1 #include "audio_mixer.h"
4 #include <bmusb/bmusb.h>
23 #include "shared/metrics.h"
25 #include "shared/timebase.h"
27 using namespace bmusb;
29 using namespace std::chrono;
30 using namespace std::placeholders;
34 // TODO: If these prove to be a bottleneck, they can be SSSE3-optimized
35 // (usually including multiple channels at a time).
37 void convert_fixed16_to_fp32(float *dst, size_t out_channel, size_t out_num_channels,
38 const uint8_t *src, size_t in_channel, size_t in_num_channels,
41 assert(in_channel < in_num_channels);
42 assert(out_channel < out_num_channels);
43 src += in_channel * 2;
46 for (size_t i = 0; i < num_samples; ++i) {
47 int16_t s = le16toh(*(int16_t *)src);
48 *dst = s * (1.0f / 32768.0f);
50 src += 2 * in_num_channels;
51 dst += out_num_channels;
55 void convert_fixed24_to_fp32(float *dst, size_t out_channel, size_t out_num_channels,
56 const uint8_t *src, size_t in_channel, size_t in_num_channels,
59 assert(in_channel < in_num_channels);
60 assert(out_channel < out_num_channels);
61 src += in_channel * 3;
64 for (size_t i = 0; i < num_samples; ++i) {
68 uint32_t s = s1 | (s1 << 8) | (s2 << 16) | (s3 << 24);
69 *dst = int(s) * (1.0f / 2147483648.0f);
71 src += 3 * in_num_channels;
72 dst += out_num_channels;
76 void convert_fixed32_to_fp32(float *dst, size_t out_channel, size_t out_num_channels,
77 const uint8_t *src, size_t in_channel, size_t in_num_channels,
80 assert(in_channel < in_num_channels);
81 assert(out_channel < out_num_channels);
82 src += in_channel * 4;
85 for (size_t i = 0; i < num_samples; ++i) {
86 int32_t s = le32toh(*(int32_t *)src);
87 *dst = s * (1.0f / 2147483648.0f);
89 src += 4 * in_num_channels;
90 dst += out_num_channels;
94 float find_peak_plain(const float *samples, size_t num_samples) __attribute__((unused));
96 float find_peak_plain(const float *samples, size_t num_samples)
98 float m = fabs(samples[0]);
99 for (size_t i = 1; i < num_samples; ++i) {
100 m = max(m, fabs(samples[i]));
106 static inline float horizontal_max(__m128 m)
108 __m128 tmp = _mm_shuffle_ps(m, m, _MM_SHUFFLE(1, 0, 3, 2));
109 m = _mm_max_ps(m, tmp);
110 tmp = _mm_shuffle_ps(m, m, _MM_SHUFFLE(2, 3, 0, 1));
111 m = _mm_max_ps(m, tmp);
112 return _mm_cvtss_f32(m);
115 float find_peak(const float *samples, size_t num_samples)
117 const __m128 abs_mask = _mm_castsi128_ps(_mm_set1_epi32(0x7fffffffu));
118 __m128 m = _mm_setzero_ps();
119 for (size_t i = 0; i < (num_samples & ~3); i += 4) {
120 __m128 x = _mm_loadu_ps(samples + i);
121 x = _mm_and_ps(x, abs_mask);
122 m = _mm_max_ps(m, x);
124 float result = horizontal_max(m);
126 for (size_t i = (num_samples & ~3); i < num_samples; ++i) {
127 result = max(result, fabs(samples[i]));
131 // Self-test. We should be bit-exact the same.
132 float reference_result = find_peak_plain(samples, num_samples);
133 if (result != reference_result) {
134 fprintf(stderr, "Error: Peak is %f [%f %f %f %f]; should be %f.\n",
136 _mm_cvtss_f32(_mm_shuffle_ps(m, m, _MM_SHUFFLE(0, 0, 0, 0))),
137 _mm_cvtss_f32(_mm_shuffle_ps(m, m, _MM_SHUFFLE(1, 1, 1, 1))),
138 _mm_cvtss_f32(_mm_shuffle_ps(m, m, _MM_SHUFFLE(2, 2, 2, 2))),
139 _mm_cvtss_f32(_mm_shuffle_ps(m, m, _MM_SHUFFLE(3, 3, 3, 3))),
147 float find_peak(const float *samples, size_t num_samples)
149 return find_peak_plain(samples, num_samples);
153 void deinterleave_samples(const vector<float> &in, vector<float> *out_l, vector<float> *out_r)
155 size_t num_samples = in.size() / 2;
156 out_l->resize(num_samples);
157 out_r->resize(num_samples);
159 const float *inptr = in.data();
160 float *lptr = &(*out_l)[0];
161 float *rptr = &(*out_r)[0];
162 for (size_t i = 0; i < num_samples; ++i) {
170 AudioMixer::AudioMixer(unsigned num_capture_cards, unsigned num_ffmpeg_inputs)
171 : num_capture_cards(num_capture_cards),
172 num_ffmpeg_inputs(num_ffmpeg_inputs),
173 ffmpeg_inputs(new AudioDevice[num_ffmpeg_inputs]),
174 limiter(OUTPUT_FREQUENCY),
175 correlation(OUTPUT_FREQUENCY)
177 for (unsigned bus_index = 0; bus_index < MAX_BUSES; ++bus_index) {
178 locut[bus_index].init(FILTER_HPF, 2);
179 eq[bus_index][EQ_BAND_BASS].init(FILTER_LOW_SHELF, 1);
180 // Note: EQ_BAND_MID isn't used (see comments in apply_eq()).
181 eq[bus_index][EQ_BAND_TREBLE].init(FILTER_HIGH_SHELF, 1);
182 compressor[bus_index].reset(new StereoCompressor(OUTPUT_FREQUENCY));
183 level_compressor[bus_index].reset(new StereoCompressor(OUTPUT_FREQUENCY));
185 set_bus_settings(bus_index, get_default_bus_settings());
187 set_limiter_enabled(global_flags.limiter_enabled);
188 set_final_makeup_gain_auto(global_flags.final_makeup_gain_auto);
190 r128.init(2, OUTPUT_FREQUENCY);
193 // hlen=16 is pretty low quality, but we use quite a bit of CPU otherwise,
194 // and there's a limit to how important the peak meter is.
