
 573
 574                 // If the first card is reporting a corrupted or otherwise dropped frame,
 575                 // just increase the pts (skipping over this frame) and don't try to compute anything new.
 576                 if (new_frames[master_card_index].frame->len == 0) {
 577                         ++stats_dropped_frames;
 578                         pts_int += new_frames[master_card_index].length;
 579                         continue;
 580                 }
 581
 582                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 583                         if (!has_new_frame[card_index] || new_frames[card_index].frame->len == 0)
 584                                 continue;
 585
 586                         CaptureCard::NewFrame *new_frame = &new_frames[card_index];
 587                         assert(new_frame->frame != nullptr);
 588                         insert_new_frame(new_frame->frame, new_frame->field, new_frame->interlaced, card_index, &input_state);
 589                         check_error();
 590
 591                         // The new texture might need uploading before use.
 592                         if (new_frame->upload_func) {
 593                                 new_frame->upload_func();
 594                                 new_frame->upload_func = nullptr;
 595                         }
 596                 }
 597
 598                 int64_t frame_duration = new_frames[master_card_index].length;
 599                 render_one_frame(frame_duration);
 600                 ++frame;
 601                 pts_int += frame_duration;
 602
 603                 now = steady_clock::now();
 604                 double elapsed = duration<double>(now - start).count();
 605                 if (frame % 100 == 0) {
 606                         printf("%d frames (%d dropped) in %.3f seconds = %.1f fps (%.1f ms/frame)",
 607                                 frame, stats_dropped_frames, elapsed, frame / elapsed,
 608                                 1e3 * elapsed / frame);
 609                 //      chain->print_phase_timing();
 610
 611                         // Check our memory usage, to see if we are close to our mlockall()
 612                         // limit (if at all set).
 613                         rusage used;
 614                         if (getrusage(RUSAGE_SELF, &used) == -1) {
 615                                 perror("getrusage(RUSAGE_SELF)");
 616                                 assert(false);
 617                         }
 618
 619                         if (uses_mlock) {
 620                                 rlimit limit;
 621                                 if (getrlimit(RLIMIT_MEMLOCK, &limit) == -1) {
 622                                         perror("getrlimit(RLIMIT_MEMLOCK)");
 623                                         assert(false);
 624                                 }
 625
 626                                 printf(", using %ld / %ld MB lockable memory (%.1f%%)",
 627                                         long(used.ru_maxrss / 1024),
 628                                         long(limit.rlim_cur / 1048576),
 629                                         float(100.0 * (used.ru_maxrss * 1024.0) / limit.rlim_cur));
 630                         } else {
 631                                 printf(", using %ld MB memory (not locked)",
 632                                         long(used.ru_maxrss / 1024));
 633                         }
 634
 635                         printf("\n");
 636                 }
 637
 638
 639                 if (should_cut.exchange(false)) {  // Test and clear.
 640                         video_encoder->do_cut(frame);
 641                 }
 642
 643 #if 0
 644                 // Reset every 100 frames, so that local variations in frame times
 645                 // (especially for the first few frames, when the shaders are
 646                 // compiled etc.) don't make it hard to measure for the entire
 647                 // remaining duration of the program.
 648                 if (frame == 10000) {
 649                         frame = 0;
 650                         start = now;
 651                 }
 652 #endif
 653                 check_error();
 654         }
 655
 656         resource_pool->clean_context();
 657 }
 658
 659 void Mixer::get_one_frame_from_each_card(unsigned master_card_index, CaptureCard::NewFrame new_frames[MAX_VIDEO_CARDS], bool has_new_frame[MAX_VIDEO_CARDS], int num_samples[MAX_VIDEO_CARDS])
 660 {
 661 start:
 662         // The first card is the master timer, so wait for it to have a new frame.
 663         // TODO: Add a timeout.
 664         unique_lock<mutex> lock(bmusb_mutex);
 665         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(); });
 666
 667         if (cards[master_card_index].new_frames.empty()) {
 668                 // We were woken up, but not due to a new frame. Deal with it
 669                 // and then restart.
