10 #include <epoxy/egl.h>
12 #include <movit/effect_chain.h>
13 #include <movit/effect_util.h>
14 #include <movit/flat_input.h>
15 #include <movit/image_format.h>
16 #include <movit/resource_pool.h>
25 #include <condition_variable>
34 #include "bmusb/bmusb.h"
36 #include "h264encode.h"
37 #include "pbo_frame_allocator.h"
38 #include "ref_counted_gl_sync.h"
43 using namespace movit;
45 using namespace std::placeholders;
47 Mixer *global_mixer = nullptr;
51 void convert_fixed24_to_fp32(float *dst, size_t out_channels, const uint8_t *src, size_t in_channels, size_t num_samples)
53 for (size_t i = 0; i < num_samples; ++i) {
54 for (size_t j = 0; j < out_channels; ++j) {
58 uint32_t s = s1 | (s1 << 8) | (s2 << 16) | (s3 << 24);
59 dst[i * out_channels + j] = int(s) * (1.0f / 4294967296.0f);
61 src += 3 * (in_channels - out_channels);
67 Mixer::Mixer(const QSurfaceFormat &format, unsigned num_cards)
68 : httpd("test.ts", WIDTH, HEIGHT),
70 mixer_surface(create_surface(format)),
71 h264_encoder_surface(create_surface(format)),
76 CHECK(init_movit(MOVIT_SHADER_DIR, MOVIT_DEBUG_OFF));
79 // Since we allow non-bouncing 4:2:2 YCbCrInputs, effective subpixel precision
80 // will be halved when sampling them, and we need to compensate here.
81 movit_texel_subpixel_precision /= 2.0;
83 resource_pool.reset(new ResourcePool);
84 theme.reset(new Theme("theme.lua", resource_pool.get(), num_cards));
85 for (unsigned i = 0; i < NUM_OUTPUTS; ++i) {
86 output_channel[i].parent = this;
89 ImageFormat inout_format;
90 inout_format.color_space = COLORSPACE_sRGB;
91 inout_format.gamma_curve = GAMMA_sRGB;
93 // Display chain; shows the live output produced by the main chain (its RGBA version).
94 display_chain.reset(new EffectChain(WIDTH, HEIGHT, resource_pool.get()));
96 display_input = new FlatInput(inout_format, FORMAT_RGB, GL_UNSIGNED_BYTE, WIDTH, HEIGHT); // FIXME: GL_UNSIGNED_BYTE is really wrong.
97 display_chain->add_input(display_input);
98 display_chain->add_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED);
99 display_chain->set_dither_bits(0); // Don't bother.
100 display_chain->finalize();
102 h264_encoder.reset(new H264Encoder(h264_encoder_surface, WIDTH, HEIGHT, &httpd));
104 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
105 printf("Configuring card %d...\n", card_index);
106 CaptureCard *card = &cards[card_index];
107 card->usb = new BMUSBCapture(card_index);
108 card->usb->set_frame_callback(bind(&Mixer::bm_frame, this, card_index, _1, _2, _3, _4, _5, _6, _7));
109 card->frame_allocator.reset(new PBOFrameAllocator(WIDTH * (HEIGHT+EXTRAHEIGHT) * 2 + 44, WIDTH, HEIGHT));
110 card->usb->set_video_frame_allocator(card->frame_allocator.get());
111 card->surface = create_surface(format);
112 card->usb->set_dequeue_thread_callbacks(
114 eglBindAPI(EGL_OPENGL_API);
115 card->context = create_context(card->surface);
116 if (!make_current(card->context, card->surface)) {
117 printf("failed to create bmusb context\n");
122 resource_pool->clean_context();
124 card->resampler.reset(new Resampler(48000.0, 48000.0, 2));
125 card->usb->configure_card();
128 BMUSBCapture::start_bm_thread();
130 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
131 cards[card_index].usb->start_bm_capture();
134 //chain->enable_phase_timing(true);
136 // Set up stuff for NV12 conversion.
