git.sesse.net Git - nageru/blob - mixer.cpp

   1 #define WIDTH 1280
   2 #define HEIGHT 720
   3
   4 #undef Success
   5
   6 #include "mixer.h"
   7
   8 #include <assert.h>
   9 #include <effect.h>
  10 #include <effect_chain.h>
  11 #include <effect_util.h>
  12 #include <epoxy/egl.h>
  13 #include <features.h>
  14 #include <image_format.h>
  15 #include <init.h>
  16 #include <overlay_effect.h>
  17 #include <padding_effect.h>
  18 #include <resample_effect.h>
  19 #include <resource_pool.h>
  20 #include <saturation_effect.h>
  21 #include <stdint.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <sys/time.h>
  25 #include <time.h>
  26 #include <util.h>
  27 #include <white_balance_effect.h>
  28 #include <ycbcr.h>
  29 #include <ycbcr_input.h>
  30 #include <cmath>
  31 #include <condition_variable>
  32 #include <cstddef>
  33 #include <memory>
  34 #include <mutex>
  35 #include <string>
  36 #include <thread>
  37 #include <vector>
  38
  39 #include "bmusb.h"
  40 #include "context.h"
  41 #include "h264encode.h"
  42 #include "pbo_frame_allocator.h"
  43 #include "ref_counted_gl_sync.h"
  44
  45 class QOpenGLContext;
  46
  47 using namespace movit;
  48 using namespace std;
  49 using namespace std::placeholders;
  50
  51 Mixer *global_mixer = nullptr;
  52
  53 Mixer::Mixer(QSurface *surface1, QSurface *surface2, QSurface *surface3, QSurface *surface4)
  54         : surface1(surface1), surface2(surface2), surface3(surface3), surface4(surface4)
  55 {
  56         CHECK(init_movit(MOVIT_SHADER_DIR, MOVIT_DEBUG_OFF));
  57         check_error();
  58
  59         chain.reset(new EffectChain(WIDTH, HEIGHT));
  60         check_error();
  61
  62         ImageFormat inout_format;
  63         inout_format.color_space = COLORSPACE_sRGB;
  64         inout_format.gamma_curve = GAMMA_sRGB;
  65
  66         YCbCrFormat ycbcr_format;
  67         ycbcr_format.chroma_subsampling_x = 2;
  68         ycbcr_format.chroma_subsampling_y = 1;
  69         ycbcr_format.cb_x_position = 0.0;
  70         ycbcr_format.cr_x_position = 0.0;
  71         ycbcr_format.cb_y_position = 0.5;
  72         ycbcr_format.cr_y_position = 0.5;
  73         ycbcr_format.luma_coefficients = YCBCR_REC_601;
  74         ycbcr_format.full_range = false;
  75
  76         input[0] = new YCbCrInput(inout_format, ycbcr_format, WIDTH, HEIGHT, YCBCR_INPUT_SPLIT_Y_AND_CBCR);
  77         chain->add_input(input[0]);
  78         input[1] = new YCbCrInput(inout_format, ycbcr_format, WIDTH, HEIGHT, YCBCR_INPUT_SPLIT_Y_AND_CBCR);
  79         chain->add_input(input[1]);
  80         resample_effect = chain->add_effect(new ResampleEffect(), input[0]);
  81         padding_effect = chain->add_effect(new IntegralPaddingEffect());
  82         float border_color[] = { 0.0f, 0.0f, 0.0f, 1.0f };
  83         CHECK(padding_effect->set_vec4("border_color", border_color));
  84
  85         resample2_effect = chain->add_effect(new ResampleEffect(), input[1]);
  86         Effect *saturation_effect = chain->add_effect(new SaturationEffect());
  87         CHECK(saturation_effect->set_float("saturation", 0.3f));
  88         Effect *wb_effect = chain->add_effect(new WhiteBalanceEffect());
  89         CHECK(wb_effect->set_float("output_color_temperature", 3500.0));
  90         padding2_effect = chain->add_effect(new IntegralPaddingEffect());
  91
  92         chain->add_effect(new OverlayEffect(), padding_effect, padding2_effect);
  93
  94         ycbcr_format.chroma_subsampling_x = 1;
  95
  96         chain->add_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED);
  97         chain->add_ycbcr_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED, ycbcr_format, YCBCR_OUTPUT_SPLIT_Y_AND_CBCR);
  98         chain->set_dither_bits(8);
  99         chain->set_output_origin(OUTPUT_ORIGIN_TOP_LEFT);
 100         chain->finalize();
 101
 102         h264_encoder.reset(new H264Encoder(surface2, WIDTH, HEIGHT, "test.mp4"));
 103
 104         printf("Configuring first card...\n");
