]> git.sesse.net Git - nageru/blob - mixer.cpp
Add a 150 Hz lo-cut filter in front of the compressor.
[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 "defs.h"
37 #include "h264encode.h"
38 #include "pbo_frame_allocator.h"
39 #include "ref_counted_gl_sync.h"
40 #include "timebase.h"
41
42 class QOpenGLContext;
43
44 using namespace movit;
45 using namespace std;
46 using namespace std::placeholders;
47
48 Mixer *global_mixer = nullptr;
49
50 namespace {
51
52 void convert_fixed24_to_fp32(float *dst, size_t out_channels, const uint8_t *src, size_t in_channels, size_t num_samples)
53 {
54         for (size_t i = 0; i < num_samples; ++i) {
55                 for (size_t j = 0; j < out_channels; ++j) {
56                         uint32_t s1 = *src++;
57                         uint32_t s2 = *src++;
58                         uint32_t s3 = *src++;
59                         uint32_t s = s1 | (s1 << 8) | (s2 << 16) | (s3 << 24);
60                         dst[i * out_channels + j] = int(s) * (1.0f / 4294967296.0f);
61                 }
62                 src += 3 * (in_channels - out_channels);
63         }
64 }
65
66 }  // namespace
67
68 Mixer::Mixer(const QSurfaceFormat &format, unsigned num_cards)
69         : httpd("test.ts", WIDTH, HEIGHT),
70           num_cards(num_cards),
71           mixer_surface(create_surface(format)),
72           h264_encoder_surface(create_surface(format)),
73           level_compressor(OUTPUT_FREQUENCY)
74 {
75         httpd.start(9095);
76
77         CHECK(init_movit(MOVIT_SHADER_DIR, MOVIT_DEBUG_OFF));
78         check_error();
79
80         // Since we allow non-bouncing 4:2:2 YCbCrInputs, effective subpixel precision
81         // will be halved when sampling them, and we need to compensate here.
82         movit_texel_subpixel_precision /= 2.0;
83
84         resource_pool.reset(new ResourcePool);
85         theme.reset(new Theme("theme.lua", resource_pool.get(), num_cards));
86         for (unsigned i = 0; i < NUM_OUTPUTS; ++i) {
87                 output_channel[i].parent = this;
88         }
89
90         ImageFormat inout_format;
91         inout_format.color_space = COLORSPACE_sRGB;
92         inout_format.gamma_curve = GAMMA_sRGB;
93
94         // Display chain; shows the live output produced by the main chain (its RGBA version).
95         display_chain.reset(new EffectChain(WIDTH, HEIGHT, resource_pool.get()));
96         check_error();
97         display_input = new FlatInput(inout_format, FORMAT_RGB, GL_UNSIGNED_BYTE, WIDTH, HEIGHT);  // FIXME: GL_UNSIGNED_BYTE is really wrong.
98         display_chain->add_input(display_input);
99         display_chain->add_output(inout_format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED);
100         display_chain->set_dither_bits(0);  // Don't bother.
101         display_chain->finalize();
102
103         h264_encoder.reset(new H264Encoder(h264_encoder_surface, WIDTH, HEIGHT, &httpd));
104
105         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
106                 printf("Configuring card %d...\n", card_index);
107                 CaptureCard *card = &cards[card_index];
108                 card->usb = new BMUSBCapture(card_index);
109                 card->usb->set_frame_callback(bind(&Mixer::bm_frame, this, card_index, _1, _2, _3, _4, _5, _6, _7));
110                 card->frame_allocator.reset(new PBOFrameAllocator(WIDTH * (HEIGHT+EXTRAHEIGHT) * 2 + 44, WIDTH, HEIGHT));
111                 card->usb->set_video_frame_allocator(card->frame_allocator.get());
112                 card->surface = create_surface(format);
113                 card->usb->set_dequeue_thread_callbacks(
114                         [card]{
115                                 eglBindAPI(EGL_OPENGL_API);
116                                 card->context = create_context(card->surface);
117                                 if (!make_current(card->context, card->surface)) {
118                                         printf("failed to create bmusb context\n");
119                                         exit(1);
120                                 }
121                         },
122                         [this]{
123                                 resource_pool->clean_context();
124                         });
125                 card->resampler.reset(new Resampler(OUTPUT_FREQUENCY, OUTPUT_FREQUENCY, 2));
126                 card->usb->configure_card();
127         }
128
129         BMUSBCapture::start_bm_thread();
130
131         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
132                 cards[card_index].usb->start_bm_capture();
133         }
134
135         //chain->enable_phase_timing(true);
136
137         // Set up stuff for NV12 conversion.