139 string cbcr_vert_shader = read_file("vs-cbcr.130.vert");
140 string cbcr_frag_shader =
143 "uniform sampler2D cbcr_tex; \n"
145 " gl_FragColor = texture2D(cbcr_tex, tc0); \n"
147 cbcr_program_num = resource_pool->compile_glsl_program(cbcr_vert_shader, cbcr_frag_shader);
155 resource_pool->release_glsl_program(cbcr_program_num);
156 BMUSBCapture::stop_bm_thread();
158 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
160 unique_lock<mutex> lock(bmusb_mutex);
161 cards[card_index].should_quit = true; // Unblock thread.
162 cards[card_index].new_data_ready_changed.notify_all();
164 cards[card_index].usb->stop_dequeue_thread();
170 int unwrap_timecode(uint16_t current_wrapped, int last)
172 uint16_t last_wrapped = last & 0xffff;
173 if (current_wrapped > last_wrapped) {
174 return (last & ~0xffff) | current_wrapped;
176 return 0x10000 + ((last & ~0xffff) | current_wrapped);
180 float find_peak(const vector<float> &samples)
182 float m = fabs(samples[0]);
183 for (size_t i = 1; i < samples.size(); ++i) {
184 m = std::max(m, fabs(samples[i]));
189 void deinterleave_samples(const vector<float> &in, vector<float> *out_l, vector<float> *out_r)
191 size_t num_samples = in.size() / 2;
192 out_l->resize(num_samples);
193 out_r->resize(num_samples);
195 const float *inptr = in.data();
196 float *lptr = &(*out_l)[0];
197 float *rptr = &(*out_r)[0];
198 for (size_t i = 0; i < num_samples; ++i) {
206 void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
207 FrameAllocator::Frame video_frame, size_t video_offset, uint16_t video_format,
208 FrameAllocator::Frame audio_frame, size_t audio_offset, uint16_t audio_format)
210 CaptureCard *card = &cards[card_index];
212 if (audio_frame.len - audio_offset > 30000) {
213 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",
214 card_index, int(audio_frame.len), int(audio_offset),
215 timecode, int(video_frame.len), int(video_offset), video_format);
216 if (video_frame.owner) {
217 video_frame.owner->release_frame(video_frame);
219 if (audio_frame.owner) {
220 audio_frame.owner->release_frame(audio_frame);
225 int unwrapped_timecode = timecode;
226 int dropped_frames = 0;
227 if (card->last_timecode != -1) {
228 unwrapped_timecode = unwrap_timecode(unwrapped_timecode, card->last_timecode);
229 dropped_frames = unwrapped_timecode - card->last_timecode - 1;
231 card->last_timecode = unwrapped_timecode;
233 // Convert the audio to stereo fp32 and add it.
234 size_t num_samples = (audio_frame.len >= audio_offset) ? (audio_frame.len - audio_offset) / 8 / 3 : 0;
236 audio.resize(num_samples * 2);
237 convert_fixed24_to_fp32(&audio[0], 2, audio_frame.data + audio_offset, 8, num_samples);
241 unique_lock<mutex> lock(card->audio_mutex);
243 int unwrapped_timecode = timecode;
244 if (dropped_frames > 60 * 2) {
245 fprintf(stderr, "Card %d lost more than two seconds (or time code jumping around), resetting resampler\n",
247 card->resampler.reset(new Resampler(48000.0, 48000.0, 2));
248 } else if (dropped_frames > 0) {
249 // Insert silence as needed.
250 fprintf(stderr, "Card %d dropped %d frame(s) (before timecode 0x%04x), inserting silence.\n",
251 card_index, dropped_frames, timecode);
252 vector<float> silence;
253 silence.resize((48000 / 60) * 2);
254 for (int i = 0; i < dropped_frames; ++i) {
255 card->resampler->add_input_samples((unwrapped_timecode - dropped_frames + i) / 60.0, silence.data(), (48000 / 60));
258 card->resampler->add_input_samples(unwrapped_timecode / 60.0, audio.data(), num_samples);
261 // Done with the audio, so release it.
