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 struct DeviceSpec {
  36         InputSourceType type;
  37         unsigned index;
  38 };
  39
  40 struct InputMapping {
  41         struct Bus {
  42                 std::string name;
  43                 DeviceSpec device;
  44                 int source_channel[2] { -1, -1 };  // Left and right. -1 = none.
  45         };
  46
  47         std::vector<Bus> buses;
  48 };
  49
  50 class AudioMixer {
  51 public:
  52         AudioMixer(unsigned num_cards);
  53         void reset_device(DeviceSpec device_spec);
  54
  55         // frame_length is in TIMEBASE units.
  56         void add_audio(DeviceSpec device_spec, const uint8_t *data, unsigned num_samples, bmusb::AudioFormat audio_format, int64_t frame_length);
  57         void add_silence(DeviceSpec device_spec, unsigned samples_per_frame, unsigned num_frames, int64_t frame_length);
  58         std::vector<float> get_output(double pts, unsigned num_samples, ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy);
  59
  60         // See comments inside get_output().
  61         void set_current_loudness(double level_lufs) { loudness_lufs = level_lufs; }
  62
  63         void set_fader_volume(unsigned bus_index, float level_db) { fader_volume_db[bus_index] = level_db; }
  64         std::vector<std::string> get_names() const;
  65         void set_name(DeviceSpec device_spec, const std::string &name);
  66
  67         void set_input_mapping(const InputMapping &input_mapping);
  68         InputMapping get_input_mapping() const;
  69
  70         void set_locut_cutoff(float cutoff_hz)
  71         {
  72                 locut_cutoff_hz = cutoff_hz;
  73         }
  74
  75         void set_locut_enabled(bool enabled)
  76         {
  77                 locut_enabled = enabled;
  78         }
  79
  80         bool get_locut_enabled() const
  81         {
  82                 return locut_enabled;
  83         }
  84
  85         float get_limiter_threshold_dbfs() const
  86         {
  87                 return limiter_threshold_dbfs;
  88         }
  89
  90         float get_compressor_threshold_dbfs() const
  91         {
  92                 return compressor_threshold_dbfs;
  93         }
  94
  95         void set_limiter_threshold_dbfs(float threshold_dbfs)
  96         {
  97                 limiter_threshold_dbfs = threshold_dbfs;
  98         }
  99
 100         void set_compressor_threshold_dbfs(float threshold_dbfs)
 101         {
 102                 compressor_threshold_dbfs = threshold_dbfs;
 103         }
 104
 105         void set_limiter_enabled(bool enabled)
 106         {
 107                 limiter_enabled = enabled;
 108         }
 109
 110         bool get_limiter_enabled() const
 111         {
 112                 return limiter_enabled;
 113         }
 114
 115         void set_compressor_enabled(bool enabled)
 116         {
 117                 compressor_enabled = enabled;
 118         }
 119
 120         bool get_compressor_enabled() const
 121         {
 122                 return compressor_enabled;
 123         }
 124
 125         void set_gain_staging_db(float gain_db)
 126         {
 127                 std::unique_lock<std::mutex> lock(compressor_mutex);
 128                 level_compressor_enabled = false;
 129                 gain_staging_db = gain_db;
 130         }
 131
 132         float get_gain_staging_db() const
 133         {
 134                 std::unique_lock<std::mutex> lock(compressor_mutex);
 135                 return gain_staging_db;
 136         }
 137
 138         void set_gain_staging_auto(bool enabled)
 139         {
 140                 std::unique_lock<std::mutex> lock(compressor_mutex);
 141                 level_compressor_enabled = enabled;
 142         }
 143
 144         bool get_gain_staging_auto() const
 145         {
 146                 std::unique_lock<std::mutex> lock(compressor_mutex);
 147                 return level_compressor_enabled;
 148         }
 149
 150         void set_final_makeup_gain_db(float gain_db)
 151         {
 152                 std::unique_lock<std::mutex> lock(compressor_mutex);
 153                 final_makeup_gain_auto = false;
 154                 final_makeup_gain = from_db(gain_db);
 155         }
 156
 157         float get_final_makeup_gain_db()
 158         {
 159                 std::unique_lock<std::mutex> lock(compressor_mutex);
 160                 return to_db(final_makeup_gain);
 161         }
 162
 163         void set_final_makeup_gain_auto(bool enabled)
 164         {
 165                 std::unique_lock<std::mutex> lock(compressor_mutex);
 166                 final_makeup_gain_auto = enabled;
 167         }
 168
 169         bool get_final_makeup_gain_auto() const
 170         {
 171                 std::unique_lock<std::mutex> lock(compressor_mutex);
 172                 return final_makeup_gain_auto;
 173         }
 174
 175 private:
 176         struct AudioDevice {
 177                 std::unique_ptr<ResamplingQueue> resampling_queue;
 178                 int64_t next_local_pts = 0;
 179                 std::string name;
 180                 // Which channels we consider interesting (ie., are part of some input_mapping).
 181                 std::set<unsigned> interesting_channels;
 182         };
 183         AudioDevice *find_audio_device(DeviceSpec device_spec);
 184
 185         void find_sample_src_from_device(const std::vector<float> *samples_card, DeviceSpec device_spec, int source_channel, const float **srcptr, unsigned *stride);
 186         void fill_audio_bus(const std::vector<float> *samples_card, const InputMapping::Bus &bus, unsigned num_samples, float *output);
 187         void reset_device_mutex_held(DeviceSpec device_spec);
 188
 189         unsigned num_cards;
 190
 191         mutable std::mutex audio_mutex;
 192
 193         AudioDevice cards[MAX_CARDS];  // Under audio_mutex.
 194
 195         StereoFilter locut;  // Default cutoff 120 Hz, 24 dB/oct.
 196         std::atomic<float> locut_cutoff_hz;
 197         std::atomic<bool> locut_enabled{true};
 198
 199         // First compressor; takes us up to about -12 dBFS.
 200         mutable std::mutex compressor_mutex;
 201         StereoCompressor level_compressor;  // Under compressor_mutex. Used to set/override gain_staging_db if <level_compressor_enabled>.
 202         float gain_staging_db = 0.0f;  // Under compressor_mutex.
 203         bool level_compressor_enabled = true;  // Under compressor_mutex.
 204
 205         static constexpr float ref_level_dbfs = -14.0f;  // Chosen so that we end up around 0 LU in practice.
 206         static constexpr float ref_level_lufs = -23.0f;  // 0 LU, more or less by definition.
 207
 208         std::atomic<float> loudness_lufs{ref_level_lufs};
 209
 210         StereoCompressor limiter;
 211         std::atomic<float> limiter_threshold_dbfs{ref_level_dbfs + 4.0f};   // 4 dB.
 212         std::atomic<bool> limiter_enabled{true};
 213         StereoCompressor compressor;
 214         std::atomic<float> compressor_threshold_dbfs{ref_level_dbfs - 12.0f};  // -12 dB.
 215         std::atomic<bool> compressor_enabled{true};
 216
 217         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.
 218         bool final_makeup_gain_auto = true;  // Under compressor_mutex.
 219
 220         InputMapping input_mapping;  // Under audio_mutex.
 221         std::atomic<float> fader_volume_db[MAX_BUSES] {{ 0.0f }};
 222 };
 223
 224 #endif  // !defined(_AUDIO_MIXER_H)