 105         cards[0].usb = new BMUSBCapture(0x1edb, 0xbd3b);  // 0xbd4f
 106         cards[0].usb->set_frame_callback(std::bind(&Mixer::bm_frame, this, 0, _1, _2, _3, _4, _5, _6, _7));
 107         cards[0].frame_allocator.reset(new PBOFrameAllocator(1280 * 750 * 2 + 44));
 108         cards[0].usb->set_video_frame_allocator(cards[0].frame_allocator.get());
 109         cards[0].usb->configure_card();
 110
 111         if (NUM_CARDS == 2) {
 112                 printf("Configuring second card...\n");
 113                 cards[1].usb = new BMUSBCapture(0x1edb, 0xbd4f);
 114                 cards[1].usb->set_frame_callback(std::bind(&Mixer::bm_frame, this, 1, _1, _2, _3, _4, _5, _6, _7));
 115                 cards[1].frame_allocator.reset(new PBOFrameAllocator(1280 * 750 * 2 + 44));
 116                 cards[1].usb->set_video_frame_allocator(cards[1].frame_allocator.get());
 117                 cards[1].usb->configure_card();
 118         }
 119
 120         BMUSBCapture::start_bm_thread();
 121
 122         for (int card_index = 0; card_index < NUM_CARDS; ++card_index) {
 123                 cards[card_index].usb->start_bm_capture();
 124         }
 125
 126         for (int card_index = 0; card_index < NUM_CARDS; ++card_index) {
 127                 bmusb_current_rendering_frame[card_index] =
 128                         cards[card_index].usb->get_video_frame_allocator()->alloc_frame();
 129                 GLint input_tex_pbo = (GLint)(intptr_t)bmusb_current_rendering_frame[card_index].userdata;
 130                 input[card_index]->set_pixel_data(0, nullptr, input_tex_pbo);
 131                 input[card_index]->set_pixel_data(1, nullptr, input_tex_pbo);
 132         }
 133
 134         //chain->enable_phase_timing(true);
 135
 136         // Set up stuff for NV12 conversion.
 137         resource_pool = chain->get_resource_pool();
 138
 139         // Cb/Cr shader.
 140         string cbcr_vert_shader = read_file("vs-cbcr.130.vert");
 141         string cbcr_frag_shader =
 142                 "#version 130 \n"
 143                 "in vec2 tc0; \n"
 144                 "uniform sampler2D cbcr_tex; \n"
 145                 "void main() { \n"
 146                 "    gl_FragColor = texture2D(cbcr_tex, tc0); \n"
 147                 "} \n";
 148         cbcr_program_num = resource_pool->compile_glsl_program(cbcr_vert_shader, cbcr_frag_shader);
 149 }
 150
 151 Mixer::~Mixer()
 152 {
 153         resource_pool->release_glsl_program(cbcr_program_num);
 154         BMUSBCapture::stop_bm_thread();
 155 }
 156
 157 void Mixer::bm_frame(int card_index, uint16_t timecode,
 158                      FrameAllocator::Frame video_frame, size_t video_offset, uint16_t video_format,
 159                      FrameAllocator::Frame audio_frame, size_t audio_offset, uint16_t audio_format)
 160 {
 161         CaptureCard *card = &cards[card_index];
 162         if (!card->thread_initialized) {
 163                 printf("initializing context for bmusb thread %d\n", card_index);
 164                 eglBindAPI(EGL_OPENGL_API);
 165                 card->context = create_context();
 166                 if (!make_current(card->context, card->surface)) {
 167                         printf("failed to create bmusb context\n");
 168                         exit(1);
 169                 }
 170                 card->thread_initialized = true;
 171         }
 172
 173         if (video_frame.len - video_offset != 1280 * 750 * 2) {
 174                 printf("dropping frame with wrong length (%ld)\n", video_frame.len - video_offset);
 175                 FILE *fp = fopen("frame.raw", "wb");
 176                 fwrite(video_frame.data, video_frame.len, 1, fp);
 177                 fclose(fp);
 178                 //exit(1);
 179                 card->usb->get_video_frame_allocator()->release_frame(video_frame);
 180                 card->usb->get_audio_frame_allocator()->release_frame(audio_frame);
 181                 return;
 182         }
 183         {
 184                 // Wait until the previous frame was consumed.
