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 (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 190                 cards[card_index].queue_length_policy.reset(card_index);
 191         }
 192
 193         // Set up stuff for NV12 conversion.
 194         //
 195         // Note: Due to the horizontally co-sited chroma/luma samples in H.264
 196         // (chrome position is left for horizontal and center for vertical),
 197         // we need to be a bit careful in our subsampling. A diagram will make
 198         // this clearer, showing some luma and chroma samples:
 199         //
 200         //     a   b   c   d
 201         //   +---+---+---+---+
 202         //   |   |   |   |   |
 203         //   | Y | Y | Y | Y |
 204         //   |   |   |   |   |
 205         //   +---+---+---+---+
 206         //
 207         // +-------+-------+
 208         // |       |       |
 209         // |   C   |   C   |
 210         // |       |       |
 211         // +-------+-------+
 212         //
 213         // Clearly, the rightmost chroma sample here needs to be equivalent to
 214         // b/4 + c/2 + d/4. (We could also implement more sophisticated filters,
 215         // of course, but as long as the upsampling is not going to be equally
 216         // sophisticated, it's probably not worth it.) If we sample once with
 217         // no mipmapping, we get just c, ie., no actual filtering in the
 218         // horizontal direction. (For the vertical direction, we can just
 219         // sample in the middle to get the right filtering.) One could imagine
 220         // we could use mipmapping (assuming we can create mipmaps cheaply),
 221         // but then, what we'd get is this:
 222         //
 223         //    (a+b)/2 (c+d)/2
 224         //   +-------+-------+
 225         //   |       |       |
 226         //   |   Y   |   Y   |
 227         //   |       |       |
 228         //   +-------+-------+
 229         //
 230         // +-------+-------+
 231         // |       |       |
 232         // |   C   |   C   |
 233         // |       |       |
 234         // +-------+-------+
 235         //
 236         // which ends up sampling equally from a and b, which clearly isn't right. Instead,
 237         // we need to do two (non-mipmapped) chroma samples, both hitting exactly in-between
 238         // source pixels.
 239         //
 240         // Sampling in-between b and c gives us the sample (b+c)/2, and similarly for c and d.
 241         // Taking the average of these gives of (b+c)/4 + (c+d)/4 = b/4 + c/2 + d/4, which is
 242         // exactly what we want.
 243         //
 244         // See also http://www.poynton.com/PDFs/Merging_RGB_and_422.pdf, pages 6–7.
 245
 246         // Cb/Cr shader.
 247         string cbcr_vert_shader =
 248                 "#version 130 \n"
 249                 " \n"
 250                 "in vec2 position; \n"
 251                 "in vec2 texcoord; \n"
 252                 "out vec2 tc0, tc1; \n"
 253                 "uniform vec2 foo_chroma_offset_0; \n"
 254                 "uniform vec2 foo_chroma_offset_1; \n"
 255                 " \n"
 256                 "void main() \n"
 257                 "{ \n"
 258                 "    // The result of glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0) is: \n"
 259                 "    // \n"
 260                 "    //   2.000  0.000  0.000 -1.000 \n"
 261                 "    //   0.000  2.000  0.000 -1.000 \n"
 262                 "    //   0.000  0.000 -2.000 -1.000 \n"
 263                 "    //   0.000  0.000  0.000  1.000 \n"
 264                 "    gl_Position = vec4(2.0 * position.x - 1.0, 2.0 * position.y - 1.0, -1.0, 1.0); \n"
 265                 "    vec2 flipped_tc = texcoord; \n"
 266                 "    tc0 = flipped_tc + foo_chroma_offset_0; \n"
 267                 "    tc1 = flipped_tc + foo_chroma_offset_1; \n"
 268                 "} \n";
 269         string cbcr_frag_shader =
 270                 "#version 130 \n"
 271                 "in vec2 tc0, tc1; \n"
 272                 "uniform sampler2D cbcr_tex; \n"
 273                 "out vec4 FragColor; \n"
 274                 "void main() { \n"
 275                 "    FragColor = 0.5 * (texture(cbcr_tex, tc0) + texture(cbcr_tex, tc1)); \n"
 276                 "} \n";
 277         vector<string> frag_shader_outputs;
 278         cbcr_program_num = resource_pool->compile_glsl_program(cbcr_vert_shader, cbcr_frag_shader, frag_shader_outputs);
 279
 280         float vertices[] = {
 281                 0.0f, 2.0f,
 282                 0.0f, 0.0f,
 283                 2.0f, 0.0f
 284         };
 285         cbcr_vbo = generate_vbo(2, GL_FLOAT, sizeof(vertices), vertices);
 286         cbcr_texture_sampler_uniform = glGetUniformLocation(cbcr_program_num, "cbcr_tex");
 287         cbcr_position_attribute_index = glGetAttribLocation(cbcr_program_num, "position");
 288         cbcr_texcoord_attribute_index = glGetAttribLocation(cbcr_program_num, "texcoord");
 289
 290         if (global_flags.enable_alsa_output) {
 291                 alsa.reset(new ALSAOutput(OUTPUT_FREQUENCY, /*num_channels=*/2));
 292         }
 293 }
 294
 295 Mixer::~Mixer()
 296 {
 297         resource_pool->release_glsl_program(cbcr_program_num);
 298         glDeleteBuffers(1, &cbcr_vbo);
 299         BMUSBCapture::stop_bm_thread();
 300
 301         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 302                 {
 303                         unique_lock<mutex> lock(bmusb_mutex);
 304                         cards[card_index].should_quit = true;  // Unblock thread.
