lisyarus/psemek
1
0
Fork 1
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Add audio compressor knee

Browse source
This commit is contained in:
Nikita Lisitsa 2022-10-07 13:09:45 +03:00
parent dba6148554
commit a80487abbc
3 changed files with 19 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
examples/audio.cpp
View file

@ -68,7 +68,7 @@ struct audio_app
{ {
mixer_ = audio::make_mixer(); mixer_ = audio::make_mixer();
volume_control_ = audio::volume_stereo(mixer_, 0.5f, 0.5f, 0.1f); volume_control_ = audio::volume_stereo(mixer_, 0.5f, 0.5f, 0.1f);
engine_.output()->stream(audio::compressor(volume_control_, audio::from_db(-2.f), 0.95f, 0.002f, 1.f)); engine_.output()->stream(audio::compressor(volume_control_, audio::from_db(-2.f), 0.95f, 0.002f, 1.f, audio::from_db(1.f)));
} }
void on_key_down(SDL_Keycode key) override void on_key_down(SDL_Keycode key) override

5
libs/audio/include/psemek/audio/effect/compressor.hpp
View file

@ -6,8 +6,9 @@
namespace psemek::audio namespace psemek::audio
{ {
stream_ptr compressor(stream_ptr stream, float volume_threshold = from_db(-1.f), float strength = 0.9f, float envelope_attack = 0.01f, float envelope_release = 1.f); stream_ptr compressor(stream_ptr stream, float volume_threshold = from_db(-2.f), float strength = 0.9f, float envelope_attack = 0.01f, float envelope_release = 1.f,
float knee = from_db(1.f));
stream_ptr limiter(stream_ptr stream, float volume_threshold = from_db(0.f), float envelope_attack = 0.01f, float envelope_release = 1.f); stream_ptr limiter(stream_ptr stream, float volume_threshold = from_db(0.f), float envelope_attack = 0.01f, float envelope_release = 1.f, float knee = 0.f);
} }

21
libs/audio/source/effect/compressor.cpp
View file

@ -1,6 +1,8 @@
#include <psemek/audio/effect/compressor.hpp> #include <psemek/audio/effect/compressor.hpp>
#include <psemek/audio/smooth.hpp> #include <psemek/audio/smooth.hpp>
#include <psemek/geom/math.hpp> #include <psemek/geom/math.hpp>
#include <psemek/geom/interval.hpp>
#include <psemek/geom/contains.hpp>
namespace psemek::audio namespace psemek::audio
{ {
@ -11,12 +13,13 @@ namespace psemek::audio
struct compressor_impl struct compressor_impl
: stream : stream
{ {
compressor_impl(stream_ptr stream, float volume_threshold, float strength, float envelope_attack, float envelope_release) compressor_impl(stream_ptr stream, float volume_threshold, float strength, float envelope_attack, float envelope_release, float knee)
: stream_(std::move(stream)) : stream_(std::move(stream))
, volume_threshold_log_(std::log(volume_threshold)) , volume_threshold_log_(std::log(volume_threshold))
, strength_(strength) , strength_(strength)
, envelope_attack_multiplier_(smoothness_to_multiplier(envelope_attack)) , envelope_attack_multiplier_(smoothness_to_multiplier(envelope_attack))
, envelope_release_multiplier_(smoothness_to_multiplier(envelope_release)) , envelope_release_multiplier_(smoothness_to_multiplier(envelope_release))
, knee_range_(geom::expand(geom::interval<float>::singleton(volume_threshold_log_), std::log(knee) * 0.5f))
{} {}
std::optional<std::size_t> length() const override std::optional<std::size_t> length() const override
@ -38,7 +41,12 @@ namespace psemek::audio
float strength = strength_; float strength = strength_;
float log_gain = strength * std::min(0.f, volume_threshold_log_ - std::log(envelope_)); float envelope_log = std::log(envelope_);
if (geom::contains(knee_range_, envelope_log))
strength *= geom::unlerp(knee_range_, envelope_log);
float log_gain = strength * std::min(0.f, volume_threshold_log_ - envelope_log);
float gain = std::exp(log_gain); float gain = std::exp(log_gain);
@ -60,19 +68,20 @@ namespace psemek::audio
float strength_; float strength_;
float envelope_attack_multiplier_; float envelope_attack_multiplier_;
float envelope_release_multiplier_; float envelope_release_multiplier_;
geom::interval<float> knee_range_;
float envelope_ = 0.f; float envelope_ = 0.f;
}; };
} }
stream_ptr compressor(stream_ptr stream, float volume_threshold, float strength, float envelope_attack, float envelope_release) stream_ptr compressor(stream_ptr stream, float volume_threshold, float strength, float envelope_attack, float envelope_release, float knee)
{ {
return std::make_shared<compressor_impl>(std::move(stream), volume_threshold, strength, envelope_attack, envelope_release); return std::make_shared<compressor_impl>(std::move(stream), volume_threshold, strength, envelope_attack, envelope_release, knee);
} }
stream_ptr limiter(stream_ptr stream, float volume_threshold, float envelope_attack, float envelope_release) stream_ptr limiter(stream_ptr stream, float volume_threshold, float envelope_attack, float envelope_release, float knee)
{ {
return compressor(std::move(stream), volume_threshold, 1.f, envelope_attack, envelope_release); return compressor(std::move(stream), volume_threshold, 1.f, envelope_attack, envelope_release, knee);
} }
} }