195 peak_resampler.setup(OUTPUT_FREQUENCY, OUTPUT_FREQUENCY * 4, /*num_channels=*/2, /*hlen=*/16, /*frel=*/1.0);
197 global_audio_mixer = this;
200 if (!global_flags.input_mapping_filename.empty()) {
201 // Must happen after ALSAPool is initialized, as it needs to know the card list.
202 current_mapping_mode = MappingMode::MULTICHANNEL;
203 InputMapping new_input_mapping;
204 if (!load_input_mapping_from_file(get_devices(),
205 global_flags.input_mapping_filename,
206 &new_input_mapping)) {
207 fprintf(stderr, "Failed to load input mapping from '%s', exiting.\n",
208 global_flags.input_mapping_filename.c_str());
211 set_input_mapping(new_input_mapping);
213 set_simple_input(/*card_index=*/0);
214 if (global_flags.multichannel_mapping_mode) {
215 current_mapping_mode = MappingMode::MULTICHANNEL;
219 global_metrics.add("audio_loudness_short_lufs", &metric_audio_loudness_short_lufs, Metrics::TYPE_GAUGE);
220 global_metrics.add("audio_loudness_integrated_lufs", &metric_audio_loudness_integrated_lufs, Metrics::TYPE_GAUGE);
221 global_metrics.add("audio_loudness_range_low_lufs", &metric_audio_loudness_range_low_lufs, Metrics::TYPE_GAUGE);
222 global_metrics.add("audio_loudness_range_high_lufs", &metric_audio_loudness_range_high_lufs, Metrics::TYPE_GAUGE);
223 global_metrics.add("audio_peak_dbfs", &metric_audio_peak_dbfs, Metrics::TYPE_GAUGE);
224 global_metrics.add("audio_final_makeup_gain_db", &metric_audio_final_makeup_gain_db, Metrics::TYPE_GAUGE);
225 global_metrics.add("audio_correlation", &metric_audio_correlation, Metrics::TYPE_GAUGE);
228 void AudioMixer::reset_resampler(DeviceSpec device_spec)
230 lock_guard<timed_mutex> lock(audio_mutex);
231 reset_resampler_mutex_held(device_spec);
234 void AudioMixer::reset_resampler_mutex_held(DeviceSpec device_spec)
236 AudioDevice *device = find_audio_device(device_spec);
238 if (device->interesting_channels.empty()) {
239 device->resampling_queue.reset();
241 device->resampling_queue.reset(new ResamplingQueue(
242 device_spec, device->capture_frequency, OUTPUT_FREQUENCY, device->interesting_channels.size(),
243 global_flags.audio_queue_length_ms * 0.001));
247 bool AudioMixer::add_audio(DeviceSpec device_spec, const uint8_t *data, unsigned num_samples, AudioFormat audio_format, int64_t frame_length, steady_clock::time_point frame_time)
249 AudioDevice *device = find_audio_device(device_spec);
251 unique_lock<timed_mutex> lock(audio_mutex, defer_lock);
252 if (!lock.try_lock_for(chrono::milliseconds(10))) {
255 if (device->resampling_queue == nullptr) {
256 // No buses use this device; throw it away.
260 unsigned num_channels = device->interesting_channels.size();
261 assert(num_channels > 0);
263 // Convert the audio to fp32.
264 unique_ptr<float[]> audio(new float[num_samples * num_channels]);
265 unsigned channel_index = 0;
266 for (auto channel_it = device->interesting_channels.cbegin(); channel_it != device->interesting_channels.end(); ++channel_it, ++channel_index) {
267 switch (audio_format.bits_per_sample) {
269 assert(num_samples == 0);
272 convert_fixed16_to_fp32(audio.get(), channel_index, num_channels, data, *channel_it, audio_format.num_channels, num_samples);
275 convert_fixed24_to_fp32(audio.get(), channel_index, num_channels, data, *channel_it, audio_format.num_channels, num_samples);
278 convert_fixed32_to_fp32(audio.get(), channel_index, num_channels, data, *channel_it, audio_format.num_channels, num_samples);
281 fprintf(stderr, "Cannot handle audio with %u bits per sample\n", audio_format.bits_per_sample);
286 // If we changed frequency since last frame, we'll need to reset the resampler.
287 if (audio_format.sample_rate != device->capture_frequency) {
288 device->capture_frequency = audio_format.sample_rate;
289 reset_resampler_mutex_held(device_spec);
293 device->resampling_queue->add_input_samples(frame_time, audio.get(), num_samples, ResamplingQueue::ADJUST_RATE);
297 bool AudioMixer::add_silence(DeviceSpec device_spec, unsigned samples_per_frame, unsigned num_frames, int64_t frame_length)
299 AudioDevice *device = find_audio_device(device_spec);
301 unique_lock<timed_mutex> lock(audio_mutex, defer_lock);
302 if (!lock.try_lock_for(chrono::milliseconds(10))) {
305 if (device->resampling_queue == nullptr) {
306 // No buses use this device; throw it away.
310 unsigned num_channels = device->interesting_channels.size();
311 assert(num_channels > 0);
313 vector<float> silence(samples_per_frame * num_channels, 0.0f);
314 for (unsigned i = 0; i < num_frames; ++i) {
315 device->resampling_queue->add_input_samples(steady_clock::now(), silence.data(), samples_per_frame, ResamplingQueue::DO_NOT_ADJUST_RATE);
320 bool AudioMixer::silence_card(DeviceSpec device_spec, bool silence)
322 AudioDevice *device = find_audio_device(device_spec);
324 unique_lock<timed_mutex> lock(audio_mutex, defer_lock);
325 if (!lock.try_lock_for(chrono::milliseconds(10))) {
329 if (device->silenced && !silence) {
330 reset_resampler_mutex_held(device_spec);
332 device->silenced = silence;
336 AudioMixer::BusSettings AudioMixer::get_default_bus_settings()
338 BusSettings settings;
339 settings.fader_volume_db = 0.0f;
340 settings.muted = false;
341 settings.locut_enabled = global_flags.locut_enabled;
342 settings.stereo_width = 1.0f;
343 for (unsigned band_index = 0; band_index < NUM_EQ_BANDS; ++band_index) {
344 settings.eq_level_db[band_index] = 0.0f;
346 settings.gain_staging_db = global_flags.initial_gain_staging_db;
347 settings.level_compressor_enabled = global_flags.gain_staging_auto;
348 settings.compressor_threshold_dbfs = ref_level_dbfs - 12.0f; // -12 dB.
