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                 input[card_index]->set_pixel_data(0, nullptr, 0);
 125                 input[card_index]->set_pixel_data(1, nullptr, 0);
 126         }
 127
 128         //chain->enable_phase_timing(true);
 129
 130         // Set up stuff for NV12 conversion.
 131         resource_pool = chain->get_resource_pool();
 132
 133         // Cb/Cr shader.
 134         string cbcr_vert_shader = read_file("vs-cbcr.130.vert");
 135         string cbcr_frag_shader =
 136                 "#version 130 \n"
 137                 "in vec2 tc0; \n"
 138                 "uniform sampler2D cbcr_tex; \n"
 139                 "void main() { \n"
 140                 "    gl_FragColor = texture2D(cbcr_tex, tc0); \n"
 141                 "} \n";
 142         cbcr_program_num = resource_pool->compile_glsl_program(cbcr_vert_shader, cbcr_frag_shader);
 143 }
 144
 145 Mixer::~Mixer()
 146 {
 147         resource_pool->release_glsl_program(cbcr_program_num);
 148         BMUSBCapture::stop_bm_thread();
 149 }
 150
 151 void Mixer::bm_frame(int card_index, uint16_t timecode,
 152                      FrameAllocator::Frame video_frame, size_t video_offset, uint16_t video_format,
 153                      FrameAllocator::Frame audio_frame, size_t audio_offset, uint16_t audio_format)
 154 {
 155         CaptureCard *card = &cards[card_index];
 156         if (!card->thread_initialized) {
 157                 printf("initializing context for bmusb thread %d\n", card_index);
 158                 eglBindAPI(EGL_OPENGL_API);
 159                 card->context = create_context();
 160                 if (!make_current(card->context, card->surface)) {
 161                         printf("failed to create bmusb context\n");
 162                         exit(1);
 163                 }
 164                 card->thread_initialized = true;
 165         }
 166
 167         if (video_frame.len - video_offset != 1280 * 750 * 2) {
 168                 printf("dropping frame with wrong length (%ld)\n", video_frame.len - video_offset);
 169                 FILE *fp = fopen("frame.raw", "wb");
 170                 fwrite(video_frame.data, video_frame.len, 1, fp);
 171                 fclose(fp);
 172                 //exit(1);
 173                 card->usb->get_video_frame_allocator()->release_frame(video_frame);
 174                 card->usb->get_audio_frame_allocator()->release_frame(audio_frame);
 175                 return;
 176         }
 177         {
 178                 // Wait until the previous frame was consumed.
 179                 std::unique_lock<std::mutex> lock(bmusb_mutex);
 180                 card->new_data_ready_changed.wait(lock, [card]{ return !card->new_data_ready; });
 181         }
 182         GLuint pbo = (GLint)(intptr_t)video_frame.userdata;
 183         check_error();
 184         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbo);
 185         check_error();
 186         glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, 0, video_frame.size);
 187         check_error();
 188         //glMemoryBarrier(GL_CLIENT_MAPPED_BUFFER_BARRIER_BIT);
 189         //check_error();
 190         GLsync fence = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, /*flags=*/0);
 191         check_error();
 192         assert(fence != nullptr);
 193         {
 194                 std::unique_lock<std::mutex> lock(bmusb_mutex);
 195                 card->new_data_ready = true;
 196                 card->new_frame = video_frame;
 197                 card->new_data_ready_fence = fence;
 198                 card->new_data_ready_changed.notify_all();
 199         }
 200
 201         // Video frame will be released later.
 202         card->usb->get_audio_frame_allocator()->release_frame(audio_frame);
 203 }
 204
 205 void Mixer::place_rectangle(Effect *resample_effect, Effect *padding_effect, float x0, float y0, float x1, float y1)
 206 {
 207         float srcx0 = 0.0f;
 208         float srcx1 = 1.0f;
 209         float srcy0 = 0.0f;
 210         float srcy1 = 1.0f;
 211
 212         // Cull.
