libobs: Add Pulseaudio audio monitoring support

Checks if the system has Pulseaudio and enables support via the
HAVE_PULSEAUDIO flag.

Closes jp9000/obs-studio#940

libobs/CMakeLists.txt

@@ -12,12 +12,20 @@ if (NOT "${FFMPEG_AVCODEC_LIBRARIES}" STREQUAL "")
 endif()
 
 if(UNIX)
+	find_package(PulseAudio)
+	if (NOT "${PULSEAUDIO_LIBRARY}" STREQUAL "")
+		message(STATUS "Found PulseAudio - Audio Monitor enabled")
+		set(HAVE_PULSEAUDIO "1")
+	else()
+		set(HAVE_PULSEAUDIO "0")
+	endif()
 	find_package(DBus QUIET)
 	if (NOT APPLE)
 		find_package(X11_XCB REQUIRED)
 	endif()
 else()
 	set(HAVE_DBUS "0")
+	set(HAVE_PULSEAUDIO "0")
 endif()
 
 find_package(ImageMagick QUIET COMPONENTS MagickCore)
@@ -145,12 +153,22 @@ elseif(UNIX)
 		util/threading-posix.c
 		util/pipe-posix.c
 		util/platform-nix.c)
+
 	set(libobs_PLATFORM_HEADERS
 		util/threading-posix.h)
-	set(libobs_audio_monitoring_SOURCES
-		audio-monitoring/null/null-audio-monitoring.c
-		)
 
+	if(HAVE_PULSEAUDIO)
+		set(libobs_audio_monitoring_HEADERS
+			audio-monitoring/pulse/pulseaudio-wrapper.h)
+
+		set(libobs_audio_monitoring_SOURCES
+			audio-monitoring/pulse/pulseaudio-wrapper.c
+			audio-monitoring/pulse/pulseaudio-enum-devices.c
+			audio-monitoring/pulse/pulseaudio-output.c)
+	else()
+		set(libobs_audio_monitoring_SOURCES
+			audio-monitoring/null/null-audio-monitoring.c)
+	endif()
 	if(DBUS_FOUND)
 		set(libobs_PLATFORM_SOURCES ${libobs_PLATFORM_SOURCES}
 			util/platform-nix-dbus.c)
@@ -168,6 +186,12 @@ elseif(UNIX)
 		${libobs_PLATFORM_DEPS}
 		${X11_XCB_LIBRARIES})
 
+	if(HAVE_PULSEAUDIO)
+		set(libobs_PLATFORM_DEPS
+			${libobs_PLATFORM_DEPS}
+			${PULSEAUDIO_LIBRARY})
+	endif()
+
 	if(${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD")
 		# use the sysinfo compatibility library on bsd
 		find_package(Libsysinfo REQUIRED)
@@ -358,7 +382,9 @@ set(libobs_SOURCES
 	${libobs_graphics_SOURCES}
 	${libobs_mediaio_SOURCES}
 	${libobs_util_SOURCES}
-	${libobs_libobs_SOURCES})
+	${libobs_libobs_SOURCES}
+	${libobs_audio_monitoring_SOURCES}
+	)
 
 set(libobs_HEADERS
 	${libobs_config_HEADERS}
@@ -367,7 +393,6 @@ set(libobs_HEADERS
 	${libobs_mediaio_HEADERS}
 	${libobs_util_HEADERS}
 	${libobs_libobs_HEADERS}
-	${libobs_audio_monitoring_SOURCES}
 	${libobs_audio_monitoring_HEADERS}
 	)
 

libobs/audio-monitoring/null/null-audio-monitoring.c

@@ -1,4 +1,4 @@
-#include "../../obs-internal.h"
+#include <obs-internal.h>
 
 void obs_enum_audio_monitoring_devices(obs_enum_audio_device_cb cb, void *data)
 {