349 settings.compressor_enabled = global_flags.compressor_enabled;
353 AudioMixer::BusSettings AudioMixer::get_bus_settings(unsigned bus_index) const
355 lock_guard<timed_mutex> lock(audio_mutex);
356 BusSettings settings;
357 settings.fader_volume_db = fader_volume_db[bus_index];
358 settings.muted = mute[bus_index];
359 settings.locut_enabled = locut_enabled[bus_index];
360 settings.stereo_width = stereo_width[bus_index];
361 for (unsigned band_index = 0; band_index < NUM_EQ_BANDS; ++band_index) {
362 settings.eq_level_db[band_index] = eq_level_db[bus_index][band_index];
364 settings.gain_staging_db = gain_staging_db[bus_index];
365 settings.level_compressor_enabled = level_compressor_enabled[bus_index];
366 settings.compressor_threshold_dbfs = compressor_threshold_dbfs[bus_index];
367 settings.compressor_enabled = compressor_enabled[bus_index];
371 void AudioMixer::set_bus_settings(unsigned bus_index, const AudioMixer::BusSettings &settings)
373 lock_guard<timed_mutex> lock(audio_mutex);
374 fader_volume_db[bus_index] = settings.fader_volume_db;
375 mute[bus_index] = settings.muted;
376 locut_enabled[bus_index] = settings.locut_enabled;
377 stereo_width[bus_index] = settings.stereo_width;
378 for (unsigned band_index = 0; band_index < NUM_EQ_BANDS; ++band_index) {
379 eq_level_db[bus_index][band_index] = settings.eq_level_db[band_index];
381 gain_staging_db[bus_index] = settings.gain_staging_db;
382 last_gain_staging_db[bus_index] = gain_staging_db[bus_index];
383 level_compressor_enabled[bus_index] = settings.level_compressor_enabled;
384 compressor_threshold_dbfs[bus_index] = settings.compressor_threshold_dbfs;
385 compressor_enabled[bus_index] = settings.compressor_enabled;
388 AudioMixer::AudioDevice *AudioMixer::find_audio_device(DeviceSpec device)
390 switch (device.type) {
391 case InputSourceType::CAPTURE_CARD:
392 return &video_cards[device.index];
393 case InputSourceType::ALSA_INPUT:
394 return &alsa_inputs[device.index];
395 case InputSourceType::FFMPEG_VIDEO_INPUT:
396 return &ffmpeg_inputs[device.index];
397 case InputSourceType::SILENCE:
404 // Get a pointer to the given channel from the given device.
405 // The channel must be picked out earlier and resampled.
406 void AudioMixer::find_sample_src_from_device(const map<DeviceSpec, vector<float>> &samples_card, DeviceSpec device_spec, int source_channel, const float **srcptr, unsigned *stride)
408 static float zero = 0.0f;
409 if (source_channel == -1 || device_spec.type == InputSourceType::SILENCE) {
414 AudioDevice *device = find_audio_device(device_spec);
415 assert(device->interesting_channels.count(source_channel) != 0);
416 unsigned channel_index = 0;
417 for (int channel : device->interesting_channels) {
418 if (channel == source_channel) break;
421 assert(channel_index < device->interesting_channels.size());
422 const auto it = samples_card.find(device_spec);
423 assert(it != samples_card.end());
424 *srcptr = &(it->second)[channel_index];
425 *stride = device->interesting_channels.size();
428 // TODO: Can be SSSE3-optimized if need be.
429 void AudioMixer::fill_audio_bus(const map<DeviceSpec, vector<float>> &samples_card, const InputMapping::Bus &bus, unsigned num_samples, float stereo_width, float *output)
431 if (bus.device.type == InputSourceType::SILENCE) {
432 memset(output, 0, num_samples * 2 * sizeof(*output));
434 assert(bus.device.type == InputSourceType::CAPTURE_CARD ||
435 bus.device.type == InputSourceType::ALSA_INPUT ||
436 bus.device.type == InputSourceType::FFMPEG_VIDEO_INPUT);
437 const float *lsrc, *rsrc;
438 unsigned lstride, rstride;
439 float *dptr = output;
440 find_sample_src_from_device(samples_card, bus.device, bus.source_channel[0], &lsrc, &lstride);
441 find_sample_src_from_device(samples_card, bus.device, bus.source_channel[1], &rsrc, &rstride);
443 // Apply stereo width settings. Set stereo width w to a 0..1 range instead of
444 // -1..1, since it makes for much easier calculations (so 0.5 = completely mono).
445 // Then, what we want is
447 // L' = wL + (1-w)R = R + w(L-R)
448 // R' = wR + (1-w)L = L + w(R-L)
450 // This can be further simplified calculation-wise by defining the weighted
451 // difference signal D = w(R-L), so that:
455 float w = 0.5f * stereo_width + 0.5f;
456 if (bus.source_channel[0] == bus.source_channel[1]) {
457 // Mono anyway, so no need to bother.
459 } else if (fabs(w) < 1e-3) {
462 swap(lstride, rstride);
465 if (fabs(w - 1.0f) < 1e-3) {
466 // No calculations needed for stereo_width = 1.
467 for (unsigned i = 0; i < num_samples; ++i) {
475 for (unsigned i = 0; i < num_samples; ++i) {
476 float left = *lsrc, right = *rsrc;
477 float diff = w * (right - left);
478 *dptr++ = right - diff;
479 *dptr++ = left + diff;
487 vector<DeviceSpec> AudioMixer::get_active_devices() const
489 vector<DeviceSpec> ret;
490 for (unsigned card_index = 0; card_index < MAX_VIDEO_CARDS; ++card_index) {
491 const DeviceSpec device_spec{InputSourceType::CAPTURE_CARD, card_index};
492 if (!find_audio_device(device_spec)->interesting_channels.empty()) {
493 ret.push_back(device_spec);
496 for (unsigned card_index = 0; card_index < MAX_ALSA_CARDS; ++card_index) {
497 const DeviceSpec device_spec{InputSourceType::ALSA_INPUT, card_index};
498 if (!find_audio_device(device_spec)->interesting_channels.empty()) {
499 ret.push_back(device_spec);
502 for (unsigned card_index = 0; card_index < num_ffmpeg_inputs; ++card_index) {
503 const DeviceSpec device_spec{InputSourceType::FFMPEG_VIDEO_INPUT, card_index};
504 if (!find_audio_device(device_spec)->interesting_channels.empty()) {
505 ret.push_back(device_spec);
513 void apply_gain(float db, float last_db, vector<float> *samples)
515 if (fabs(db - last_db) < 1e-3) {
516 // Constant over this frame.
