]> git.sesse.net Git - nageru/blob - mixer.cpp
Re-run IWYU, again with lots of manual cleanup.
[nageru] / mixer.cpp
1 #define WIDTH 1280
2 #define HEIGHT 720
3 #define EXTRAHEIGHT 30
4
5 #undef Success
6
7 #include "mixer.h"
8
9 #include <assert.h>
10 #include <epoxy/egl.h>
11 #include <init.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>
17 #include <stdint.h>
18 #include <stdio.h>
19 #include <stdlib.h>
20 #include <sys/time.h>
21 #include <time.h>
22 #include <util.h>
23 #include <algorithm>
24 #include <cmath>
25 #include <condition_variable>
26 #include <cstddef>
27 #include <memory>
28 #include <mutex>
29 #include <string>
30 #include <thread>
31 #include <utility>
32 #include <vector>
33
34 #include "bmusb/bmusb.h"
35 #include "context.h"
36 #include "h264encode.h"
37 #include "pbo_frame_allocator.h"
38 #include "ref_counted_gl_sync.h"
39 #include "timebase.h"
40
41 class QOpenGLContext;
42
43 using namespace movit;
44 using namespace std;
45 using namespace std::placeholders;
46
47 Mixer *global_mixer = nullptr;
48
49 namespace {
50
51 void convert_fixed24_to_fp32(float *dst, size_t out_channels, const uint8_t *src, size_t in_channels, size_t num_samples)
52 {
53         for (size_t i = 0; i < num_samples; ++i) {
54                 for (size_t j = 0; j < out_channels; ++j) {
55                         uint32_t s1 = *src++;
56                         uint32_t s2 = *src++;
57                         uint32_t s3 = *src++;
58                         uint32_t s = s1 | (s1 << 8) | (s2 << 16) | (s3 << 24);
59                         dst[i * out_channels + j] = int(s) * (1.0f / 4294967296.0f);
60                 }
61                 src += 3 * (in_channels - out_channels);
62         }
63 }
64
65 }  // namespace
66
67 Mixer::Mixer(const QSurfaceFormat &format, unsigned num_cards)
68         : httpd("test.ts", WIDTH, HEIGHT),
69           num_cards(num_cards),
70           mixer_surface(create_surface(format)),
71           h264_encoder_surface(create_surface(format))
72 {
73         httpd.start(9095);
74
75         CHECK(init_movit(MOVIT_SHADER_DIR, MOVIT_DEBUG_OFF));
76         check_error();
77
78         // Since we allow non-bouncing 4:2:2 YCbCrInputs, effective subpixel precision
79         // will be halved when sampling them, and we need to compensate here.
80         movit_texel_subpixel_precision /= 2.0;
81
82         resource_pool.reset(new ResourcePool);
83         theme.reset(new Theme("theme.lua", resource_pool.get(), num_cards));
84         output_channel[OUTPUT_LIVE].parent = this;
85         output_channel[OUTPUT_PREVIEW].parent = this;
86         output_channel[OUTPUT_INPUT0].parent = this;
87         output_channel[OUTPUT_INPUT1].parent = this;
88
89         ImageFormat inout_format;
90         inout_format.color_space = COLORSPACE_sRGB;
91         inout_format.gamma_curve = GAMMA_sRGB;
92
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()));
95         check_error();
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();
101
102         h264_encoder.reset(new H264Encoder(h264_encoder_surface, WIDTH, HEIGHT, &httpd));
103
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(
113                         [card]{
114                                 eglBindAPI(EGL_OPENGL_API);
115                                 card->context = create_context();
116                                 if (!make_current(card->context, card->surface)) {
117                                         printf("failed to create bmusb context\n");
118                                         exit(1);
119                                 }
120                         },
121                         [this]{
122                                 resource_pool->clean_context();
123                         });
124                 card->resampler.reset(new Resampler(48000.0, 48000.0, 2));
125                 card->usb->configure_card();
126         }
127
128         BMUSBCapture::start_bm_thread();
129
130         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
131                 cards[card_index].usb->start_bm_capture();
132         }
133
134         //chain->enable_phase_timing(true);
135
136         // Set up stuff for NV12 conversion.
137
138         // Cb/Cr shader.
