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 <map>
  18 #include <memory>
  19 #include <mutex>
  20 #include <set>
  21 #include <vector>
  22
  23 #include "bmusb/bmusb.h"
  24 #include "db.h"
  25 #include "defs.h"
  26 #include "filter.h"
  27 #include "resampling_queue.h"
  28 #include "stereocompressor.h"
  29
  30 namespace bmusb {
  31 struct AudioFormat;
  32 }  // namespace bmusb
  33
  34 enum class InputSourceType { SILENCE, CAPTURE_CARD };
  35
  36 struct InputMapping {
  37         struct Bus {
  38                 std::string name;
  39                 InputSourceType input_source_type;
  40                 unsigned input_source_index;
  41                 int source_channel[2] { -1, -1 };  // Left and right. -1 = none.
  42         };
  43
  44         std::vector<Bus> buses;
  45 };
  46
  47 class AudioMixer {
  48 public:
  49         AudioMixer(unsigned num_cards);
  50         void reset_card(unsigned card_index);
  51
  52         // frame_length is in TIMEBASE units.
  53         void add_audio(unsigned card_index, const uint8_t *data, unsigned num_samples, bmusb::AudioFormat audio_format, int64_t frame_length);
  54         void add_silence(unsigned card_index, unsigned samples_per_frame, unsigned num_frames, int64_t frame_length);
  55         std::vector<float> get_output(double pts, unsigned num_samples, ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy);
  56
  57         // See comments inside get_output().
  58         void set_current_loudness(double level_lufs) { loudness_lufs = level_lufs; }
  59
  60         void set_fader_volume(unsigned bus_index, float level_db) { fader_volume_db[bus_index] = level_db; }
  61         std::vector<std::string> get_names() const;
  62         void set_name(unsigned card_index, const std::string &name);
  63
  64         void set_input_mapping(const InputMapping &input_mapping);
  65         InputMapping get_input_mapping() const;
  66
  67         void set_locut_cutoff(float cutoff_hz)
  68         {
  69                 locut_cutoff_hz = cutoff_hz;
  70         }
  71
  72         void set_locut_enabled(bool enabled)
  73         {
  74                 locut_enabled = enabled;
  75         }
  76
  77         bool get_locut_enabled() const
  78         {
  79                 return locut_enabled;
  80         }
  81
  82         float get_limiter_threshold_dbfs() const
  83         {
  84                 return limiter_threshold_dbfs;
  85         }
  86
  87         float get_compressor_threshold_dbfs() const
  88         {
  89                 return compressor_threshold_dbfs;
  90         }
  91
  92         void set_limiter_threshold_dbfs(float threshold_dbfs)
  93         {
  94                 limiter_threshold_dbfs = threshold_dbfs;
  95         }
  96
  97         void set_compressor_threshold_dbfs(float threshold_dbfs)
  98         {
  99                 compressor_threshold_dbfs = threshold_dbfs;
 100         }
 101
 102         void set_limiter_enabled(bool enabled)
 103         {
 104                 limiter_enabled = enabled;
 105         }
 106
 107         bool get_limiter_enabled() const
 108         {
 109                 return limiter_enabled;
 110         }
 111
 112         void set_compressor_enabled(bool enabled)
 113         {
 114                 compressor_enabled = enabled;
 115         }
 116
 117         bool get_compressor_enabled() const
 118         {
 119                 return compressor_enabled;
 120         }
 121
 122         void set_gain_staging_db(float gain_db)
 123         {
 124                 std::unique_lock<std::mutex> lock(compressor_mutex);
 125                 level_compressor_enabled = false;
 126                 gain_staging_db = gain_db;
 127         }
 128
 129         float get_gain_staging_db() const
 130         {
 131                 std::unique_lock<std::mutex> lock(compressor_mutex);
 132                 return gain_staging_db;
 133         }
 134
 135         void set_gain_staging_auto(bool enabled)
 136         {
 137                 std::unique_lock<std::mutex> lock(compressor_mutex);
 138                 level_compressor_enabled = enabled;
 139         }
 140
 141         bool get_gain_staging_auto() const
 142         {
 143                 std::unique_lock<std::mutex> lock(compressor_mutex);
 144                 return level_compressor_enabled;
 145         }
 146
 147         void set_final_makeup_gain_db(float gain_db)
 148         {
 149                 std::unique_lock<std::mutex> lock(compressor_mutex);
 150                 final_makeup_gain_auto = false;
 151                 final_makeup_gain = from_db(gain_db);
 152         }
 153
 154         float get_final_makeup_gain_db()
 155         {
 156                 std::unique_lock<std::mutex> lock(compressor_mutex);
 157                 return to_db(final_makeup_gain);
 158         }
 159
 160         void set_final_makeup_gain_auto(bool enabled)
 161         {
 162                 std::unique_lock<std::mutex> lock(compressor_mutex);
 163                 final_makeup_gain_auto = enabled;
 164         }
 165
 166         bool get_final_makeup_gain_auto() const
 167         {
 168                 std::unique_lock<std::mutex> lock(compressor_mutex);
 169                 return final_makeup_gain_auto;
 170         }
 171
 172 private:
 173         void find_sample_src_from_capture_card(const std::vector<float> *samples_card, unsigned card_index, int source_channel, const float **srcptr, unsigned *stride);
 174         void reset_card_mutex_held(unsigned card_index);
 175
 176         unsigned num_cards;
 177
 178         mutable std::mutex audio_mutex;
 179
 180         struct CaptureCard {
 181                 std::unique_ptr<ResamplingQueue> resampling_queue;
 182                 int64_t next_local_pts = 0;
 183                 std::string name;
 184                 // Which channels we consider interesting (ie., are part of some input_mapping).
 185                 std::set<unsigned> interesting_channels;
 186         };
 187         CaptureCard cards[MAX_CARDS];  // Under audio_mutex.
 188
 189         StereoFilter locut;  // Default cutoff 120 Hz, 24 dB/oct.
 190         std::atomic<float> locut_cutoff_hz;
 191         std::atomic<bool> locut_enabled{true};
 192
 193         // First compressor; takes us up to about -12 dBFS.
 194         mutable std::mutex compressor_mutex;
 195         StereoCompressor level_compressor;  // Under compressor_mutex. Used to set/override gain_staging_db if <level_compressor_enabled>.
 196         float gain_staging_db = 0.0f;  // Under compressor_mutex.
 197         bool level_compressor_enabled = true;  // Under compressor_mutex.
 198
 199         static constexpr float ref_level_dbfs = -14.0f;  // Chosen so that we end up around 0 LU in practice.
 200         static constexpr float ref_level_lufs = -23.0f;  // 0 LU, more or less by definition.
 201
 202         std::atomic<float> loudness_lufs{ref_level_lufs};
 203
 204         StereoCompressor limiter;
 205         std::atomic<float> limiter_threshold_dbfs{ref_level_dbfs + 4.0f};   // 4 dB.
 206         std::atomic<bool> limiter_enabled{true};
 207         StereoCompressor compressor;
 208         std::atomic<float> compressor_threshold_dbfs{ref_level_dbfs - 12.0f};  // -12 dB.
 209         std::atomic<bool> compressor_enabled{true};
 210
 211         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.
 212         bool final_makeup_gain_auto = true;  // Under compressor_mutex.
 213
 214         InputMapping input_mapping;  // Under audio_mutex.
 215         std::atomic<float> fader_volume_db[MAX_BUSES] {{ 0.0f }};
 216 };
 217
 218 #endif  // !defined(_AUDIO_MIXER_H)