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         r128.init(2, OUTPUT_FREQUENCY);
151         r128.integr_start();
152
153         locut.init(FILTER_HPF, 2);
154 }
155
156 Mixer::~Mixer()
157 {
158         resource_pool->release_glsl_program(cbcr_program_num);
159         BMUSBCapture::stop_bm_thread();
160
161         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
162                 {
163                         unique_lock<mutex> lock(bmusb_mutex);
164                         cards[card_index].should_quit = true;  // Unblock thread.
165                         cards[card_index].new_data_ready_changed.notify_all();
166                 }
167                 cards[card_index].usb->stop_dequeue_thread();
168         }
169 }
170
171 namespace {
172
173 int unwrap_timecode(uint16_t current_wrapped, int last)
174 {
175         uint16_t last_wrapped = last & 0xffff;
176         if (current_wrapped > last_wrapped) {
177                 return (last & ~0xffff) | current_wrapped;
178         } else {
179                 return 0x10000 + ((last & ~0xffff) | current_wrapped);
180         }
181 }
182
183 float find_peak(const vector<float> &samples)
184 {
185         float m = fabs(samples[0]);
186         for (size_t i = 1; i < samples.size(); ++i) {
187                 m = std::max(m, fabs(samples[i]));
188         }
189         return m;
190 }
191
192 void deinterleave_samples(const vector<float> &in, vector<float> *out_l, vector<float> *out_r)
193 {
194         size_t num_samples = in.size() / 2;
195         out_l->resize(num_samples);
196         out_r->resize(num_samples);
197
198         const float *inptr = in.data();
199         float *lptr = &(*out_l)[0];
200         float *rptr = &(*out_r)[0];
201         for (size_t i = 0; i < num_samples; ++i) {
202                 *lptr++ = *inptr++;
203                 *rptr++ = *inptr++;
204         }
205 }
206
207 }  // namespace
208
209 void Mixer::bm_frame(unsigned card_index, uint16_t timecode,
210                      FrameAllocator::Frame video_frame, size_t video_offset, uint16_t video_format,
211                      FrameAllocator::Frame audio_frame, size_t audio_offset, uint16_t audio_format)
212 {
213         CaptureCard *card = &cards[card_index];
214
215         if (audio_frame.len - audio_offset > 30000) {
216                 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",
217                         card_index, int(audio_frame.len), int(audio_offset),
218                         timecode, int(video_frame.len), int(video_offset), video_format);
219                 if (video_frame.owner) {
220                         video_frame.owner->release_frame(video_frame);
221                 }
222                 if (audio_frame.owner) {
223                         audio_frame.owner->release_frame(audio_frame);
224                 }
225                 return;
226         }
227
228         int unwrapped_timecode = timecode;
229         int dropped_frames = 0;
230         if (card->last_timecode != -1) {
231                 unwrapped_timecode = unwrap_timecode(unwrapped_timecode, card->last_timecode);
232                 dropped_frames = unwrapped_timecode - card->last_timecode - 1;
233         }
234         card->last_timecode = unwrapped_timecode;
235
236         // Convert the audio to stereo fp32 and add it.
237         size_t num_samples = (audio_frame.len >= audio_offset) ? (audio_frame.len - audio_offset) / 8 / 3 : 0;
238         vector<float> audio;
239         audio.resize(num_samples * 2);
240         convert_fixed24_to_fp32(&audio[0], 2, audio_frame.data + audio_offset, 8, num_samples);
241
242         // Add the audio.