libobs/audio-monitoring/pulse/pulseaudio-enum-devices.c

@@ -0,0 +1,33 @@
+#include <obs-internal.h>
+#include "pulseaudio-wrapper.h"
+
+static void pulseaudio_output_info(pa_context *c, const pa_source_info *i,
+		int eol, void *userdata)
+{
+	UNUSED_PARAMETER(c);
+	if (eol != 0 || i->monitor_of_sink == PA_INVALID_INDEX)
+		goto skip;
+
+	struct enum_cb *ecb = (struct enum_cb *) userdata;
+	if (ecb->cont)
+		ecb->cont = ecb->cb(ecb->data, i->description, i->name);
+
+skip:
+	pulseaudio_signal(0);
+}
+
+void obs_enum_audio_monitoring_devices(obs_enum_audio_device_cb cb,
+		void *data)
+{
+	struct enum_cb *ecb = bzalloc(sizeof(struct enum_cb));
+	ecb->cb = cb;
+	ecb->data = data;
+	ecb->cont = 1;
+
+	pulseaudio_init();
+	pa_source_info_cb_t pa_cb = pulseaudio_output_info;
+	pulseaudio_get_source_info_list(pa_cb, (void *) ecb);
+	pulseaudio_unref();
+
+	bfree(ecb);
+}

