git.sesse.net Git - nageru/blob - audio_mixer.h

   1 #ifndef _AUDIO_MIXER_H
   2 #define _AUDIO_MIXER_H 1
   3
   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.
   8 //
   9 // All operations on AudioMixer (except destruction) are thread-safe.
  10 //
  11 // TODO: There might be more audio stuff that should be moved here
  12 // from Mixer.
  13
  14 #include <math.h>
  15 #include <stdint.h>
  16 #include <atomic>
  17 #include <memory>
  18 #include <mutex>
  19 #include <vector>
  20
  21 #include "bmusb/bmusb.h"
  22 #include "db.h"
  23 #include "defs.h"
  24 #include "filter.h"
  25 #include "resampling_queue.h"
  26 #include "stereocompressor.h"
  27
  28 namespace bmusb {
  29 struct AudioFormat;
  30 }  // namespace bmusb
  31
  32 enum class InputSourceType { SILENCE, CAPTURE_CARD };
  33
  34 struct InputMapping {
  35         struct Input {
  36                 std::string name;
  37                 InputSourceType input_source_type;
  38                 unsigned input_source_index;
  39                 int source_channel[2] { -1, -1 };  // Left and right. -1 = none.
  40         };
  41
  42         std::vector<Input> inputs;
  43 };
  44
  45 class AudioMixer {
  46 public:
  47         AudioMixer(unsigned num_cards);
  48         void reset_card(unsigned card_index);
  49
  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);
  54
  55         // See comments inside get_output().
  56         void set_current_loudness(double level_lufs) { loudness_lufs = level_lufs; }
  57
  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);
  61
  62         void set_input_mapping(const InputMapping &input_mapping);
  63         InputMapping get_input_mapping() const;
  64
  65         void set_locut_cutoff(float cutoff_hz)
  66         {
  67                 locut_cutoff_hz = cutoff_hz;
  68         }
  69
  70         void set_locut_enabled(bool enabled)
  71         {
  72                 locut_enabled = enabled;
  73         }
  74
  75         bool get_locut_enabled() const
  76         {
  77                 return locut_enabled;
  78         }
  79
  80         float get_limiter_threshold_dbfs() const
  81         {
  82                 return limiter_threshold_dbfs;
  83         }
  84
  85         float get_compressor_threshold_dbfs() const
  86         {
  87                 return compressor_threshold_dbfs;
  88         }
  89
  90         void set_limiter_threshold_dbfs(float threshold_dbfs)
  91         {
  92                 limiter_threshold_dbfs = threshold_dbfs;
  93         }
  94
  95         void set_compressor_threshold_dbfs(float threshold_dbfs)
  96         {
  97                 compressor_threshold_dbfs = threshold_dbfs;
  98         }
  99
 100         void set_limiter_enabled(bool enabled)
 101         {
 102                 limiter_enabled = enabled;
 103         }
 104
 105         bool get_limiter_enabled() const
 106         {
 107                 return limiter_enabled;
 108         }
 109
 110         void set_compressor_enabled(bool enabled)
 111         {
 112                 compressor_enabled = enabled;
 113         }
 114
 115         bool get_compressor_enabled() const
 116         {
 117                 return compressor_enabled;
 118         }
 119
 120         void set_gain_staging_db(float gain_db)
 121         {
 122                 std::unique_lock<std::mutex> lock(compressor_mutex);
 123                 level_compressor_enabled = false;
 124                 gain_staging_db = gain_db;
 125         }
 126
 127         float get_gain_staging_db() const
 128         {
 129                 std::unique_lock<std::mutex> lock(compressor_mutex);
 130                 return gain_staging_db;
 131         }
 132
 133         void set_gain_staging_auto(bool enabled)
 134         {
 135                 std::unique_lock<std::mutex> lock(compressor_mutex);
 136                 level_compressor_enabled = enabled;
 137         }
 138
 139         bool get_gain_staging_auto() const
 140         {
 141                 std::unique_lock<std::mutex> lock(compressor_mutex);
 142                 return level_compressor_enabled;
 143         }
 144
 145         void set_final_makeup_gain_db(float gain_db)
 146         {
 147                 std::unique_lock<std::mutex> lock(compressor_mutex);
 148                 final_makeup_gain_auto = false;
 149                 final_makeup_gain = from_db(gain_db);
 150         }
 151
 152         float get_final_makeup_gain_db()
 153         {
 154                 std::unique_lock<std::mutex> lock(compressor_mutex);
 155                 return to_db(final_makeup_gain);
 156         }
 157
 158         void set_final_makeup_gain_auto(bool enabled)
 159         {
 160                 std::unique_lock<std::mutex> lock(compressor_mutex);
 161                 final_makeup_gain_auto = enabled;
 162         }
 163
 164         bool get_final_makeup_gain_auto() const
 165         {
 166                 std::unique_lock<std::mutex> lock(compressor_mutex);
 167                 return final_makeup_gain_auto;
 168         }
 169
 170 private:
 171         unsigned num_cards;
 172
 173         struct CaptureCard {
 174                 std::atomic<float> fader_volume_db{0.0f};
 175
 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;
 180                 std::string name;
 181         };
 182         CaptureCard cards[MAX_CARDS];
 183
 184         StereoFilter locut;  // Default cutoff 120 Hz, 24 dB/oct.
 185         std::atomic<float> locut_cutoff_hz;
 186         std::atomic<bool> locut_enabled{true};
 187
 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.
 193
 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.
 196
 197         std::atomic<float> loudness_lufs{ref_level_lufs};
 198
 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};
 205
 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.
 208
 209         mutable std::mutex mapping_mutex;
 210         InputMapping input_mapping;  // Under mapping_mutex.
 211 };
 212
 213 #endif  // !defined(_AUDIO_MIXER_H)