 670                 assert(cards[master_card_index].capture->get_disconnected());
 671                 handle_hotplugged_cards();
 672                 goto start;
 673         }
 674
 675         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 676                 CaptureCard *card = &cards[card_index];
 677                 if (card->new_frames.empty()) {
 678                         assert(card_index != master_card_index);
 679                         card->queue_length_policy.update_policy(-1);
 680                         continue;
 681                 }
 682                 new_frames[card_index] = move(card->new_frames.front());
 683                 has_new_frame[card_index] = true;
 684                 card->new_frames.pop();
 685                 card->new_frames_changed.notify_all();
 686
 687                 int num_samples_times_timebase = OUTPUT_FREQUENCY * new_frames[card_index].length + card->fractional_samples;
 688                 num_samples[card_index] = num_samples_times_timebase / TIMEBASE;
 689                 card->fractional_samples = num_samples_times_timebase % TIMEBASE;
 690                 assert(num_samples[card_index] >= 0);
 691
 692                 if (card_index == master_card_index) {
 693                         // We don't use the queue length policy for the master card,
 694                         // but we will if it stops being the master. Thus, clear out
 695                         // the policy in case we switch in the future.
 696                         card->queue_length_policy.reset(card_index);
 697                 } else {
 698                         // If we have excess frames compared to the policy for this card,
 699                         // drop frames from the head.
 700                         card->queue_length_policy.update_policy(card->new_frames.size());
 701                         while (card->new_frames.size() > card->queue_length_policy.get_safe_queue_length()) {
 702                                 card->new_frames.pop();
 703                         }
 704                 }
 705         }
 706 }
 707
 708 void Mixer::handle_hotplugged_cards()
 709 {
 710         // Check for cards that have been disconnected since last frame.
 711         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 712                 CaptureCard *card = &cards[card_index];
 713                 if (card->capture->get_disconnected()) {
 714                         fprintf(stderr, "Card %u went away, replacing with a fake card.\n", card_index);
 715                         FakeCapture *capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
 716                         configure_card(card_index, capture, /*is_fake_capture=*/true);
 717                         card->queue_length_policy.reset(card_index);
 718                         card->capture->start_bm_capture();
 719                 }
 720         }
 721
 722         // Check for cards that have been connected since last frame.
 723         vector<libusb_device *> hotplugged_cards_copy;
 724         {
 725                 lock_guard<mutex> lock(hotplug_mutex);
 726                 swap(hotplugged_cards, hotplugged_cards_copy);
 727         }
 728         for (libusb_device *new_dev : hotplugged_cards_copy) {
 729                 // Look for a fake capture card where we can stick this in.
 730                 int free_card_index = -1;
 731                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 732                         if (cards[card_index].is_fake_capture) {
 733                                 free_card_index = int(card_index);
 734                                 break;
 735                         }
 736                 }
 737
 738                 if (free_card_index == -1) {
 739                         fprintf(stderr, "New card plugged in, but no free slots -- ignoring.\n");
 740                         libusb_unref_device(new_dev);
 741                 } else {
 742                         // BMUSBCapture takes ownership.
 743                         fprintf(stderr, "New card plugged in, choosing slot %d.\n", free_card_index);
 744                         CaptureCard *card = &cards[free_card_index];
 745                         BMUSBCapture *capture = new BMUSBCapture(free_card_index, new_dev);
 746                         configure_card(free_card_index, capture, /*is_fake_capture=*/false);
 747                         card->queue_length_policy.reset(free_card_index);
 748                         capture->set_card_disconnected_callback(bind(&Mixer::bm_hotplug_remove, this, free_card_index));
 749                         capture->start_bm_capture();
 750                 }
 751         }
 752 }
 753
 754
 755 void Mixer::schedule_audio_resampling_tasks(unsigned dropped_frames, int num_samples_per_frame, int length_per_frame)
 756 {
 757         // Resample the audio as needed, including from previously dropped frames.
 758         assert(num_cards > 0);
 759         for (unsigned frame_num = 0; frame_num < dropped_frames + 1; ++frame_num) {
 760                 const bool dropped_frame = (frame_num != dropped_frames);
 761                 {
 762                         // Signal to the audio thread to process this frame.
 763                         // Note that if the frame is a dropped frame, we signal that
 764                         // we don't want to use this frame as base for adjusting
 765                         // the resampler rate. The reason for this is that the timing
 766                         // of these frames is often way too late; they typically don't
 767                         // “arrive” before we synthesize them. Thus, we could end up
 768                         // in a situation where we have inserted e.g. five audio frames
 769                         // into the queue before we then start pulling five of them
 770                         // back out. This makes ResamplingQueue overestimate the delay,
 771                         // causing undue resampler changes. (We _do_ use the last,
 772                         // non-dropped frame; perhaps we should just discard that as well,
 773                         // since dropped frames are expected to be rare, and it might be
 774                         // better to just wait until we have a slightly more normal situation).