243         {
244                 unique_lock<mutex> lock(card->audio_mutex);
245
246                 int unwrapped_timecode = timecode;
247                 if (dropped_frames > FPS * 2) {
248                         fprintf(stderr, "Card %d lost more than two seconds (or time code jumping around), resetting resampler\n",
249                                 card_index);
250                         card->resampler.reset(new Resampler(OUTPUT_FREQUENCY, OUTPUT_FREQUENCY, 2));
251                 } else if (dropped_frames > 0) {
252                         // Insert silence as needed.
253                         fprintf(stderr, "Card %d dropped %d frame(s) (before timecode 0x%04x), inserting silence.\n",
254                                 card_index, dropped_frames, timecode);
255                         vector<float> silence;
256                         silence.resize((OUTPUT_FREQUENCY / FPS) * 2);
257                         for (int i = 0; i < dropped_frames; ++i) {
258                                 card->resampler->add_input_samples((unwrapped_timecode - dropped_frames + i) / double(FPS), silence.data(), (OUTPUT_FREQUENCY / FPS));
259                         }
260                 }
261                 card->resampler->add_input_samples(unwrapped_timecode / double(FPS), audio.data(), num_samples);
262         }
263
264         // Done with the audio, so release it.
265         if (audio_frame.owner) {
266                 audio_frame.owner->release_frame(audio_frame);
267         }
268
269         {
270                 // Wait until the previous frame was consumed.
271                 unique_lock<mutex> lock(bmusb_mutex);
272                 card->new_data_ready_changed.wait(lock, [card]{ return !card->new_data_ready || card->should_quit; });
273                 if (card->should_quit) return;
274         }
275
276         if (video_frame.len - video_offset != WIDTH * (HEIGHT+EXTRAHEIGHT) * 2) {
277                 if (video_frame.len != 0) {
278                         printf("Card %d: Dropping video frame with wrong length (%ld)\n",
279                                 card_index, video_frame.len - video_offset);
280                 }
281                 if (video_frame.owner) {
282                         video_frame.owner->release_frame(video_frame);
283                 }
284
285                 // Still send on the information that we _had_ a frame, even though it's corrupted,
286                 // so that pts can go up accordingly.
287                 {
288                         unique_lock<mutex> lock(bmusb_mutex);
289                         card->new_data_ready = true;
290                         card->new_frame = RefCountedFrame(FrameAllocator::Frame());
291                         card->new_data_ready_fence = nullptr;
292                         card->dropped_frames = dropped_frames;
293                         card->new_data_ready_changed.notify_all();
294                 }
295                 return;
296         }
297
298         const PBOFrameAllocator::Userdata *userdata = (const PBOFrameAllocator::Userdata *)video_frame.userdata;
299         GLuint pbo = userdata->pbo;
300         check_error();
301         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, pbo);
302         check_error();
303         glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, 0, video_frame.size);
304         check_error();
305         //glMemoryBarrier(GL_CLIENT_MAPPED_BUFFER_BARRIER_BIT);
306         //check_error();
307
308         // Upload the textures.
309         glBindTexture(GL_TEXTURE_2D, userdata->tex_y);
310         check_error();
311         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));
312         check_error();
313         glBindTexture(GL_TEXTURE_2D, userdata->tex_cbcr);
314         check_error();
315         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, WIDTH/2, HEIGHT, GL_RG, GL_UNSIGNED_BYTE, BUFFER_OFFSET(WIDTH * 25 + 22));
316         check_error();
317         glBindTexture(GL_TEXTURE_2D, 0);
318         check_error();
319         GLsync fence = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, /*flags=*/0);              
320         check_error();
321         assert(fence != nullptr);
322
323         {
324                 unique_lock<mutex> lock(bmusb_mutex);
325                 card->new_data_ready = true;
326                 card->new_frame = RefCountedFrame(video_frame);
327                 card->new_data_ready_fence = fence;
328                 card->dropped_frames = dropped_frames;
329                 card->new_data_ready_changed.notify_all();
330         }
331 }
332
333 void Mixer::thread_func()
334 {
335         eglBindAPI(EGL_OPENGL_API);
336         QOpenGLContext *context = create_context(mixer_surface);
337         if (!make_current(context, mixer_surface)) {
338                 printf("oops\n");
339                 exit(1);
340         }
341
342         struct timespec start, now;
343         clock_gettime(CLOCK_MONOTONIC, &start);
344
345         int frame = 0;
346         int dropped_frames = 0;
347
348         while (!should_quit) {
349                 CaptureCard card_copy[MAX_CARDS];
350
351                 {
352                         unique_lock<mutex> lock(bmusb_mutex);
353
354                         // The first card is the master timer, so wait for it to have a new frame.