libobs/audio-monitoring/pulse/pulseaudio-output.c

@@ -0,0 +1,469 @@
+#include "obs-internal.h"
+#include "pulseaudio-wrapper.h"
+
+#define PULSE_DATA(voidptr) struct audio_monitor *data = voidptr;
+#define blog(level, msg, ...) blog(level, "pulse-am: " msg, ##__VA_ARGS__)
+
+struct audio_monitor {
+	obs_source_t 		*source;
+	pa_stream    		*stream;
+	char         		*device;
+
+	enum speaker_layout 	speakers;
+	pa_sample_format_t  	format;
+	uint_fast32_t       	samples_per_sec;
+	uint_fast32_t       	bytes_per_frame;
+	uint_fast8_t        	channels;
+
+	uint_fast32_t 		packets;
+	uint_fast64_t 		frames;
+
+	struct circlebuf  	new_data;
+	audio_resampler_t 	*resampler;
+	size_t            	buffer_size;
+	size_t            	bytesRemaining;
+
+	size_t          	bytes_per_channel;
+	bool 			ignore;
+	pthread_mutex_t 	playback_mutex;
+};
+
+static enum speaker_layout pulseaudio_channels_to_obs_speakers(
+		uint_fast32_t channels)
+{
+	if ((channels >= 1 && channels <= 6) || channels == 8)
+		return (enum speaker_layout) channels;
+	return SPEAKERS_UNKNOWN;
+}
+
+static enum audio_format pulseaudio_to_obs_audio_format(
+		pa_sample_format_t format)
+{
+	switch (format) {
+	case PA_SAMPLE_U8:
+		return AUDIO_FORMAT_U8BIT;
+	case PA_SAMPLE_S16LE:
+		return AUDIO_FORMAT_16BIT;
+	case PA_SAMPLE_S32LE:
+		return AUDIO_FORMAT_32BIT;
+	case PA_SAMPLE_FLOAT32LE:
+		return AUDIO_FORMAT_FLOAT;
+	default:
+		return AUDIO_FORMAT_UNKNOWN;
+	}
+}
+
+static void process_byte(void *p, size_t frames, size_t channels, float vol)
+{
+	register char *cur = (char *) p;
+	register char *end = cur + frames * channels;
+
+	while (cur < end)
+		*(cur++) *= vol;
+}
+
+static void process_short(void *p, size_t frames, size_t channels, float vol)
+{
+	register short *cur = (short *) p;
+	register short *end = cur + frames * channels;
+
+	while (cur < end)
+		*(cur++) *= vol;
+}
+
+static void process_float(void *p, size_t frames, size_t channels, float vol)
+{
+	register float *cur = (float *) p;
+	register float *end = cur + frames * channels;
+
+	while (cur < end)
+		*(cur++) *= vol;
+}
+
+void process_volume(const struct audio_monitor *monitor, float vol,
+		uint8_t *const *resample_data, uint32_t resample_frames)
+{
+	switch (monitor->bytes_per_channel) {
+	case 1:
+		process_byte(resample_data[0], resample_frames,
+				monitor->channels, vol);
+		break;
+	case 2:
+		process_short(resample_data[0], resample_frames,
+				monitor->channels, vol);
+		break;
+	default:
+		process_float(resample_data[0], resample_frames,
+				monitor->channels, vol);
+		break;
+	}
+}
+
+static void do_stream_write(void *param)
+{
+	PULSE_DATA(param);
+	uint8_t *buffer = NULL;
+
+	while (data->new_data.size >= data->buffer_size &&
+			data->bytesRemaining > 0) {
+		size_t bytesToFill = data->buffer_size;
+
+		if (bytesToFill > data->bytesRemaining)
+			bytesToFill = data->bytesRemaining;
+
+		pa_stream_begin_write(data->stream, (void **) &buffer,
+				&bytesToFill);
+
+		circlebuf_pop_front(&data->new_data, buffer, bytesToFill);
+
+		pulseaudio_lock();
+		pa_stream_write(data->stream, buffer, bytesToFill, NULL,
+				0LL, PA_SEEK_RELATIVE);
+		pulseaudio_unlock();
+
+		data->bytesRemaining -= bytesToFill;
+	}
+}
+
+static void on_audio_playback(void *param, obs_source_t *source,
+		const struct audio_data *audio_data, bool muted)
+{
+	struct audio_monitor *monitor = param;
+	float vol = source->user_volume;
+	size_t bytes;
+
+	uint8_t *resample_data[MAX_AV_PLANES];
+	uint32_t resample_frames;
+	uint64_t ts_offset;
+	bool success;
+
+	if (pthread_mutex_trylock(&monitor->playback_mutex) != 0)
+		return;
+
+	if (os_atomic_load_long(&source->activate_refs) == 0)
+		goto unlock;
+
+	success = audio_resampler_resample(monitor->resampler, resample_data,
+			&resample_frames, &ts_offset,
+			(const uint8_t *const *) audio_data->data,
+			(uint32_t) audio_data->frames);
+
+	if (!success)
+		goto unlock;
+
+	bytes = monitor->bytes_per_frame * resample_frames;
+
+	if (muted) {
+		memset(resample_data[0], 0, bytes);
+	} else {