 305                         cards[card_index].new_frames_changed.notify_all();
 306                 }
 307                 cards[card_index].capture->stop_dequeue_thread();
 308         }
 309
 310         video_encoder.reset(nullptr);
 311 }
 312
 313 void Mixer::configure_card(unsigned card_index, CaptureInterface *capture, bool is_fake_capture)
 314 {
 315         printf("Configuring card %d...\n", card_index);
 316
 317         CaptureCard *card = &cards[card_index];
 318         if (card->capture != nullptr) {
 319                 card->capture->stop_dequeue_thread();
 320                 delete card->capture;
 321         }
 322         card->capture = capture;
 323         card->is_fake_capture = is_fake_capture;
 324         card->capture->set_frame_callback(bind(&Mixer::bm_frame, this, card_index, _1, _2, _3, _4, _5, _6, _7));
 325         if (card->frame_allocator == nullptr) {
 326                 card->frame_allocator.reset(new PBOFrameAllocator(8 << 20, global_flags.width, global_flags.height));  // 8 MB.
 327         }
 328         card->capture->set_video_frame_allocator(card->frame_allocator.get());
 329         if (card->surface == nullptr) {
 330                 card->surface = create_surface_with_same_format(mixer_surface);
 331         }
 332         while (!card->new_frames.empty()) card->new_frames.pop();
 333         card->fractional_samples = 0;
 334         card->last_timecode = -1;
 335         card->capture->configure_card();
 336
 337         DeviceSpec device{InputSourceType::CAPTURE_CARD, card_index};
 338         audio_mixer.reset_resampler(device);
 339         audio_mixer.set_display_name(device, card->capture->get_description());
 340         audio_mixer.trigger_state_changed_callback();
 341 }
 342
 343
 344 namespace {
 345
 346 int unwrap_timecode(uint16_t current_wrapped, int last)
 347 {
 348         uint16_t last_wrapped = last & 0xffff;
 349         if (current_wrapped > last_wrapped) {
 350                 return (last & ~0xffff) | current_wrapped;
 351         } else {
 352                 return 0x10000 + ((last & ~0xffff) | current_wrapped);
 353         }
 354 }
 355
 356 }  // namespace
 357
 358 void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
 359                      FrameAllocator::Frame video_frame, size_t video_offset, VideoFormat video_format,
 360                      FrameAllocator::Frame audio_frame, size_t audio_offset, AudioFormat audio_format)
 361 {
 362         DeviceSpec device{InputSourceType::CAPTURE_CARD, card_index};
 363         CaptureCard *card = &cards[card_index];
 364
 365         if (is_mode_scanning[card_index]) {
 366                 if (video_format.has_signal) {
 367                         // Found a stable signal, so stop scanning.
 368                         is_mode_scanning[card_index] = false;
 369                 } else {
 370                         static constexpr double switch_time_s = 0.5;  // Should be enough time for the signal to stabilize.
 371                         steady_clock::time_point now = steady_clock::now();
 372                         double sec_since_last_switch = duration<double>(steady_clock::now() - last_mode_scan_change[card_index]).count();
 373                         if (sec_since_last_switch > switch_time_s) {
 374                                 // It isn't this mode; try the next one.
 375                                 mode_scanlist_index[card_index]++;
 376                                 mode_scanlist_index[card_index] %= mode_scanlist[card_index].size();
 377                                 cards[card_index].capture->set_video_mode(mode_scanlist[card_index][mode_scanlist_index[card_index]]);
 378                                 last_mode_scan_change[card_index] = now;
 379                         }
 380                 }
 381         }
 382
 383         int64_t frame_length = int64_t(TIMEBASE) * video_format.frame_rate_den / video_format.frame_rate_nom;
 384         assert(frame_length > 0);
 385
 386         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;
 387         if (num_samples > OUTPUT_FREQUENCY / 10) {
 388                 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",
 389                         card_index, int(audio_frame.len), int(audio_offset),
 390                         timecode, int(video_frame.len), int(video_offset), video_format.id);
 391                 if (video_frame.owner) {
 392                         video_frame.owner->release_frame(video_frame);
 393                 }
 394                 if (audio_frame.owner) {
 395                         audio_frame.owner->release_frame(audio_frame);
 396                 }
 397                 return;
 398         }
 399
 400         int dropped_frames = 0;
 401         if (card->last_timecode != -1) {
 402                 dropped_frames = unwrap_timecode(timecode, card->last_timecode) - card->last_timecode - 1;
 403         }
 404
 405         // Number of samples per frame if we need to insert silence.
 406         // (Could be nonintegral, but resampling will save us then.)
 407         const int silence_samples = OUTPUT_FREQUENCY * video_format.frame_rate_den / video_format.frame_rate_nom;
 408
 409         if (dropped_frames > MAX_FPS * 2) {
 410                 fprintf(stderr, "Card %d lost more than two seconds (or time code jumping around; from 0x%04x to 0x%04x), resetting resampler\n",
 411                         card_index, card->last_timecode, timecode);
 412                 audio_mixer.reset_resampler(device);
 413                 dropped_frames = 0;
 414         } else if (dropped_frames > 0) {
 415                 // Insert silence as needed.