517 const float gain = from_db(db);
518 for (size_t i = 0; i < samples->size(); ++i) {
519 (*samples)[i] *= gain;
522 // We need to do a fade.
523 unsigned num_samples = samples->size() / 2;
524 float gain = from_db(last_db);
525 const float gain_inc = pow(from_db(db - last_db), 1.0 / num_samples);
526 for (size_t i = 0; i < num_samples; ++i) {
527 (*samples)[i * 2 + 0] *= gain;
528 (*samples)[i * 2 + 1] *= gain;
536 vector<float> AudioMixer::get_output(steady_clock::time_point ts, unsigned num_samples, ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy)
538 map<DeviceSpec, vector<float>> samples_card;
539 vector<float> samples_bus;
541 lock_guard<timed_mutex> lock(audio_mutex);
543 // Pick out all the interesting channels from all the cards.
544 for (const DeviceSpec &device_spec : get_active_devices()) {
545 AudioDevice *device = find_audio_device(device_spec);
546 samples_card[device_spec].resize(num_samples * device->interesting_channels.size());
547 if (device->silenced) {
548 memset(&samples_card[device_spec][0], 0, samples_card[device_spec].size() * sizeof(float));
550 device->resampling_queue->get_output_samples(
552 &samples_card[device_spec][0],
554 rate_adjustment_policy);
558 vector<float> samples_out, left, right;
559 samples_out.resize(num_samples * 2);
560 samples_bus.resize(num_samples * 2);
561 for (unsigned bus_index = 0; bus_index < input_mapping.buses.size(); ++bus_index) {
562 fill_audio_bus(samples_card, input_mapping.buses[bus_index], num_samples, stereo_width[bus_index], &samples_bus[0]);
563 apply_eq(bus_index, &samples_bus);
566 lock_guard<mutex> lock(compressor_mutex);
568 // Apply a level compressor to get the general level right.
569 // Basically, if it's over about -40 dBFS, we squeeze it down to that level
570 // (or more precisely, near it, since we don't use infinite ratio),
571 // then apply a makeup gain to get it to -14 dBFS. -14 dBFS is, of course,
572 // entirely arbitrary, but from practical tests with speech, it seems to
573 // put ut around -23 LUFS, so it's a reasonable starting point for later use.
574 if (level_compressor_enabled[bus_index]) {
575 float threshold = 0.01f; // -40 dBFS.
577 float attack_time = 0.5f;
578 float release_time = 20.0f;
579 float makeup_gain = from_db(ref_level_dbfs - (-40.0f)); // +26 dB.
580 level_compressor[bus_index]->process(samples_bus.data(), samples_bus.size() / 2, threshold, ratio, attack_time, release_time, makeup_gain);
581 gain_staging_db[bus_index] = to_db(level_compressor[bus_index]->get_attenuation() * makeup_gain);
583 // Just apply the gain we already had.
584 float db = gain_staging_db[bus_index];
585 float last_db = last_gain_staging_db[bus_index];
586 apply_gain(db, last_db, &samples_bus);
588 last_gain_staging_db[bus_index] = gain_staging_db[bus_index];
591 printf("level=%f (%+5.2f dBFS) attenuation=%f (%+5.2f dB) end_result=%+5.2f dB\n",
592 level_compressor.get_level(), to_db(level_compressor.get_level()),
593 level_compressor.get_attenuation(), to_db(level_compressor.get_attenuation()),
594 to_db(level_compressor.get_level() * level_compressor.get_attenuation() * makeup_gain));
597 // The real compressor.
598 if (compressor_enabled[bus_index]) {
599 float threshold = from_db(compressor_threshold_dbfs[bus_index]);
601 float attack_time = 0.005f;
602 float release_time = 0.040f;
603 float makeup_gain = 2.0f; // +6 dB.
604 compressor[bus_index]->process(samples_bus.data(), samples_bus.size() / 2, threshold, ratio, attack_time, release_time, makeup_gain);
605 // compressor_att = compressor.get_attenuation();
609 add_bus_to_master(bus_index, samples_bus, &samples_out);
610 deinterleave_samples(samples_bus, &left, &right);
611 measure_bus_levels(bus_index, left, right);
615 lock_guard<mutex> lock(compressor_mutex);
617 // Finally a limiter at -4 dB (so, -10 dBFS) to take out the worst peaks only.
618 // Note that since ratio is not infinite, we could go slightly higher than this.
619 if (limiter_enabled) {
620 float threshold = from_db(limiter_threshold_dbfs);
622 float attack_time = 0.0f; // Instant.
623 float release_time = 0.020f;
624 float makeup_gain = 1.0f; // 0 dB.
625 limiter.process(samples_out.data(), samples_out.size() / 2, threshold, ratio, attack_time, release_time, makeup_gain);
626 // limiter_att = limiter.get_attenuation();
629 // printf("limiter=%+5.1f compressor=%+5.1f\n", to_db(limiter_att), to_db(compressor_att));
632 // At this point, we are most likely close to +0 LU (at least if the
633 // faders sum to 0 dB and the compressors are on), but all of our
634 // measurements have been on raw sample values, not R128 values.
635 // So we have a final makeup gain to get us to +0 LU; the gain
636 // adjustments required should be relatively small, and also, the
637 // offset shouldn't change much (only if the type of audio changes
638 // significantly). Thus, we shoot for updating this value basically
639 // “whenever we process buffers”, since the R128 calculation isn't exactly
640 // something we get out per-sample.
642 // Note that there's a feedback loop here, so we choose a very slow filter
643 // (half-time of 30 seconds).
644 double target_loudness_factor, alpha;
645 double loudness_lu = r128.loudness_M() - ref_level_lufs;
646 target_loudness_factor = final_makeup_gain * from_db(-loudness_lu);
648 // If we're outside +/- 5 LU (after correction), we don't count it as
649 // a normal signal (probably silence) and don't change the
650 // correction factor; just apply what we already have.
651 if (fabs(loudness_lu) >= 5.0 || !final_makeup_gain_auto) {
654 // Formula adapted from
655 // https://en.wikipedia.org/wiki/Low-pass_filter#Simple_infinite_impulse_response_filter.
