2 #define _AUDIO_MIXER_H 1
4 // The audio mixer, dealing with extracting the right signals from
5 // each capture card, resampling signals so that they are in sync,
6 // processing them with effects (if desired), and then mixing them
7 // all together into one final audio signal.
9 // All operations on AudioMixer (except destruction) are thread-safe.
11 // TODO: There might be more audio stuff that should be moved here
21 #include "bmusb/bmusb.h"
25 #include "resampling_queue.h"
26 #include "stereocompressor.h"
32 enum class InputSourceType { SILENCE, CAPTURE_CARD };
37 InputSourceType input_source_type;
38 unsigned input_source_index;
39 int source_channel[2] { -1, -1 }; // Left and right. -1 = none.
42 std::vector<Input> inputs;
47 AudioMixer(unsigned num_cards);
48 void reset_card(unsigned card_index);
50 // frame_length is in TIMEBASE units.
51 void add_audio(unsigned card_index, const uint8_t *data, unsigned num_samples, bmusb::AudioFormat audio_format, int64_t frame_length);
52 void add_silence(unsigned card_index, unsigned samples_per_frame, unsigned num_frames, int64_t frame_length);
53 std::vector<float> get_output(double pts, unsigned num_samples, ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy);
55 // See comments inside get_output().
56 void set_current_loudness(double level_lufs) { loudness_lufs = level_lufs; }
58 void set_fader_volume(unsigned card_index, float level_db) { cards[card_index].fader_volume_db = level_db; }
59 std::vector<std::string> get_names() const;
60 void set_name(unsigned card_index, const std::string &name);
62 void set_input_mapping(const InputMapping &input_mapping);
63 InputMapping get_input_mapping() const;
65 void set_locut_cutoff(float cutoff_hz)
67 locut_cutoff_hz = cutoff_hz;
70 void set_locut_enabled(bool enabled)
72 locut_enabled = enabled;
75 bool get_locut_enabled() const
80 float get_limiter_threshold_dbfs() const
82 return limiter_threshold_dbfs;
85 float get_compressor_threshold_dbfs() const
87 return compressor_threshold_dbfs;
90 void set_limiter_threshold_dbfs(float threshold_dbfs)
92 limiter_threshold_dbfs = threshold_dbfs;
95 void set_compressor_threshold_dbfs(float threshold_dbfs)
97 compressor_threshold_dbfs = threshold_dbfs;
100 void set_limiter_enabled(bool enabled)
102 limiter_enabled = enabled;
105 bool get_limiter_enabled() const
107 return limiter_enabled;
110 void set_compressor_enabled(bool enabled)
112 compressor_enabled = enabled;
115 bool get_compressor_enabled() const
117 return compressor_enabled;
120 void set_gain_staging_db(float gain_db)
122 std::unique_lock<std::mutex> lock(compressor_mutex);
123 level_compressor_enabled = false;
124 gain_staging_db = gain_db;
127 float get_gain_staging_db() const
129 std::unique_lock<std::mutex> lock(compressor_mutex);
130 return gain_staging_db;
133 void set_gain_staging_auto(bool enabled)
135 std::unique_lock<std::mutex> lock(compressor_mutex);
136 level_compressor_enabled = enabled;
139 bool get_gain_staging_auto() const
141 std::unique_lock<std::mutex> lock(compressor_mutex);
142 return level_compressor_enabled;
145 void set_final_makeup_gain_db(float gain_db)
147 std::unique_lock<std::mutex> lock(compressor_mutex);
148 final_makeup_gain_auto = false;
149 final_makeup_gain = from_db(gain_db);
152 float get_final_makeup_gain_db()
154 std::unique_lock<std::mutex> lock(compressor_mutex);
155 return to_db(final_makeup_gain);
158 void set_final_makeup_gain_auto(bool enabled)
160 std::unique_lock<std::mutex> lock(compressor_mutex);
161 final_makeup_gain_auto = enabled;
164 bool get_final_makeup_gain_auto() const
166 std::unique_lock<std::mutex> lock(compressor_mutex);
167 return final_makeup_gain_auto;
174 std::atomic<float> fader_volume_db{0.0f};
176 // Everything below audio_mutex is protected by it.
177 mutable std::mutex audio_mutex;
178 std::unique_ptr<ResamplingQueue> resampling_queue;
179 int64_t next_local_pts = 0;
182 CaptureCard cards[MAX_CARDS];
184 StereoFilter locut; // Default cutoff 120 Hz, 24 dB/oct.
185 std::atomic<float> locut_cutoff_hz;
186 std::atomic<bool> locut_enabled{true};
188 // First compressor; takes us up to about -12 dBFS.
189 mutable std::mutex compressor_mutex;
190 StereoCompressor level_compressor; // Under compressor_mutex. Used to set/override gain_staging_db if <level_compressor_enabled>.
191 float gain_staging_db = 0.0f; // Under compressor_mutex.
192 bool level_compressor_enabled = true; // Under compressor_mutex.
194 static constexpr float ref_level_dbfs = -14.0f; // Chosen so that we end up around 0 LU in practice.
195 static constexpr float ref_level_lufs = -23.0f; // 0 LU, more or less by definition.
197 std::atomic<float> loudness_lufs{ref_level_lufs};
199 StereoCompressor limiter;
200 std::atomic<float> limiter_threshold_dbfs{ref_level_dbfs + 4.0f}; // 4 dB.
201 std::atomic<bool> limiter_enabled{true};
202 StereoCompressor compressor;
203 std::atomic<float> compressor_threshold_dbfs{ref_level_dbfs - 12.0f}; // -12 dB.
204 std::atomic<bool> compressor_enabled{true};
206 double final_makeup_gain = 1.0; // Under compressor_mutex. Read/write by the user. Note: Not in dB, we want the numeric precision so that we can change it slowly.
207 bool final_makeup_gain_auto = true; // Under compressor_mutex.
209 mutable std::mutex mapping_mutex;
210 InputMapping input_mapping; // Under mapping_mutex.
213 #endif // !defined(_AUDIO_MIXER_H)