262 if (audio_frame.owner) {
263 audio_frame.owner->release_frame(audio_frame);
267 // Wait until the previous frame was consumed.
268 unique_lock<mutex> lock(bmusb_mutex);
269 card->new_data_ready_changed.wait(lock, [card]{ return !card->new_data_ready || card->should_quit; });
270 if (card->should_quit) return;
273 if (video_frame.len - video_offset != WIDTH * (HEIGHT+EXTRAHEIGHT) * 2) {
274 if (video_frame.len != 0) {
275 printf("Card %d: Dropping video frame with wrong length (%ld)\n",
276 card_index, video_frame.len - video_offset);
278 if (video_frame.owner) {
279 video_frame.owner->release_frame(video_frame);
282 // Still send on the information that we _had_ a frame, even though it's corrupted,
283 // so that pts can go up accordingly.
285 unique_lock<mutex> lock(bmusb_mutex);
286 card->new_data_ready = true;
287 card->new_frame = RefCountedFrame(FrameAllocator::Frame());
288 card->new_data_ready_fence = nullptr;
289 card->dropped_frames = dropped_frames;
290 card->new_data_ready_changed.notify_all();
295 const PBOFrameAllocator::Userdata *userdata = (const PBOFrameAllocator::Userdata *)video_frame.userdata;
296 GLuint pbo = userdata->pbo;
298 glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbo);
300 glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, 0, video_frame.size);
302 //glMemoryBarrier(GL_CLIENT_MAPPED_BUFFER_BARRIER_BIT);
305 // Upload the textures.
306 glBindTexture(GL_TEXTURE_2D, userdata->tex_y);
308 glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, WIDTH, HEIGHT, GL_RED, GL_UNSIGNED_BYTE, BUFFER_OFFSET((WIDTH * (HEIGHT+EXTRAHEIGHT) * 2 + 44) / 2 + WIDTH * 25 + 22));
310 glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr);
312 glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, WIDTH/2, HEIGHT, GL_RG, GL_UNSIGNED_BYTE, BUFFER_OFFSET(WIDTH * 25 + 22));
314 glBindTexture(GL_TEXTURE_2D, 0);
316 GLsync fence = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, /*flags=*/0);
318 assert(fence != nullptr);
321 unique_lock<mutex> lock(bmusb_mutex);
322 card->new_data_ready = true;
323 card->new_frame = RefCountedFrame(video_frame);
324 card->new_data_ready_fence = fence;
325 card->dropped_frames = dropped_frames;
326 card->new_data_ready_changed.notify_all();
330 void Mixer::thread_func()
332 eglBindAPI(EGL_OPENGL_API);
333 QOpenGLContext *context = create_context(mixer_surface);
334 if (!make_current(context, mixer_surface)) {
339 struct timespec start, now;
340 clock_gettime(CLOCK_MONOTONIC, &start);
343 int dropped_frames = 0;
345 while (!should_quit) {
346 CaptureCard card_copy[MAX_CARDS];
349 unique_lock<mutex> lock(bmusb_mutex);
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; });
355 for (unsigned 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_copy[card_index].dropped_frames = card->dropped_frames;
362 card->new_data_ready = false;
363 card->new_data_ready_changed.notify_all();
367 // Resample the audio as needed, including from previously dropped frames.
368 for (unsigned frame_num = 0; frame_num < card_copy[0].dropped_frames + 1; ++frame_num) {
369 process_audio_one_frame();
370 if (frame_num != card_copy[0].dropped_frames) {
371 // For dropped frames, increase the pts.