 775                         unique_lock<mutex> lock(audio_mutex);
 776                         bool adjust_rate = !dropped_frame;
 777                         audio_task_queue.push(AudioTask{pts_int, num_samples_per_frame, adjust_rate});
 778                         audio_task_queue_changed.notify_one();
 779                 }
 780                 if (dropped_frame) {
 781                         // For dropped frames, increase the pts. Note that if the format changed
 782                         // in the meantime, we have no way of detecting that; we just have to
 783                         // assume the frame length is always the same.
 784                         pts_int += length_per_frame;
 785                 }
 786         }
 787 }
 788
 789 void Mixer::render_one_frame(int64_t duration)
 790 {
 791         // Get the main chain from the theme, and set its state immediately.
 792         Theme::Chain theme_main_chain = theme->get_chain(0, pts(), global_flags.width, global_flags.height, input_state);
 793         EffectChain *chain = theme_main_chain.chain;
 794         theme_main_chain.setup_chain();
 795         //theme_main_chain.chain->enable_phase_timing(true);
 796
 797         GLuint y_tex, cbcr_tex;
 798         bool got_frame = video_encoder->begin_frame(&y_tex, &cbcr_tex);
 799         assert(got_frame);
 800
 801         // Render main chain.
 802         GLuint cbcr_full_tex = resource_pool->create_2d_texture(GL_RG8, global_flags.width, global_flags.height);
 803         GLuint rgba_tex = resource_pool->create_2d_texture(GL_RGB565, global_flags.width, global_flags.height);  // Saves texture bandwidth, although dithering gets messed up.
 804         GLuint fbo = resource_pool->create_fbo(y_tex, cbcr_full_tex, rgba_tex);
 805         check_error();
 806         chain->render_to_fbo(fbo, global_flags.width, global_flags.height);
 807         resource_pool->release_fbo(fbo);
 808
 809         subsample_chroma(cbcr_full_tex, cbcr_tex);
 810         resource_pool->release_2d_texture(cbcr_full_tex);
 811
 812         // Set the right state for rgba_tex.
 813         glBindFramebuffer(GL_FRAMEBUFFER, 0);
 814         glBindTexture(GL_TEXTURE_2D, rgba_tex);
 815         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 816         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 817         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 818
 819         const int64_t av_delay = TIMEBASE / 10;  // Corresponds to the fixed delay in resampling_queue.h. TODO: Make less hard-coded.
 820         RefCountedGLsync fence = video_encoder->end_frame(pts_int + av_delay, duration, theme_main_chain.input_frames);
 821
 822         // The live frame just shows the RGBA texture we just rendered.
 823         // It owns rgba_tex now.
 824         DisplayFrame live_frame;
 825         live_frame.chain = display_chain.get();
 826         live_frame.setup_chain = [this, rgba_tex]{
 827                 display_input->set_texture_num(rgba_tex);
 828         };
 829         live_frame.ready_fence = fence;
 830         live_frame.input_frames = {};
 831         live_frame.temp_textures = { rgba_tex };
 832         output_channel[OUTPUT_LIVE].output_frame(live_frame);
 833
 834         // Set up preview and any additional channels.
 835         for (int i = 1; i < theme->get_num_channels() + 2; ++i) {
 836                 DisplayFrame display_frame;
 837                 Theme::Chain chain = theme->get_chain(i, pts(), global_flags.width, global_flags.height, input_state);  // FIXME: dimensions
 838                 display_frame.chain = chain.chain;
 839                 display_frame.setup_chain = chain.setup_chain;
 840                 display_frame.ready_fence = fence;
 841                 display_frame.input_frames = chain.input_frames;
 842                 display_frame.temp_textures = {};
 843                 output_channel[i].output_frame(display_frame);
 844         }
 845 }
 846
 847 void Mixer::audio_thread_func()
 848 {
 849         while (!should_quit) {
 850                 AudioTask task;
 851
 852                 {
 853                         unique_lock<mutex> lock(audio_mutex);
 854                         audio_task_queue_changed.wait(lock, [this]{ return should_quit || !audio_task_queue.empty(); });
 855                         if (should_quit) {
 856                                 return;
 857                         }
 858                         task = audio_task_queue.front();
 859                         audio_task_queue.pop();
 860                 }
 861
 862                 ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy =
 863                         task.adjust_rate ? ResamplingQueue::ADJUST_RATE : ResamplingQueue::DO_NOT_ADJUST_RATE;
 864                 vector<float> samples_out = audio_mixer.get_output(
 865                         double(task.pts_int) / TIMEBASE,
 866                         task.num_samples,
 867                         rate_adjustment_policy);
 868
 869                 // Send the samples to the sound card, then add them to the output.
