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_fader_volume(unsigned card_index, float level_db) { cards[card_index].fader_volume_db = level_db; }
47 void set_locut_cutoff(float cutoff_hz)
49 locut_cutoff_hz = cutoff_hz;
52 void set_locut_enabled(bool enabled)
54 locut_enabled = enabled;
57 bool get_locut_enabled() const
62 float get_limiter_threshold_dbfs() const
64 return limiter_threshold_dbfs;
67 float get_compressor_threshold_dbfs() const
69 return compressor_threshold_dbfs;
72 void set_limiter_threshold_dbfs(float threshold_dbfs)
74 limiter_threshold_dbfs = threshold_dbfs;
77 void set_compressor_threshold_dbfs(float threshold_dbfs)
79 compressor_threshold_dbfs = threshold_dbfs;
82 void set_limiter_enabled(bool enabled)
84 limiter_enabled = enabled;
87 bool get_limiter_enabled() const
89 return limiter_enabled;
92 void set_compressor_enabled(bool enabled)
94 compressor_enabled = enabled;
97 bool get_compressor_enabled() const
99 return compressor_enabled;
102 void set_gain_staging_db(float gain_db)
104 std::unique_lock<std::mutex> lock(compressor_mutex);
105 level_compressor_enabled = false;
106 gain_staging_db = gain_db;
109 float get_gain_staging_db() const
111 std::unique_lock<std::mutex> lock(compressor_mutex);
112 return gain_staging_db;
115 void set_gain_staging_auto(bool enabled)
117 std::unique_lock<std::mutex> lock(compressor_mutex);
118 level_compressor_enabled = enabled;
121 bool get_gain_staging_auto() const
123 std::unique_lock<std::mutex> lock(compressor_mutex);
124 return level_compressor_enabled;
127 void set_final_makeup_gain_db(float gain_db)
129 std::unique_lock<std::mutex> lock(compressor_mutex);
130 final_makeup_gain_auto = false;
131 final_makeup_gain = from_db(gain_db);
134 float get_final_makeup_gain_db()
136 std::unique_lock<std::mutex> lock(compressor_mutex);
137 return to_db(final_makeup_gain);
140 void set_final_makeup_gain_auto(bool enabled)
142 std::unique_lock<std::mutex> lock(compressor_mutex);
143 final_makeup_gain_auto = enabled;
146 bool get_final_makeup_gain_auto() const
148 std::unique_lock<std::mutex> lock(compressor_mutex);
149 return final_makeup_gain_auto;
156 std::mutex audio_mutex;
157 std::unique_ptr<ResamplingQueue> resampling_queue; // Under audio_mutex.
158 int64_t next_local_pts = 0; // Beginning of next frame, in TIMEBASE units. Under audio_mutex.
159 std::atomic<float> fader_volume_db{0.0f};
161 CaptureCard cards[MAX_CARDS];
163 StereoFilter locut; // Default cutoff 120 Hz, 24 dB/oct.
164 std::atomic<float> locut_cutoff_hz;
165 std::atomic<bool> locut_enabled{true};
167 // First compressor; takes us up to about -12 dBFS.
168 mutable std::mutex compressor_mutex;
169 StereoCompressor level_compressor; // Under compressor_mutex. Used to set/override gain_staging_db if <level_compressor_enabled>.
170 float gain_staging_db = 0.0f; // Under compressor_mutex.
171 bool level_compressor_enabled = true; // Under compressor_mutex.
173 static constexpr float ref_level_dbfs = -14.0f; // Chosen so that we end up around 0 LU in practice.
174 static constexpr float ref_level_lufs = -23.0f; // 0 LU, more or less by definition.
176 std::atomic<float> loudness_lufs{ref_level_lufs};
178 StereoCompressor limiter;
179 std::atomic<float> limiter_threshold_dbfs{ref_level_dbfs + 4.0f}; // 4 dB.
180 std::atomic<bool> limiter_enabled{true};
181 StereoCompressor compressor;
182 std::atomic<float> compressor_threshold_dbfs{ref_level_dbfs - 12.0f}; // -12 dB.
183 std::atomic<bool> compressor_enabled{true};
185 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.
186 bool final_makeup_gain_auto = true; // Under compressor_mutex.
189 #endif // !defined(_AUDIO_MIXER_H)