 185                 std::unique_lock<std::mutex> lock(bmusb_mutex);
 186                 card->new_data_ready_changed.wait(lock, [card]{ return !card->new_data_ready; });
 187         }
 188         GLuint pbo = (GLint)(intptr_t)video_frame.userdata;
 189         check_error();
 190         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbo);
 191         check_error();
 192         glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, 0, video_frame.size);
 193         check_error();
 194         //glMemoryBarrier(GL_CLIENT_MAPPED_BUFFER_BARRIER_BIT);
 195         //check_error();
 196         GLsync fence = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, /*flags=*/0);
 197         check_error();
 198         assert(fence != nullptr);
 199         {
 200                 std::unique_lock<std::mutex> lock(bmusb_mutex);
 201                 card->new_data_ready = true;
 202                 card->new_frame = video_frame;
 203                 card->new_data_ready_fence = fence;
 204                 card->new_data_ready_changed.notify_all();
 205         }
 206
 207         // Video frame will be released later.
 208         card->usb->get_audio_frame_allocator()->release_frame(audio_frame);
 209 }
 210
 211 void Mixer::place_rectangle(Effect *resample_effect, Effect *padding_effect, float x0, float y0, float x1, float y1)
 212 {
 213         float srcx0 = 0.0f;
 214         float srcx1 = 1.0f;
 215         float srcy0 = 0.0f;
 216         float srcy1 = 1.0f;
 217
 218         // Cull.
 219         if (x0 > 1280.0 || x1 < 0.0 || y0 > 720.0 || y1 < 0.0) {
 220                 CHECK(resample_effect->set_int("width", 1));
 221                 CHECK(resample_effect->set_int("height", 1));
 222                 CHECK(resample_effect->set_float("zoom_x", 1280.0));
 223                 CHECK(resample_effect->set_float("zoom_y", 720.0));
 224                 CHECK(padding_effect->set_int("left", 2000));
 225                 CHECK(padding_effect->set_int("top", 2000));
 226                 return;
 227         }
 228
 229         // Clip. (TODO: Clip on upper/left sides, too.)
 230         if (x1 > 1280.0) {
 231                 srcx1 = (1280.0 - x0) / (x1 - x0);
 232                 x1 = 1280.0;
 233         }
 234         if (y1 > 720.0) {
 235                 srcy1 = (720.0 - y0) / (y1 - y0);
 236                 y1 = 720.0;
 237         }
 238
 239         float x_subpixel_offset = x0 - floor(x0);
 240         float y_subpixel_offset = y0 - floor(y0);
 241
 242         // Resampling must be to an integral number of pixels. Round up,
 243         // and then add an extra pixel so we have some leeway for the border.
 244         int width = int(ceil(x1 - x0)) + 1;
 245         int height = int(ceil(y1 - y0)) + 1;
 246         CHECK(resample_effect->set_int("width", width));
 247         CHECK(resample_effect->set_int("height", height));
 248
 249         // Correct the discrepancy with zoom. (This will leave a small
 250         // excess edge of pixels and subpixels, which we'll correct for soon.)
 251         float zoom_x = (x1 - x0) / (width * (srcx1 - srcx0));
 252         float zoom_y = (y1 - y0) / (height * (srcy1 - srcy0));
 253         CHECK(resample_effect->set_float("zoom_x", zoom_x));
 254         CHECK(resample_effect->set_float("zoom_y", zoom_y));
 255         CHECK(resample_effect->set_float("zoom_center_x", 0.0f));
 256         CHECK(resample_effect->set_float("zoom_center_y", 0.0f));
 257
 258         // Padding must also be to a whole-pixel offset.
 259         CHECK(padding_effect->set_int("left", floor(x0)));
 260         CHECK(padding_effect->set_int("top", floor(y0)));
 261
 262         // Correct _that_ discrepancy by subpixel offset in the resampling.
 263         CHECK(resample_effect->set_float("left", -x_subpixel_offset / zoom_x));
 264         CHECK(resample_effect->set_float("top", -y_subpixel_offset / zoom_y));
 265
 266         // Finally, adjust the border so it is exactly where we want it.
