obs-studio/plugins/obs-filters/noise-suppress-filter.c

#include <stdint.h>
#include <inttypes.h>

#include <util/circlebuf.h>
#include <obs-module.h>

#ifdef LIBSPEEXDSP_ENABLED
#include <speex/speex_preprocess.h>
#endif

#ifdef LIBRNNOISE_ENABLED
#ifdef _MSC_VER
#define ssize_t intptr_t
#endif
#include <rnnoise.h>
#include <media-io/audio-resampler.h>
#endif

/* -------------------------------------------------------- */

#define do_log(level, format, ...)                    \
	blog(level, "[noise suppress: '%s'] " format, \
	     obs_source_get_name(ng->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_SUPPRESS_LEVEL "suppress_level"
#define S_METHOD "method"
#define S_METHOD_SPEEX "speex"
#define S_METHOD_RNN "rnnoise"

#define MT_ obs_module_text
#define TEXT_SUPPRESS_LEVEL MT_("NoiseSuppress.SuppressLevel")
#define TEXT_METHOD MT_("NoiseSuppress.Method")
#define TEXT_METHOD_SPEEX MT_("NoiseSuppress.Method.Speex")
#define TEXT_METHOD_RNN MT_("NoiseSuppress.Method.RNNoise")

#define MAX_PREPROC_CHANNELS 8

/* RNNoise constants, these can't be changed */
#define RNNOISE_SAMPLE_RATE 48000
#define RNNOISE_FRAME_SIZE 480

/* If the following constant changes, RNNoise breaks */
#define BUFFER_SIZE_MSEC 10

/* -------------------------------------------------------- */

struct noise_suppress_data {
	obs_source_t *context;
	int suppress_level;

	uint64_t last_timestamp;
	uint64_t latency;

	size_t frames;
	size_t channels;

	struct circlebuf info_buffer;
	struct circlebuf input_buffers[MAX_PREPROC_CHANNELS];
	struct circlebuf output_buffers[MAX_PREPROC_CHANNELS];

	bool use_rnnoise;

#ifdef LIBSPEEXDSP_ENABLED
	/* Speex preprocessor state */
	SpeexPreprocessState *spx_states[MAX_PREPROC_CHANNELS];
#endif

#ifdef LIBRNNOISE_ENABLED
	/* RNNoise state */
	DenoiseState *rnn_states[MAX_PREPROC_CHANNELS];

	/* Resampler */
	audio_resampler_t *rnn_resampler;
	audio_resampler_t *rnn_resampler_back;
#endif

	/* PCM buffers */
	float *copy_buffers[MAX_PREPROC_CHANNELS];
#ifdef LIBSPEEXDSP_ENABLED
	spx_int16_t *spx_segment_buffers[MAX_PREPROC_CHANNELS];
#endif
#ifdef LIBRNNOISE_ENABLED
	float *rnn_segment_buffers[MAX_PREPROC_CHANNELS];
#endif

	/* output data */
	struct obs_audio_data output_audio;
	DARRAY(float) output_data;
};

/* -------------------------------------------------------- */

#define SUP_MIN -60
#define SUP_MAX 0

static const float c_32_to_16 = (float)INT16_MAX;
static const float c_16_to_32 = ((float)INT16_MAX + 1.0f);

/* -------------------------------------------------------- */

static const char *noise_suppress_name(void *unused)
{
	UNUSED_PARAMETER(unused);
	return obs_module_text("NoiseSuppress");
}

static void noise_suppress_destroy(void *data)
{
	struct noise_suppress_data *ng = data;

	for (size_t i = 0; i < ng->channels; i++) {
#ifdef LIBSPEEXDSP_ENABLED
		speex_preprocess_state_destroy(ng->spx_states[i]);
#endif
#ifdef LIBRNNOISE_ENABLED
		rnnoise_destroy(ng->rnn_states[i]);
#endif
		circlebuf_free(&ng->input_buffers[i]);
		circlebuf_free(&ng->output_buffers[i]);
	}

