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 "alsa_input.h"
  24 #include "bmusb/bmusb.h"
  25 #include "db.h"
  26 #include "defs.h"
  27 #include "filter.h"
  28 #include "resampling_queue.h"
  29 #include "stereocompressor.h"
  30
  31 namespace bmusb {
  32 struct AudioFormat;
  33 }  // namespace bmusb
  34
  35 enum class InputSourceType { SILENCE, CAPTURE_CARD, ALSA_INPUT };
  36 struct DeviceSpec {
  37         InputSourceType type;
  38         unsigned index;
  39
  40         bool operator== (const DeviceSpec &other) const {
  41                 return type == other.type && index == other.index;
  42         }
  43
  44         bool operator< (const DeviceSpec &other) const {
  45                 if (type != other.type)
  46                         return type < other.type;
  47                 return index < other.index;
  48         }
  49 };
  50 struct DeviceInfo {
  51         std::string name;
  52         unsigned num_channels;
  53 };
  54
  55 static inline uint64_t DeviceSpec_to_key(const DeviceSpec &device_spec)
  56 {
  57         return (uint64_t(device_spec.type) << 32) | device_spec.index;
  58 }
  59
  60 static inline DeviceSpec key_to_DeviceSpec(uint64_t key)
  61 {
  62         return DeviceSpec{ InputSourceType(key >> 32), unsigned(key & 0xffffffff) };
  63 }
  64
  65 struct InputMapping {
  66         struct Bus {
  67                 std::string name;
  68                 DeviceSpec device;
  69                 int source_channel[2] { -1, -1 };  // Left and right. -1 = none.
  70         };
  71
  72         std::vector<Bus> buses;
  73 };
  74
  75 class AudioMixer {
  76 public:
  77         AudioMixer(unsigned num_cards);
  78         ~AudioMixer();
  79         void reset_resampler(DeviceSpec device_spec);
  80
  81         // Add audio (or silence) to the given device's queue. Can return false if
  82         // the lock wasn't successfully taken; if so, you should simply try again.
  83         // (This is to avoid a deadlock where a card hangs on the mutex in add_audio()
  84         // while we are trying to shut it down from another thread that also holds
  85         // the mutex.) frame_length is in TIMEBASE units.
  86         bool add_audio(DeviceSpec device_spec, const uint8_t *data, unsigned num_samples, bmusb::AudioFormat audio_format, int64_t frame_length);
  87         bool add_silence(DeviceSpec device_spec, unsigned samples_per_frame, unsigned num_frames, int64_t frame_length);
  88
  89         std::vector<float> get_output(double pts, unsigned num_samples, ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy);
  90
  91         // See comments inside get_output().
  92         void set_current_loudness(double level_lufs) { loudness_lufs = level_lufs; }
  93
  94         void set_fader_volume(unsigned bus_index, float level_db) { fader_volume_db[bus_index] = level_db; }
  95         std::map<DeviceSpec, DeviceInfo> get_devices() const;
  96         void set_name(DeviceSpec device_spec, const std::string &name);
  97
  98         void set_input_mapping(const InputMapping &input_mapping);
  99         InputMapping get_input_mapping() const;
 100
 101         void set_locut_cutoff(float cutoff_hz)
 102         {
 103                 locut_cutoff_hz = cutoff_hz;
 104         }
 105
 106         void set_locut_enabled(bool enabled)
 107         {
 108                 locut_enabled = enabled;
 109         }
 110
 111         bool get_locut_enabled() const
 112         {
 113                 return locut_enabled;
 114         }
 115
 116         float get_limiter_threshold_dbfs() const
 117         {
 118                 return limiter_threshold_dbfs;
 119         }
 120
 121         float get_compressor_threshold_dbfs() const
 122         {
 123                 return compressor_threshold_dbfs;
 124         }
 125
 126         void set_limiter_threshold_dbfs(float threshold_dbfs)
 127         {
 128                 limiter_threshold_dbfs = threshold_dbfs;
 129         }
 130
 131         void set_compressor_threshold_dbfs(float threshold_dbfs)
 132         {
 133                 compressor_threshold_dbfs = threshold_dbfs;
 134         }
 135
 136         void set_limiter_enabled(bool enabled)
 137         {
 138                 limiter_enabled = enabled;
 139         }
 140
 141         bool get_limiter_enabled() const
 142         {
 143                 return limiter_enabled;
 144         }
 145
 146         void set_compressor_enabled(bool enabled)
 147         {
 148                 compressor_enabled = enabled;
 149         }
 150
 151         bool get_compressor_enabled() const
 152         {
 153                 return compressor_enabled;
 154         }
 155
 156         void set_gain_staging_db(float gain_db)
 157         {
 158                 std::unique_lock<std::mutex> lock(compressor_mutex);
 159                 level_compressor_enabled = false;