 416                 fprintf(stderr, "Card %d dropped %d frame(s) (before timecode 0x%04x), inserting silence.\n",
 417                         card_index, dropped_frames, timecode);
 418
 419                 bool success;
 420                 do {
 421                         success = audio_mixer.add_silence(device, silence_samples, dropped_frames, frame_length);
 422                 } while (!success);
 423         }
 424
 425         audio_mixer.add_audio(device, audio_frame.data + audio_offset, num_samples, audio_format, frame_length);
 426
 427         // Done with the audio, so release it.
 428         if (audio_frame.owner) {
 429                 audio_frame.owner->release_frame(audio_frame);
 430         }
 431
 432         card->last_timecode = timecode;
 433
 434         size_t expected_length = video_format.width * (video_format.height + video_format.extra_lines_top + video_format.extra_lines_bottom) * 2;
 435         if (video_frame.len - video_offset == 0 ||
 436             video_frame.len - video_offset != expected_length) {
 437                 if (video_frame.len != 0) {
 438                         printf("Card %d: Dropping video frame with wrong length (%ld; expected %ld)\n",
 439                                 card_index, video_frame.len - video_offset, expected_length);
 440                 }
 441                 if (video_frame.owner) {
 442                         video_frame.owner->release_frame(video_frame);
 443                 }
 444
 445                 // Still send on the information that we _had_ a frame, even though it's corrupted,
 446                 // so that pts can go up accordingly.
 447                 {
 448                         unique_lock<mutex> lock(bmusb_mutex);
 449                         CaptureCard::NewFrame new_frame;
 450                         new_frame.frame = RefCountedFrame(FrameAllocator::Frame());
 451                         new_frame.length = frame_length;
 452                         new_frame.interlaced = false;
 453                         new_frame.dropped_frames = dropped_frames;
 454                         card->new_frames.push(move(new_frame));
 455                         card->new_frames_changed.notify_all();
 456                 }
 457                 return;
 458         }
 459
 460         PBOFrameAllocator::Userdata *userdata = (PBOFrameAllocator::Userdata *)video_frame.userdata;
 461
 462         unsigned num_fields = video_format.interlaced ? 2 : 1;
 463         steady_clock::time_point frame_upload_start;
 464         if (video_format.interlaced) {
 465                 // Send the two fields along as separate frames; the other side will need to add
 466                 // a deinterlacer to actually get this right.
 467                 assert(video_format.height % 2 == 0);
 468                 video_format.height /= 2;
 469                 assert(frame_length % 2 == 0);
 470                 frame_length /= 2;
 471                 num_fields = 2;
 472                 frame_upload_start = steady_clock::now();
 473         }
 474         userdata->last_interlaced = video_format.interlaced;
 475         userdata->last_has_signal = video_format.has_signal;
 476         userdata->last_is_connected = video_format.is_connected;
 477         userdata->last_frame_rate_nom = video_format.frame_rate_nom;
 478         userdata->last_frame_rate_den = video_format.frame_rate_den;
 479         RefCountedFrame frame(video_frame);
 480
 481         // Upload the textures.
 482         size_t cbcr_width = video_format.width / 2;
 483         size_t cbcr_offset = video_offset / 2;
 484         size_t y_offset = video_frame.size / 2 + video_offset / 2;
 485
 486         for (unsigned field = 0; field < num_fields; ++field) {
 487                 // Put the actual texture upload in a lambda that is executed in the main thread.
 488                 // It is entirely possible to do this in the same thread (and it might even be
 489                 // faster, depending on the GPU and driver), but it appears to be trickling
 490                 // driver bugs very easily.
 491                 //
 492                 // Note that this means we must hold on to the actual frame data in <userdata>
 493                 // until the upload command is run, but we hold on to <frame> much longer than that
 494                 // (in fact, all the way until we no longer use the texture in rendering).
 495                 auto upload_func = [field, video_format, y_offset, cbcr_offset, cbcr_width, userdata]() {
 496                         unsigned field_start_line = (field == 1) ? video_format.second_field_start : video_format.extra_lines_top + field * (video_format.height + 22);
 497
 498                         if (userdata->tex_y[field] == 0 ||
 499                             userdata->tex_cbcr[field] == 0 ||
 500                             video_format.width != userdata->last_width[field] ||
 501                             video_format.height != userdata->last_height[field]) {
 502                                 // We changed resolution since last use of this texture, so we need to create
 503                                 // a new object. Note that this each card has its own PBOFrameAllocator,
 504                                 // we don't need to worry about these flip-flopping between resolutions.
