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         bool operator== (const DeviceSpec &other) const {
  40                 return type == other.type && index == other.index;
  41         }
  42
  43         bool operator< (const DeviceSpec &other) const {
  44                 if (type != other.type)
  45                         return type < other.type;
  46                 return index < other.index;
  47         }
  48 };
  49
  50 static inline uint64_t DeviceSpec_to_key(const DeviceSpec &device_spec)
  51 {
  52         return (uint64_t(device_spec.type) << 32) | device_spec.index;
  53 }
  54
  55 static inline DeviceSpec key_to_DeviceSpec(uint64_t key)
  56 {
  57         return DeviceSpec{ InputSourceType(key >> 32), unsigned(key & 0xffffffff) };
  58 }
  59
  60 struct InputMapping {
  61         struct Bus {
  62                 std::string name;
  63                 DeviceSpec device;
  64                 int source_channel[2] { -1, -1 };  // Left and right. -1 = none.
  65         };
  66
  67         std::vector<Bus> buses;
  68 };
  69
  70 class AudioMixer {
  71 public:
  72         AudioMixer(unsigned num_cards);
  73         void reset_device(DeviceSpec device_spec);
  74
  75         // frame_length is in TIMEBASE units.
  76         void add_audio(DeviceSpec device_spec, const uint8_t *data, unsigned num_samples, bmusb::AudioFormat audio_format, int64_t frame_length);
  77         void add_silence(DeviceSpec device_spec, unsigned samples_per_frame, unsigned num_frames, int64_t frame_length);
  78         std::vector<float> get_output(double pts, unsigned num_samples, ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy);
  79
  80         // See comments inside get_output().
  81         void set_current_loudness(double level_lufs) { loudness_lufs = level_lufs; }
  82
  83         void set_fader_volume(unsigned bus_index, float level_db) { fader_volume_db[bus_index] = level_db; }
  84         std::map<DeviceSpec, std::string> get_names() const;
  85         void set_name(DeviceSpec device_spec, const std::string &name);
  86
  87         void set_input_mapping(const InputMapping &input_mapping);
  88         InputMapping get_input_mapping() const;
  89
  90         void set_locut_cutoff(float cutoff_hz)
  91         {
  92                 locut_cutoff_hz = cutoff_hz;
  93         }
  94
  95         void set_locut_enabled(bool enabled)
  96         {
  97                 locut_enabled = enabled;
  98         }
  99
 100         bool get_locut_enabled() const
 101         {
 102                 return locut_enabled;
 103         }
 104
 105         float get_limiter_threshold_dbfs() const
 106         {
 107                 return limiter_threshold_dbfs;
 108         }
 109
 110         float get_compressor_threshold_dbfs() const
 111         {
 112                 return compressor_threshold_dbfs;
 113         }
 114
 115         void set_limiter_threshold_dbfs(float threshold_dbfs)
 116         {
 117                 limiter_threshold_dbfs = threshold_dbfs;
 118         }
 119
 120         void set_compressor_threshold_dbfs(float threshold_dbfs)
 121         {
 122                 compressor_threshold_dbfs = threshold_dbfs;
 123         }
 124
 125         void set_limiter_enabled(bool enabled)
 126         {
 127                 limiter_enabled = enabled;
 128         }
 129
 130         bool get_limiter_enabled() const
 131         {
 132                 return limiter_enabled;
 133         }
 134
 135         void set_compressor_enabled(bool enabled)
 136         {
 137                 compressor_enabled = enabled;
 138         }
 139
 140         bool get_compressor_enabled() const
 141         {
 142                 return compressor_enabled;
 143         }
 144
 145         void set_gain_staging_db(float gain_db)
 146         {
 147                 std::unique_lock<std::mutex> lock(compressor_mutex);
 148                 level_compressor_enabled = false;
 149                 gain_staging_db = gain_db;
 150         }
 151
 152         float get_gain_staging_db() const
 153         {