 213         if (x0 > 1280.0 || x1 < 0.0 || y0 > 720.0 || y1 < 0.0) {
 214                 CHECK(resample_effect->set_int("width", 1));
 215                 CHECK(resample_effect->set_int("height", 1));
 216                 CHECK(resample_effect->set_float("zoom_x", 1280.0));
 217                 CHECK(resample_effect->set_float("zoom_y", 720.0));
 218                 CHECK(padding_effect->set_int("left", 2000));
 219                 CHECK(padding_effect->set_int("top", 2000));
 220                 return;
 221         }
 222
 223         // Clip. (TODO: Clip on upper/left sides, too.)
 224         if (x1 > 1280.0) {
 225                 srcx1 = (1280.0 - x0) / (x1 - x0);
 226                 x1 = 1280.0;
 227         }
 228         if (y1 > 720.0) {
 229                 srcy1 = (720.0 - y0) / (y1 - y0);
 230                 y1 = 720.0;
 231         }
 232
 233         float x_subpixel_offset = x0 - floor(x0);
 234         float y_subpixel_offset = y0 - floor(y0);
 235
 236         // Resampling must be to an integral number of pixels. Round up,
 237         // and then add an extra pixel so we have some leeway for the border.
 238         int width = int(ceil(x1 - x0)) + 1;
 239         int height = int(ceil(y1 - y0)) + 1;
 240         CHECK(resample_effect->set_int("width", width));
 241         CHECK(resample_effect->set_int("height", height));
 242
 243         // Correct the discrepancy with zoom. (This will leave a small
 244         // excess edge of pixels and subpixels, which we'll correct for soon.)
 245         float zoom_x = (x1 - x0) / (width * (srcx1 - srcx0));
 246         float zoom_y = (y1 - y0) / (height * (srcy1 - srcy0));
 247         CHECK(resample_effect->set_float("zoom_x", zoom_x));
 248         CHECK(resample_effect->set_float("zoom_y", zoom_y));
 249         CHECK(resample_effect->set_float("zoom_center_x", 0.0f));
 250         CHECK(resample_effect->set_float("zoom_center_y", 0.0f));
 251
 252         // Padding must also be to a whole-pixel offset.
 253         CHECK(padding_effect->set_int("left", floor(x0)));
 254         CHECK(padding_effect->set_int("top", floor(y0)));
 255
 256         // Correct _that_ discrepancy by subpixel offset in the resampling.
 257         CHECK(resample_effect->set_float("left", -x_subpixel_offset / zoom_x));
 258         CHECK(resample_effect->set_float("top", -y_subpixel_offset / zoom_y));
 259
 260         // Finally, adjust the border so it is exactly where we want it.
 261         CHECK(padding_effect->set_float("border_offset_left", x_subpixel_offset));
 262         CHECK(padding_effect->set_float("border_offset_right", x1 - (floor(x0) + width)));
 263         CHECK(padding_effect->set_float("border_offset_top", y_subpixel_offset));
 264         CHECK(padding_effect->set_float("border_offset_bottom", y1 - (floor(y0) + height)));
 265 }
 266
 267 void Mixer::thread_func()
 268 {
 269         cards[0].surface = surface3;
 270 #if NUM_CARDS == 2
 271         cards[1].surface = surface4;
 272 #endif
 273
 274         eglBindAPI(EGL_OPENGL_API);
 275         QOpenGLContext *context = create_context();
 276         if (!make_current(context, surface1)) {
 277                 printf("oops\n");
 278                 exit(1);
 279         }
 280
 281         struct timespec start, now;
 282         clock_gettime(CLOCK_MONOTONIC, &start);
 283
 284         while (!should_quit) {
 285                 ++frame;
 286
 287                 //int width0 = lrintf(848 * (1.0 + 0.2 * sin(frame * 0.02)));
 288                 int width0 = 848;
 289                 int height0 = lrintf(width0 * 9.0 / 16.0);
 290
 291                 //float top0 = 96 + 48 * sin(frame * 0.005);
 292                 //float left0 = 96 + 48 * cos(frame * 0.006);
 293                 float top0 = 48;
 294                 float left0 = 16;
 295                 float bottom0 = top0 + height0;
 296                 float right0 = left0 + width0;
 297
 298                 int width1 = 384;
 299                 int height1 = 216;
 300