 505                                 glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr[field]);
 506                                 check_error();
 507                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_RG8, cbcr_width, video_format.height, 0, GL_RG, GL_UNSIGNED_BYTE, nullptr);
 508                                 check_error();
 509                                 glBindTexture(GL_TEXTURE_2D, userdata->tex_y[field]);
 510                                 check_error();
 511                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, video_format.width, video_format.height, 0, GL_RED, GL_UNSIGNED_BYTE, nullptr);
 512                                 check_error();
 513                                 userdata->last_width[field] = video_format.width;
 514                                 userdata->last_height[field] = video_format.height;
 515                         }
 516
 517                         GLuint pbo = userdata->pbo;
 518                         check_error();
 519                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER, pbo);
 520                         check_error();
 521
 522                         size_t field_y_start = y_offset + video_format.width * field_start_line;
 523                         size_t field_cbcr_start = cbcr_offset + cbcr_width * field_start_line * sizeof(uint16_t);
 524
 525                         if (global_flags.flush_pbos) {
 526                                 glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, field_y_start, video_format.width * video_format.height);
 527                                 check_error();
 528                                 glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, field_cbcr_start, cbcr_width * video_format.height * sizeof(uint16_t));
 529                                 check_error();
 530                         }
 531
 532                         glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr[field]);
 533                         check_error();
 534                         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, cbcr_width, video_format.height, GL_RG, GL_UNSIGNED_BYTE, BUFFER_OFFSET(field_cbcr_start));
 535                         check_error();
 536                         glBindTexture(GL_TEXTURE_2D, userdata->tex_y[field]);
 537                         check_error();
 538                         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, video_format.width, video_format.height, GL_RED, GL_UNSIGNED_BYTE, BUFFER_OFFSET(field_y_start));
 539                         check_error();
 540                         glBindTexture(GL_TEXTURE_2D, 0);
 541                         check_error();
 542                         glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
 543                         check_error();
 544                 };
 545
 546                 if (field == 1) {
 547                         // Don't upload the second field as fast as we can; wait until
 548                         // the field time has approximately passed. (Otherwise, we could
 549                         // get timing jitter against the other sources, and possibly also
 550                         // against the video display, although the latter is not as critical.)
 551                         // This requires our system clock to be reasonably close to the
 552                         // video clock, but that's not an unreasonable assumption.
 553                         steady_clock::time_point second_field_start = frame_upload_start +
 554                                 nanoseconds(frame_length * 1000000000 / TIMEBASE);
 555                         this_thread::sleep_until(second_field_start);
 556                 }
 557
 558                 {
 559                         unique_lock<mutex> lock(bmusb_mutex);
 560                         CaptureCard::NewFrame new_frame;
 561                         new_frame.frame = frame;
 562                         new_frame.length = frame_length;
 563                         new_frame.field = field;
 564                         new_frame.interlaced = video_format.interlaced;
 565                         new_frame.upload_func = upload_func;
 566                         new_frame.dropped_frames = dropped_frames;
 567                         new_frame.received_timestamp = video_frame.received_timestamp;  // Ignore the audio timestamp.
 568                         card->new_frames.push(move(new_frame));
 569                         card->new_frames_changed.notify_all();
 570                 }
 571         }
 572 }
 573
 574 void Mixer::bm_hotplug_add(libusb_device *dev)
 575 {
 576         lock_guard<mutex> lock(hotplug_mutex);
 577         hotplugged_cards.push_back(dev);
 578 }
 579
 580 void Mixer::bm_hotplug_remove(unsigned card_index)
 581 {
 582         cards[card_index].new_frames_changed.notify_all();
 583 }
 584
 585 void Mixer::thread_func()
 586 {
 587         eglBindAPI(EGL_OPENGL_API);
 588         QOpenGLContext *context = create_context(mixer_surface);
 589         if (!make_current(context, mixer_surface)) {
 590                 printf("oops\n");
 591                 exit(1);
 592         }
 593
 594         // Start the actual capture. (We don't want to do it before we're actually ready
 595         // to process output frames.)
 596         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 597                 cards[card_index].capture->start_bm_capture();
 598         }
 599
 600         steady_clock::time_point start, now;
 601         start = steady_clock::now();
 602
 603         int frame = 0;
 604         int stats_dropped_frames = 0;
 605
 606         while (!should_quit) {
 607                 CaptureCard::NewFrame new_frames[MAX_VIDEO_CARDS];
 608                 bool has_new_frame[MAX_VIDEO_CARDS] = { false };
 609                 int num_samples[MAX_VIDEO_CARDS] = { 0 };
 610
 611                 unsigned master_card_index = theme->map_signal(master_clock_channel);
 612                 assert(master_card_index < num_cards);
 613
 614                 get_one_frame_from_each_card(master_card_index, new_frames, has_new_frame, num_samples);
 615                 schedule_audio_resampling_tasks(new_frames[master_card_index].dropped_frames, num_samples[master_card_index], new_frames[master_card_index].length);
 616                 stats_dropped_frames += new_frames[master_card_index].dropped_frames;
 617
 618                 handle_hotplugged_cards();
 619
 620                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 621                         if (card_index == master_card_index || !has_new_frame[card_index]) {
 622                                 continue;
 623                         }
 624                         if (new_frames[card_index].frame->len == 0) {
 625                                 ++new_frames[card_index].dropped_frames;
 626                         }
 627                         if (new_frames[card_index].dropped_frames > 0) {
 628                                 printf("Card %u dropped %d frames before this\n",
 629                                         card_index, int(new_frames[card_index].dropped_frames));
 630                         }
 631                 }
 632
 633                 // If the first card is reporting a corrupted or otherwise dropped frame,
 634                 // just increase the pts (skipping over this frame) and don't try to compute anything new.
 635                 if (new_frames[master_card_index].frame->len == 0) {
 636                         ++stats_dropped_frames;
 637                         pts_int += new_frames[master_card_index].length;
 638                         continue;
 639                 }
 640
 641                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 642                         if (!has_new_frame[card_index] || new_frames[card_index].frame->len == 0)
 643                                 continue;
 644
 645                         CaptureCard::NewFrame *new_frame = &new_frames[card_index];
 646                         assert(new_frame->frame != nullptr);
 647                         insert_new_frame(new_frame->frame, new_frame->field, new_frame->interlaced, card_index, &input_state);
 648                         check_error();
 649
 650                         // The new texture might need uploading before use.