139         string cbcr_vert_shader = read_file("vs-cbcr.130.vert");
140         string cbcr_frag_shader =
141                 "#version 130 \n"
142                 "in vec2 tc0; \n"
143                 "uniform sampler2D cbcr_tex; \n"
144                 "void main() { \n"
145                 "    gl_FragColor = texture2D(cbcr_tex, tc0); \n"
146                 "} \n";
147         cbcr_program_num = resource_pool->compile_glsl_program(cbcr_vert_shader, cbcr_frag_shader);
148
149         r128.init(2, 48000);
150         r128.integr_start();
151 }
152
153 Mixer::~Mixer()
154 {
155         resource_pool->release_glsl_program(cbcr_program_num);
156         BMUSBCapture::stop_bm_thread();
157
158         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
159                 {
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();
163                 }
164                 cards[card_index].usb->stop_dequeue_thread();
165         }
166 }
167
168 namespace {
169
170 int unwrap_timecode(uint16_t current_wrapped, int last)
171 {
172         uint16_t last_wrapped = last & 0xffff;
173         if (current_wrapped > last_wrapped) {
174                 return (last & ~0xffff) | current_wrapped;
175         } else {
176                 return 0x10000 + ((last & ~0xffff) | current_wrapped);
177         }
178 }
179
180 float find_peak(const vector<float> &samples)
181 {
182         float m = fabs(samples[0]);
183         for (size_t i = 1; i < samples.size(); ++i) {
184                 m = std::max(m, fabs(samples[i]));
185         }
186         return m;
187 }
188
189 void deinterleave_samples(const vector<float> &in, vector<float> *out_l, vector<float> *out_r)
190 {
191         size_t num_samples = in.size() / 2;
192         out_l->resize(num_samples);
193         out_r->resize(num_samples);
194
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) {
199                 *lptr++ = *inptr++;
200                 *rptr++ = *inptr++;
201         }
202 }
203
204 }  // namespace
205
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)
209 {
210         CaptureCard *card = &cards[card_index];
211
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);
218                 }
219                 if (audio_frame.owner) {
220                         audio_frame.owner->release_frame(audio_frame);
221                 }
222                 return;
223         }
224
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;
230         }
231         card->last_timecode = unwrapped_timecode;
232
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;
235         vector<float> audio;
236         audio.resize(num_samples * 2);
237         convert_fixed24_to_fp32(&audio[0], 2, audio_frame.data + audio_offset, 8, num_samples);
238
239         // Add the audio.
240         {
241                 unique_lock<mutex> lock(card->audio_mutex);
242
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",
246                                 card_index);
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));
256                         }
257                 }
258                 card->resampler->add_input_samples(unwrapped_timecode / 60.0, audio.data(), num_samples);
259         }
260
261         // Done with the audio, so release it.
262         if (audio_frame.owner) {
263                 audio_frame.owner->release_frame(audio_frame);
264         }
265
266         {
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;
271         }
272
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);
277                 }
278                 if (video_frame.owner) {
279                         video_frame.owner->release_frame(video_frame);
280                 }
281
282                 // Still send on the information that we _had_ a frame, even though it's corrupted,
283                 // so that pts can go up accordingly.
284                 {
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();
291                 }
292                 return;
293         }
294
295         const PBOFrameAllocator::Userdata *userdata = (const PBOFrameAllocator::Userdata *)video_frame.userdata;
296         GLuint pbo = userdata->pbo;
297         check_error();
298         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbo);
299         check_error();
300         glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, 0, video_frame.size);
301         check_error();
302         //glMemoryBarrier(GL_CLIENT_MAPPED_BUFFER_BARRIER_BIT);
303         //check_error();
304
305         // Upload the textures.
306         glBindTexture(GL_TEXTURE_2D, userdata->tex_y);
307         check_error();
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));
309         check_error();
310         glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr);
311         check_error();
312         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, WIDTH/2, HEIGHT, GL_RG, GL_UNSIGNED_BYTE, BUFFER_OFFSET(WIDTH * 25 + 22));
313         check_error();
314         glBindTexture(GL_TEXTURE_2D, 0);
315         check_error();
316         GLsync fence = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, /*flags=*/0);              
317         check_error();
318         assert(fence != nullptr);
319
320         {
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();
327         }
328 }
329
330 void Mixer::thread_func()
331 {
332         eglBindAPI(EGL_OPENGL_API);
333         QOpenGLContext *context = create_context();
334         if (!make_current(context, mixer_surface)) {
335                 printf("oops\n");
336                 exit(1);
337         }
338
339         struct timespec start, now;
340         clock_gettime(CLOCK_MONOTONIC, &start);
341
342         int frame = 0;
343         int dropped_frames = 0;
344
345         while (!should_quit) {
346                 CaptureCard card_copy[MAX_CARDS];
347
348                 {
349                         unique_lock<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 (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].new_frame_audio = move(card->new_frame_audio);
362                                 card_copy[card_index].dropped_frames = card->dropped_frames;
363                                 card->new_data_ready = false;
364                                 card->new_data_ready_changed.notify_all();
365                         }
366                 }
367
368                 // Resample the audio as needed, including from previously dropped frames.