#ifdef LIBSPEEXDSP_ENABLED
	bfree(ng->spx_segment_buffers[0]);
#endif
#ifdef LIBRNNOISE_ENABLED
	bfree(ng->rnn_segment_buffers[0]);

	if (ng->rnn_resampler) {
		audio_resampler_destroy(ng->rnn_resampler);
		audio_resampler_destroy(ng->rnn_resampler_back);
	}
#endif

	bfree(ng->copy_buffers[0]);
	circlebuf_free(&ng->info_buffer);
	da_free(ng->output_data);
	bfree(ng);
}

static inline void alloc_channel(struct noise_suppress_data *ng,
				 uint32_t sample_rate, size_t channel,
				 size_t frames)
{
#ifdef LIBSPEEXDSP_ENABLED
	ng->spx_states[channel] =
		speex_preprocess_state_init((int)frames, sample_rate);
#endif
#ifdef LIBRNNOISE_ENABLED
	ng->rnn_states[channel] = rnnoise_create(NULL);
#endif
	circlebuf_reserve(&ng->input_buffers[channel], frames * sizeof(float));
	circlebuf_reserve(&ng->output_buffers[channel], frames * sizeof(float));
}

static inline enum speaker_layout convert_speaker_layout(uint8_t channels)
{
	switch (channels) {
	case 0:
		return SPEAKERS_UNKNOWN;
	case 1:
		return SPEAKERS_MONO;
	case 2:
		return SPEAKERS_STEREO;
	case 3:
		return SPEAKERS_2POINT1;
	case 4:
		return SPEAKERS_4POINT0;
	case 5:
		return SPEAKERS_4POINT1;
	case 6:
		return SPEAKERS_5POINT1;
	case 8:
		return SPEAKERS_7POINT1;
	default:
		return SPEAKERS_UNKNOWN;
	}
}

static void noise_suppress_update(void *data, obs_data_t *s)
{
	struct noise_suppress_data *ng = data;

	uint32_t sample_rate = audio_output_get_sample_rate(obs_get_audio());
	size_t channels = audio_output_get_channels(obs_get_audio());
	size_t frames = (size_t)sample_rate / (1000 / BUFFER_SIZE_MSEC);
	const char *method = obs_data_get_string(s, S_METHOD);

	ng->suppress_level = (int)obs_data_get_int(s, S_SUPPRESS_LEVEL);
	ng->latency = 1000000000LL / (1000 / BUFFER_SIZE_MSEC);
	ng->use_rnnoise = strcmp(method, S_METHOD_RNN) == 0;

	/* Process 10 millisecond segments to keep latency low */
	/* Also RNNoise only supports buffers of this exact size. */
	ng->frames = frames;
	ng->channels = channels;

	/* Ignore if already allocated */
#if defined(LIBSPEEXDSP_ENABLED)
	if (ng->spx_states[0])
		return;
#else
	if (ng->rnn_states[0])
		return;
#endif

	/* One speex/rnnoise state for each channel (limit 2) */
	ng->copy_buffers[0] = bmalloc(frames * channels * sizeof(float));
#ifdef LIBSPEEXDSP_ENABLED
	ng->spx_segment_buffers[0] =
		bmalloc(frames * channels * sizeof(spx_int16_t));
#endif
#ifdef LIBRNNOISE_ENABLED
	ng->rnn_segment_buffers[0] =
		bmalloc(RNNOISE_FRAME_SIZE * channels * sizeof(float));
#endif
	for (size_t c = 1; c < channels; ++c) {
		ng->copy_buffers[c] = ng->copy_buffers[c - 1] + frames;
#ifdef LIBSPEEXDSP_ENABLED
		ng->spx_segment_buffers[c] =
			ng->spx_segment_buffers[c - 1] + frames;
#endif
#ifdef LIBRNNOISE_ENABLED
		ng->rnn_segment_buffers[c] =
			ng->rnn_segment_buffers[c - 1] + RNNOISE_FRAME_SIZE;
#endif
	}

	for (size_t i = 0; i < channels; i++)
		alloc_channel(ng, sample_rate, i, frames);