+		if (!close_float(vol, 1.0f, EPSILON)) {
+			process_volume(monitor, vol, resample_data,
+					resample_frames);
+		}
+	}
+
+	circlebuf_push_back(&monitor->new_data, resample_data[0], bytes);
+	monitor->packets++;
+	monitor->frames += resample_frames;
+
+unlock:
+	pthread_mutex_unlock(&monitor->playback_mutex);
+	do_stream_write(param);
+}
+
+static void pulseaudio_stream_write(pa_stream *p, size_t nbytes, void *userdata)
+{
+	UNUSED_PARAMETER(p);
+	PULSE_DATA(userdata);
+
+	pthread_mutex_lock(&data->playback_mutex);
+	data->bytesRemaining += nbytes;
+	pthread_mutex_unlock(&data->playback_mutex);
+
+	pulseaudio_signal(0);
+}
+
+static void pulseaudio_server_info(pa_context *c, const pa_server_info *i,
+		void *userdata)
+{
+	UNUSED_PARAMETER(c);
+	UNUSED_PARAMETER(userdata);
+
+	blog(LOG_INFO, "Server name: '%s %s'", i->server_name,
+			i->server_version);
+
+	pulseaudio_signal(0);
+}
+
+static void pulseaudio_source_info(pa_context *c, const pa_source_info *i,
+		int eol, void *userdata)
+{
+	UNUSED_PARAMETER(c);
+	PULSE_DATA(userdata);
+	// An error occured
+	if (eol < 0) {
+		data->format = PA_SAMPLE_INVALID;
+		goto skip;
+	}
+	// Terminating call for multi instance callbacks
+	if (eol > 0)
+		goto skip;
+
+	blog(LOG_INFO, "Audio format: %s, %"PRIu32" Hz, %"PRIu8" channels",
+			pa_sample_format_to_string(i->sample_spec.format),
+			i->sample_spec.rate, i->sample_spec.channels);
+
+	pa_sample_format_t format = i->sample_spec.format;
+	if (pulseaudio_to_obs_audio_format(format) == AUDIO_FORMAT_UNKNOWN) {
+		format = PA_SAMPLE_S16LE;
+
+		blog(LOG_INFO, "Sample format %s not supported by OBS,"
+				"using %s instead for recording",
+				pa_sample_format_to_string(
+						i->sample_spec.format),
+				pa_sample_format_to_string(format));
+	}
+
+	uint8_t channels = i->sample_spec.channels;
+	if (pulseaudio_channels_to_obs_speakers(channels) == SPEAKERS_UNKNOWN) {
+		channels = 2;
+
+		blog(LOG_INFO, "%c channels not supported by OBS,"
+				"using %c instead for recording",
+				i->sample_spec.channels,
+				channels);
+	}
+
+	data->format = format;
+	data->samples_per_sec = i->sample_spec.rate;
+	data->channels = channels;
+skip:
+	pulseaudio_signal(0);
+}
+
+static void pulseaudio_stop_playback(struct audio_monitor *monitor)
+{
+	if (monitor->stream) {
+		pa_stream_disconnect(monitor->stream);
+		pa_stream_unref(monitor->stream);
+		monitor->stream = NULL;
+	}
+
+	blog(LOG_INFO, "Stopped Monitoring in '%s'", monitor->device);
+	blog(LOG_INFO, "Got %"PRIuFAST32" packets with %"PRIuFAST64" frames",
+			monitor->packets, monitor->frames);
+
+	monitor->packets = 0;
+	monitor->frames = 0;
+}
+
+static bool audio_monitor_init(struct audio_monitor *monitor,
+		obs_source_t *source)
+{
+	pthread_mutex_init_value(&monitor->playback_mutex);
+
+	monitor->source = source;
+
+	const char *id = obs->audio.monitoring_device_id;
+	if (!id)
+		return false;
+
+	if (source->info.output_flags & OBS_SOURCE_DO_NOT_SELF_MONITOR) {
+		obs_data_t *s = obs_source_get_settings(source);
+		const char *s_dev_id = obs_data_get_string(s, "device_id");
+		bool match = devices_match(s_dev_id, id);
+		obs_data_release(s);
+
+		if (match) {
+			monitor->ignore = true;
+			blog(LOG_INFO, "Prevented feedback-loop in '%s'",
+					s_dev_id);
+			return true;
+		}
+	}
+
+	pulseaudio_init();
+
+	if (strcmp(id, "default") == 0)
+		get_default_id(&monitor->device);
+	else
+		monitor->device = bstrdup(id);
+
+	if (!monitor->device)
+		return false;
+
+	if (pulseaudio_get_server_info(pulseaudio_server_info,
+			(void *) monitor) < 0) {
+		blog(LOG_ERROR, "Unable to get server info !");
+		return false;
+	}
+
+	if (pulseaudio_get_source_info(pulseaudio_source_info, monitor->device,
+			(void *) monitor) < 0) {
+		blog(LOG_ERROR, "Unable to get source info !");
+		return false;
+	}
+	if (monitor->format == PA_SAMPLE_INVALID) {
+		blog(LOG_ERROR,
+				"An error occurred while getting the source info!");
+		return false;
+	}
+
+	pa_sample_spec spec;
+	spec.format = monitor->format;
+	spec.rate = (uint32_t) monitor->samples_per_sec;