369                 vector<float> samples_out;
370                 // TODO: Allow using audio from the other card(s) as well.
371                 for (unsigned frame_num = 0; frame_num < card_copy[0].dropped_frames + 1; ++frame_num) {
372                         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
373                                 samples_out.resize((48000 / 60) * 2);
374                                 {
375                                         unique_lock<mutex> lock(cards[card_index].audio_mutex);
376                                         if (!cards[card_index].resampler->get_output_samples(pts(), &samples_out[0], 48000 / 60)) {
377                                                 printf("Card %d reported previous underrun.\n", card_index);
378                                         }
379                                 }
380                                 if (card_index == 0) {
381                                         vector<float> left, right;
382                                         peak = std::max(peak, find_peak(samples_out));
383                                         deinterleave_samples(samples_out, &left, &right);
384                                         float *ptrs[] = { left.data(), right.data() };
385                                         r128.process(left.size(), ptrs);
386                                         h264_encoder->add_audio(pts_int, move(samples_out));
387                                 }
388                         }
389                         if (frame_num != card_copy[0].dropped_frames) {
390                                 // For dropped frames, increase the pts.
391                                 ++dropped_frames;
392                                 pts_int += TIMEBASE / 60;
393                         }
394                 }
395
396                 if (audio_level_callback != nullptr) {
397                         double loudness_s = r128.loudness_S();
398                         double loudness_i = r128.integrated();
399                         double loudness_range_low = r128.range_min();
400                         double loudness_range_high = r128.range_max();
401
402                         audio_level_callback(loudness_s, 20.0 * log10(peak),
403                                              loudness_i, loudness_range_low, loudness_range_high);
404                 }
405
406                 for (unsigned card_index = 1; card_index < num_cards; ++card_index) {
407                         if (card_copy[card_index].new_data_ready && card_copy[card_index].new_frame->len == 0) {
408                                 ++card_copy[card_index].dropped_frames;
409                         }
410                         if (card_copy[card_index].dropped_frames > 0) {
411                                 printf("Card %u dropped %d frames before this\n",
412                                         card_index, int(card_copy[card_index].dropped_frames));
413                         }
414                 }
415
416                 // If the first card is reporting a corrupted or otherwise dropped frame,
417                 // just increase the pts (skipping over this frame) and don't try to compute anything new.
418                 if (card_copy[0].new_frame->len == 0) {
419                         ++dropped_frames;
420                         pts_int += TIMEBASE / 60;
421                         continue;
422                 }
423
424                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
425                         CaptureCard *card = &card_copy[card_index];
426                         if (!card->new_data_ready || card->new_frame->len == 0)
427                                 continue;
428
429                         assert(card->new_frame != nullptr);
430                         bmusb_current_rendering_frame[card_index] = card->new_frame;
431                         check_error();
432
433                         // The new texture might still be uploaded,
434                         // tell the GPU to wait until it's there.
435                         if (card->new_data_ready_fence) {
436                                 glWaitSync(card->new_data_ready_fence, /*flags=*/0, GL_TIMEOUT_IGNORED);
437                                 check_error();
438                                 glDeleteSync(card->new_data_ready_fence);
439                                 check_error();
440                         }
441                         const PBOFrameAllocator::Userdata *userdata = (const PBOFrameAllocator::Userdata *)card->new_frame->userdata;
442                         theme->set_input_textures(card_index, userdata->tex_y, userdata->tex_cbcr);
443                 }
444
445                 // Get the main chain from the theme, and set its state immediately.
446                 pair<EffectChain *, function<void()>> theme_main_chain = theme->get_chain(0, pts(), WIDTH, HEIGHT);
447                 EffectChain *chain = theme_main_chain.first;
448                 theme_main_chain.second();
449
450                 GLuint y_tex, cbcr_tex;
451                 bool got_frame = h264_encoder->begin_frame(&y_tex, &cbcr_tex);
452                 assert(got_frame);
453
454                 // Render main chain.