373 pts_int += TIMEBASE / 60;
377 if (audio_level_callback != nullptr) {
378 double loudness_s = r128.loudness_S();
379 double loudness_i = r128.integrated();
380 double loudness_range_low = r128.range_min();
381 double loudness_range_high = r128.range_max();
383 audio_level_callback(loudness_s, 20.0 * log10(peak),
384 loudness_i, loudness_range_low, loudness_range_high);
387 for (unsigned card_index = 1; card_index < num_cards; ++card_index) {
388 if (card_copy[card_index].new_data_ready && card_copy[card_index].new_frame->len == 0) {
389 ++card_copy[card_index].dropped_frames;
391 if (card_copy[card_index].dropped_frames > 0) {
392 printf("Card %u dropped %d frames before this\n",
393 card_index, int(card_copy[card_index].dropped_frames));
397 // If the first card is reporting a corrupted or otherwise dropped frame,
398 // just increase the pts (skipping over this frame) and don't try to compute anything new.
399 if (card_copy[0].new_frame->len == 0) {
401 pts_int += TIMEBASE / 60;
405 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
406 CaptureCard *card = &card_copy[card_index];
407 if (!card->new_data_ready || card->new_frame->len == 0)
410 assert(card->new_frame != nullptr);
411 bmusb_current_rendering_frame[card_index] = card->new_frame;
414 // The new texture might still be uploaded,
415 // tell the GPU to wait until it's there.
416 if (card->new_data_ready_fence) {
417 glWaitSync(card->new_data_ready_fence, /*flags=*/0, GL_TIMEOUT_IGNORED);
419 glDeleteSync(card->new_data_ready_fence);
422 const PBOFrameAllocator::Userdata *userdata = (const PBOFrameAllocator::Userdata *)card->new_frame->userdata;
423 theme->set_input_textures(card_index, userdata->tex_y, userdata->tex_cbcr);
426 // Get the main chain from the theme, and set its state immediately.
427 pair<EffectChain *, function<void()>> theme_main_chain = theme->get_chain(0, pts(), WIDTH, HEIGHT);
428 EffectChain *chain = theme_main_chain.first;
429 theme_main_chain.second();
431 GLuint y_tex, cbcr_tex;
432 bool got_frame = h264_encoder->begin_frame(&y_tex, &cbcr_tex);
435 // Render main chain.
436 GLuint cbcr_full_tex = resource_pool->create_2d_texture(GL_RG8, WIDTH, HEIGHT);
437 GLuint rgba_tex = resource_pool->create_2d_texture(GL_RGB565, WIDTH, HEIGHT); // Saves texture bandwidth, although dithering gets messed up.
438 GLuint fbo = resource_pool->create_fbo(y_tex, cbcr_full_tex, rgba_tex);
440 chain->render_to_fbo(fbo, WIDTH, HEIGHT);
441 resource_pool->release_fbo(fbo);
443 subsample_chroma(cbcr_full_tex, cbcr_tex);
444 resource_pool->release_2d_texture(cbcr_full_tex);
446 // Set the right state for rgba_tex.
447 glBindFramebuffer(GL_FRAMEBUFFER, 0);
448 glBindTexture(GL_TEXTURE_2D, rgba_tex);
449 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
450 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
451 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
453 RefCountedGLsync fence(GL_SYNC_GPU_COMMANDS_COMPLETE, /*flags=*/0);
456 // Make sure the H.264 gets a reference to all the
457 // input frames needed, so that they are not released back
458 // until the rendering is done.
459 vector<RefCountedFrame> input_frames;
460 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
461 input_frames.push_back(bmusb_current_rendering_frame[card_index]);
463 const int64_t av_delay = TIMEBASE / 10; // Corresponds to the fixed delay in resampler.h. TODO: Make less hard-coded.
464 h264_encoder->end_frame(fence, pts_int + av_delay, input_frames);
466 pts_int += TIMEBASE / 60;
468 // The live frame just shows the RGBA texture we just rendered.
469 // It owns rgba_tex now.
