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