 651                         if (new_frame->upload_func) {
 652                                 new_frame->upload_func();
 653                                 new_frame->upload_func = nullptr;
 654                         }
 655                 }
 656
 657                 int64_t frame_duration = new_frames[master_card_index].length;
 658                 render_one_frame(frame_duration);
 659                 ++frame;
 660                 pts_int += frame_duration;
 661
 662                 now = steady_clock::now();
 663                 double elapsed = duration<double>(now - start).count();
 664                 if (frame % 100 == 0) {
 665                         printf("%d frames (%d dropped) in %.3f seconds = %.1f fps (%.1f ms/frame)",
 666                                 frame, stats_dropped_frames, elapsed, frame / elapsed,
 667                                 1e3 * elapsed / frame);
 668                 //      chain->print_phase_timing();
 669
 670                         // Check our memory usage, to see if we are close to our mlockall()
 671                         // limit (if at all set).
 672                         rusage used;
 673                         if (getrusage(RUSAGE_SELF, &used) == -1) {
 674                                 perror("getrusage(RUSAGE_SELF)");
 675                                 assert(false);
 676                         }
 677
 678                         if (uses_mlock) {
 679                                 rlimit limit;
 680                                 if (getrlimit(RLIMIT_MEMLOCK, &limit) == -1) {
 681                                         perror("getrlimit(RLIMIT_MEMLOCK)");
 682                                         assert(false);
 683                                 }
 684
 685                                 printf(", using %ld / %ld MB lockable memory (%.1f%%)",
 686                                         long(used.ru_maxrss / 1024),
 687                                         long(limit.rlim_cur / 1048576),
 688                                         float(100.0 * (used.ru_maxrss * 1024.0) / limit.rlim_cur));
 689                         } else {
 690                                 printf(", using %ld MB memory (not locked)",
 691                                         long(used.ru_maxrss / 1024));
 692                         }
 693
 694                         printf("\n");
 695                 }
 696
 697
 698                 if (should_cut.exchange(false)) {  // Test and clear.
 699                         video_encoder->do_cut(frame);
 700                 }
 701
 702 #if 0
 703                 // Reset every 100 frames, so that local variations in frame times
 704                 // (especially for the first few frames, when the shaders are
 705                 // compiled etc.) don't make it hard to measure for the entire
 706                 // remaining duration of the program.
 707                 if (frame == 10000) {
 708                         frame = 0;
 709                         start = now;
 710                 }
 711 #endif
 712                 check_error();
 713         }
 714
 715         resource_pool->clean_context();
 716 }
 717
 718 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])
 719 {
 720 start:
 721         // The first card is the master timer, so wait for it to have a new frame.
 722         // TODO: Add a timeout.
 723         unique_lock<mutex> lock(bmusb_mutex);
 724         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(); });
 725
 726         if (cards[master_card_index].new_frames.empty()) {
 727                 // We were woken up, but not due to a new frame. Deal with it
 728                 // and then restart.
 729                 assert(cards[master_card_index].capture->get_disconnected());
 730                 handle_hotplugged_cards();
 731                 goto start;
 732         }
 733
 734         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 735                 CaptureCard *card = &cards[card_index];
 736                 if (card->new_frames.empty()) {
 737                         assert(card_index != master_card_index);
 738                         card->queue_length_policy.update_policy(-1);
 739                         continue;
 740                 }
 741                 new_frames[card_index] = move(card->new_frames.front());
 742                 has_new_frame[card_index] = true;
 743                 card->new_frames.pop();
 744                 card->new_frames_changed.notify_all();
 745
 746                 int num_samples_times_timebase = OUTPUT_FREQUENCY * new_frames[card_index].length + card->fractional_samples;
 747                 num_samples[card_index] = num_samples_times_timebase / TIMEBASE;
 748                 card->fractional_samples = num_samples_times_timebase % TIMEBASE;
 749                 assert(num_samples[card_index] >= 0);
 750
 751                 if (card_index == master_card_index) {
 752                         // We don't use the queue length policy for the master card,
 753                         // but we will if it stops being the master. Thus, clear out
 754                         // the policy in case we switch in the future.
 755                         card->queue_length_policy.reset(card_index);
 756                 } else {
 757                         // If we have excess frames compared to the policy for this card,
 758                         // drop frames from the head.
 759                         card->queue_length_policy.update_policy(card->new_frames.size());
 760                         while (card->new_frames.size() > card->queue_length_policy.get_safe_queue_length()) {
 761                                 card->new_frames.pop();
 762                         }
 763                 }
 764         }
 765 }
 766
 767 void Mixer::handle_hotplugged_cards()
 768 {
 769         // Check for cards that have been disconnected since last frame.
 770         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 771                 CaptureCard *card = &cards[card_index];
 772                 if (card->capture->get_disconnected()) {
 773                         fprintf(stderr, "Card %u went away, replacing with a fake card.\n", card_index);
 774                         FakeCapture *capture = new FakeCapture(global_flags.width, global_flags.height, FAKE_FPS, OUTPUT_FREQUENCY, card_index, global_flags.fake_cards_audio);
 775                         configure_card(card_index, capture, /*is_fake_capture=*/true);
 776                         card->queue_length_policy.reset(card_index);
 777                         card->capture->start_bm_capture();
 778                 }
 779         }
 780
 781         // Check for cards that have been connected since last frame.