 870                 if (alsa) {
 871                         alsa->write(samples_out);
 872                 }
 873                 video_encoder->add_audio(task.pts_int, move(samples_out));
 874         }
 875 }
 876
 877 void Mixer::subsample_chroma(GLuint src_tex, GLuint dst_tex)
 878 {
 879         GLuint vao;
 880         glGenVertexArrays(1, &vao);
 881         check_error();
 882
 883         glBindVertexArray(vao);
 884         check_error();
 885
 886         // Extract Cb/Cr.
 887         GLuint fbo = resource_pool->create_fbo(dst_tex);
 888         glBindFramebuffer(GL_FRAMEBUFFER, fbo);
 889         glViewport(0, 0, global_flags.width/2, global_flags.height/2);
 890         check_error();
 891
 892         glUseProgram(cbcr_program_num);
 893         check_error();
 894
 895         glActiveTexture(GL_TEXTURE0);
 896         check_error();
 897         glBindTexture(GL_TEXTURE_2D, src_tex);
 898         check_error();
 899         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 900         check_error();
 901         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 902         check_error();
 903         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 904         check_error();
 905
 906         float chroma_offset_0[] = { -0.5f / global_flags.width, 0.0f };
 907         set_uniform_vec2(cbcr_program_num, "foo", "chroma_offset_0", chroma_offset_0);
 908
 909         glBindBuffer(GL_ARRAY_BUFFER, cbcr_vbo);
 910         check_error();
 911
 912         for (GLint attr_index : { cbcr_position_attribute_index, cbcr_texcoord_attribute_index }) {
 913                 glEnableVertexAttribArray(attr_index);
 914                 check_error();
 915                 glVertexAttribPointer(attr_index, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
 916                 check_error();
 917         }
 918
 919         glDrawArrays(GL_TRIANGLES, 0, 3);
 920         check_error();
 921
 922         for (GLint attr_index : { cbcr_position_attribute_index, cbcr_texcoord_attribute_index }) {
 923                 glDisableVertexAttribArray(attr_index);
 924                 check_error();
 925         }
 926
 927         glUseProgram(0);
 928         check_error();
 929         glBindFramebuffer(GL_FRAMEBUFFER, 0);
 930         check_error();
 931
 932         resource_pool->release_fbo(fbo);
 933         glDeleteVertexArrays(1, &vao);
 934 }
 935
 936 void Mixer::release_display_frame(DisplayFrame *frame)
 937 {
 938         for (GLuint texnum : frame->temp_textures) {
 939                 resource_pool->release_2d_texture(texnum);
 940         }
 941         frame->temp_textures.clear();
 942         frame->ready_fence.reset();
 943         frame->input_frames.clear();
 944 }
 945
 946 void Mixer::start()
 947 {
 948         mixer_thread = thread(&Mixer::thread_func, this);
 949         audio_thread = thread(&Mixer::audio_thread_func, this);
 950 }
 951
 952 void Mixer::quit()
 953 {
 954         should_quit = true;
 955         audio_task_queue_changed.notify_one();
 956         mixer_thread.join();
 957         audio_thread.join();
 958 }
 959
 960 void Mixer::transition_clicked(int transition_num)
 961 {
 962         theme->transition_clicked(transition_num, pts());
 963 }
 964
 965 void Mixer::channel_clicked(int preview_num)
 966 {
 967         theme->channel_clicked(preview_num);
 968 }
 969
 970 void Mixer::start_mode_scanning(unsigned card_index)
 971 {
 972         assert(card_index < num_cards);
 973         if (is_mode_scanning[card_index]) {
 974                 return;
 975         }
 976         is_mode_scanning[card_index] = true;
 977         mode_scanlist[card_index].clear();
 978         for (const auto &mode : cards[card_index].capture->get_available_video_modes()) {
 979                 mode_scanlist[card_index].push_back(mode.first);
 980         }
 981         assert(!mode_scanlist[card_index].empty());
 982         mode_scanlist_index[card_index] = 0;
 983         cards[card_index].capture->set_video_mode(mode_scanlist[card_index][0]);
 984         last_mode_scan_change[card_index] = steady_clock::now();
 985 }
 986
 987 Mixer::OutputChannel::~OutputChannel()
 988 {
 989         if (has_current_frame) {
 990                 parent->release_display_frame(&current_frame);
 991         }
 992         if (has_ready_frame) {
 993                 parent->release_display_frame(&ready_frame);
 994         }
 995 }
 996
 997 void Mixer::OutputChannel::output_frame(DisplayFrame frame)
 998 {
 999         // Store this frame for display. Remove the ready frame if any
1000         // (it was seemingly never used).
