mirror of
https://github.com/obsproject/obs-studio.git
synced 2024-09-20 13:08:50 +02:00
obs-filters: Add downward expander filter
The downward expander acts as an advanced gate with smoother effect since it lowers the level instead of discarding audio when below the threshold.
This commit is contained in:
pkviet
pkv
parent
87ca80deac
commit
fcc9f4e1f9
@ -50,7 +50,8 @@ set(obs-filters_SOURCES
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mask-filter.c
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invert-audio-polarity.c
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compressor-filter.c
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limiter-filter.c)
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limiter-filter.c
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expander-filter.c)
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add_library(obs-filters MODULE
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${obs-filters_SOURCES}
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@ -79,3 +79,16 @@ Compressor.SidechainSource="Sidechain/Ducking Source"
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Limiter="Limiter"
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Limiter.Threshold="Threshold (dB)"
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Limiter.ReleaseTime="Release (ms)"
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Expander="Expander"
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Expander.Ratio="Ratio (X:1)"
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Expander.Threshold="Threshold (dB)"
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Expander.AttackTime="Attack (ms)"
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Expander.ReleaseTime="Release (ms)"
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Expander.OutputGain="Output Gain (dB)"
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Expander.Detector="Detection"
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Expander.RMS="RMS"
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Expander.Peak="Peak"
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Expander.None="None"
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Expander.Presets="Presets"
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Expander.Presets.Expander="Expander"
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Expander.Presets.Gate="Gate"
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407
plugins/obs-filters/expander-filter.c
Normal file
407
plugins/obs-filters/expander-filter.c
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@ -0,0 +1,407 @@
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#include <stdint.h>
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#include <inttypes.h>
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#include <math.h>
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#include <obs-module.h>
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#include <media-io/audio-math.h>
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#include <util/platform.h>
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#include <util/circlebuf.h>
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#include <util/threading.h>
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/* -------------------------------------------------------- */
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#define do_log(level, format, ...) \
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blog(level, "[expander: '%s'] " format, \
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obs_source_get_name(cd->context), ##__VA_ARGS__)
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#define warn(format, ...) do_log(LOG_WARNING, format, ##__VA_ARGS__)
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#define info(format, ...) do_log(LOG_INFO, format, ##__VA_ARGS__)
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#ifdef _DEBUG
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#define debug(format, ...) do_log(LOG_DEBUG, format, ##__VA_ARGS__)
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#else
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#define debug(format, ...)
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#endif
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/* -------------------------------------------------------- */
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#define S_RATIO "ratio"
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#define S_THRESHOLD "threshold"
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#define S_ATTACK_TIME "attack_time"
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#define S_RELEASE_TIME "release_time"
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#define S_OUTPUT_GAIN "output_gain"
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#define S_DETECTOR "detector"
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#define S_PRESETS "presets"
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#define MT_ obs_module_text
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#define TEXT_RATIO MT_("expander.Ratio")
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#define TEXT_THRESHOLD MT_("expander.Threshold")
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#define TEXT_ATTACK_TIME MT_("expander.AttackTime")
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#define TEXT_RELEASE_TIME MT_("expander.ReleaseTime")
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#define TEXT_OUTPUT_GAIN MT_("expander.OutputGain")
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#define TEXT_DETECTOR MT_("expander.Detector")
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#define TEXT_PEAK MT_("expander.Peak")
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#define TEXT_RMS MT_("expander.RMS")
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#define TEXT_NONE MT_("expander.None")
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#define TEXT_PRESETS MT_("expander.Presets")
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#define TEXT_PRESETS_EXP MT_("expander.Presets.Expander")
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#define TEXT_PRESETS_GATE MT_("expander.Presets.Gate")
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#define MIN_RATIO 1.0
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#define MAX_RATIO 20.0
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#define MIN_THRESHOLD_DB -60.0
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#define MAX_THRESHOLD_DB 0.0f
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#define MIN_OUTPUT_GAIN_DB -32.0
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#define MAX_OUTPUT_GAIN_DB 32.0
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#define MIN_ATK_RLS_MS 1
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#define MAX_RLS_MS 1000
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#define MAX_ATK_MS 100
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#define DEFAULT_AUDIO_BUF_MS 10
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#define MS_IN_S 1000
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#define MS_IN_S_F ((float)MS_IN_S)
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/* -------------------------------------------------------- */
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struct expander_data {
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obs_source_t *context;
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float *envelope_buf;
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size_t envelope_buf_len;
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float ratio;
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float threshold;
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float attack_gain;
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float release_gain;
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float output_gain;
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size_t num_channels;
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size_t sample_rate;
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float envelope;