 782         vector<libusb_device *> hotplugged_cards_copy;
 783         {
 784                 lock_guard<mutex> lock(hotplug_mutex);
 785                 swap(hotplugged_cards, hotplugged_cards_copy);
 786         }
 787         for (libusb_device *new_dev : hotplugged_cards_copy) {
 788                 // Look for a fake capture card where we can stick this in.
 789                 int free_card_index = -1;
 790                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
 791                         if (cards[card_index].is_fake_capture) {
 792                                 free_card_index = int(card_index);
 793                                 break;
 794                         }
 795                 }
 796
 797                 if (free_card_index == -1) {
 798                         fprintf(stderr, "New card plugged in, but no free slots -- ignoring.\n");
 799                         libusb_unref_device(new_dev);
 800                 } else {
 801                         // BMUSBCapture takes ownership.
 802                         fprintf(stderr, "New card plugged in, choosing slot %d.\n", free_card_index);
 803                         CaptureCard *card = &cards[free_card_index];
 804                         BMUSBCapture *capture = new BMUSBCapture(free_card_index, new_dev);
 805                         configure_card(free_card_index, capture, /*is_fake_capture=*/false);
 806                         card->queue_length_policy.reset(free_card_index);
 807                         capture->set_card_disconnected_callback(bind(&Mixer::bm_hotplug_remove, this, free_card_index));
 808                         capture->start_bm_capture();
 809                 }
 810         }
 811 }
 812
 813
 814 void Mixer::schedule_audio_resampling_tasks(unsigned dropped_frames, int num_samples_per_frame, int length_per_frame)
 815 {
 816         // Resample the audio as needed, including from previously dropped frames.
 817         assert(num_cards > 0);
 818         for (unsigned frame_num = 0; frame_num < dropped_frames + 1; ++frame_num) {
 819                 const bool dropped_frame = (frame_num != dropped_frames);
 820                 {
 821                         // Signal to the audio thread to process this frame.
 822                         // Note that if the frame is a dropped frame, we signal that
 823                         // we don't want to use this frame as base for adjusting
 824                         // the resampler rate. The reason for this is that the timing
 825                         // of these frames is often way too late; they typically don't
 826                         // “arrive” before we synthesize them. Thus, we could end up
 827                         // in a situation where we have inserted e.g. five audio frames
 828                         // into the queue before we then start pulling five of them
 829                         // back out. This makes ResamplingQueue overestimate the delay,
 830                         // causing undue resampler changes. (We _do_ use the last,
 831                         // non-dropped frame; perhaps we should just discard that as well,
 832                         // since dropped frames are expected to be rare, and it might be
 833                         // better to just wait until we have a slightly more normal situation).
 834                         unique_lock<mutex> lock(audio_mutex);
 835                         bool adjust_rate = !dropped_frame;
 836                         audio_task_queue.push(AudioTask{pts_int, num_samples_per_frame, adjust_rate});
 837                         audio_task_queue_changed.notify_one();
 838                 }
 839                 if (dropped_frame) {
 840                         // For dropped frames, increase the pts. Note that if the format changed
 841                         // in the meantime, we have no way of detecting that; we just have to
 842                         // assume the frame length is always the same.
 843                         pts_int += length_per_frame;
 844                 }
 845         }
 846 }
 847
 848 void Mixer::render_one_frame(int64_t duration)
 849 {
 850         // Get the main chain from the theme, and set its state immediately.
 851         Theme::Chain theme_main_chain = theme->get_chain(0, pts(), global_flags.width, global_flags.height, input_state);
 852         EffectChain *chain = theme_main_chain.chain;
 853         theme_main_chain.setup_chain();
 854         //theme_main_chain.chain->enable_phase_timing(true);
 855
 856         GLuint y_tex, cbcr_tex;
 857         bool got_frame = video_encoder->begin_frame(&y_tex, &cbcr_tex);
 858         assert(got_frame);
 859
 860         // Render main chain.
 861         GLuint cbcr_full_tex = resource_pool->create_2d_texture(GL_RG8, global_flags.width, global_flags.height);
 862         GLuint rgba_tex = resource_pool->create_2d_texture(GL_RGB565, global_flags.width, global_flags.height);  // Saves texture bandwidth, although dithering gets messed up.
 863         GLuint fbo = resource_pool->create_fbo(y_tex, cbcr_full_tex, rgba_tex);
 864         check_error();
 865         chain->render_to_fbo(fbo, global_flags.width, global_flags.height);
 866         resource_pool->release_fbo(fbo);
 867
 868         subsample_chroma(cbcr_full_tex, cbcr_tex);
 869         resource_pool->release_2d_texture(cbcr_full_tex);
 870
 871         // Set the right state for rgba_tex.
 872         glBindFramebuffer(GL_FRAMEBUFFER, 0);
 873         glBindTexture(GL_TEXTURE_2D, rgba_tex);
 874         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 875         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 876         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 877
 878         const int64_t av_delay = lrint(global_flags.audio_queue_length_ms * 0.001 * TIMEBASE);  // Corresponds to the delay in ResamplingQueue.