470 DisplayFrame live_frame;
471 live_frame.chain = display_chain.get();
472 live_frame.setup_chain = [this, rgba_tex]{
473 display_input->set_texture_num(rgba_tex);
475 live_frame.ready_fence = fence;
476 live_frame.input_frames = {};
477 live_frame.temp_textures = { rgba_tex };
478 output_channel[OUTPUT_LIVE].output_frame(live_frame);
480 // Set up preview and any additional channels.
481 for (int i = 1; i < theme->get_num_channels() + 2; ++i) {
482 DisplayFrame display_frame;
483 pair<EffectChain *, function<void()>> chain = theme->get_chain(i, pts(), WIDTH, HEIGHT); // FIXME: dimensions
484 display_frame.chain = chain.first;
485 display_frame.setup_chain = chain.second;
486 display_frame.ready_fence = fence;
488 // FIXME: possible to do better?
489 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
490 display_frame.input_frames.push_back(bmusb_current_rendering_frame[card_index]);
492 display_frame.temp_textures = {};
493 output_channel[i].output_frame(display_frame);
496 clock_gettime(CLOCK_MONOTONIC, &now);
497 double elapsed = now.tv_sec - start.tv_sec +
498 1e-9 * (now.tv_nsec - start.tv_nsec);
499 if (frame % 100 == 0) {
500 printf("%d frames (%d dropped) in %.3f seconds = %.1f fps (%.1f ms/frame)\n",
501 frame, dropped_frames, elapsed, frame / elapsed,
502 1e3 * elapsed / frame);
503 // chain->print_phase_timing();
507 // Reset every 100 frames, so that local variations in frame times
508 // (especially for the first few frames, when the shaders are
509 // compiled etc.) don't make it hard to measure for the entire
510 // remaining duration of the program.
511 if (frame == 10000) {
519 resource_pool->clean_context();
522 void Mixer::process_audio_one_frame()
524 vector<float> samples_card;
525 vector<float> samples_out;
526 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
527 samples_card.resize((48000 / 60) * 2);
529 unique_lock<mutex> lock(cards[card_index].audio_mutex);
530 if (!cards[card_index].resampler->get_output_samples(pts(), &samples_card[0], 48000 / 60)) {
531 printf("Card %d reported previous underrun.\n", card_index);
534 // TODO: Allow using audio from the other card(s) as well.
535 if (card_index == 0) {
536 samples_out = move(samples_card);
540 // Apply a level compressor to get the general level right.
541 // Basically, if it's over about -40 dBFS, we squeeze it down to that level
542 // (or more precisely, near it, since we don't use infinite ratio),
543 // then apply a makeup gain to get it to -12 dBFS. -12 dBFS is, of course,
544 // entirely arbitrary, but from practical tests with speech, it seems to
545 // put ut around -23 LUFS, so it's a reasonable starting point for later use.
547 // TODO: Hook this up to a UI, so we can see the effects, and/or turn it off
548 // to control the gain manually instead. For now, there's only the #if-ed out
551 // TODO: Add the actual compressors/limiters (for taking care of transients)
552 // later in the chain.
553 float threshold = 0.01f; // -40 dBFS.
555 float attack_time = 0.1f;
556 float release_time = 10.0f;
557 float makeup_gain = pow(10.0f, 28.0f / 20.0f); // +28 dB takes us to -12 dBFS.
558 compressor.process(samples_out.data(), samples_out.size() / 2, threshold, ratio, attack_time, release_time, makeup_gain);
561 printf("level=%f (%+5.2f dBFS) attenuation=%f (%+5.2f dB) end_result=%+5.2f dB\n",
562 compressor.get_level(), 20.0 * log10(compressor.get_level()),
563 compressor.get_attenuation(), 20.0 * log10(compressor.get_attenuation()),
564 20.0 * log10(compressor.get_level() * compressor.get_attenuation() * makeup_gain));
567 // Find peak and R128 levels.