355                         // TODO: Make configurable, and with a timeout.
356                         cards[0].new_data_ready_changed.wait(lock, [this]{ return cards[0].new_data_ready; });
357
358                         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
359                                 CaptureCard *card = &cards[card_index];
360                                 card_copy[card_index].usb = card->usb;
361                                 card_copy[card_index].new_data_ready = card->new_data_ready;
362                                 card_copy[card_index].new_frame = card->new_frame;
363                                 card_copy[card_index].new_data_ready_fence = card->new_data_ready_fence;
364                                 card_copy[card_index].dropped_frames = card->dropped_frames;
365                                 card->new_data_ready = false;
366                                 card->new_data_ready_changed.notify_all();
367                         }
368                 }
369
370                 // Resample the audio as needed, including from previously dropped frames.
371                 for (unsigned frame_num = 0; frame_num < card_copy[0].dropped_frames + 1; ++frame_num) {
372                         process_audio_one_frame();
373                         if (frame_num != card_copy[0].dropped_frames) {
374                                 // For dropped frames, increase the pts.
375                                 ++dropped_frames;
376                                 pts_int += TIMEBASE / FPS;
377                         }
378                 }
379
380                 if (audio_level_callback != nullptr) {
381                         double loudness_s = r128.loudness_S();
382                         double loudness_i = r128.integrated();
383                         double loudness_range_low = r128.range_min();
384                         double loudness_range_high = r128.range_max();
385
386                         audio_level_callback(loudness_s, 20.0 * log10(peak),
387                                              loudness_i, loudness_range_low, loudness_range_high);
388                 }
389
390                 for (unsigned card_index = 1; card_index < num_cards; ++card_index) {
391                         if (card_copy[card_index].new_data_ready && card_copy[card_index].new_frame->len == 0) {
392                                 ++card_copy[card_index].dropped_frames;
393                         }
394                         if (card_copy[card_index].dropped_frames > 0) {
395                                 printf("Card %u dropped %d frames before this\n",
396                                         card_index, int(card_copy[card_index].dropped_frames));
397                         }
398                 }
399
400                 // If the first card is reporting a corrupted or otherwise dropped frame,
401                 // just increase the pts (skipping over this frame) and don't try to compute anything new.
402                 if (card_copy[0].new_frame->len == 0) {
403                         ++dropped_frames;
404                         pts_int += TIMEBASE / FPS;
405                         continue;
406                 }
407
408                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
409                         CaptureCard *card = &card_copy[card_index];
410                         if (!card->new_data_ready || card->new_frame->len == 0)
411                                 continue;
412
413                         assert(card->new_frame != nullptr);
414                         bmusb_current_rendering_frame[card_index] = card->new_frame;
415                         check_error();
416
417                         // The new texture might still be uploaded,
418                         // tell the GPU to wait until it's there.
419                         if (card->new_data_ready_fence) {
420                                 glWaitSync(card->new_data_ready_fence, /*flags=*/0, GL_TIMEOUT_IGNORED);
421                                 check_error();
422                                 glDeleteSync(card->new_data_ready_fence);
423                                 check_error();
424                         }
425                         const PBOFrameAllocator::Userdata *userdata = (const PBOFrameAllocator::Userdata *)card->new_frame->userdata;
426                         theme->set_input_textures(card_index, userdata->tex_y, userdata->tex_cbcr);
427                 }
428
429                 // Get the main chain from the theme, and set its state immediately.