 879         RefCountedGLsync fence = video_encoder->end_frame(pts_int + av_delay, duration, theme_main_chain.input_frames);
 880
 881         // The live frame just shows the RGBA texture we just rendered.
 882         // It owns rgba_tex now.
 883         DisplayFrame live_frame;
 884         live_frame.chain = display_chain.get();
 885         live_frame.setup_chain = [this, rgba_tex]{
 886                 display_input->set_texture_num(rgba_tex);
 887         };
 888         live_frame.ready_fence = fence;
 889         live_frame.input_frames = {};
 890         live_frame.temp_textures = { rgba_tex };
 891         output_channel[OUTPUT_LIVE].output_frame(live_frame);
 892
 893         // Set up preview and any additional channels.
 894         for (int i = 1; i < theme->get_num_channels() + 2; ++i) {
 895                 DisplayFrame display_frame;
 896                 Theme::Chain chain = theme->get_chain(i, pts(), global_flags.width, global_flags.height, input_state);  // FIXME: dimensions
 897                 display_frame.chain = chain.chain;
 898                 display_frame.setup_chain = chain.setup_chain;
 899                 display_frame.ready_fence = fence;
 900                 display_frame.input_frames = chain.input_frames;
 901                 display_frame.temp_textures = {};
 902                 output_channel[i].output_frame(display_frame);
 903         }
 904 }
 905
 906 void Mixer::audio_thread_func()
 907 {
 908         while (!should_quit) {
 909                 AudioTask task;
 910
 911                 {
 912                         unique_lock<mutex> lock(audio_mutex);
 913                         audio_task_queue_changed.wait(lock, [this]{ return should_quit || !audio_task_queue.empty(); });
 914                         if (should_quit) {
 915                                 return;
 916                         }
 917                         task = audio_task_queue.front();
 918                         audio_task_queue.pop();
 919                 }
 920
 921                 ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy =
 922                         task.adjust_rate ? ResamplingQueue::ADJUST_RATE : ResamplingQueue::DO_NOT_ADJUST_RATE;
 923                 vector<float> samples_out = audio_mixer.get_output(
 924                         double(task.pts_int) / TIMEBASE,
 925                         task.num_samples,
 926                         rate_adjustment_policy);
 927
 928                 // Send the samples to the sound card, then add them to the output.
 929                 if (alsa) {
 930                         alsa->write(samples_out);
 931                 }
 932                 video_encoder->add_audio(task.pts_int, move(samples_out));
 933         }
 934 }
 935
 936 void Mixer::subsample_chroma(GLuint src_tex, GLuint dst_tex)
 937 {
 938         GLuint vao;
 939         glGenVertexArrays(1, &vao);
 940         check_error();
 941
 942         glBindVertexArray(vao);
 943         check_error();
 944
 945         // Extract Cb/Cr.
 946         GLuint fbo = resource_pool->create_fbo(dst_tex);
 947         glBindFramebuffer(GL_FRAMEBUFFER, fbo);
 948         glViewport(0, 0, global_flags.width/2, global_flags.height/2);
 949         check_error();
 950
 951         glUseProgram(cbcr_program_num);
 952         check_error();
 953
 954         glActiveTexture(GL_TEXTURE0);
 955         check_error();
 956         glBindTexture(GL_TEXTURE_2D, src_tex);
 957         check_error();
 958         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 959         check_error();
 960         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 961         check_error();
 962         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 963         check_error();
 964
 965         float chroma_offset_0[] = { -1.0f / global_flags.width, 0.0f };
 966         float chroma_offset_1[] = { -0.0f / global_flags.width, 0.0f };
 967         set_uniform_vec2(cbcr_program_num, "foo", "chroma_offset_0", chroma_offset_0);
 968         set_uniform_vec2(cbcr_program_num, "foo", "chroma_offset_1", chroma_offset_1);
 969
 970         glUniform1i(cbcr_texture_sampler_uniform, 0);
 971
 972         glBindBuffer(GL_ARRAY_BUFFER, cbcr_vbo);
 973         check_error();
 974
 975         for (GLint attr_index : { cbcr_position_attribute_index, cbcr_texcoord_attribute_index }) {
 976                 glEnableVertexAttribArray(attr_index);
 977                 check_error();
 978                 glVertexAttribPointer(attr_index, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
 979                 check_error();
 980         }
 981
 982         glDrawArrays(GL_TRIANGLES, 0, 3);
 983         check_error();
 984
 985         for (GLint attr_index : { cbcr_position_attribute_index, cbcr_texcoord_attribute_index }) {
 986                 glDisableVertexAttribArray(attr_index);
 987                 check_error();
 988         }
 989
 990         glUseProgram(0);
 991         check_error();
 992         glBindFramebuffer(GL_FRAMEBUFFER, 0);
 993         check_error();
 994
 995         resource_pool->release_fbo(fbo);
 996         glDeleteVertexArrays(1, &vao);
 997 }
 998
 999 void Mixer::release_display_frame(DisplayFrame *frame)
1000 {
1001         for (GLuint texnum : frame->temp_textures) {
1002                 resource_pool->release_2d_texture(texnum);
1003         }
1004         frame->temp_textures.clear();
1005         frame->ready_fence.reset();
1006         frame->input_frames.clear();
1007 }
1008
1009 void Mixer::start()
1010 {
1011         mixer_thread = thread(&Mixer::thread_func, this);
1012         audio_thread = thread(&Mixer::audio_thread_func, this);
1013 }
1014
1015 void Mixer::quit()
1016 {
1017         should_quit = true;