 267         CHECK(padding_effect->set_float("border_offset_left", x_subpixel_offset));
 268         CHECK(padding_effect->set_float("border_offset_right", x1 - (floor(x0) + width)));
 269         CHECK(padding_effect->set_float("border_offset_top", y_subpixel_offset));
 270         CHECK(padding_effect->set_float("border_offset_bottom", y1 - (floor(y0) + height)));
 271 }
 272
 273 void Mixer::thread_func()
 274 {
 275         cards[0].surface = surface3;
 276 #if NUM_CARDS == 2
 277         cards[1].surface = surface4;
 278 #endif
 279
 280         eglBindAPI(EGL_OPENGL_API);
 281         QOpenGLContext *context = create_context();
 282         if (!make_current(context, surface1)) {
 283                 printf("oops\n");
 284                 exit(1);
 285         }
 286
 287         struct timespec start, now;
 288         clock_gettime(CLOCK_MONOTONIC, &start);
 289
 290         GLuint vao;
 291         glGenVertexArrays(1, &vao);
 292         check_error();
 293
 294         while (!should_quit) {
 295                 ++frame;
 296
 297                 //int width0 = lrintf(848 * (1.0 + 0.2 * sin(frame * 0.02)));
 298                 int width0 = 848;
 299                 int height0 = lrintf(width0 * 9.0 / 16.0);
 300
 301                 //float top0 = 96 + 48 * sin(frame * 0.005);
 302                 //float left0 = 96 + 48 * cos(frame * 0.006);
 303                 float top0 = 48;
 304                 float left0 = 16;
 305                 float bottom0 = top0 + height0;
 306                 float right0 = left0 + width0;
 307
 308                 int width1 = 384;
 309                 int height1 = 216;
 310
 311                 float bottom1 = 720 - 48;
 312                 float right1 = 1280 - 16;
 313                 float top1 = bottom1 - height1;
 314                 float left1 = right1 - width1;
 315
 316                 if (current_source == SOURCE_INPUT1) {
 317                         top0 = 0.0;
 318                         bottom0 = HEIGHT;
 319                         left0 = 0.0;
 320                         right0 = WIDTH;
 321
 322                         top1 = HEIGHT + 10;
 323                         bottom1 = HEIGHT + 20;
 324                         left1 = WIDTH + 10;
 325                         right1 = WIDTH + 20;
 326                 } else if (current_source == SOURCE_INPUT2) {
 327                         top1 = 0.0;
 328                         bottom1 = HEIGHT;
 329                         left1 = 0.0;
 330                         right1 = WIDTH;
 331
 332                         top0 = HEIGHT + 10;
 333                         bottom0 = HEIGHT + 20;
 334                         left0 = WIDTH + 10;
 335                         right0 = WIDTH + 20;
 336                 } else {
 337                         float t = 0.5 + 0.5 * cos(frame * 0.006);
 338                         float scale0 = 1.0 + t * (1280.0 / 848.0 - 1.0);
 339                         float tx0 = 0.0 + t * (-16.0 * scale0);
 340                         float ty0 = 0.0 + t * (-48.0 * scale0);
 341
 342                         top0 = top0 * scale0 + ty0;
 343                         bottom0 = bottom0 * scale0 + ty0;
 344                         left0 = left0 * scale0 + tx0;
 345                         right0 = right0 * scale0 + tx0;
 346
 347                         top1 = top1 * scale0 + ty0;
 348                         bottom1 = bottom1 * scale0 + ty0;
 349                         left1 = left1 * scale0 + tx0;
 350                         right1 = right1 * scale0 + tx0;
 351                 }
 352
 353                 place_rectangle(resample_effect, padding_effect, left0, top0, right0, bottom0);
 354                 place_rectangle(resample2_effect, padding2_effect, left1, top1, right1, bottom1);
 355
 356                 CaptureCard card_copy[NUM_CARDS];
 357
 358                 {
 359                         std::unique_lock<std::mutex> lock(bmusb_mutex);
 360
 361                         // The first card is the master timer, so wait for it to have a new frame.
 362                         // TODO: Make configurable, and with a timeout.