 160                 gain_staging_db = gain_db;
 161         }
 162
 163         float get_gain_staging_db() const
 164         {
 165                 std::unique_lock<std::mutex> lock(compressor_mutex);
 166                 return gain_staging_db;
 167         }
 168
 169         void set_gain_staging_auto(bool enabled)
 170         {
 171                 std::unique_lock<std::mutex> lock(compressor_mutex);
 172                 level_compressor_enabled = enabled;
 173         }
 174
 175         bool get_gain_staging_auto() const
 176         {
 177                 std::unique_lock<std::mutex> lock(compressor_mutex);
 178                 return level_compressor_enabled;
 179         }
 180
 181         void set_final_makeup_gain_db(float gain_db)
 182         {
 183                 std::unique_lock<std::mutex> lock(compressor_mutex);
 184                 final_makeup_gain_auto = false;
 185                 final_makeup_gain = from_db(gain_db);
 186         }
 187
 188         float get_final_makeup_gain_db()
 189         {
 190                 std::unique_lock<std::mutex> lock(compressor_mutex);
 191                 return to_db(final_makeup_gain);
 192         }
 193
 194         void set_final_makeup_gain_auto(bool enabled)
 195         {
 196                 std::unique_lock<std::mutex> lock(compressor_mutex);
 197                 final_makeup_gain_auto = enabled;
 198         }
 199
 200         bool get_final_makeup_gain_auto() const
 201         {
 202                 std::unique_lock<std::mutex> lock(compressor_mutex);
 203                 return final_makeup_gain_auto;
 204         }
 205
 206 private:
 207         struct AudioDevice {
 208                 std::unique_ptr<ResamplingQueue> resampling_queue;
 209                 int64_t next_local_pts = 0;
 210                 std::string name;
 211                 unsigned capture_frequency = OUTPUT_FREQUENCY;
 212                 // Which channels we consider interesting (ie., are part of some input_mapping).
 213                 std::set<unsigned> interesting_channels;
 214                 // Only used for ALSA cards, obviously.
 215                 std::unique_ptr<ALSAInput> alsa_device;
 216         };
 217         AudioDevice *find_audio_device(DeviceSpec device_spec);
 218
 219         void find_sample_src_from_device(const std::map<DeviceSpec, std::vector<float>> &samples_card, DeviceSpec device_spec, int source_channel, const float **srcptr, unsigned *stride);
 220         void fill_audio_bus(const std::map<DeviceSpec, std::vector<float>> &samples_card, const InputMapping::Bus &bus, unsigned num_samples, float *output);
 221         void reset_resampler_mutex_held(DeviceSpec device_spec);
 222         void reset_alsa_mutex_held(DeviceSpec device_spec);
 223         std::map<DeviceSpec, DeviceInfo> get_devices_mutex_held() const;
 224
 225         unsigned num_cards;
 226
 227         mutable std::timed_mutex audio_mutex;
 228
 229         AudioDevice video_cards[MAX_VIDEO_CARDS];  // Under audio_mutex.
 230
 231         // TODO: Figure out a better way to unify these two, as they are sharing indexing.
 232         AudioDevice alsa_inputs[MAX_ALSA_CARDS];  // Under audio_mutex.
 233         std::vector<ALSAInput::Device> available_alsa_cards;
 234
 235         StereoFilter locut;  // Default cutoff 120 Hz, 24 dB/oct.
 236         std::atomic<float> locut_cutoff_hz;
 237         std::atomic<bool> locut_enabled{true};
 238
 239         // First compressor; takes us up to about -12 dBFS.
 240         mutable std::mutex compressor_mutex;
 241         StereoCompressor level_compressor;  // Under compressor_mutex. Used to set/override gain_staging_db if <level_compressor_enabled>.
 242         float gain_staging_db = 0.0f;  // Under compressor_mutex.
 243         bool level_compressor_enabled = true;  // Under compressor_mutex.
 244
 245         static constexpr float ref_level_dbfs = -14.0f;  // Chosen so that we end up around 0 LU in practice.
 246         static constexpr float ref_level_lufs = -23.0f;  // 0 LU, more or less by definition.
 247
 248         std::atomic<float> loudness_lufs{ref_level_lufs};
 249
 250         StereoCompressor limiter;
 251         std::atomic<float> limiter_threshold_dbfs{ref_level_dbfs + 4.0f};   // 4 dB.
 252         std::atomic<bool> limiter_enabled{true};
 253         StereoCompressor compressor;
 254         std::atomic<float> compressor_threshold_dbfs{ref_level_dbfs - 12.0f};  // -12 dB.
 255         std::atomic<bool> compressor_enabled{true};
 256
 257         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.
 258         bool final_makeup_gain_auto = true;  // Under compressor_mutex.
 259
 260         InputMapping input_mapping;  // Under audio_mutex.
 261         std::atomic<float> fader_volume_db[MAX_BUSES] {{ 0.0f }};
 262 };
 263
 264 #endif  // !defined(_AUDIO_MIXER_H)