From 941d040fd95e8425bc8019ec366458f0b21fb2c0 Mon Sep 17 00:00:00 2001 From: Julian Miller Date: Wed, 15 Feb 2017 20:36:50 -0500 Subject: [PATCH] obs-filters: Add audio compression filter Closes jp9000/obs-studio#799 --- plugins/obs-filters/CMakeLists.txt | 3 +- plugins/obs-filters/compressor-filter.c | 230 ++++++++++++++++++++++ plugins/obs-filters/data/locale/en-US.ini | 6 + plugins/obs-filters/obs-filters.c | 2 + 4 files changed, 240 insertions(+), 1 deletion(-) create mode 100644 plugins/obs-filters/compressor-filter.c diff --git a/plugins/obs-filters/CMakeLists.txt b/plugins/obs-filters/CMakeLists.txt index 5f13ec205..54b19e563 100644 --- a/plugins/obs-filters/CMakeLists.txt +++ b/plugins/obs-filters/CMakeLists.txt @@ -31,7 +31,8 @@ set(obs-filters_SOURCES sharpness-filter.c gain-filter.c noise-gate-filter.c - mask-filter.c) + mask-filter.c + compressor-filter.c) add_library(obs-filters MODULE ${obs-filters_SOURCES} diff --git a/plugins/obs-filters/compressor-filter.c b/plugins/obs-filters/compressor-filter.c new file mode 100644 index 000000000..ca6cef8da --- /dev/null +++ b/plugins/obs-filters/compressor-filter.c @@ -0,0 +1,230 @@ +#include +#include +#include + +#include +#include + +/* -------------------------------------------------------- */ + +#define do_log(level, format, ...) \ + blog(level, "[compressor: '%s'] " format, \ + obs_source_get_name(cd->context), ##__VA_ARGS__) + +#define warn(format, ...) do_log(LOG_WARNING, format, ##__VA_ARGS__) +#define info(format, ...) do_log(LOG_INFO, format, ##__VA_ARGS__) + +#ifdef _DEBUG +#define debug(format, ...) do_log(LOG_DEBUG, format, ##__VA_ARGS__) +#else +#define debug(format, ...) +#endif + +/* -------------------------------------------------------- */ + +#define S_RATIO "ratio" +#define S_THRESHOLD "threshold" +#define S_ATTACK_TIME "attack_time" +#define S_RELEASE_TIME "release_time" +#define S_OUTPUT_GAIN "output_gain" + +#define MT_ obs_module_text +#define TEXT_RATIO MT_("Compressor.Ratio") +#define TEXT_THRESHOLD MT_("Compressor.Threshold") +#define TEXT_ATTACK_TIME MT_("Compressor.AttackTime") +#define TEXT_RELEASE_TIME MT_("Compressor.ReleaseTime") +#define TEXT_OUTPUT_GAIN MT_("Compressor.OutputGain") + +#define MIN_RATIO 1.0f +#define MAX_RATIO 32.0f +#define MIN_THRESHOLD_DB -60.0f +#define MAX_THRESHOLD_DB 0.0f +#define MIN_OUTPUT_GAIN_DB -32.0f +#define MAX_OUTPUT_GAIN_DB 32.0f +#define MIN_ATK_RLS_MS 1 +#define MAX_ATK_RLS_MS 100 +#define DEFAULT_AUDIO_BUF_MS 10 + +#define MS_IN_S 1000 +#define MS_IN_S_F ((float)MS_IN_S) + +/* -------------------------------------------------------- */ + +struct compressor_data { + obs_source_t *context; + float *envelope_buf; + size_t envelope_buf_len; + + float ratio; + float threshold; + float attack_gain; + float release_gain; + float output_gain; + + size_t num_channels; + float envelope; + float slope; +}; + +/* -------------------------------------------------------- */ + +static inline void resize_env_buffer(struct compressor_data *cd, size_t len) +{ + cd->envelope_buf_len = len; + cd->envelope_buf = brealloc(cd->envelope_buf, len * sizeof(float)); +} + +static inline float gain_coefficient(uint32_t sample_rate, float time) +{ + return (float)exp(-1.0f / (sample_rate * time)); +} + +static const char *compressor_name(void *unused) +{ + UNUSED_PARAMETER(unused); + return obs_module_text("Compressor"); +} + +static void compressor_update(void *data, obs_data_t *s) +{ + struct compressor_data *cd = data; + + const uint32_t sample_rate = + audio_output_get_sample_rate(obs_get_audio()); + const size_t num_channels = + audio_output_get_channels(obs_get_audio()); + const float attack_time_ms = + (float)obs_data_get_int(s, S_ATTACK_TIME); + const float release_time_ms = + (float)obs_data_get_int(s, S_RELEASE_TIME); + const float output_gain_db = + (float)obs_data_get_double(s, S_OUTPUT_GAIN); + + if (cd->envelope_buf_len <= 0) { + resize_env_buffer(cd, + sample_rate * DEFAULT_AUDIO_BUF_MS / MS_IN_S); + } + + cd->ratio = (float)obs_data_get_double(s, S_RATIO); + cd->threshold = (float)obs_data_get_double(s, S_THRESHOLD); + cd->attack_gain = gain_coefficient(sample_rate, + attack_time_ms / MS_IN_S_F); + cd->release_gain = gain_coefficient(sample_rate, + release_time_ms / MS_IN_S_F); + cd->output_gain = db_to_mul(output_gain_db); + cd->num_channels = num_channels; + cd->slope = 1.0f - (1.0f / cd->ratio); +} + +static void *compressor_create(obs_data_t *settings, obs_source_t *filter) +{ + struct compressor_data *cd = bzalloc(sizeof(struct compressor_data)); + cd->context = filter; + compressor_update(cd, settings); + return cd; +} + +static void compressor_destroy(void *data) +{ + struct compressor_data *cd = data; + bfree(cd->envelope_buf); + bfree(cd); +} + +static inline void analyze_envelope(struct compressor_data *cd, + const float **samples, const uint32_t num_samples) +{ + if (cd->envelope_buf_len < num_samples) { + resize_env_buffer(cd, num_samples); + } + + memset(cd->envelope_buf, 0, num_samples * sizeof(cd->envelope_buf[0])); + for (size_t chan = 0; chan < cd->num_channels; ++chan) { + if (samples[chan]) { + float env = cd->envelope; + for (uint32_t i = 0; i < num_samples; ++i) { + const float env_in = fabsf(samples[chan][i]); + if (env < env_in) { + env = env_in + cd->attack_gain * + (env - env_in); + } else { + env = env_in + cd->release_gain * + (env - env_in); + } + cd->envelope_buf[i] = fmaxf( + cd->envelope_buf[i], env); + } + } + } + cd->envelope = cd->envelope_buf[num_samples - 1]; +} + +static inline void process_compression(const struct compressor_data *cd, + float **samples, uint32_t num_samples) +{ + for (size_t i = 0; i < num_samples; ++i) { + const float env_db = mul_to_db(cd->envelope_buf[i]); + float gain = cd->slope * (cd->threshold - env_db); + gain = db_to_mul(fminf(0, gain)); + + for (size_t c = 0; c < cd->num_channels; ++c) { + if (samples[c]) { + samples[c][i] *= gain * cd->output_gain; + } + } + } +} + +static struct obs_audio_data *compressor_filter_audio(void *data, + struct obs_audio_data *audio) +{ + struct compressor_data *cd = data; + const uint32_t num_samples = audio->frames; + float **samples = (float**)audio->data; + + analyze_envelope(cd, samples, num_samples); + process_compression(cd, samples, num_samples); + + return audio; +} + +static void compressor_defaults(obs_data_t *s) +{ + obs_data_set_default_double(s, S_RATIO, 10.0f); + obs_data_set_default_double(s, S_THRESHOLD, -18.0f); + obs_data_set_default_int(s, S_ATTACK_TIME, 6); + obs_data_set_default_int(s, S_RELEASE_TIME, 60); + obs_data_set_default_double(s, S_OUTPUT_GAIN, 0.0f); +} + +static obs_properties_t *compressor_properties(void *data) +{ + obs_properties_t *props = obs_properties_create(); + + obs_properties_add_float_slider(props, S_RATIO, + TEXT_RATIO, MIN_RATIO, MAX_RATIO, 0.5f); + obs_properties_add_float_slider(props, S_THRESHOLD, + TEXT_THRESHOLD, MIN_THRESHOLD_DB, MAX_THRESHOLD_DB, 0.1f); + obs_properties_add_int_slider(props, S_ATTACK_TIME, + TEXT_ATTACK_TIME, MIN_ATK_RLS_MS, MAX_ATK_RLS_MS, 1); + obs_properties_add_int_slider(props, S_RELEASE_TIME, + TEXT_RELEASE_TIME, MIN_ATK_RLS_MS, MAX_ATK_RLS_MS, 1); + obs_properties_add_float_slider(props, S_OUTPUT_GAIN, + TEXT_OUTPUT_GAIN, MIN_OUTPUT_GAIN_DB, MAX_OUTPUT_GAIN_DB, 0.1f); + + UNUSED_PARAMETER(data); + return props; +} + +struct obs_source_info compressor_filter = { + .id = "compressor_filter", + .type = OBS_SOURCE_TYPE_FILTER, + .output_flags = OBS_SOURCE_AUDIO, + .get_name = compressor_name, + .create = compressor_create, + .destroy = compressor_destroy, + .update = compressor_update, + .filter_audio = compressor_filter_audio, + .get_defaults = compressor_defaults, + .get_properties = compressor_properties, +}; diff --git a/plugins/obs-filters/data/locale/en-US.ini b/plugins/obs-filters/data/locale/en-US.ini index 6dceff888..e183d03e9 100644 --- a/plugins/obs-filters/data/locale/en-US.ini +++ b/plugins/obs-filters/data/locale/en-US.ini @@ -66,3 +66,9 @@ NoiseSuppress.SuppressLevel="Suppression Level (dB)" Saturation="Saturation" HueShift="Hue Shift" Amount="Amount" +Compressor="Compressor" +Compressor.Ratio="Ratio (X:1)" +Compressor.Threshold="Threshold (dB)" +Compressor.AttackTime="Attack (ms)" +Compressor.ReleaseTime="Release (ms)" +Compressor.OutputGain="Output Gain (dB)" diff --git a/plugins/obs-filters/obs-filters.c b/plugins/obs-filters/obs-filters.c index b7234ff08..6c0e413b5 100644 --- a/plugins/obs-filters/obs-filters.c +++ b/plugins/obs-filters/obs-filters.c @@ -20,6 +20,7 @@ extern struct obs_source_info async_delay_filter; extern struct obs_source_info noise_suppress_filter; #endif extern struct obs_source_info noise_gate_filter; +extern struct obs_source_info compressor_filter; bool obs_module_load(void) { @@ -38,5 +39,6 @@ bool obs_module_load(void) obs_register_source(&noise_suppress_filter); #endif obs_register_source(&noise_gate_filter); + obs_register_source(&compressor_filter); return true; }