430                 pair<EffectChain *, function<void()>> theme_main_chain = theme->get_chain(0, pts(), WIDTH, HEIGHT);
431                 EffectChain *chain = theme_main_chain.first;
432                 theme_main_chain.second();
433
434                 GLuint y_tex, cbcr_tex;
435                 bool got_frame = h264_encoder->begin_frame(&y_tex, &cbcr_tex);
436                 assert(got_frame);
437
438                 // Render main chain.
439                 GLuint cbcr_full_tex = resource_pool->create_2d_texture(GL_RG8, WIDTH, HEIGHT);
440                 GLuint rgba_tex = resource_pool->create_2d_texture(GL_RGB565, WIDTH, HEIGHT);  // Saves texture bandwidth, although dithering gets messed up.
441                 GLuint fbo = resource_pool->create_fbo(y_tex, cbcr_full_tex, rgba_tex);
442                 check_error();
443                 chain->render_to_fbo(fbo, WIDTH, HEIGHT);
444                 resource_pool->release_fbo(fbo);
445
446                 subsample_chroma(cbcr_full_tex, cbcr_tex);
447                 resource_pool->release_2d_texture(cbcr_full_tex);
448
449                 // Set the right state for rgba_tex.
450                 glBindFramebuffer(GL_FRAMEBUFFER, 0);
451                 glBindTexture(GL_TEXTURE_2D, rgba_tex);
452                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
453                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
454                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
455
456                 RefCountedGLsync fence(GL_SYNC_GPU_COMMANDS_COMPLETE, /*flags=*/0);
457                 check_error();
458
459                 // Make sure the H.264 gets a reference to all the
460                 // input frames needed, so that they are not released back
461                 // until the rendering is done.
462                 vector<RefCountedFrame> input_frames;
463                 for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
464                         input_frames.push_back(bmusb_current_rendering_frame[card_index]);
465                 }
466                 const int64_t av_delay = TIMEBASE / 10;  // Corresponds to the fixed delay in resampler.h. TODO: Make less hard-coded.
467                 h264_encoder->end_frame(fence, pts_int + av_delay, input_frames);
468                 ++frame;
469                 pts_int += TIMEBASE / FPS;
470
471                 // The live frame just shows the RGBA texture we just rendered.
472                 // It owns rgba_tex now.
473                 DisplayFrame live_frame;
474                 live_frame.chain = display_chain.get();
475                 live_frame.setup_chain = [this, rgba_tex]{
476                         display_input->set_texture_num(rgba_tex);
477                 };
478                 live_frame.ready_fence = fence;
479                 live_frame.input_frames = {};
480                 live_frame.temp_textures = { rgba_tex };
481                 output_channel[OUTPUT_LIVE].output_frame(live_frame);
482
483                 // Set up preview and any additional channels.
484                 for (int i = 1; i < theme->get_num_channels() + 2; ++i) {
485                         DisplayFrame display_frame;
486                         pair<EffectChain *, function<void()>> chain = theme->get_chain(i, pts(), WIDTH, HEIGHT);  // FIXME: dimensions
487                         display_frame.chain = chain.first;
488                         display_frame.setup_chain = chain.second;
489                         display_frame.ready_fence = fence;
490
491                         // FIXME: possible to do better?
492                         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
493                                 display_frame.input_frames.push_back(bmusb_current_rendering_frame[card_index]);
494                         }
495                         display_frame.temp_textures = {};
496                         output_channel[i].output_frame(display_frame);
497                 }
498
499                 clock_gettime(CLOCK_MONOTONIC, &now);
500                 double elapsed = now.tv_sec - start.tv_sec +
501                         1e-9 * (now.tv_nsec - start.tv_nsec);
502                 if (frame % 100 == 0) {
503                         printf("%d frames (%d dropped) in %.3f seconds = %.1f fps (%.1f ms/frame)\n",
504                                 frame, dropped_frames, elapsed, frame / elapsed,
505                                 1e3 * elapsed / frame);
506                 //      chain->print_phase_timing();
507                 }
508
509 #if 0
510                 // Reset every 100 frames, so that local variations in frame times
511                 // (especially for the first few frames, when the shaders are
512                 // compiled etc.) don't make it hard to measure for the entire
513                 // remaining duration of the program.
