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"
34 AudioMixer(unsigned num_cards);
35 void reset_card(unsigned card_index);
37 // frame_length is in TIMEBASE units.
38 void add_audio(unsigned card_index, const uint8_t *data, unsigned num_samples, bmusb::AudioFormat audio_format, int64_t frame_length);
39 void add_silence(unsigned card_index, unsigned samples_per_frame, unsigned num_frames, int64_t frame_length);
40 std::vector<float> get_output(double pts, unsigned num_samples, ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy);
42 // See comments inside get_output().
43 void set_current_loudness(double level_lufs) { loudness_lufs = level_lufs; }
45 void set_locut_cutoff(float cutoff_hz)
47 locut_cutoff_hz = cutoff_hz;
50 void set_locut_enabled(bool enabled)
52 locut_enabled = enabled;
55 bool get_locut_enabled() const
60 float get_limiter_threshold_dbfs() const
62 return limiter_threshold_dbfs;
65 float get_compressor_threshold_dbfs() const
67 return compressor_threshold_dbfs;
70 void set_limiter_threshold_dbfs(float threshold_dbfs)
72 limiter_threshold_dbfs = threshold_dbfs;
75 void set_compressor_threshold_dbfs(float threshold_dbfs)
77 compressor_threshold_dbfs = threshold_dbfs;
80 void set_limiter_enabled(bool enabled)
82 limiter_enabled = enabled;
85 bool get_limiter_enabled() const
87 return limiter_enabled;
90 void set_compressor_enabled(bool enabled)
92 compressor_enabled = enabled;
95 bool get_compressor_enabled() const
97 return compressor_enabled;
100 void set_gain_staging_db(float gain_db)
102 std::unique_lock<std::mutex> lock(compressor_mutex);
103 level_compressor_enabled = false;
104 gain_staging_db = gain_db;
107 float get_gain_staging_db() const
109 std::unique_lock<std::mutex> lock(compressor_mutex);
110 return gain_staging_db;
113 void set_gain_staging_auto(bool enabled)
115 std::unique_lock<std::mutex> lock(compressor_mutex);
116 level_compressor_enabled = enabled;
119 bool get_gain_staging_auto() const
121 std::unique_lock<std::mutex> lock(compressor_mutex);
122 return level_compressor_enabled;
125 void set_final_makeup_gain_db(float gain_db)
127 std::unique_lock<std::mutex> lock(compressor_mutex);
128 final_makeup_gain_auto = false;
129 final_makeup_gain = from_db(gain_db);
132 float get_final_makeup_gain_db()
134 std::unique_lock<std::mutex> lock(compressor_mutex);
135 return to_db(final_makeup_gain);
138 void set_final_makeup_gain_auto(bool enabled)
140 std::unique_lock<std::mutex> lock(compressor_mutex);
141 final_makeup_gain_auto = enabled;
144 bool get_final_makeup_gain_auto() const
146 std::unique_lock<std::mutex> lock(compressor_mutex);
147 return final_makeup_gain_auto;
154 std::mutex audio_mutex;
155 std::unique_ptr<ResamplingQueue> resampling_queue; // Under audio_mutex.
156 int64_t next_local_pts = 0; // Beginning of next frame, in TIMEBASE units. Under audio_mutex.
158 CaptureCard cards[MAX_CARDS];
160 StereoFilter locut; // Default cutoff 120 Hz, 24 dB/oct.
161 std::atomic<float> locut_cutoff_hz;
162 std::atomic<bool> locut_enabled{true};
164 // First compressor; takes us up to about -12 dBFS.
165 mutable std::mutex compressor_mutex;
166 StereoCompressor level_compressor; // Under compressor_mutex. Used to set/override gain_staging_db if <level_compressor_enabled>.
167 float gain_staging_db = 0.0f; // Under compressor_mutex.
168 bool level_compressor_enabled = true; // Under compressor_mutex.
170 static constexpr float ref_level_dbfs = -14.0f; // Chosen so that we end up around 0 LU in practice.
171 static constexpr float ref_level_lufs = -23.0f; // 0 LU, more or less by definition.
173 std::atomic<float> loudness_lufs{ref_level_lufs};
175 StereoCompressor limiter;
176 std::atomic<float> limiter_threshold_dbfs{ref_level_dbfs + 4.0f}; // 4 dB.
177 std::atomic<bool> limiter_enabled{true};
178 StereoCompressor compressor;
179 std::atomic<float> compressor_threshold_dbfs{ref_level_dbfs - 12.0f}; // -12 dB.
180 std::atomic<bool> compressor_enabled{true};
182 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.
183 bool final_makeup_gain_auto = true; // Under compressor_mutex.
186 #endif // !defined(_AUDIO_MIXER_H)