656 const double half_time_s = 30.0;
657 const double fc_mul_2pi_delta_t = 1.0 / (half_time_s * OUTPUT_FREQUENCY);
658 alpha = fc_mul_2pi_delta_t / (fc_mul_2pi_delta_t + 1.0);
662 lock_guard<mutex> lock(compressor_mutex);
663 double m = final_makeup_gain;
664 for (size_t i = 0; i < samples_out.size(); i += 2) {
665 samples_out[i + 0] *= m;
666 samples_out[i + 1] *= m;
667 m += (target_loudness_factor - m) * alpha;
669 final_makeup_gain = m;
672 update_meters(samples_out);
679 void apply_filter_fade(StereoFilter *filter, float *data, unsigned num_samples, float cutoff_hz, float db, float last_db)
681 // A granularity of 32 samples is an okay tradeoff between speed and
682 // smoothness; recalculating the filters is pretty expensive, so it's
683 // good that we don't do this all the time.
684 static constexpr unsigned filter_granularity_samples = 32;
686 const float cutoff_linear = cutoff_hz * 2.0 * M_PI / OUTPUT_FREQUENCY;
687 if (fabs(db - last_db) < 1e-3) {
688 // Constant over this frame.
689 if (fabs(db) > 0.01f) {
690 filter->render(data, num_samples, cutoff_linear, 0.5f, db / 40.0f);
693 // We need to do a fade. (Rounding up avoids division by zero.)
694 unsigned num_blocks = (num_samples + filter_granularity_samples - 1) / filter_granularity_samples;
695 const float inc_db_norm = (db - last_db) / 40.0f / num_blocks;
696 float db_norm = db / 40.0f;
697 for (size_t i = 0; i < num_samples; i += filter_granularity_samples) {
698 size_t samples_this_block = std::min<size_t>(num_samples - i, filter_granularity_samples);
699 filter->render(data + i * 2, samples_this_block, cutoff_linear, 0.5f, db_norm);
700 db_norm += inc_db_norm;
707 void AudioMixer::apply_eq(unsigned bus_index, vector<float> *samples_bus)
709 constexpr float bass_freq_hz = 200.0f;
710 constexpr float treble_freq_hz = 4700.0f;
712 // Cut away everything under 120 Hz (or whatever the cutoff is);
713 // we don't need it for voice, and it will reduce headroom
714 // and confuse the compressor. (In particular, any hums at 50 or 60 Hz
715 // should be dampened.)
716 if (locut_enabled[bus_index]) {
717 locut[bus_index].render(samples_bus->data(), samples_bus->size() / 2, locut_cutoff_hz * 2.0 * M_PI / OUTPUT_FREQUENCY, 0.5f);
720 // Apply the rest of the EQ. Since we only have a simple three-band EQ,
721 // we can implement it with two shelf filters. We use a simple gain to
722 // set the mid-level filter, and then offset the low and high bands
723 // from that if we need to. (We could perhaps have folded the gain into
724 // the next part, but it's so cheap that the trouble isn't worth it.)
726 // If any part of the EQ has changed appreciably since last frame,
727 // we fade smoothly during the course of this frame.
728 const float bass_db = eq_level_db[bus_index][EQ_BAND_BASS];
729 const float mid_db = eq_level_db[bus_index][EQ_BAND_MID];
730 const float treble_db = eq_level_db[bus_index][EQ_BAND_TREBLE];
732 const float last_bass_db = last_eq_level_db[bus_index][EQ_BAND_BASS];
733 const float last_mid_db = last_eq_level_db[bus_index][EQ_BAND_MID];
734 const float last_treble_db = last_eq_level_db[bus_index][EQ_BAND_TREBLE];
736 assert(samples_bus->size() % 2 == 0);
737 const unsigned num_samples = samples_bus->size() / 2;
739 apply_gain(mid_db, last_mid_db, samples_bus);
741 apply_filter_fade(&eq[bus_index][EQ_BAND_BASS], samples_bus->data(), num_samples, bass_freq_hz, bass_db - mid_db, last_bass_db - last_mid_db);
742 apply_filter_fade(&eq[bus_index][EQ_BAND_TREBLE], samples_bus->data(), num_samples, treble_freq_hz, treble_db - mid_db, last_treble_db - last_mid_db);
744 last_eq_level_db[bus_index][EQ_BAND_BASS] = bass_db;
745 last_eq_level_db[bus_index][EQ_BAND_MID] = mid_db;
746 last_eq_level_db[bus_index][EQ_BAND_TREBLE] = treble_db;
749 void AudioMixer::add_bus_to_master(unsigned bus_index, const vector<float> &samples_bus, vector<float> *samples_out)
751 assert(samples_bus.size() == samples_out->size());
752 assert(samples_bus.size() % 2 == 0);
753 unsigned num_samples = samples_bus.size() / 2;
754 const float new_volume_db = mute[bus_index] ? -90.0f : fader_volume_db[bus_index].load();
755 if (fabs(new_volume_db - last_fader_volume_db[bus_index]) > 1e-3) {
756 // The volume has changed; do a fade over the course of this frame.
757 // (We might have some numerical issues here, but it seems to sound OK.)
758 // For the purpose of fading here, the silence floor is set to -90 dB
759 // (the fader only goes to -84).
760 float old_volume = from_db(max<float>(last_fader_volume_db[bus_index], -90.0f));
761 float volume = from_db(max<float>(new_volume_db, -90.0f));
763 float volume_inc = pow(volume / old_volume, 1.0 / num_samples);
765 if (bus_index == 0) {
766 for (unsigned i = 0; i < num_samples; ++i) {
767 (*samples_out)[i * 2 + 0] = samples_bus[i * 2 + 0] * volume;
768 (*samples_out)[i * 2 + 1] = samples_bus[i * 2 + 1] * volume;
769 volume *= volume_inc;
772 for (unsigned i = 0; i < num_samples; ++i) {
773 (*samples_out)[i * 2 + 0] += samples_bus[i * 2 + 0] * volume;
774 (*samples_out)[i * 2 + 1] += samples_bus[i * 2 + 1] * volume;
775 volume *= volume_inc;
778 } else if (new_volume_db > -90.0f) {
779 float volume = from_db(new_volume_db);
780 if (bus_index == 0) {
781 for (unsigned i = 0; i < num_samples; ++i) {
782 (*samples_out)[i * 2 + 0] = samples_bus[i * 2 + 0] * volume;
783 (*samples_out)[i * 2 + 1] = samples_bus[i * 2 + 1] * volume;
786 for (unsigned i = 0; i < num_samples; ++i) {
787 (*samples_out)[i * 2 + 0] += samples_bus[i * 2 + 0] * volume;
788 (*samples_out)[i * 2 + 1] += samples_bus[i * 2 + 1] * volume;
793 last_fader_volume_db[bus_index] = new_volume_db;
796 void AudioMixer::measure_bus_levels(unsigned bus_index, const vector<float> &left, const vector<float> &right)
798 assert(left.size() == right.size());
799 const float volume = mute[bus_index] ? 0.0f : from_db(fader_volume_db[bus_index]);
800 const float peak_levels[2] = {
801 find_peak(left.data(), left.size()) * volume,
802 find_peak(right.data(), right.size()) * volume
804 for (unsigned channel = 0; channel < 2; ++channel) {
805 // Compute the current value, including hold and falloff.