514                 if (frame == 10000) {
515                         frame = 0;
516                         start = now;
517                 }
518 #endif
519                 check_error();
520         }
521
522         resource_pool->clean_context();
523 }
524
525 void Mixer::process_audio_one_frame()
526 {
527         vector<float> samples_card;
528         vector<float> samples_out;
529         for (unsigned card_index = 0; card_index < num_cards; ++card_index) {
530                 samples_card.resize((OUTPUT_FREQUENCY / FPS) * 2);
531                 {
532                         unique_lock<mutex> lock(cards[card_index].audio_mutex);
533                         if (!cards[card_index].resampler->get_output_samples(pts(), &samples_card[0], OUTPUT_FREQUENCY / FPS)) {
534                                 printf("Card %d reported previous underrun.\n", card_index);
535                         }
536                 }
537                 // TODO: Allow using audio from the other card(s) as well.
538                 if (card_index == 0) {
539                         samples_out = move(samples_card);
540                 }
541         }
542
543         // Cut away everything under 150 Hz; we don't need it for voice,
544         // and it will reduce headroom and confuse the compressor.
545         // (In particular, any hums at 50 or 60 Hz should be dampened.)
546         locut.render(samples_out.data(), samples_out.size() / 2, 150.0 * 2.0 * M_PI / OUTPUT_FREQUENCY, 0.5f);
547
548         // Apply a level compressor to get the general level right.
549         // Basically, if it's over about -40 dBFS, we squeeze it down to that level
550         // (or more precisely, near it, since we don't use infinite ratio),
551         // then apply a makeup gain to get it to -12 dBFS. -12 dBFS is, of course,
552         // entirely arbitrary, but from practical tests with speech, it seems to
553         // put ut around -23 LUFS, so it's a reasonable starting point for later use.
554         //
555         // TODO: Hook this up to a UI, so we can see the effects, and/or turn it off
556         // to control the gain manually instead. For now, there's only the #if-ed out
557         // code below.
558         //
559         // TODO: Add the actual compressors/limiters (for taking care of transients)
560         // later in the chain.
561         float threshold = 0.01f;   // -40 dBFS.
562         float ratio = 20.0f;
563         float attack_time = 0.1f;
564         float release_time = 10.0f;
565         float makeup_gain = pow(10.0f, 28.0f / 20.0f);  // +28 dB takes us to -12 dBFS.
566         level_compressor.process(samples_out.data(), samples_out.size() / 2, threshold, ratio, attack_time, release_time, makeup_gain);
567
568 #if 0
569         printf("level=%f (%+5.2f dBFS) attenuation=%f (%+5.2f dB) end_result=%+5.2f dB\n",
570                 compressor.get_level(), 20.0 * log10(compressor.get_level()),
571                 compressor.get_attenuation(), 20.0 * log10(compressor.get_attenuation()),
572                 20.0 * log10(compressor.get_level() * compressor.get_attenuation() * makeup_gain));
573 #endif
574
575         // Find peak and R128 levels.
576         peak = std::max(peak, find_peak(samples_out));
577         vector<float> left, right;
578         deinterleave_samples(samples_out, &left, &right);
579         float *ptrs[] = { left.data(), right.data() };
580         r128.process(left.size(), ptrs);
581
582         // Actually add the samples to the output.
583         h264_encoder->add_audio(pts_int, move(samples_out));
584 }
585
586 void Mixer::subsample_chroma(GLuint src_tex, GLuint dst_tex)
587 {
588         GLuint vao;
589         glGenVertexArrays(1, &vao);
590         check_error();
591
592         float vertices[] = {
593                 0.0f, 2.0f,
594                 0.0f, 0.0f,
595                 2.0f, 0.0f
596         };
597
598         glBindVertexArray(vao);
599         check_error();
600
601         // Extract Cb/Cr.