#ifdef LIBRNNOISE_ENABLED
	if (sample_rate == RNNOISE_SAMPLE_RATE) {
		ng->rnn_resampler = NULL;
		ng->rnn_resampler_back = NULL;
	} else {
		struct resample_info src, dst;
		src.samples_per_sec = sample_rate;
		src.format = AUDIO_FORMAT_FLOAT_PLANAR;
		src.speakers = convert_speaker_layout((uint8_t)channels);

		dst.samples_per_sec = RNNOISE_SAMPLE_RATE;
		dst.format = AUDIO_FORMAT_FLOAT_PLANAR;
		dst.speakers = convert_speaker_layout((uint8_t)channels);

		ng->rnn_resampler = audio_resampler_create(&dst, &src);
		ng->rnn_resampler_back = audio_resampler_create(&src, &dst);
	}
#endif
}

static void *noise_suppress_create(obs_data_t *settings, obs_source_t *filter)
{
	struct noise_suppress_data *ng =
		bzalloc(sizeof(struct noise_suppress_data));

	ng->context = filter;
	noise_suppress_update(ng, settings);
	return ng;
}

static inline void process_speexdsp(struct noise_suppress_data *ng)
{
#ifdef LIBSPEEXDSP_ENABLED
	/* Set args */
	for (size_t i = 0; i < ng->channels; i++)
		speex_preprocess_ctl(ng->spx_states[i],
				     SPEEX_PREPROCESS_SET_NOISE_SUPPRESS,
				     &ng->suppress_level);

	/* Convert to 16bit */
	for (size_t i = 0; i < ng->channels; i++)
		for (size_t j = 0; j < ng->frames; j++) {
			float s = ng->copy_buffers[i][j];
			if (s > 1.0f)
				s = 1.0f;
			else if (s < -1.0f)
				s = -1.0f;
			ng->spx_segment_buffers[i][j] =
				(spx_int16_t)(s * c_32_to_16);
		}

	/* Execute */
	for (size_t i = 0; i < ng->channels; i++)
		speex_preprocess_run(ng->spx_states[i],
				     ng->spx_segment_buffers[i]);

	/* Convert back to 32bit */
	for (size_t i = 0; i < ng->channels; i++)
		for (size_t j = 0; j < ng->frames; j++)
			ng->copy_buffers[i][j] =
				(float)ng->spx_segment_buffers[i][j] /
				c_16_to_32;
#endif
}

static inline void process_rnnoise(struct noise_suppress_data *ng)
{
#ifdef LIBRNNOISE_ENABLED
	/* Adjust signal level to what RNNoise expects, resample if necessary */
	if (ng->rnn_resampler) {
		float *output[MAX_PREPROC_CHANNELS];
		uint32_t out_frames;
		uint64_t ts_offset;
		audio_resampler_resample(ng->rnn_resampler, (uint8_t **)output,
					 &out_frames, &ts_offset,
					 (const uint8_t **)ng->copy_buffers,
					 (uint32_t)ng->frames);

		for (size_t i = 0; i < ng->channels; i++) {
			for (ssize_t j = 0, k = (ssize_t)out_frames -
						RNNOISE_FRAME_SIZE;
			     j < RNNOISE_FRAME_SIZE; ++j, ++k) {
				if (k >= 0) {
					ng->rnn_segment_buffers[i][j] =
						output[i][k] * 32768.0f;
				} else {
					ng->rnn_segment_buffers[i][j] = 0;
				}
			}
		}
	} else {
		for (size_t i = 0; i < ng->channels; i++) {
			for (size_t j = 0; j < RNNOISE_FRAME_SIZE; ++j) {
				ng->rnn_segment_buffers[i][j] =
					ng->copy_buffers[i][j] * 32768.0f;
			}
		}
	}

	/* Execute */
	for (size_t i = 0; i < ng->channels; i++) {
		rnnoise_process_frame(ng->rnn_states[i],
				      ng->rnn_segment_buffers[i],
				      ng->rnn_segment_buffers[i]);
	}