 154                 std::unique_lock<std::mutex> lock(compressor_mutex);
 155                 return gain_staging_db;
 156         }
 157
 158         void set_gain_staging_auto(bool enabled)
 159         {
 160                 std::unique_lock<std::mutex> lock(compressor_mutex);
 161                 level_compressor_enabled = enabled;
 162         }
 163
 164         bool get_gain_staging_auto() const
 165         {
 166                 std::unique_lock<std::mutex> lock(compressor_mutex);
 167                 return level_compressor_enabled;
 168         }
 169
 170         void set_final_makeup_gain_db(float gain_db)
 171         {
 172                 std::unique_lock<std::mutex> lock(compressor_mutex);
 173                 final_makeup_gain_auto = false;
 174                 final_makeup_gain = from_db(gain_db);
 175         }
 176
 177         float get_final_makeup_gain_db()
 178         {
 179                 std::unique_lock<std::mutex> lock(compressor_mutex);
 180                 return to_db(final_makeup_gain);
 181         }
 182
 183         void set_final_makeup_gain_auto(bool enabled)
 184         {
 185                 std::unique_lock<std::mutex> lock(compressor_mutex);
 186                 final_makeup_gain_auto = enabled;
 187         }
 188
 189         bool get_final_makeup_gain_auto() const
 190         {
 191                 std::unique_lock<std::mutex> lock(compressor_mutex);
 192                 return final_makeup_gain_auto;
 193         }
 194
 195 private:
 196         struct AudioDevice {
 197                 std::unique_ptr<ResamplingQueue> resampling_queue;
 198                 int64_t next_local_pts = 0;
 199                 std::string name;
 200                 unsigned capture_frequency = OUTPUT_FREQUENCY;
 201                 // Which channels we consider interesting (ie., are part of some input_mapping).
 202                 std::set<unsigned> interesting_channels;
 203         };
 204         AudioDevice *find_audio_device(DeviceSpec device_spec);
 205
 206         void find_sample_src_from_device(const std::vector<float> *samples_card, DeviceSpec device_spec, int source_channel, const float **srcptr, unsigned *stride);
 207         void fill_audio_bus(const std::vector<float> *samples_card, const InputMapping::Bus &bus, unsigned num_samples, float *output);
 208         void reset_device_mutex_held(DeviceSpec device_spec);
 209
 210         unsigned num_cards;
 211
 212         mutable std::mutex audio_mutex;
 213
 214         AudioDevice cards[MAX_CARDS];  // Under audio_mutex.
 215
 216         StereoFilter locut;  // Default cutoff 120 Hz, 24 dB/oct.
 217         std::atomic<float> locut_cutoff_hz;
 218         std::atomic<bool> locut_enabled{true};
 219
 220         // First compressor; takes us up to about -12 dBFS.
 221         mutable std::mutex compressor_mutex;
 222         StereoCompressor level_compressor;  // Under compressor_mutex. Used to set/override gain_staging_db if <level_compressor_enabled>.
 223         float gain_staging_db = 0.0f;  // Under compressor_mutex.
 224         bool level_compressor_enabled = true;  // Under compressor_mutex.
 225
 226         static constexpr float ref_level_dbfs = -14.0f;  // Chosen so that we end up around 0 LU in practice.
 227         static constexpr float ref_level_lufs = -23.0f;  // 0 LU, more or less by definition.
 228
 229         std::atomic<float> loudness_lufs{ref_level_lufs};
 230
 231         StereoCompressor limiter;
 232         std::atomic<float> limiter_threshold_dbfs{ref_level_dbfs + 4.0f};   // 4 dB.
 233         std::atomic<bool> limiter_enabled{true};
 234         StereoCompressor compressor;
 235         std::atomic<float> compressor_threshold_dbfs{ref_level_dbfs - 12.0f};  // -12 dB.
 236         std::atomic<bool> compressor_enabled{true};
 237
 238         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.
 239         bool final_makeup_gain_auto = true;  // Under compressor_mutex.
 240
 241         InputMapping input_mapping;  // Under audio_mutex.
 242         std::atomic<float> fader_volume_db[MAX_BUSES] {{ 0.0f }};
 243 };
 244
 245 #endif  // !defined(_AUDIO_MIXER_H)