568 peak = std::max(peak, find_peak(samples_out));
569 vector<float> left, right;
570 deinterleave_samples(samples_out, &left, &right);
571 float *ptrs[] = { left.data(), right.data() };
572 r128.process(left.size(), ptrs);
574 // Actually add the samples to the output.
575 h264_encoder->add_audio(pts_int, move(samples_out));
578 void Mixer::subsample_chroma(GLuint src_tex, GLuint dst_tex)
581 glGenVertexArrays(1, &vao);
590 glBindVertexArray(vao);
594 GLuint fbo = resource_pool->create_fbo(dst_tex);
595 glBindFramebuffer(GL_FRAMEBUFFER, fbo);
596 glViewport(0, 0, WIDTH/2, HEIGHT/2);
599 glUseProgram(cbcr_program_num);
602 glActiveTexture(GL_TEXTURE0);
604 glBindTexture(GL_TEXTURE_2D, src_tex);
606 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
608 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
610 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
613 float chroma_offset_0[] = { -0.5f / WIDTH, 0.0f };
614 set_uniform_vec2(cbcr_program_num, "foo", "chroma_offset_0", chroma_offset_0);
616 GLuint position_vbo = fill_vertex_attribute(cbcr_program_num, "position", 2, GL_FLOAT, sizeof(vertices), vertices);
617 GLuint texcoord_vbo = fill_vertex_attribute(cbcr_program_num, "texcoord", 2, GL_FLOAT, sizeof(vertices), vertices); // Same as vertices.
619 glDrawArrays(GL_TRIANGLES, 0, 3);
622 cleanup_vertex_attribute(cbcr_program_num, "position", position_vbo);
623 cleanup_vertex_attribute(cbcr_program_num, "texcoord", texcoord_vbo);
628 resource_pool->release_fbo(fbo);
629 glDeleteVertexArrays(1, &vao);
632 void Mixer::release_display_frame(DisplayFrame *frame)
634 for (GLuint texnum : frame->temp_textures) {
635 resource_pool->release_2d_texture(texnum);
637 frame->temp_textures.clear();
638 frame->ready_fence.reset();
639 frame->input_frames.clear();
644 mixer_thread = thread(&Mixer::thread_func, this);
653 void Mixer::transition_clicked(int transition_num)
655 theme->transition_clicked(transition_num, pts());
658 void Mixer::channel_clicked(int preview_num)
660 theme->channel_clicked(preview_num);
663 Mixer::OutputChannel::~OutputChannel()
665 if (has_current_frame) {
666 parent->release_display_frame(¤t_frame);
668 if (has_ready_frame) {
669 parent->release_display_frame(&ready_frame);
673 void Mixer::OutputChannel::output_frame(DisplayFrame frame)
675 // Store this frame for display. Remove the ready frame if any
676 // (it was seemingly never used).
678 unique_lock<mutex> lock(frame_mutex);
679 if (has_ready_frame) {
680 parent->release_display_frame(&ready_frame);
683 has_ready_frame = true;
686 if (has_new_frame_ready_callback) {
687 new_frame_ready_callback();
691 bool Mixer::OutputChannel::get_display_frame(DisplayFrame *frame)
693 unique_lock<mutex> lock(frame_mutex);
694 if (!has_current_frame && !has_ready_frame) {
698 if (has_current_frame && has_ready_frame) {
699 // We have a new ready frame. Toss the current one.
700 parent->release_display_frame(¤t_frame);
701 has_current_frame = false;
703 if (has_ready_frame) {
704 assert(!has_current_frame);
705 current_frame = ready_frame;
706 ready_frame.ready_fence.reset(); // Drop the refcount.
707 ready_frame.input_frames.clear(); // Drop the refcounts.
708 has_current_frame = true;
709 has_ready_frame = false;
712 *frame = current_frame;
716 void Mixer::OutputChannel::set_frame_ready_callback(Mixer::new_frame_ready_callback_t callback)
718 new_frame_ready_callback = callback;
719 has_new_frame_ready_callback = true;