806 // The constants are borrowed from zita-mu1 by Fons Adriaensen.
807 static constexpr float hold_sec = 0.5f;
808 static constexpr float falloff_db_sec = 15.0f; // dB/sec falloff after hold.
810 PeakHistory &history = peak_history[bus_index][channel];
811 history.historic_peak = max(history.historic_peak, peak_levels[channel]);
812 if (history.age_seconds < hold_sec) {
813 current_peak = history.last_peak;
815 current_peak = history.last_peak * from_db(-falloff_db_sec * (history.age_seconds - hold_sec));
818 // See if we have a new peak to replace the old (possibly falling) one.
819 if (peak_levels[channel] > current_peak) {
820 history.last_peak = peak_levels[channel];
821 history.age_seconds = 0.0f; // Not 100% correct, but more than good enough given our frame sizes.
822 current_peak = peak_levels[channel];
824 history.age_seconds += float(left.size()) / OUTPUT_FREQUENCY;
826 history.current_level = peak_levels[channel];
827 history.current_peak = current_peak;
831 void AudioMixer::update_meters(const vector<float> &samples)
833 // Upsample 4x to find interpolated peak.
834 peak_resampler.inp_data = const_cast<float *>(samples.data());
835 peak_resampler.inp_count = samples.size() / 2;
837 vector<float> interpolated_samples;
838 interpolated_samples.resize(samples.size());
840 lock_guard<mutex> lock(audio_measure_mutex);
842 while (peak_resampler.inp_count > 0) { // About four iterations.
843 peak_resampler.out_data = &interpolated_samples[0];
844 peak_resampler.out_count = interpolated_samples.size() / 2;
845 peak_resampler.process();
846 size_t out_stereo_samples = interpolated_samples.size() / 2 - peak_resampler.out_count;
847 peak = max<float>(peak, find_peak(interpolated_samples.data(), out_stereo_samples * 2));
848 peak_resampler.out_data = nullptr;
852 // Find R128 levels and L/R correlation.
853 vector<float> left, right;
854 deinterleave_samples(samples, &left, &right);
855 float *ptrs[] = { left.data(), right.data() };
857 lock_guard<mutex> lock(audio_measure_mutex);
858 r128.process(left.size(), ptrs);
859 correlation.process_samples(samples);
862 send_audio_level_callback();
865 void AudioMixer::reset_meters()
867 lock_guard<mutex> lock(audio_measure_mutex);
868 peak_resampler.reset();
875 void AudioMixer::send_audio_level_callback()
877 if (audio_level_callback == nullptr) {
881 lock_guard<mutex> lock(audio_measure_mutex);
882 double loudness_s = r128.loudness_S();
883 double loudness_i = r128.integrated();
884 double loudness_range_low = r128.range_min();
885 double loudness_range_high = r128.range_max();
887 metric_audio_loudness_short_lufs = loudness_s;
888 metric_audio_loudness_integrated_lufs = loudness_i;
889 metric_audio_loudness_range_low_lufs = loudness_range_low;
890 metric_audio_loudness_range_high_lufs = loudness_range_high;
891 metric_audio_peak_dbfs = to_db(peak);
892 metric_audio_final_makeup_gain_db = to_db(final_makeup_gain);
893 metric_audio_correlation = correlation.get_correlation();
895 vector<BusLevel> bus_levels;
896 bus_levels.resize(input_mapping.buses.size());
898 lock_guard<mutex> lock(compressor_mutex);
899 for (unsigned bus_index = 0; bus_index < bus_levels.size(); ++bus_index) {
900 BusLevel &levels = bus_levels[bus_index];
901 BusMetrics &metrics = bus_metrics[bus_index];
903 levels.current_level_dbfs[0] = metrics.current_level_dbfs[0] = to_db(peak_history[bus_index][0].current_level);
904 levels.current_level_dbfs[1] = metrics.current_level_dbfs[1] = to_db(peak_history[bus_index][1].current_level);
905 levels.peak_level_dbfs[0] = metrics.peak_level_dbfs[0] = to_db(peak_history[bus_index][0].current_peak);
906 levels.peak_level_dbfs[1] = metrics.peak_level_dbfs[1] = to_db(peak_history[bus_index][1].current_peak);
907 levels.historic_peak_dbfs = metrics.historic_peak_dbfs = to_db(
908 max(peak_history[bus_index][0].historic_peak,
909 peak_history[bus_index][1].historic_peak));
910 levels.gain_staging_db = metrics.gain_staging_db = gain_staging_db[bus_index];
911 if (compressor_enabled[bus_index]) {
912 levels.compressor_attenuation_db = metrics.compressor_attenuation_db = -to_db(compressor[bus_index]->get_attenuation());
914 levels.compressor_attenuation_db = 0.0;
915 metrics.compressor_attenuation_db = 0.0 / 0.0;
920 audio_level_callback(loudness_s, to_db(peak), bus_levels,
921 loudness_i, loudness_range_low, loudness_range_high,
922 to_db(final_makeup_gain),
923 correlation.get_correlation());
926 map<DeviceSpec, DeviceInfo> AudioMixer::get_devices()
928 lock_guard<timed_mutex> lock(audio_mutex);
930 map<DeviceSpec, DeviceInfo> devices;
931 for (unsigned card_index = 0; card_index < num_capture_cards; ++card_index) {
932 const DeviceSpec spec{ InputSourceType::CAPTURE_CARD, card_index };