	/* Revert signal level adjustment, resample back if necessary */
	if (ng->rnn_resampler) {
		float *output[MAX_PREPROC_CHANNELS];
		uint32_t out_frames;
		uint64_t ts_offset;
		audio_resampler_resample(
			ng->rnn_resampler_back, (uint8_t **)output, &out_frames,
			&ts_offset, (const uint8_t **)ng->rnn_segment_buffers,
			RNNOISE_FRAME_SIZE);

		for (size_t i = 0; i < ng->channels; i++) {
			for (ssize_t j = 0,
				     k = (ssize_t)out_frames - ng->frames;
			     j < (ssize_t)ng->frames; ++j, ++k) {
				if (k >= 0) {
					ng->copy_buffers[i][j] =
						output[i][k] / 32768.0f;
				} else {
					ng->copy_buffers[i][j] = 0;
				}
			}
		}
	} else {
		for (size_t i = 0; i < ng->channels; i++) {
			for (size_t j = 0; j < RNNOISE_FRAME_SIZE; ++j) {
				ng->copy_buffers[i][j] =
					ng->rnn_segment_buffers[i][j] /
					32768.0f;
			}
		}
	}
#else
	UNUSED_PARAMETER(ng);
#endif
}

static inline void process(struct noise_suppress_data *ng)
{
	/* Pop from input circlebuf */
	for (size_t i = 0; i < ng->channels; i++)
		circlebuf_pop_front(&ng->input_buffers[i], ng->copy_buffers[i],
				    ng->frames * sizeof(float));

	if (ng->use_rnnoise) {
		process_rnnoise(ng);
	} else {
		process_speexdsp(ng);
	}

	/* Push to output circlebuf */
	for (size_t i = 0; i < ng->channels; i++)
		circlebuf_push_back(&ng->output_buffers[i], ng->copy_buffers[i],
				    ng->frames * sizeof(float));
}

struct ng_audio_info {
	uint32_t frames;
	uint64_t timestamp;
};

static inline void clear_circlebuf(struct circlebuf *buf)
{
	circlebuf_pop_front(buf, NULL, buf->size);
}

static void reset_data(struct noise_suppress_data *ng)
{
	for (size_t i = 0; i < ng->channels; i++) {
		clear_circlebuf(&ng->input_buffers[i]);
		clear_circlebuf(&ng->output_buffers[i]);
	}

	clear_circlebuf(&ng->info_buffer);
}

static struct obs_audio_data *
noise_suppress_filter_audio(void *data, struct obs_audio_data *audio)
{
	struct noise_suppress_data *ng = data;
	struct ng_audio_info info;
	size_t segment_size = ng->frames * sizeof(float);
	size_t out_size;

#ifdef LIBSPEEXDSP_ENABLED
	if (!ng->spx_states[0])
		return audio;
#else
	if (!ng->rnn_states[0])
		return audio;
#endif

	/* -----------------------------------------------
	 * if timestamp has dramatically changed, consider it a new stream of
	 * audio data.  clear all circular buffers to prevent old audio data
	 * from being processed as part of the new data. */
	if (ng->last_timestamp) {
		int64_t diff = llabs((int64_t)ng->last_timestamp -
				     (int64_t)audio->timestamp);

		if (diff > 1000000000LL)
			reset_data(ng);
	}

	ng->last_timestamp = audio->timestamp;

	/* -----------------------------------------------
	 * push audio packet info (timestamp/frame count) to info circlebuf */
	info.frames = audio->frames;
	info.timestamp = audio->timestamp;
	circlebuf_push_back(&ng->info_buffer, &info, sizeof(info));

	/* -----------------------------------------------
	 * push back current audio data to input circlebuf */
	for (size_t i = 0; i < ng->channels; i++)
		circlebuf_push_back(&ng->input_buffers[i], audio->data[i],
				    audio->frames * sizeof(float));

	/* -----------------------------------------------
	 * pop/process each 10ms segments, push back to output circlebuf */
	while (ng->input_buffers[0].size >= segment_size)
		process(ng);

	/* -----------------------------------------------
	 * peek front of info circlebuf, check to see if we have enough to
	 * pop the expected packet size, if not, return null */
	memset(&info, 0, sizeof(info));
	circlebuf_peek_front(&ng->info_buffer, &info, sizeof(info));
	out_size = info.frames * sizeof(float);

	if (ng->output_buffers[0].size < out_size)
		return NULL;