 363                         cards[0].new_data_ready_changed.wait(lock, [this]{ return cards[0].new_data_ready; });
 364
 365                         for (int card_index = 0; card_index < NUM_CARDS; ++card_index) {
 366                                 CaptureCard *card = &cards[card_index];
 367                                 card_copy[card_index].usb = card->usb;
 368                                 card_copy[card_index].new_data_ready = card->new_data_ready;
 369                                 card_copy[card_index].new_frame = card->new_frame;
 370                                 card_copy[card_index].new_data_ready_fence = card->new_data_ready_fence;
 371                                 card->new_data_ready = false;
 372                                 card->new_data_ready_changed.notify_all();
 373                         }
 374                 }
 375
 376                 vector<FrameAllocator::Frame> input_frames_to_release;
 377
 378                 for (int card_index = 0; card_index < NUM_CARDS; ++card_index) {
 379                         CaptureCard *card = &card_copy[card_index];
 380                         if (!card->new_data_ready)
 381                                 continue;
 382
 383                         // Now we're done with the previous frame, so we can definitely
 384                         // release it when this is done rendering. (Actually, we could do
 385                         // it one frame earlier, but before we have a new one, there's no
 386                         // knowing when the current one is released.)
 387                         input_frames_to_release.push_back(bmusb_current_rendering_frame[card_index]);
 388                         bmusb_current_rendering_frame[card_index] = card->new_frame;
 389                         check_error();
 390
 391                         // The new texture might still be uploaded,
 392                         // tell the GPU to wait until it's there.
 393                         if (card->new_data_ready_fence)
 394                                 glWaitSync(card->new_data_ready_fence, /*flags=*/0, GL_TIMEOUT_IGNORED);
 395                         check_error();
 396                         glDeleteSync(card->new_data_ready_fence);
 397                         check_error();
 398                         GLint input_tex_pbo = (GLint)(intptr_t)card->new_frame.userdata;
 399                         input[card_index]->set_pixel_data(0, (unsigned char *)BUFFER_OFFSET((1280 * 750 * 2 + 44) / 2 + 1280 * 25 + 22), input_tex_pbo);
 400                         input[card_index]->set_pixel_data(1, (unsigned char *)BUFFER_OFFSET(1280 * 25 + 22), input_tex_pbo);
 401
 402                         if (NUM_CARDS == 1) {
 403                                 // Set to the other one, too.
 404                                 input[1]->set_pixel_data(0, (unsigned char *)BUFFER_OFFSET((1280 * 750 * 2 + 44) / 2 + 1280 * 25 + 22), input_tex_pbo);
 405                                 input[1]->set_pixel_data(1, (unsigned char *)BUFFER_OFFSET(1280 * 25 + 22), input_tex_pbo);
 406                         }
 407                 }
 408
 409                 GLuint y_tex, cbcr_tex;
 410                 bool got_frame = h264_encoder->begin_frame(&y_tex, &cbcr_tex);
 411                 assert(got_frame);
 412
 413                 GLuint chroma_tex = resource_pool->create_2d_texture(GL_RG8, WIDTH, HEIGHT);
 414
 415                 // Render chain.
 416                 GLuint rgba_tex = resource_pool->create_2d_texture(GL_RGBA8, WIDTH, HEIGHT);
 417                 GLuint ycbcr_fbo = resource_pool->create_fbo(y_tex, chroma_tex, rgba_tex);
 418                 chain->render_to_fbo(ycbcr_fbo, WIDTH, HEIGHT);
 419                 resource_pool->release_fbo(ycbcr_fbo);
 420
 421                 // Set up for extraction.
 422                 float vertices[] = {
 423                         0.0f, 2.0f,
 424                         0.0f, 0.0f,
 425                         2.0f, 0.0f
 426                 };
 427
 428                 glBindVertexArray(vao);
 429                 check_error();
 430
 431                 // Extract Cb/Cr.
 432                 GLuint cbcr_fbo = resource_pool->create_fbo(cbcr_tex);
 433                 glBindFramebuffer(GL_FRAMEBUFFER, cbcr_fbo);
 434                 glViewport(0, 0, WIDTH/2, HEIGHT/2);
 435                 check_error();
 436
 437                 glUseProgram(cbcr_program_num);
 438                 check_error();
 439
 440                 glActiveTexture(GL_TEXTURE0);
 441                 check_error();
 442                 glBindTexture(GL_TEXTURE_2D, chroma_tex);
 443                 check_error();
 444                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 445                 check_error();
 446                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 447                 check_error();
 448                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 449                 check_error();
 450
 451                 float chroma_offset_0[] = { -0.5f / WIDTH, 0.0f };
 452                 set_uniform_vec2(cbcr_program_num, "foo", "chroma_offset_0", chroma_offset_0);
 453
 454                 GLuint position_vbo = fill_vertex_attribute(cbcr_program_num, "position", 2, GL_FLOAT, sizeof(vertices), vertices);
 455                 GLuint texcoord_vbo = fill_vertex_attribute(cbcr_program_num, "texcoord", 2, GL_FLOAT, sizeof(vertices), vertices);  // Same as vertices.