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float slope;
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int detector;
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float runave;
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bool is_gate;
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float *runaverage;
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size_t runaverage_len;
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float *maxspl;
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size_t maxspl_len;
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float *env_in;
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size_t env_in_len;
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};
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enum {
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RMS_DETECT,
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RMS_STILLWELL_DETECT,
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PEAK_DETECT,
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NO_DETECT,
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};
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/* -------------------------------------------------------- */
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static void resize_env_buffer(struct expander_data *cd, size_t len)
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{
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cd->envelope_buf_len = len;
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cd->envelope_buf = brealloc(cd->envelope_buf, len * sizeof(float));
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}
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static void resize_runaverage_buffer(struct expander_data *cd, size_t len)
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{
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cd->runaverage_len = len;
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cd->runaverage = brealloc(cd->runaverage, len * sizeof(float));
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}
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static void resize_maxspl_buffer(struct expander_data *cd, size_t len)
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{
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cd->maxspl_len = len;
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cd->maxspl = brealloc(cd->maxspl, len * sizeof(float));
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}
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static void resize_env_in_buffer(struct expander_data *cd, size_t len)
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{
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cd->env_in_len = len;
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cd->env_in = brealloc(cd->env_in, len * sizeof(float));
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}
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static inline float gain_coefficient(uint32_t sample_rate, float time)
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{
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return (float)exp(-1.0f / (sample_rate * time));
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}
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static const char *expander_name(void *unused)
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{
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UNUSED_PARAMETER(unused);
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return obs_module_text("Expander");
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}
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static void expander_defaults(obs_data_t *s)
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{
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const char *presets = obs_data_get_string(s, S_PRESETS);
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bool is_expander_preset = true;
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if (strcmp(presets, "gate") == 0)
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is_expander_preset = false;
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obs_data_set_default_string(s, S_PRESETS, is_expander_preset ?
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"expander" : "gate");
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obs_data_set_default_double(s, S_RATIO, is_expander_preset ?
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2.0 : 10.0);
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obs_data_set_default_double(s, S_THRESHOLD, -40.0f);
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obs_data_set_default_int(s, S_ATTACK_TIME, 10);
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obs_data_set_default_int(s, S_RELEASE_TIME, is_expander_preset ?
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50 : 125);
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obs_data_set_default_double(s, S_OUTPUT_GAIN, 0.0);
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obs_data_set_default_string(s, S_DETECTOR, "RMS");
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}
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static void expander_update(void *data, obs_data_t *s)
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{
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struct expander_data *cd = data;
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const char *presets = obs_data_get_string(s, S_PRESETS);
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if (strcmp(presets, "expander") == 0 && cd->is_gate) {
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obs_data_clear(s);
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obs_data_set_string(s, S_PRESETS, "expander");
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expander_defaults(s);
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cd->is_gate = false;
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}
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if (strcmp(presets, "gate") == 0 && !cd->is_gate) {
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obs_data_clear(s);
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obs_data_set_string(s, S_PRESETS, "gate");
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expander_defaults(s);
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cd->is_gate = true;
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}
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const uint32_t sample_rate =
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audio_output_get_sample_rate(obs_get_audio());
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const size_t num_channels =
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audio_output_get_channels(obs_get_audio());
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const float attack_time_ms =
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(float)obs_data_get_int(s, S_ATTACK_TIME);
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const float release_time_ms =
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(float)obs_data_get_int(s, S_RELEASE_TIME);
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const float output_gain_db =
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(float)obs_data_get_double(s, S_OUTPUT_GAIN);
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cd->ratio = (float)obs_data_get_double(s, S_RATIO);
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cd->threshold = (float)obs_data_get_double(s, S_THRESHOLD);
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cd->attack_gain = gain_coefficient(sample_rate,
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attack_time_ms / MS_IN_S_F);
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cd->release_gain = gain_coefficient(sample_rate,
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release_time_ms / MS_IN_S_F);
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cd->output_gain = db_to_mul(output_gain_db);
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cd->num_channels = num_channels;
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cd->sample_rate = sample_rate;