 301                 float bottom1 = 720 - 48;
 302                 float right1 = 1280 - 16;
 303                 float top1 = bottom1 - height1;
 304                 float left1 = right1 - width1;
 305
 306                 if (current_source == SOURCE_INPUT1) {
 307                         top0 = 0.0;
 308                         bottom0 = HEIGHT;
 309                         left0 = 0.0;
 310                         right0 = WIDTH;
 311
 312                         top1 = HEIGHT + 10;
 313                         bottom1 = HEIGHT + 20;
 314                         left1 = WIDTH + 10;
 315                         right1 = WIDTH + 20;
 316                 } else if (current_source == SOURCE_INPUT2) {
 317                         top1 = 0.0;
 318                         bottom1 = HEIGHT;
 319                         left1 = 0.0;
 320                         right1 = WIDTH;
 321
 322                         top0 = HEIGHT + 10;
 323                         bottom0 = HEIGHT + 20;
 324                         left0 = WIDTH + 10;
 325                         right0 = WIDTH + 20;
 326                 } else {
 327                         float t = 0.5 + 0.5 * cos(frame * 0.006);
 328                         float scale0 = 1.0 + t * (1280.0 / 848.0 - 1.0);
 329                         float tx0 = 0.0 + t * (-16.0 * scale0);
 330                         float ty0 = 0.0 + t * (-48.0 * scale0);
 331
 332                         top0 = top0 * scale0 + ty0;
 333                         bottom0 = bottom0 * scale0 + ty0;
 334                         left0 = left0 * scale0 + tx0;
 335                         right0 = right0 * scale0 + tx0;
 336
 337                         top1 = top1 * scale0 + ty0;
 338                         bottom1 = bottom1 * scale0 + ty0;
 339                         left1 = left1 * scale0 + tx0;
 340                         right1 = right1 * scale0 + tx0;
 341                 }
 342
 343                 place_rectangle(resample_effect, padding_effect, left0, top0, right0, bottom0);
 344                 place_rectangle(resample2_effect, padding2_effect, left1, top1, right1, bottom1);
 345
 346                 CaptureCard card_copy[NUM_CARDS];
 347
 348                 {
 349                         std::unique_lock<std::mutex> lock(bmusb_mutex);
 350
 351                         // The first card is the master timer, so wait for it to have a new frame.
 352                         // TODO: Make configurable, and with a timeout.
 353                         cards[0].new_data_ready_changed.wait(lock, [this]{ return cards[0].new_data_ready; });
 354
 355                         for (int card_index = 0; card_index < NUM_CARDS; ++card_index) {
 356                                 CaptureCard *card = &cards[card_index];
 357                                 card_copy[card_index].usb = card->usb;
 358                                 card_copy[card_index].new_data_ready = card->new_data_ready;
 359                                 card_copy[card_index].new_frame = card->new_frame;
 360                                 card_copy[card_index].new_data_ready_fence = card->new_data_ready_fence;
 361                                 card->new_data_ready = false;
 362                                 card->new_data_ready_changed.notify_all();
 363                         }
 364                 }
 365
 366                 vector<FrameAllocator::Frame> input_frames_to_release;
 367
 368                 for (int card_index = 0; card_index < NUM_CARDS; ++card_index) {
 369                         CaptureCard *card = &card_copy[card_index];
 370                         if (!card->new_data_ready)
 371                                 continue;
 372
 373                         // Now we're done with the previous frame, so we can definitely
 374                         // release it when this is done rendering. (Actually, we could do
 375                         // it one frame earlier, but before we have a new one, there's no
 376                         // knowing when the current one is released.)