+	spec.channels = monitor->channels;
+
+	if (!pa_sample_spec_valid(&spec)) {
+		blog(LOG_ERROR, "Sample spec is not valid");
+		return false;
+	}
+
+	const struct audio_output_info *info = audio_output_get_info(
+			obs->audio.audio);
+
+	struct resample_info from = {
+		.samples_per_sec = info->samples_per_sec,
+		.speakers	 = info->speakers,
+		.format		 = AUDIO_FORMAT_FLOAT_PLANAR
+	};
+	struct resample_info to = {
+		.samples_per_sec = (uint32_t) monitor->samples_per_sec,
+		.speakers	 = pulseaudio_channels_to_obs_speakers(
+				monitor->channels),
+		.format 	 = pulseaudio_to_obs_audio_format
+				(monitor->format)
+	};
+
+	monitor->resampler = audio_resampler_create(&to, &from);
+	if (!monitor->resampler) {
+		blog(LOG_WARNING, "%s: %s", __FUNCTION__,
+				"Failed to create resampler");
+		return false;
+	}
+
+	monitor->bytes_per_channel = get_audio_bytes_per_channel(
+			pulseaudio_to_obs_audio_format(monitor->format));
+	monitor->speakers = pulseaudio_channels_to_obs_speakers(spec.channels);
+	monitor->bytes_per_frame = pa_frame_size(&spec);
+
+	monitor->stream = pulseaudio_stream_new(
+			obs_source_get_name(monitor->source), &spec, NULL);
+	if (!monitor->stream) {
+		blog(LOG_ERROR, "Unable to create stream");
+		return false;
+	}
+
+	pa_buffer_attr attr;
+	attr.fragsize = (uint32_t) -1;
+	attr.maxlength = (uint32_t) -1;
+	attr.minreq = (uint32_t) -1;
+	attr.prebuf = (uint32_t) -1;
+	attr.tlength = pa_usec_to_bytes(25000, &spec);
+
+	monitor->buffer_size =
+			monitor->bytes_per_frame * pa_usec_to_bytes(100, &spec);
+
+	pa_stream_flags_t flags = PA_STREAM_ADJUST_LATENCY;
+
+	if (pthread_mutex_init(&monitor->playback_mutex, NULL) != 0) {
+		blog(LOG_WARNING, "%s: %s", __FUNCTION__,
+				"Failed to init mutex");
+		return false;
+	}
+
+	int_fast32_t ret = pulseaudio_connect_playback(monitor->stream,
+			monitor->device, &attr, flags);
+	if (ret < 0) {
+		pulseaudio_stop_playback(monitor);
+		blog(LOG_ERROR, "Unable to connect to stream");
+		return false;
+	}
+
+	blog(LOG_INFO, "Started Monitoring in '%s'", monitor->device);
+	return true;
+}
+
+static void audio_monitor_init_final(struct audio_monitor *monitor)
+{
+	if (monitor->ignore)
+		return;
+
+	obs_source_add_audio_capture_callback(monitor->source,
+			on_audio_playback, monitor);
+
+	pulseaudio_write_callback(monitor->stream, pulseaudio_stream_write,
+			(void *) monitor);
+}
+
+static inline void audio_monitor_free(struct audio_monitor *monitor)
+{
+	if (monitor->ignore)
+		return;
+
+	if (monitor->source)
+		obs_source_remove_audio_capture_callback(monitor->source,
+				on_audio_playback, monitor);
+
+	audio_resampler_destroy(monitor->resampler);
+	circlebuf_free(&monitor->new_data);
+
+	if (monitor->stream)
+		pulseaudio_stop_playback(monitor);
+	pulseaudio_unref();
+
+	bfree(monitor->device);
+}
+
+struct audio_monitor *audio_monitor_create(obs_source_t *source)
+{
+	struct audio_monitor monitor = {0};
+	struct audio_monitor *out;
+
+	if (!audio_monitor_init(&monitor, source))
+		goto fail;
+
+	out = bmemdup(&monitor, sizeof(monitor));
+
+	pthread_mutex_lock(&obs->audio.monitoring_mutex);
+	da_push_back(obs->audio.monitors, &out);
+	pthread_mutex_unlock(&obs->audio.monitoring_mutex);
+
+	audio_monitor_init_final(out);
+	return out;
+
+fail:
+	audio_monitor_free(&monitor);
+	return NULL;
+}
+
+void audio_monitor_reset(struct audio_monitor *monitor)
+{
+	struct audio_monitor new_monitor = {0};
+	bool success;
+	audio_monitor_free(monitor);
+
+	pthread_mutex_lock(&monitor->playback_mutex);
+	success = audio_monitor_init(&new_monitor, monitor->source);
+	pthread_mutex_unlock(&monitor->playback_mutex);
+
+	if (success) {
+		*monitor = new_monitor;
+		audio_monitor_init_final(monitor);
+	} else {
+		audio_monitor_free(&new_monitor);
+	}
+}
+
+void audio_monitor_destroy(struct audio_monitor *monitor)
+{
+	if (monitor) {
+		audio_monitor_free(monitor);
+
+		pthread_mutex_lock(&obs->audio.monitoring_mutex);
+		da_erase_item(obs->audio.monitors, &monitor);
+		pthread_mutex_unlock(&obs->audio.monitoring_mutex);
+
+		bfree(monitor);
+	}
+}