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cd->slope = 1.0f - cd->ratio;
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const char *detect_mode = obs_data_get_string(s, S_DETECTOR);
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if (strcmp(detect_mode, "RMS") == 0)
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cd->detector = RMS_DETECT;
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if (strcmp(detect_mode, "peak") == 0)
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cd->detector = PEAK_DETECT;
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if (strcmp(detect_mode, "none") == 0)
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cd->detector = NO_DETECT;
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size_t sample_len = sample_rate * DEFAULT_AUDIO_BUF_MS / MS_IN_S;
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if (cd->envelope_buf_len == 0)
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resize_env_buffer(cd, sample_len);
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if (cd->runaverage_len == 0)
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resize_runaverage_buffer(cd, sample_len);
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if (cd->maxspl_len == 0)
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resize_maxspl_buffer(cd, sample_len);
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if (cd->env_in_len == 0)
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resize_env_in_buffer(cd, sample_len);
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}
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static void *expander_create(obs_data_t *settings, obs_source_t *filter)
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{
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struct expander_data *cd = bzalloc(sizeof(struct expander_data));
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cd->context = filter;
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cd->runave = 0;
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cd->is_gate = false;
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const char *presets = obs_data_get_string(settings, S_PRESETS);
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if (strcmp(presets, "gate") == 0)
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cd->is_gate = true;
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expander_update(cd, settings);
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return cd;
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}
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static void expander_destroy(void *data)
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{
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struct expander_data *cd = data;
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bfree(cd->envelope_buf);
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bfree(cd->runaverage);
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bfree(cd->maxspl);
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bfree(cd->env_in);
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bfree(cd);
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}
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static void analyze_envelope(struct expander_data *cd,
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float **samples, const uint32_t num_samples)
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{
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if (cd->envelope_buf_len < num_samples) {
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resize_env_buffer(cd, num_samples);
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}
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if (cd->runaverage_len < num_samples) {
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resize_runaverage_buffer(cd, num_samples);
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}
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if (cd->maxspl_len < num_samples) {
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resize_maxspl_buffer(cd, num_samples);
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}
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if (cd->env_in_len < num_samples) {
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resize_env_in_buffer(cd, num_samples);
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}
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const float attack_gain = cd->attack_gain;
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const float release_gain = cd->release_gain;
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// 10 ms RMS window
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const float rmscoef = exp2f((float)-100.0 / (float)cd->sample_rate);
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// 2.5 microsec Peak window
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const float peakcoef = exp2f((float)-1000.0 /((float)0.0025 *
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(float)cd->sample_rate));
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memset(cd->envelope_buf, 0, num_samples * sizeof(cd->envelope_buf[0]));
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memset(cd->runaverage, 0, num_samples * sizeof(cd->runaverage[0]));
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memset(cd->maxspl, 0, num_samples * sizeof(cd->maxspl[0]));
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memset(cd->env_in, 0, num_samples * sizeof(cd->env_in[0]));
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for (size_t chan = 0; chan < cd->num_channels; ++chan) {
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if (!samples[chan])
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continue;
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float *envelope_buf = cd->envelope_buf;
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float *runave = cd->runaverage;
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float *maxspl = cd->maxspl;
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float *env_in = cd->env_in;
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float env = cd->envelope;
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float RMSdet = 0;
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runave[0] = cd->runave;
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maxspl[0] = fabsf(samples[chan][0]);
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env_in[0] = sqrtf(fmaxf(cd->runave, 0));
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if (cd->detector == RMS_DETECT)
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for (uint32_t i = 1; i < num_samples; ++i) {
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runave[i] = rmscoef * runave[i - 1] +
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(1 - rmscoef) *
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powf(samples[chan][i], 2.0);
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env_in[i] = sqrtf(runave[i]);
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}
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else if (cd->detector == PEAK_DETECT)
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for (uint32_t i = 1; i < num_samples; ++i) {
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maxspl[i] = powf(fmaxf(fabsf(maxspl[i - 1]),
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fabsf(samples[chan][i])), 2);
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runave[i] = peakcoef * runave[i - 1] +
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(1 - peakcoef) * maxspl[i];
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env_in[i] = sqrtf(runave[i]);
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}
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else if (cd->detector == NO_DETECT)
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for (uint32_t i = 1; i < num_samples; ++i) {
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runave[i] = powf(samples[chan][i], 2);
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env_in[i] = fabsf(samples[chan][i]);
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}
