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 class AudioMixer {
  33 public:
  34         AudioMixer(unsigned num_cards);
  35         void reset_card(unsigned card_index);
  36
  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);
  41
  42         // See comments inside get_output().
  43         void set_current_loudness(double level_lufs) { loudness_lufs = level_lufs; }
  44
  45         void set_fader_volume(unsigned card_index, float level_db) { cards[card_index].fader_volume_db = level_db; }
  46
  47         void set_locut_cutoff(float cutoff_hz)
  48         {
  49                 locut_cutoff_hz = cutoff_hz;
  50         }
  51
  52         void set_locut_enabled(bool enabled)
  53         {
  54                 locut_enabled = enabled;
  55         }
  56
  57         bool get_locut_enabled() const
  58         {
  59                 return locut_enabled;
  60         }
  61
  62         float get_limiter_threshold_dbfs() const
  63         {
  64                 return limiter_threshold_dbfs;
  65         }
  66
  67         float get_compressor_threshold_dbfs() const
  68         {
  69                 return compressor_threshold_dbfs;
  70         }
  71
  72         void set_limiter_threshold_dbfs(float threshold_dbfs)
  73         {
  74                 limiter_threshold_dbfs = threshold_dbfs;
  75         }
  76
  77         void set_compressor_threshold_dbfs(float threshold_dbfs)
  78         {
  79                 compressor_threshold_dbfs = threshold_dbfs;
  80         }
  81
  82         void set_limiter_enabled(bool enabled)
  83         {
  84                 limiter_enabled = enabled;
  85         }
  86
  87         bool get_limiter_enabled() const
  88         {
  89                 return limiter_enabled;
  90         }
  91
  92         void set_compressor_enabled(bool enabled)
  93         {
  94                 compressor_enabled = enabled;
  95         }
  96
  97         bool get_compressor_enabled() const
  98         {
  99                 return compressor_enabled;
 100         }
 101
 102         void set_gain_staging_db(float gain_db)
 103         {
 104                 std::unique_lock<std::mutex> lock(compressor_mutex);
 105                 level_compressor_enabled = false;
 106                 gain_staging_db = gain_db;
 107         }
 108
 109         float get_gain_staging_db() const
 110         {
 111                 std::unique_lock<std::mutex> lock(compressor_mutex);
 112                 return gain_staging_db;
 113         }
 114
 115         void set_gain_staging_auto(bool enabled)
 116         {
 117                 std::unique_lock<std::mutex> lock(compressor_mutex);
 118                 level_compressor_enabled = enabled;
 119         }
 120
 121         bool get_gain_staging_auto() const
 122         {
 123                 std::unique_lock<std::mutex> lock(compressor_mutex);
 124                 return level_compressor_enabled;
 125         }
 126
 127         void set_final_makeup_gain_db(float gain_db)
 128         {
 129                 std::unique_lock<std::mutex> lock(compressor_mutex);
 130                 final_makeup_gain_auto = false;
 131                 final_makeup_gain = from_db(gain_db);
 132         }
 133
 134         float get_final_makeup_gain_db()
 135         {
 136                 std::unique_lock<std::mutex> lock(compressor_mutex);
 137                 return to_db(final_makeup_gain);
 138         }
 139
 140         void set_final_makeup_gain_auto(bool enabled)
 141         {
 142                 std::unique_lock<std::mutex> lock(compressor_mutex);
 143                 final_makeup_gain_auto = enabled;
 144         }
 145
 146         bool get_final_makeup_gain_auto() const
 147         {
 148                 std::unique_lock<std::mutex> lock(compressor_mutex);
 149                 return final_makeup_gain_auto;
 150         }
 151
 152 private:
 153         unsigned num_cards;
 154
 155         struct CaptureCard {
 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};
 160         };
 161         CaptureCard cards[MAX_CARDS];
 162
 163         StereoFilter locut;  // Default cutoff 120 Hz, 24 dB/oct.
 164         std::atomic<float> locut_cutoff_hz;
 165         std::atomic<bool> locut_enabled{true};
 166
 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.
 172
 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.
 175
 176         std::atomic<float> loudness_lufs{ref_level_lufs};
 177
 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};
 184
 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.
 187 };
 188
 189 #endif  // !defined(_AUDIO_MIXER_H)