 377                         if (bmusb_current_rendering_frame[card_index].owner != nullptr) {
 378                                 input_frames_to_release.push_back(bmusb_current_rendering_frame[card_index]);
 379                         }
 380                         bmusb_current_rendering_frame[card_index] = card->new_frame;
 381                         check_error();
 382
 383                         // The new texture might still be uploaded,
 384                         // tell the GPU to wait until it's there.
 385                         if (card->new_data_ready_fence)
 386                                 glWaitSync(card->new_data_ready_fence, /*flags=*/0, GL_TIMEOUT_IGNORED);
 387                         check_error();
 388                         glDeleteSync(card->new_data_ready_fence);
 389                         check_error();
 390                         GLint input_tex_pbo = (GLint)(intptr_t)card->new_frame.userdata;
 391                         input[card_index]->set_pixel_data(0, (unsigned char *)BUFFER_OFFSET((1280 * 750 * 2 + 44) / 2 + 1280 * 25 + 22), input_tex_pbo);
 392                         input[card_index]->set_pixel_data(1, (unsigned char *)BUFFER_OFFSET(1280 * 25 + 22), input_tex_pbo);
 393
 394                         if (NUM_CARDS == 1) {
 395                                 // Set to the other one, too.
 396                                 input[1]->set_pixel_data(0, (unsigned char *)BUFFER_OFFSET((1280 * 750 * 2 + 44) / 2 + 1280 * 25 + 22), input_tex_pbo);
 397                                 input[1]->set_pixel_data(1, (unsigned char *)BUFFER_OFFSET(1280 * 25 + 22), input_tex_pbo);
 398                         }
 399                 }
 400
 401                 GLuint y_tex, cbcr_tex;
 402                 bool got_frame = h264_encoder->begin_frame(&y_tex, &cbcr_tex);
 403                 assert(got_frame);
 404
 405                 // Render chain.
 406                 GLuint cbcr_full_tex = resource_pool->create_2d_texture(GL_RG8, WIDTH, HEIGHT);
 407                 GLuint rgba_tex = resource_pool->create_2d_texture(GL_RGBA8, WIDTH, HEIGHT);
 408                 GLuint fbo = resource_pool->create_fbo(y_tex, cbcr_full_tex, rgba_tex);
 409                 chain->render_to_fbo(fbo, WIDTH, HEIGHT);
 410                 resource_pool->release_fbo(fbo);
 411
 412                 subsample_chroma(cbcr_full_tex, cbcr_tex);
 413                 resource_pool->release_2d_texture(cbcr_full_tex);
 414
 415                 RefCountedGLsync fence(GL_SYNC_GPU_COMMANDS_COMPLETE, /*flags=*/0);
 416                 check_error();
 417                 h264_encoder->end_frame(fence, input_frames_to_release);
 418
 419                 // Store this frame for display. Remove the ready frame if any
 420                 // (it was seemingly never used).
 421                 {
 422                         std::unique_lock<std::mutex> lock(display_frame_mutex);
 423                         if (has_ready_display_frame) {
 424                                 resource_pool->release_2d_texture(ready_display_frame.texnum);
 425                                 ready_display_frame.ready_fence.reset();
 426                         }
 427                         ready_display_frame.texnum = rgba_tex;
 428                         ready_display_frame.ready_fence = fence;
 429                         has_ready_display_frame = true;
 430                 }
 431
 432                 if (has_new_frame_ready_callback) {
 433                         new_frame_ready_callback();
 434                 }
 435
 436                 clock_gettime(CLOCK_MONOTONIC, &now);
 437                 double elapsed = now.tv_sec - start.tv_sec +
 438                         1e-9 * (now.tv_nsec - start.tv_nsec);
 439                 if (frame % 100 == 0) {
 440                         printf("%d frames in %.3f seconds = %.1f fps (%.1f ms/frame)\n",
 441                                 frame, elapsed, frame / elapsed,
 442                                 1e3 * elapsed / frame);
 443                 //      chain->print_phase_timing();
 444                 }
 445
 446                 // Reset every 100 frames, so that local variations in frame times
 447                 // (especially for the first few frames, when the shaders are
 448                 // compiled etc.) don't make it hard to measure for the entire
 449                 // remaining duration of the program.