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cd->runave = runave[num_samples-1];
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for (uint32_t i = 0; i < num_samples; ++i) {
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if (env < env_in[i]) {
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env = env_in[i] + attack_gain
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* (env - env_in[i]);
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} else {
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env = env_in[i] + release_gain
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* (env - env_in[i]);
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}
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envelope_buf[i] = fmaxf(envelope_buf[i], env);
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}
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}
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cd->envelope = cd->envelope_buf[num_samples - 1];
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}
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static inline void process_expansion(const struct expander_data *cd,
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float **samples, uint32_t num_samples)
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{
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for (size_t i = 0; i < num_samples; ++i) {
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float env_db = mul_to_db(cd->envelope_buf[i]);
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float gain = fmaxf(cd->slope * (cd->threshold - env_db),
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-60.0);
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gain = db_to_mul(fminf(0, gain));
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for (size_t c = 0; c < cd->num_channels; ++c) {
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if (samples[c]) {
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samples[c][i] *= gain * cd->output_gain;
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}
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}
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}
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}
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static struct obs_audio_data *expander_filter_audio(void *data,
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struct obs_audio_data *audio)
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{
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struct expander_data *cd = data;
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const uint32_t num_samples = audio->frames;
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if (num_samples == 0)
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return audio;
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float **samples = (float**)audio->data;
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analyze_envelope(cd, samples, num_samples);
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process_expansion(cd, samples, num_samples);
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return audio;
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}
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static bool presets_changed(obs_properties_t *props, obs_property_t *prop,
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obs_data_t *settings)
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{
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return true;
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}
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static obs_properties_t *expander_properties(void *data)
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{
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struct expander_data *cd = data;
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obs_properties_t *props = obs_properties_create();
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obs_source_t *parent = NULL;
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if (cd)
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parent = obs_filter_get_parent(cd->context);
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obs_property_t *presets = obs_properties_add_list(props, S_PRESETS,
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TEXT_PRESETS, OBS_COMBO_TYPE_LIST,
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OBS_COMBO_FORMAT_STRING);
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obs_property_list_add_string(presets, TEXT_PRESETS_EXP, "expander");
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obs_property_list_add_string(presets, TEXT_PRESETS_GATE, "gate");
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obs_property_set_modified_callback(presets, presets_changed);
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obs_properties_add_float_slider(props, S_RATIO,
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TEXT_RATIO, MIN_RATIO, MAX_RATIO, 0.1);
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obs_properties_add_float_slider(props, S_THRESHOLD,
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TEXT_THRESHOLD, MIN_THRESHOLD_DB, MAX_THRESHOLD_DB,
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0.1);
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obs_properties_add_int_slider(props, S_ATTACK_TIME,
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TEXT_ATTACK_TIME, MIN_ATK_RLS_MS, MAX_ATK_MS, 1);
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obs_properties_add_int_slider(props, S_RELEASE_TIME,
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TEXT_RELEASE_TIME, MIN_ATK_RLS_MS, MAX_RLS_MS, 1);
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obs_properties_add_float_slider(props, S_OUTPUT_GAIN,
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TEXT_OUTPUT_GAIN, MIN_OUTPUT_GAIN_DB,
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MAX_OUTPUT_GAIN_DB, 0.1);
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obs_property_t *detect = obs_properties_add_list(props, S_DETECTOR,
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TEXT_DETECTOR, OBS_COMBO_TYPE_LIST,
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OBS_COMBO_FORMAT_STRING);
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obs_property_list_add_string(detect, TEXT_RMS, "RMS");
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obs_property_list_add_string(detect, TEXT_PEAK, "peak");
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obs_property_list_add_string(detect, TEXT_NONE, "none");
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UNUSED_PARAMETER(data);
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return props;
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}
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struct obs_source_info expander_filter = {
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.id = "expander_filter",
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.type = OBS_SOURCE_TYPE_FILTER,
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.output_flags = OBS_SOURCE_AUDIO,
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.get_name = expander_name,
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.create = expander_create,
|
||||
.destroy = expander_destroy,
|
||||
.update = expander_update,
|
||||
.filter_audio = expander_filter_audio,
|
||||
.get_defaults = expander_defaults,
|
||||
.get_properties = expander_properties,
|
||||
};
|
||||
@ -27,6 +27,7 @@ extern struct obs_source_info invert_polarity_filter;
|
||||
extern struct obs_source_info noise_gate_filter;
|
||||
extern struct obs_source_info compressor_filter;
|
||||
extern struct obs_source_info limiter_filter;
|
||||
extern struct obs_source_info expander_filter;
|
||||
|
||||
bool obs_module_load(void)
|
||||
{
|
||||
@ -49,5 +50,6 @@ bool obs_module_load(void)
|
||||
obs_register_source(&noise_gate_filter);
|
||||
obs_register_source(&compressor_filter);
|
||||
obs_register_source(&limiter_filter);
|
||||
obs_register_source(&expander_filter);
|
||||
return true;
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user