 456
 457                 glDrawArrays(GL_TRIANGLES, 0, 3);
 458                 check_error();
 459
 460                 RefCountedGLsync fence(GL_SYNC_GPU_COMMANDS_COMPLETE, /*flags=*/0);
 461                 check_error();
 462
 463                 cleanup_vertex_attribute(cbcr_program_num, "position", position_vbo);
 464                 cleanup_vertex_attribute(cbcr_program_num, "texcoord", texcoord_vbo);
 465
 466                 glUseProgram(0);
 467                 check_error();
 468
 469                 resource_pool->release_fbo(cbcr_fbo);
 470                 resource_pool->release_2d_texture(chroma_tex);
 471
 472                 h264_encoder->end_frame(fence, input_frames_to_release);
 473
 474                 // Store this frame for display. Remove the ready frame if any
 475                 // (it was seemingly never used).
 476                 {
 477                         std::unique_lock<std::mutex> lock(display_frame_mutex);
 478                         if (has_ready_display_frame) {
 479                                 resource_pool->release_2d_texture(ready_display_frame.texnum);
 480                                 ready_display_frame.ready_fence.reset();
 481                         }
 482                         ready_display_frame.texnum = rgba_tex;
 483                         ready_display_frame.ready_fence = fence;
 484                         has_ready_display_frame = true;
 485                 }
 486
 487                 if (has_new_frame_ready_callback) {
 488                         new_frame_ready_callback();
 489                 }
 490
 491                 clock_gettime(CLOCK_MONOTONIC, &now);
 492                 double elapsed = now.tv_sec - start.tv_sec +
 493                         1e-9 * (now.tv_nsec - start.tv_nsec);
 494                 if (frame % 100 == 0) {
 495                         printf("%d frames in %.3f seconds = %.1f fps (%.1f ms/frame)\n",
 496                                 frame, elapsed, frame / elapsed,
 497                                 1e3 * elapsed / frame);
 498                 //      chain->print_phase_timing();
 499                 }
 500
 501                 // Reset every 100 frames, so that local variations in frame times
 502                 // (especially for the first few frames, when the shaders are
 503                 // compiled etc.) don't make it hard to measure for the entire
 504                 // remaining duration of the program.
 505                 if (frame == 10000) {
 506                         frame = 0;
 507                         start = now;
 508                 }
 509                 check_error();
 510         }
 511         glDeleteVertexArrays(1, &vao);
 512 }
 513
 514 bool Mixer::get_display_frame(DisplayFrame *frame)
 515 {
 516         std::unique_lock<std::mutex> lock(display_frame_mutex);
 517         if (!has_current_display_frame && !has_ready_display_frame) {
 518                 return false;
 519         }
 520
 521         if (has_current_display_frame && has_ready_display_frame) {
 522                 // We have a new ready frame. Toss the current one.
 523                 resource_pool->release_2d_texture(current_display_frame.texnum);
 524                 current_display_frame.ready_fence.reset();
 525                 has_current_display_frame = false;
 526         }
 527         if (has_ready_display_frame) {
 528                 assert(!has_current_display_frame);
 529                 current_display_frame = ready_display_frame;
 530                 ready_display_frame.ready_fence.reset();  // Drop the refcount.
 531                 has_current_display_frame = true;
 532                 has_ready_display_frame = false;
 533         }
 534
 535         *frame = current_display_frame;
 536         return true;
 537 }
 538
 539 void Mixer::set_frame_ready_fallback(new_frame_ready_callback_t callback)
 540 {
 541         new_frame_ready_callback = callback;
 542         has_new_frame_ready_callback = true;
 543 }
 544
 545 void Mixer::start()
 546 {
 547         mixer_thread = std::thread(&Mixer::thread_func, this);
 548 }
 549
 550 void Mixer::quit()
 551 {
 552         should_quit = true;
 553         mixer_thread.join();
 554 }
 555
 556 void Mixer::cut(Source source)
 557 {
 558         current_source = source;
 559 }