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 "defs.h"
  23 #include "filter.h"
  24 #include "resampling_queue.h"
  25 #include "stereocompressor.h"
  26
  27 namespace bmusb {
  28 struct AudioFormat;
  29 }  // namespace bmusb
  30
  31 class AudioMixer {
  32 public:
  33         AudioMixer(unsigned num_cards);
  34         void reset_card(unsigned card_index);
  35
  36         // frame_length is in TIMEBASE units.
  37         void add_audio(unsigned card_index, const uint8_t *data, unsigned num_samples, bmusb::AudioFormat audio_format, int64_t frame_length);
  38         void add_silence(unsigned card_index, unsigned samples_per_frame, unsigned num_frames, int64_t frame_length);
  39         std::vector<float> get_output(double pts, unsigned num_samples, ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy);
  40
  41         // See comments inside get_output().
  42         void set_current_loudness(double level_lufs) { loudness_lufs = level_lufs; }
  43
  44         void set_locut_cutoff(float cutoff_hz)
  45         {
  46                 locut_cutoff_hz = cutoff_hz;
  47         }
  48
  49         void set_locut_enabled(bool enabled)
  50         {
  51                 locut_enabled = enabled;
  52         }
  53
  54         bool get_locut_enabled() const
  55         {
  56                 return locut_enabled;
  57         }
  58
  59         float get_limiter_threshold_dbfs() const
  60         {
  61                 return limiter_threshold_dbfs;
  62         }
  63
  64         float get_compressor_threshold_dbfs() const
  65         {
  66                 return compressor_threshold_dbfs;
  67         }
  68
  69         void set_limiter_threshold_dbfs(float threshold_dbfs)
  70         {
  71                 limiter_threshold_dbfs = threshold_dbfs;
  72         }
  73
  74         void set_compressor_threshold_dbfs(float threshold_dbfs)
  75         {
  76                 compressor_threshold_dbfs = threshold_dbfs;
  77         }
  78
  79         void set_limiter_enabled(bool enabled)
  80         {
  81                 limiter_enabled = enabled;
  82         }
  83
  84         bool get_limiter_enabled() const
  85         {
  86                 return limiter_enabled;
  87         }
  88
  89         void set_compressor_enabled(bool enabled)
  90         {
  91                 compressor_enabled = enabled;
  92         }
  93
  94         bool get_compressor_enabled() const
  95         {
  96                 return compressor_enabled;
  97         }
  98
  99         void set_gain_staging_db(float gain_db)
 100         {
 101                 std::unique_lock<std::mutex> lock(compressor_mutex);
 102                 level_compressor_enabled = false;
 103                 gain_staging_db = gain_db;
 104         }
 105
 106         float get_gain_staging_db() const
 107         {
 108                 std::unique_lock<std::mutex> lock(compressor_mutex);
 109                 return gain_staging_db;
 110         }
 111
 112         void set_gain_staging_auto(bool enabled)
 113         {
 114                 std::unique_lock<std::mutex> lock(compressor_mutex);
 115                 level_compressor_enabled = enabled;
 116         }
 117
 118         bool get_gain_staging_auto() const
 119         {
 120                 std::unique_lock<std::mutex> lock(compressor_mutex);
 121                 return level_compressor_enabled;
 122         }
 123
 124         void set_final_makeup_gain_db(float gain_db)
 125         {
 126                 std::unique_lock<std::mutex> lock(compressor_mutex);
 127                 final_makeup_gain_auto = false;
 128                 final_makeup_gain = pow(10.0f, gain_db / 20.0f);
 129         }
 130
 131         float get_final_makeup_gain_db()
 132         {
 133                 std::unique_lock<std::mutex> lock(compressor_mutex);
 134                 return 20.0 * log10(final_makeup_gain);
 135         }
 136
 137         void set_final_makeup_gain_auto(bool enabled)
 138         {
 139                 std::unique_lock<std::mutex> lock(compressor_mutex);
 140                 final_makeup_gain_auto = enabled;
 141         }
 142
 143         bool get_final_makeup_gain_auto() const
 144         {
 145                 std::unique_lock<std::mutex> lock(compressor_mutex);
 146                 return final_makeup_gain_auto;
 147         }
 148
 149 private:
 150         unsigned num_cards;
 151
 152         struct CaptureCard {
 153                 std::mutex audio_mutex;
 154                 std::unique_ptr<ResamplingQueue> resampling_queue;  // Under audio_mutex.
 155                 int64_t next_local_pts = 0;  // Beginning of next frame, in TIMEBASE units. Under audio_mutex.
 156         };
 157         CaptureCard cards[MAX_CARDS];
 158
 159         StereoFilter locut;  // Default cutoff 120 Hz, 24 dB/oct.
 160         std::atomic<float> locut_cutoff_hz;
 161         std::atomic<bool> locut_enabled{true};
 162
 163         // First compressor; takes us up to about -12 dBFS.
 164         mutable std::mutex compressor_mutex;
 165         StereoCompressor level_compressor;  // Under compressor_mutex. Used to set/override gain_staging_db if <level_compressor_enabled>.
 166         float gain_staging_db = 0.0f;  // Under compressor_mutex.
 167         bool level_compressor_enabled = true;  // Under compressor_mutex.
 168
 169         static constexpr float ref_level_dbfs = -14.0f;  // Chosen so that we end up around 0 LU in practice.
 170         static constexpr float ref_level_lufs = -23.0f;  // 0 LU, more or less by definition.
 171
 172         std::atomic<float> loudness_lufs{ref_level_lufs};
 173
 174         StereoCompressor limiter;
 175         std::atomic<float> limiter_threshold_dbfs{ref_level_dbfs + 4.0f};   // 4 dB.
 176         std::atomic<bool> limiter_enabled{true};
 177         StereoCompressor compressor;
 178         std::atomic<float> compressor_threshold_dbfs{ref_level_dbfs - 12.0f};  // -12 dB.
 179         std::atomic<bool> compressor_enabled{true};
 180
 181         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.
 182         bool final_makeup_gain_auto = true;  // Under compressor_mutex.
 183 };
 184
 185 #endif  // !defined(_AUDIO_MIXER_H)