 450                 if (frame == 10000) {
 451                         frame = 0;
 452                         start = now;
 453                 }
 454                 check_error();
 455         }
 456 }
 457
 458 void Mixer::subsample_chroma(GLuint src_tex, GLuint dst_tex)
 459 {
 460         GLuint vao;
 461         glGenVertexArrays(1, &vao);
 462         check_error();
 463
 464         float vertices[] = {
 465                 0.0f, 2.0f,
 466                 0.0f, 0.0f,
 467                 2.0f, 0.0f
 468         };
 469
 470         glBindVertexArray(vao);
 471         check_error();
 472
 473         // Extract Cb/Cr.
 474         GLuint fbo = resource_pool->create_fbo(dst_tex);
 475         glBindFramebuffer(GL_FRAMEBUFFER, fbo);
 476         glViewport(0, 0, WIDTH/2, HEIGHT/2);
 477         check_error();
 478
 479         glUseProgram(cbcr_program_num);
 480         check_error();
 481
 482         glActiveTexture(GL_TEXTURE0);
 483         check_error();
 484         glBindTexture(GL_TEXTURE_2D, src_tex);
 485         check_error();
 486         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 487         check_error();
 488         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 489         check_error();
 490         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 491         check_error();
 492
 493         float chroma_offset_0[] = { -0.5f / WIDTH, 0.0f };
 494         set_uniform_vec2(cbcr_program_num, "foo", "chroma_offset_0", chroma_offset_0);
 495
 496         GLuint position_vbo = fill_vertex_attribute(cbcr_program_num, "position", 2, GL_FLOAT, sizeof(vertices), vertices);
 497         GLuint texcoord_vbo = fill_vertex_attribute(cbcr_program_num, "texcoord", 2, GL_FLOAT, sizeof(vertices), vertices);  // Same as vertices.
 498
 499         glDrawArrays(GL_TRIANGLES, 0, 3);
 500         check_error();
 501
 502         cleanup_vertex_attribute(cbcr_program_num, "position", position_vbo);
 503         cleanup_vertex_attribute(cbcr_program_num, "texcoord", texcoord_vbo);
 504
 505         glUseProgram(0);
 506         check_error();
 507
 508         resource_pool->release_fbo(fbo);
 509         glDeleteVertexArrays(1, &vao);
 510 }
 511
 512 bool Mixer::get_display_frame(DisplayFrame *frame)
 513 {
 514         std::unique_lock<std::mutex> lock(display_frame_mutex);
 515         if (!has_current_display_frame && !has_ready_display_frame) {
 516                 return false;
 517         }
 518
 519         if (has_current_display_frame && has_ready_display_frame) {
 520                 // We have a new ready frame. Toss the current one.
 521                 resource_pool->release_2d_texture(current_display_frame.texnum);
 522                 current_display_frame.ready_fence.reset();
 523                 has_current_display_frame = false;
 524         }
 525         if (has_ready_display_frame) {
 526                 assert(!has_current_display_frame);
 527                 current_display_frame = ready_display_frame;
 528                 ready_display_frame.ready_fence.reset();  // Drop the refcount.
 529                 has_current_display_frame = true;
 530                 has_ready_display_frame = false;
 531         }
 532
 533         *frame = current_display_frame;
 534         return true;
 535 }
 536
 537 void Mixer::set_frame_ready_fallback(new_frame_ready_callback_t callback)
 538 {
 539         new_frame_ready_callback = callback;
 540         has_new_frame_ready_callback = true;
 541 }
 542
 543 void Mixer::start()
 544 {
 545         mixer_thread = std::thread(&Mixer::thread_func, this);
 546 }
 547
 548 void Mixer::quit()
 549 {
 550         should_quit = true;
 551         mixer_thread.join();
 552 }
 553
 554 void Mixer::cut(Source source)
 555 {
 556         current_source = source;
 557 }