933 const AudioDevice *device = &video_cards[card_index];
935 info.display_name = device->display_name;
936 info.num_channels = 8;
937 devices.insert(make_pair(spec, info));
939 vector<ALSAPool::Device> available_alsa_devices = alsa_pool.get_devices();
940 for (unsigned card_index = 0; card_index < available_alsa_devices.size(); ++card_index) {
941 const DeviceSpec spec{ InputSourceType::ALSA_INPUT, card_index };
942 const ALSAPool::Device &device = available_alsa_devices[card_index];
944 info.display_name = device.display_name();
945 info.num_channels = device.num_channels;
946 info.alsa_name = device.name;
947 info.alsa_info = device.info;
948 info.alsa_address = device.address;
949 devices.insert(make_pair(spec, info));
951 for (unsigned card_index = 0; card_index < num_ffmpeg_inputs; ++card_index) {
952 const DeviceSpec spec{ InputSourceType::FFMPEG_VIDEO_INPUT, card_index };
953 const AudioDevice *device = &ffmpeg_inputs[card_index];
955 info.display_name = device->display_name;
956 info.num_channels = 2;
957 devices.insert(make_pair(spec, info));
962 void AudioMixer::set_display_name(DeviceSpec device_spec, const string &name)
964 AudioDevice *device = find_audio_device(device_spec);
966 lock_guard<timed_mutex> lock(audio_mutex);
967 device->display_name = name;
970 void AudioMixer::serialize_device(DeviceSpec device_spec, DeviceSpecProto *device_spec_proto)
972 lock_guard<timed_mutex> lock(audio_mutex);
973 switch (device_spec.type) {
974 case InputSourceType::SILENCE:
975 device_spec_proto->set_type(DeviceSpecProto::SILENCE);
977 case InputSourceType::CAPTURE_CARD:
978 device_spec_proto->set_type(DeviceSpecProto::CAPTURE_CARD);
979 device_spec_proto->set_index(device_spec.index);
980 device_spec_proto->set_display_name(video_cards[device_spec.index].display_name);
982 case InputSourceType::ALSA_INPUT:
983 alsa_pool.serialize_device(device_spec.index, device_spec_proto);
985 case InputSourceType::FFMPEG_VIDEO_INPUT:
986 device_spec_proto->set_type(DeviceSpecProto::FFMPEG_VIDEO_INPUT);
987 device_spec_proto->set_index(device_spec.index);
988 device_spec_proto->set_display_name(ffmpeg_inputs[device_spec.index].display_name);
993 void AudioMixer::set_simple_input(unsigned card_index)
995 assert(card_index < num_capture_cards + num_ffmpeg_inputs);
996 InputMapping new_input_mapping;
997 InputMapping::Bus input;
999 if (card_index >= num_capture_cards) {
1000 input.device = DeviceSpec{InputSourceType::FFMPEG_VIDEO_INPUT, card_index - num_capture_cards};
1002 input.device = DeviceSpec{InputSourceType::CAPTURE_CARD, card_index};
1004 input.source_channel[0] = 0;
1005 input.source_channel[1] = 1;
1007 new_input_mapping.buses.push_back(input);
1009 lock_guard<timed_mutex> lock(audio_mutex);
1010 current_mapping_mode = MappingMode::SIMPLE;
1011 set_input_mapping_lock_held(new_input_mapping);
1012 fader_volume_db[0] = 0.0f;
1015 unsigned AudioMixer::get_simple_input() const
1017 lock_guard<timed_mutex> lock(audio_mutex);
1018 if (input_mapping.buses.size() == 1 &&
1019 input_mapping.buses[0].device.type == InputSourceType::CAPTURE_CARD &&
1020 input_mapping.buses[0].source_channel[0] == 0 &&
1021 input_mapping.buses[0].source_channel[1] == 1) {
1022 return input_mapping.buses[0].device.index;
1023 } else if (input_mapping.buses.size() == 1 &&
1024 input_mapping.buses[0].device.type == InputSourceType::FFMPEG_VIDEO_INPUT &&
1025 input_mapping.buses[0].source_channel[0] == 0 &&
1026 input_mapping.buses[0].source_channel[1] == 1) {
1027 return input_mapping.buses[0].device.index + num_capture_cards;
1029 return numeric_limits<unsigned>::max();
1033 void AudioMixer::set_input_mapping(const InputMapping &new_input_mapping)
1035 lock_guard<timed_mutex> lock(audio_mutex);
1036 set_input_mapping_lock_held(new_input_mapping);
1037 current_mapping_mode = MappingMode::MULTICHANNEL;
1040 AudioMixer::MappingMode AudioMixer::get_mapping_mode() const
1042 lock_guard<timed_mutex> lock(audio_mutex);
1043 return current_mapping_mode;
1046 void AudioMixer::set_input_mapping_lock_held(const InputMapping &new_input_mapping)
1048 map<DeviceSpec, set<unsigned>> interesting_channels;
1049 for (const InputMapping::Bus &bus : new_input_mapping.buses) {
1050 if (bus.device.type == InputSourceType::CAPTURE_CARD ||
1051 bus.device.type == InputSourceType::ALSA_INPUT ||
1052 bus.device.type == InputSourceType::FFMPEG_VIDEO_INPUT) {
1053 for (unsigned channel = 0; channel < 2; ++channel) {
1054 if (bus.source_channel[channel] != -1) {
1055 interesting_channels[bus.device].insert(bus.source_channel[channel]);
1059 assert(bus.device.type == InputSourceType::SILENCE);
1063 // Kill all the old metrics, and set up new ones.