455                 GLuint cbcr_full_tex = resource_pool->create_2d_texture(GL_RG8, WIDTH, HEIGHT);
456                 GLuint rgba_tex = resource_pool->create_2d_texture(GL_RGB565, WIDTH, HEIGHT);  // Saves texture bandwidth, although dithering gets messed up.
457                 GLuint fbo = resource_pool->create_fbo(y_tex, cbcr_full_tex, rgba_tex);
458                 check_error();
459                 chain->render_to_fbo(fbo, WIDTH, HEIGHT);
460                 resource_pool->release_fbo(fbo);
461
462                 subsample_chroma(cbcr_full_tex, cbcr_tex);
463                 resource_pool->release_2d_texture(cbcr_full_tex);
464
465                 // Set the right state for rgba_tex.
466                 glBindFramebuffer(GL_FRAMEBUFFER, 0);
467                 glBindTexture(GL_TEXTURE_2D, rgba_tex);
468                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
469                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
470                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
471
472                 RefCountedGLsync fence(GL_SYNC_GPU_COMMANDS_COMPLETE, /*flags=*/0);
473                 check_error();
474
475                 // Make sure the H.264 gets a reference to all the
476                 // input frames needed, so that they are not released back
477                 // until the rendering is done.
478                 vector<RefCountedFrame> input_frames;
479                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
480                         input_frames.push_back(bmusb_current_rendering_frame[card_index]);
481                 }
482                 const int64_t av_delay = TIMEBASE / 10;  // Corresponds to the fixed delay in resampler.h. TODO: Make less hard-coded.
483                 h264_encoder->end_frame(fence, pts_int + av_delay, input_frames);
484                 ++frame;
485                 pts_int += TIMEBASE / 60;
486
487                 // The live frame just shows the RGBA texture we just rendered.
488                 // It owns rgba_tex now.
489                 DisplayFrame live_frame;
490                 live_frame.chain = display_chain.get();
491                 live_frame.setup_chain = [this, rgba_tex]{
492                         display_input->set_texture_num(rgba_tex);
493                 };
494                 live_frame.ready_fence = fence;
495                 live_frame.input_frames = {};
496                 live_frame.temp_textures = { rgba_tex };
497                 output_channel[OUTPUT_LIVE].output_frame(live_frame);
498
499                 // Set up preview and any additional channels.
500                 for (int i = 1; i < theme->get_num_channels() + 2; ++i) {
501                         DisplayFrame display_frame;
502                         pair<EffectChain *, function<void()>> chain = theme->get_chain(i, pts(), WIDTH, HEIGHT);  // FIXME: dimensions
503                         display_frame.chain = chain.first;
504                         display_frame.setup_chain = chain.second;
505                         display_frame.ready_fence = fence;
506
507                         // FIXME: possible to do better?
508                         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
509                                 display_frame.input_frames.push_back(bmusb_current_rendering_frame[card_index]);
510                         }
511                         display_frame.temp_textures = {};
512                         output_channel[i].output_frame(display_frame);
513                 }
514
515                 clock_gettime(CLOCK_MONOTONIC, &now);
516                 double elapsed = now.tv_sec - start.tv_sec +
517                         1e-9 * (now.tv_nsec - start.tv_nsec);
518                 if (frame % 100 == 0) {
519                         printf("%d frames (%d dropped) in %.3f seconds = %.1f fps (%.1f ms/frame)\n",
520                                 frame, dropped_frames, elapsed, frame / elapsed,
521                                 1e3 * elapsed / frame);
522                 //      chain->print_phase_timing();
523                 }
524
525 #if 0
526                 // Reset every 100 frames, so that local variations in frame times
527                 // (especially for the first few frames, when the shaders are
528                 // compiled etc.) don't make it hard to measure for the entire
529                 // remaining duration of the program.
530                 if (frame == 10000) {
531                         frame = 0;
532                         start = now;
533                 }
534 #endif
535                 check_error();
536         }
537
538         resource_pool->clean_context();
539 }
540
541 void Mixer::subsample_chroma(GLuint src_tex, GLuint dst_tex)
542 {
543         GLuint vao;
544         glGenVertexArrays(1, &vao);
545         check_error();
546
547         float vertices[] = {
548                 0.0f, 2.0f,
549                 0.0f, 0.0f,
550                 2.0f, 0.0f
551         };
552
553         glBindVertexArray(vao);
554         check_error();
555
556         // Extract Cb/Cr.