1018         audio_task_queue_changed.notify_one();
1019         mixer_thread.join();
1020         audio_thread.join();
1021 }
1022
1023 void Mixer::transition_clicked(int transition_num)
1024 {
1025         theme->transition_clicked(transition_num, pts());
1026 }
1027
1028 void Mixer::channel_clicked(int preview_num)
1029 {
1030         theme->channel_clicked(preview_num);
1031 }
1032
1033 void Mixer::start_mode_scanning(unsigned card_index)
1034 {
1035         assert(card_index < num_cards);
1036         if (is_mode_scanning[card_index]) {
1037                 return;
1038         }
1039         is_mode_scanning[card_index] = true;
1040         mode_scanlist[card_index].clear();
1041         for (const auto &mode : cards[card_index].capture->get_available_video_modes()) {
1042                 mode_scanlist[card_index].push_back(mode.first);
1043         }
1044         assert(!mode_scanlist[card_index].empty());
1045         mode_scanlist_index[card_index] = 0;
1046         cards[card_index].capture->set_video_mode(mode_scanlist[card_index][0]);
1047         last_mode_scan_change[card_index] = steady_clock::now();
1048 }
1049
1050 Mixer::OutputChannel::~OutputChannel()
1051 {
1052         if (has_current_frame) {
1053                 parent->release_display_frame(&current_frame);
1054         }
1055         if (has_ready_frame) {
1056                 parent->release_display_frame(&ready_frame);
1057         }
1058 }
1059
1060 void Mixer::OutputChannel::output_frame(DisplayFrame frame)
1061 {
1062         // Store this frame for display. Remove the ready frame if any
1063         // (it was seemingly never used).
1064         {
1065                 unique_lock<mutex> lock(frame_mutex);
1066                 if (has_ready_frame) {
1067                         parent->release_display_frame(&ready_frame);
1068                 }
1069                 ready_frame = frame;
1070                 has_ready_frame = true;
1071         }
1072
1073         if (new_frame_ready_callback) {
1074                 new_frame_ready_callback();
1075         }
1076
1077         // Reduce the number of callbacks by filtering duplicates. The reason
1078         // why we bother doing this is that Qt seemingly can get into a state
1079         // where its builds up an essentially unbounded queue of signals,
1080         // consuming more and more memory, and there's no good way of collapsing
1081         // user-defined signals or limiting the length of the queue.
1082         if (transition_names_updated_callback) {
1083                 vector<string> transition_names = global_mixer->get_transition_names();
1084                 bool changed = false;
1085                 if (transition_names.size() != last_transition_names.size()) {
1086                         changed = true;
1087                 } else {
1088                         for (unsigned i = 0; i < transition_names.size(); ++i) {
1089                                 if (transition_names[i] != last_transition_names[i]) {
1090                                         changed = true;
1091                                         break;
1092                                 }
1093                         }
1094                 }
1095                 if (changed) {
1096                         transition_names_updated_callback(transition_names);
1097                         last_transition_names = transition_names;
1098                 }
1099         }
1100         if (name_updated_callback) {
1101                 string name = global_mixer->get_channel_name(channel);
1102                 if (name != last_name) {
1103                         name_updated_callback(name);
1104                         last_name = name;
1105                 }
1106         }
1107         if (color_updated_callback) {
1108                 string color = global_mixer->get_channel_color(channel);
1109                 if (color != last_color) {
1110                         color_updated_callback(color);
1111                         last_color = color;
1112                 }
1113         }
1114 }
1115
1116 bool Mixer::OutputChannel::get_display_frame(DisplayFrame *frame)
1117 {
1118         unique_lock<mutex> lock(frame_mutex);
1119         if (!has_current_frame && !has_ready_frame) {
1120                 return false;
1121         }
1122
1123         if (has_current_frame && has_ready_frame) {
1124                 // We have a new ready frame. Toss the current one.
1125                 parent->release_display_frame(&current_frame);
1126                 has_current_frame = false;
1127         }
1128         if (has_ready_frame) {
1129                 assert(!has_current_frame);
1130                 current_frame = ready_frame;
1131                 ready_frame.ready_fence.reset();  // Drop the refcount.
1132                 ready_frame.input_frames.clear();  // Drop the refcounts.
1133                 has_current_frame = true;
1134                 has_ready_frame = false;
1135         }
1136
1137         *frame = current_frame;
1138         return true;
1139 }
1140
1141 void Mixer::OutputChannel::set_frame_ready_callback(Mixer::new_frame_ready_callback_t callback)
1142 {
1143         new_frame_ready_callback = callback;
1144 }
1145
1146 void Mixer::OutputChannel::set_transition_names_updated_callback(Mixer::transition_names_updated_callback_t callback)
1147 {
1148         transition_names_updated_callback = callback;
1149 }
1150
1151 void Mixer::OutputChannel::set_name_updated_callback(Mixer::name_updated_callback_t callback)
1152 {
1153         name_updated_callback = callback;
1154 }
1155
1156 void Mixer::OutputChannel::set_color_updated_callback(Mixer::color_updated_callback_t callback)
1157 {
1158         color_updated_callback = callback;
1159 }
1160
1161 mutex RefCountedGLsync::fence_lock;