OBS插件学习入门：一个非常简单的、调节音量的filter

#include <obs-module.h>
#include <math.h>struct volume_data {
obs_source_t *context;
size_t channels;
float factor;
};static const char *volume_name(void *unused)
{
UNUSED_PARAMETER(unused);
return obs_module_text("Volume");
}static void volume_destroy(void *data)
{
struct volume_data *gf = data;
bfree(gf);
}static void volume_update(void *data, obs_data_t *s)
{
struct volume_data *gf = data;
double val = obs_data_get_double(s, "volume");
gf->channels = audio_output_get_channels(obs_get_audio());
gf->factor = (float)val;
}static void *volume_create(obs_data_t *settings, obs_source_t *filter)
{
struct volume_data *gf = bzalloc(sizeof(*gf));
gf->context = filter;
volume_update(gf, settings);
return gf;
}static struct obs_audio_data *volume_filter_audio(void *data, struct obs_audio_data *audio)
{
struct volume_data *gf = data;
const size_t channels = gf->channels;
float **adata = (float**)audio->data;
const float factor = gf->factor; for (size_t c = ; c < channels; c++) {
if (audio->data[c]) {
for (size_t i = ; i < audio->frames; i++) {
adata[c][i] *= factor;
}
}
} return audio;
}static void volume_defaults(obs_data_t *s)
{
obs_data_set_default_double(s, "volume", 1.0f);
}static obs_properties_t *volume_properties(void *data)
{
obs_properties_t *ppts = obs_properties_create(); obs_properties_add_float_slider(ppts, "volume", "Volume", , 1.0, 0.1); UNUSED_PARAMETER(data);
return ppts;
}struct obs_source_info volume_filter = {
.id = "volume_filter",
.type = OBS_SOURCE_TYPE_FILTER,
.output_flags = OBS_SOURCE_AUDIO,
.get_name = volume_name,
.create = volume_create,
.destroy = volume_destroy,
.update = volume_update,
.filter_audio = volume_filter_audio,
.get_defaults = volume_defaults,
.get_properties = volume_properties,
};