557         GLuint fbo = resource_pool->create_fbo(dst_tex);
558         glBindFramebuffer(GL_FRAMEBUFFER, fbo);
559         glViewport(0, 0, WIDTH/2, HEIGHT/2);
560         check_error();
561
562         glUseProgram(cbcr_program_num);
563         check_error();
564
565         glActiveTexture(GL_TEXTURE0);
566         check_error();
567         glBindTexture(GL_TEXTURE_2D, src_tex);
568         check_error();
569         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
570         check_error();
571         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
572         check_error();
573         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
574         check_error();
575
576         float chroma_offset_0[] = { -0.5f / WIDTH, 0.0f };
577         set_uniform_vec2(cbcr_program_num, "foo", "chroma_offset_0", chroma_offset_0);
578
579         GLuint position_vbo = fill_vertex_attribute(cbcr_program_num, "position", 2, GL_FLOAT, sizeof(vertices), vertices);
580         GLuint texcoord_vbo = fill_vertex_attribute(cbcr_program_num, "texcoord", 2, GL_FLOAT, sizeof(vertices), vertices);  // Same as vertices.
581
582         glDrawArrays(GL_TRIANGLES, 0, 3);
583         check_error();
584
585         cleanup_vertex_attribute(cbcr_program_num, "position", position_vbo);
586         cleanup_vertex_attribute(cbcr_program_num, "texcoord", texcoord_vbo);
587
588         glUseProgram(0);
589         check_error();
590
591         resource_pool->release_fbo(fbo);
592         glDeleteVertexArrays(1, &vao);
593 }
594
595 void Mixer::release_display_frame(DisplayFrame *frame)
596 {
597         for (GLuint texnum : frame->temp_textures) {
598                 resource_pool->release_2d_texture(texnum);
599         }
600         frame->temp_textures.clear();
601         frame->ready_fence.reset();
602         frame->input_frames.clear();
603 }
604
605 void Mixer::start()
606 {
607         mixer_thread = thread(&Mixer::thread_func, this);
608 }
609
610 void Mixer::quit()
611 {
612         should_quit = true;
613         mixer_thread.join();
614 }
615
616 void Mixer::transition_clicked(int transition_num)
617 {
618         theme->transition_clicked(transition_num, pts());
619 }
620
621 void Mixer::channel_clicked(int preview_num)
622 {
623         theme->channel_clicked(preview_num);
624 }
625
626 Mixer::OutputChannel::~OutputChannel()
627 {
628         if (has_current_frame) {
629                 parent->release_display_frame(&current_frame);
630         }
631         if (has_ready_frame) {
632                 parent->release_display_frame(&ready_frame);
633         }
634 }
635
636 void Mixer::OutputChannel::output_frame(DisplayFrame frame)
637 {
638         // Store this frame for display. Remove the ready frame if any
639         // (it was seemingly never used).
640         {
641                 unique_lock<mutex> lock(frame_mutex);
642                 if (has_ready_frame) {
643                         parent->release_display_frame(&ready_frame);
644                 }
645                 ready_frame = frame;
646                 has_ready_frame = true;
647         }
648
649         if (has_new_frame_ready_callback) {
650                 new_frame_ready_callback();
651         }
652 }
653
654 bool Mixer::OutputChannel::get_display_frame(DisplayFrame *frame)
655 {
656         unique_lock<mutex> lock(frame_mutex);
657         if (!has_current_frame && !has_ready_frame) {
658                 return false;
659         }
660
661         if (has_current_frame && has_ready_frame) {
662                 // We have a new ready frame. Toss the current one.
663                 parent->release_display_frame(&current_frame);
664                 has_current_frame = false;
665         }
666         if (has_ready_frame) {
667                 assert(!has_current_frame);
668                 current_frame = ready_frame;
669                 ready_frame.ready_fence.reset();  // Drop the refcount.
670                 ready_frame.input_frames.clear();  // Drop the refcounts.
671                 has_current_frame = true;
672                 has_ready_frame = false;
673         }
674
675         *frame = current_frame;
676         return true;
677 }
678
679 void Mixer::OutputChannel::set_frame_ready_callback(Mixer::new_frame_ready_callback_t callback)
680 {
681         new_frame_ready_callback = callback;
682         has_new_frame_ready_callback = true;
683 }