1001         {
1002                 unique_lock<mutex> lock(frame_mutex);
1003                 if (has_ready_frame) {
1004                         parent->release_display_frame(&ready_frame);
1005                 }
1006                 ready_frame = frame;
1007                 has_ready_frame = true;
1008         }
1009
1010         if (new_frame_ready_callback) {
1011                 new_frame_ready_callback();
1012         }
1013
1014         // Reduce the number of callbacks by filtering duplicates. The reason
1015         // why we bother doing this is that Qt seemingly can get into a state
1016         // where its builds up an essentially unbounded queue of signals,
1017         // consuming more and more memory, and there's no good way of collapsing
1018         // user-defined signals or limiting the length of the queue.
1019         if (transition_names_updated_callback) {
1020                 vector<string> transition_names = global_mixer->get_transition_names();
1021                 bool changed = false;
1022                 if (transition_names.size() != last_transition_names.size()) {
1023                         changed = true;
1024                 } else {
1025                         for (unsigned i = 0; i < transition_names.size(); ++i) {
1026                                 if (transition_names[i] != last_transition_names[i]) {
1027                                         changed = true;
1028                                         break;
1029                                 }
1030                         }
1031                 }
1032                 if (changed) {
1033                         transition_names_updated_callback(transition_names);
1034                         last_transition_names = transition_names;
1035                 }
1036         }
1037         if (name_updated_callback) {
1038                 string name = global_mixer->get_channel_name(channel);
1039                 if (name != last_name) {
1040                         name_updated_callback(name);
1041                         last_name = name;
1042                 }
1043         }
1044         if (color_updated_callback) {
1045                 string color = global_mixer->get_channel_color(channel);
1046                 if (color != last_color) {
1047                         color_updated_callback(color);
1048                         last_color = color;
1049                 }
1050         }
1051 }
1052
1053 bool Mixer::OutputChannel::get_display_frame(DisplayFrame *frame)
1054 {
1055         unique_lock<mutex> lock(frame_mutex);
1056         if (!has_current_frame && !has_ready_frame) {
1057                 return false;
1058         }
1059
1060         if (has_current_frame && has_ready_frame) {
1061                 // We have a new ready frame. Toss the current one.
1062                 parent->release_display_frame(&current_frame);
1063                 has_current_frame = false;
1064         }
1065         if (has_ready_frame) {
1066                 assert(!has_current_frame);
1067                 current_frame = ready_frame;
1068                 ready_frame.ready_fence.reset();  // Drop the refcount.
1069                 ready_frame.input_frames.clear();  // Drop the refcounts.
1070                 has_current_frame = true;
1071                 has_ready_frame = false;
1072         }
1073
1074         *frame = current_frame;
1075         return true;
1076 }
1077
1078 void Mixer::OutputChannel::set_frame_ready_callback(Mixer::new_frame_ready_callback_t callback)
1079 {
1080         new_frame_ready_callback = callback;
1081 }
1082
1083 void Mixer::OutputChannel::set_transition_names_updated_callback(Mixer::transition_names_updated_callback_t callback)
1084 {
1085         transition_names_updated_callback = callback;
1086 }
1087
1088 void Mixer::OutputChannel::set_name_updated_callback(Mixer::name_updated_callback_t callback)
1089 {
1090         name_updated_callback = callback;
1091 }
1092
1093 void Mixer::OutputChannel::set_color_updated_callback(Mixer::color_updated_callback_t callback)
1094 {
1095         color_updated_callback = callback;
1096 }
1097
1098 mutex RefCountedGLsync::fence_lock;