602         GLuint fbo = resource_pool->create_fbo(dst_tex);
603         glBindFramebuffer(GL_FRAMEBUFFER, fbo);
604         glViewport(0, 0, WIDTH/2, HEIGHT/2);
605         check_error();
606
607         glUseProgram(cbcr_program_num);
608         check_error();
609
610         glActiveTexture(GL_TEXTURE0);
611         check_error();
612         glBindTexture(GL_TEXTURE_2D, src_tex);
613         check_error();
614         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
615         check_error();
616         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
617         check_error();
618         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
619         check_error();
620
621         float chroma_offset_0[] = { -0.5f / WIDTH, 0.0f };
622         set_uniform_vec2(cbcr_program_num, "foo", "chroma_offset_0", chroma_offset_0);
623
624         GLuint position_vbo = fill_vertex_attribute(cbcr_program_num, "position", 2, GL_FLOAT, sizeof(vertices), vertices);
625         GLuint texcoord_vbo = fill_vertex_attribute(cbcr_program_num, "texcoord", 2, GL_FLOAT, sizeof(vertices), vertices);  // Same as vertices.
626
627         glDrawArrays(GL_TRIANGLES, 0, 3);
628         check_error();
629
630         cleanup_vertex_attribute(cbcr_program_num, "position", position_vbo);
631         cleanup_vertex_attribute(cbcr_program_num, "texcoord", texcoord_vbo);
632
633         glUseProgram(0);
634         check_error();
635
636         resource_pool->release_fbo(fbo);
637         glDeleteVertexArrays(1, &vao);
638 }
639
640 void Mixer::release_display_frame(DisplayFrame *frame)
641 {
642         for (GLuint texnum : frame->temp_textures) {
643                 resource_pool->release_2d_texture(texnum);
644         }
645         frame->temp_textures.clear();
646         frame->ready_fence.reset();
647         frame->input_frames.clear();
648 }
649
650 void Mixer::start()
651 {
652         mixer_thread = thread(&Mixer::thread_func, this);
653 }
654
655 void Mixer::quit()
656 {
657         should_quit = true;
658         mixer_thread.join();
659 }
660
661 void Mixer::transition_clicked(int transition_num)
662 {
663         theme->transition_clicked(transition_num, pts());
664 }
665
666 void Mixer::channel_clicked(int preview_num)
667 {
668         theme->channel_clicked(preview_num);
669 }
670
671 Mixer::OutputChannel::~OutputChannel()
672 {
673         if (has_current_frame) {
674                 parent->release_display_frame(&current_frame);
675         }
676         if (has_ready_frame) {
677                 parent->release_display_frame(&ready_frame);
678         }
679 }
680
681 void Mixer::OutputChannel::output_frame(DisplayFrame frame)
682 {
683         // Store this frame for display. Remove the ready frame if any
684         // (it was seemingly never used).
685         {
686                 unique_lock<mutex> lock(frame_mutex);
687                 if (has_ready_frame) {
688                         parent->release_display_frame(&ready_frame);
689                 }
690                 ready_frame = frame;
691                 has_ready_frame = true;
692         }
693
694         if (has_new_frame_ready_callback) {
695                 new_frame_ready_callback();
696         }
697 }
698
699 bool Mixer::OutputChannel::get_display_frame(DisplayFrame *frame)
700 {
701         unique_lock<mutex> lock(frame_mutex);
702         if (!has_current_frame && !has_ready_frame) {
703                 return false;
704         }
705
706         if (has_current_frame && has_ready_frame) {
707                 // We have a new ready frame. Toss the current one.
708                 parent->release_display_frame(&current_frame);
709                 has_current_frame = false;
710         }
711         if (has_ready_frame) {
712                 assert(!has_current_frame);
713                 current_frame = ready_frame;
714                 ready_frame.ready_fence.reset();  // Drop the refcount.
715                 ready_frame.input_frames.clear();  // Drop the refcounts.
716                 has_current_frame = true;
717                 has_ready_frame = false;
718         }
719
720         *frame = current_frame;
721         return true;
722 }
723
724 void Mixer::OutputChannel::set_frame_ready_callback(Mixer::new_frame_ready_callback_t callback)
725 {
726         new_frame_ready_callback = callback;
727         has_new_frame_ready_callback = true;
728 }