	/* -----------------------------------------------
	 * if there's enough audio data buffered in the output circlebuf,
	 * pop and return a packet */
	circlebuf_pop_front(&ng->info_buffer, NULL, sizeof(info));
	da_resize(ng->output_data, out_size * ng->channels);

	for (size_t i = 0; i < ng->channels; i++) {
		ng->output_audio.data[i] =
			(uint8_t *)&ng->output_data.array[i * out_size];

		circlebuf_pop_front(&ng->output_buffers[i],
				    ng->output_audio.data[i], out_size);
	}

	ng->output_audio.frames = info.frames;
	ng->output_audio.timestamp = info.timestamp - ng->latency;
	return &ng->output_audio;
}

static bool noise_suppress_method_modified(obs_properties_t *props,
					   obs_property_t *property,
					   obs_data_t *settings)
{
	obs_property_t *p_suppress_level =
		obs_properties_get(props, S_SUPPRESS_LEVEL);
	const char *method = obs_data_get_string(settings, S_METHOD);
	bool enable_level = strcmp(method, S_METHOD_SPEEX) == 0;

	obs_property_set_visible(p_suppress_level, enable_level);

	UNUSED_PARAMETER(property);
	return true;
}

static void noise_suppress_defaults_v1(obs_data_t *s)
{
	obs_data_set_default_int(s, S_SUPPRESS_LEVEL, -30);
#if defined(LIBRNNOISE_ENABLED) && !defined(LIBSPEEXDSP_ENABLED)
	obs_data_set_default_string(s, S_METHOD, S_METHOD_RNN);
#else
	obs_data_set_default_string(s, S_METHOD, S_METHOD_SPEEX);
#endif
}

static void noise_suppress_defaults_v2(obs_data_t *s)
{
	obs_data_set_default_int(s, S_SUPPRESS_LEVEL, -30);
#if defined(LIBRNNOISE_ENABLED)
	obs_data_set_default_string(s, S_METHOD, S_METHOD_RNN);
#else
	obs_data_set_default_string(s, S_METHOD, S_METHOD_SPEEX);
#endif
}

static obs_properties_t *noise_suppress_properties(void *data)
{
	obs_properties_t *ppts = obs_properties_create();

#if defined(LIBRNNOISE_ENABLED) && defined(LIBSPEEXDSP_ENABLED)
	obs_property_t *method = obs_properties_add_list(
		ppts, S_METHOD, TEXT_METHOD, OBS_COMBO_TYPE_LIST,
		OBS_COMBO_FORMAT_STRING);
	obs_property_list_add_string(method, TEXT_METHOD_SPEEX, S_METHOD_SPEEX);
	obs_property_list_add_string(method, TEXT_METHOD_RNN, S_METHOD_RNN);

	obs_property_set_modified_callback(method,
					   noise_suppress_method_modified);
#endif

#ifdef LIBSPEEXDSP_ENABLED
	obs_property_t *speex_slider = obs_properties_add_int_slider(
		ppts, S_SUPPRESS_LEVEL, TEXT_SUPPRESS_LEVEL, SUP_MIN, SUP_MAX,
		1);
	obs_property_int_set_suffix(speex_slider, " dB");
#endif

	UNUSED_PARAMETER(data);
	return ppts;
}

struct obs_source_info noise_suppress_filter = {
	.id = "noise_suppress_filter",
	.type = OBS_SOURCE_TYPE_FILTER,
	.output_flags = OBS_SOURCE_AUDIO | OBS_SOURCE_CAP_OBSOLETE,
	.get_name = noise_suppress_name,
	.create = noise_suppress_create,
	.destroy = noise_suppress_destroy,
	.update = noise_suppress_update,
	.filter_audio = noise_suppress_filter_audio,
	.get_defaults = noise_suppress_defaults_v1,
	.get_properties = noise_suppress_properties,
};

struct obs_source_info noise_suppress_filter_v2 = {
	.id = "noise_suppress_filter",
	.version = 2,
	.type = OBS_SOURCE_TYPE_FILTER,
	.output_flags = OBS_SOURCE_AUDIO,
	.get_name = noise_suppress_name,
	.create = noise_suppress_create,
	.destroy = noise_suppress_destroy,
	.update = noise_suppress_update,
	.filter_audio = noise_suppress_filter_audio,
	.get_defaults = noise_suppress_defaults_v2,
	.get_properties = noise_suppress_properties,
};