1064 for (unsigned bus_index = 0; bus_index < input_mapping.buses.size(); ++bus_index) {
1065 BusMetrics &metrics = bus_metrics[bus_index];
1067 vector<pair<string, string>> labels_left = metrics.labels;
1068 labels_left.emplace_back("channel", "left");
1069 vector<pair<string, string>> labels_right = metrics.labels;
1070 labels_right.emplace_back("channel", "right");
1072 global_metrics.remove("bus_current_level_dbfs", labels_left);
1073 global_metrics.remove("bus_current_level_dbfs", labels_right);
1074 global_metrics.remove("bus_peak_level_dbfs", labels_left);
1075 global_metrics.remove("bus_peak_level_dbfs", labels_right);
1076 global_metrics.remove("bus_historic_peak_dbfs", metrics.labels);
1077 global_metrics.remove("bus_gain_staging_db", metrics.labels);
1078 global_metrics.remove("bus_compressor_attenuation_db", metrics.labels);
1080 bus_metrics.reset(new BusMetrics[new_input_mapping.buses.size()]);
1081 for (unsigned bus_index = 0; bus_index < new_input_mapping.buses.size(); ++bus_index) {
1082 const InputMapping::Bus &bus = new_input_mapping.buses[bus_index];
1083 BusMetrics &metrics = bus_metrics[bus_index];
1085 char bus_index_str[16], source_index_str[16], source_channels_str[64];
1086 snprintf(bus_index_str, sizeof(bus_index_str), "%u", bus_index);
1087 snprintf(source_index_str, sizeof(source_index_str), "%u", bus.device.index);
1088 snprintf(source_channels_str, sizeof(source_channels_str), "%d:%d", bus.source_channel[0], bus.source_channel[1]);
1090 vector<pair<string, string>> labels;
1091 metrics.labels.emplace_back("index", bus_index_str);
1092 metrics.labels.emplace_back("name", bus.name);
1093 if (bus.device.type == InputSourceType::SILENCE) {
1094 metrics.labels.emplace_back("source_type", "silence");
1095 } else if (bus.device.type == InputSourceType::CAPTURE_CARD) {
1096 metrics.labels.emplace_back("source_type", "capture_card");
1097 } else if (bus.device.type == InputSourceType::ALSA_INPUT) {
1098 metrics.labels.emplace_back("source_type", "alsa_input");
1099 } else if (bus.device.type == InputSourceType::FFMPEG_VIDEO_INPUT) {
1100 metrics.labels.emplace_back("source_type", "ffmpeg_video_input");
1104 metrics.labels.emplace_back("source_index", source_index_str);
1105 metrics.labels.emplace_back("source_channels", source_channels_str);
1107 vector<pair<string, string>> labels_left = metrics.labels;
1108 labels_left.emplace_back("channel", "left");
1109 vector<pair<string, string>> labels_right = metrics.labels;
1110 labels_right.emplace_back("channel", "right");
1112 global_metrics.add("bus_current_level_dbfs", labels_left, &metrics.current_level_dbfs[0], Metrics::TYPE_GAUGE);
1113 global_metrics.add("bus_current_level_dbfs", labels_right, &metrics.current_level_dbfs[1], Metrics::TYPE_GAUGE);
1114 global_metrics.add("bus_peak_level_dbfs", labels_left, &metrics.peak_level_dbfs[0], Metrics::TYPE_GAUGE);
1115 global_metrics.add("bus_peak_level_dbfs", labels_right, &metrics.peak_level_dbfs[1], Metrics::TYPE_GAUGE);
1116 global_metrics.add("bus_historic_peak_dbfs", metrics.labels, &metrics.historic_peak_dbfs, Metrics::TYPE_GAUGE);
1117 global_metrics.add("bus_gain_staging_db", metrics.labels, &metrics.gain_staging_db, Metrics::TYPE_GAUGE);
1118 global_metrics.add("bus_compressor_attenuation_db", metrics.labels, &metrics.compressor_attenuation_db, Metrics::TYPE_GAUGE);
1121 // Reset resamplers for all cards that don't have the exact same state as before.
1122 for (unsigned card_index = 0; card_index < MAX_VIDEO_CARDS; ++card_index) {
1123 const DeviceSpec device_spec{InputSourceType::CAPTURE_CARD, card_index};
1124 AudioDevice *device = find_audio_device(device_spec);
1125 if (device->interesting_channels != interesting_channels[device_spec]) {
1126 device->interesting_channels = interesting_channels[device_spec];
1127 reset_resampler_mutex_held(device_spec);
1130 for (unsigned card_index = 0; card_index < MAX_ALSA_CARDS; ++card_index) {
1131 const DeviceSpec device_spec{InputSourceType::ALSA_INPUT, card_index};
1132 AudioDevice *device = find_audio_device(device_spec);
1133 if (interesting_channels[device_spec].empty()) {
1134 alsa_pool.release_device(card_index);
1136 alsa_pool.hold_device(card_index);
1138 if (device->interesting_channels != interesting_channels[device_spec]) {
1139 device->interesting_channels = interesting_channels[device_spec];
1140 alsa_pool.reset_device(device_spec.index);
1141 reset_resampler_mutex_held(device_spec);
1144 for (unsigned card_index = 0; card_index < num_ffmpeg_inputs; ++card_index) {
1145 const DeviceSpec device_spec{InputSourceType::FFMPEG_VIDEO_INPUT, card_index};
1146 AudioDevice *device = find_audio_device(device_spec);
1147 if (device->interesting_channels != interesting_channels[device_spec]) {
1148 device->interesting_channels = interesting_channels[device_spec];
1149 reset_resampler_mutex_held(device_spec);
1153 input_mapping = new_input_mapping;
1156 InputMapping AudioMixer::get_input_mapping() const
1158 lock_guard<timed_mutex> lock(audio_mutex);
1159 return input_mapping;
1162 unsigned AudioMixer::num_buses() const
1164 lock_guard<timed_mutex> lock(audio_mutex);
1165 return input_mapping.buses.size();
1168 void AudioMixer::reset_peak(unsigned bus_index)
1170 lock_guard<timed_mutex> lock(audio_mutex);
1171 for (unsigned channel = 0; channel < 2; ++channel) {
1172 PeakHistory &history = peak_history[bus_index][channel];
1173 history.current_level = 0.0f;
1174 history.historic_peak = 0.0f;
1175 history.current_peak = 0.0f;
1176 history.last_peak = 0.0f;
1177 history.age_seconds = 0.0f;
1181 bool AudioMixer::is_mono(unsigned bus_index)
1183 lock_guard<timed_mutex> lock(audio_mutex);
1184 const InputMapping::Bus &bus = input_mapping.buses[bus_index];
1185 if (bus.device.type == InputSourceType::SILENCE) {
1188 assert(bus.device.type == InputSourceType::CAPTURE_CARD ||
1189 bus.device.type == InputSourceType::ALSA_INPUT ||
1190 bus.device.type == InputSourceType::FFMPEG_VIDEO_INPUT);
1191 return bus.source_channel[0] == bus.source_channel[1];
1195 AudioMixer *global_audio_mixer = nullptr;