libobs/audio-monitoring/pulse/pulseaudio-wrapper.c

@@ -0,0 +1,330 @@
+/*
+Copyright (C) 2014 by Leonhard Oelke <[email protected]>
+Copyright (C) 2017 by Fabio Madia <[email protected]>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <pthread.h>
+
+#include <pulse/thread-mainloop.h>
+
+#include <util/base.h>
+#include <obs.h>
+
+#include "pulseaudio-wrapper.h"
+
+/* global data */
+static uint_fast32_t pulseaudio_refs = 0;
+static pthread_mutex_t pulseaudio_mutex = PTHREAD_MUTEX_INITIALIZER;
+static pa_threaded_mainloop *pulseaudio_mainloop = NULL;
+static pa_context *pulseaudio_context = NULL;
+
+static void pulseaudio_default_devices(pa_context *c, const pa_server_info *i,
+		void *userdata)
+{
+	UNUSED_PARAMETER(c);
+	struct pulseaudio_default_output *d =
+			(struct pulseaudio_default_output *) userdata;
+	d->default_sink_name = bstrdup(i->default_sink_name);
+	pulseaudio_signal(0);
+}
+
+void get_default_id(char **id)
+{
+	pulseaudio_init();
+	struct pulseaudio_default_output *pdo = bzalloc(
+			sizeof(struct pulseaudio_default_output));
+	pulseaudio_get_server_info(
+			(pa_server_info_cb_t) pulseaudio_default_devices,
+			(void *) pdo);
+	*id = bzalloc(strlen(pdo->default_sink_name) + 9);
+	strcat(*id, pdo->default_sink_name);
+	strcat(*id, ".monitor");
+	bfree(pdo->default_sink_name);
+	bfree(pdo);
+	pulseaudio_unref();
+}
+
+bool devices_match(const char *id1, const char *id2)
+{
+	bool match;
+	char *name1 = NULL;
+	char *name2 = NULL;
+
+	if (!id1 || !id2)
+		return false;
+
+	if (strcmp(id1, "default") == 0) {
+		get_default_id(&name1);
+		id1 = name1;
+	}
+	if (strcmp(id2, "default") == 0) {
+		get_default_id(&name2);
+		id2 = name2;
+	}
+
+	match = strcmp(id1, id2) == 0;
+	bfree(name1);
+	bfree(name2);
+	return match;
+}
+
+/**
+ * context status change callback
+ *
+ * @todo this is currently a noop, we want to reconnect here if the connection
+ *       is lost ...
+ */
+static void pulseaudio_context_state_changed(pa_context *c, void *userdata)
+{
+	UNUSED_PARAMETER(userdata);
+	UNUSED_PARAMETER(c);
+
+	pulseaudio_signal(0);
+}
+
+/**
+ * get the default properties
+ */
+static pa_proplist *pulseaudio_properties()
+{
+	pa_proplist *p = pa_proplist_new();
+
+	pa_proplist_sets(p, PA_PROP_APPLICATION_NAME, "OBS");
+	pa_proplist_sets(p, PA_PROP_APPLICATION_ICON_NAME, "obs");
+	pa_proplist_sets(p, PA_PROP_MEDIA_ROLE, "production");
+
+	return p;
+}
+
+/**
+ * Initialize the pulse audio context with properties and callback
+ */
+static void pulseaudio_init_context()
+{
+	pulseaudio_lock();
+
+	pa_proplist *p = pulseaudio_properties();
+	pulseaudio_context = pa_context_new_with_proplist(
+			pa_threaded_mainloop_get_api(pulseaudio_mainloop),
+			"OBS-Monitor", p);
+
+	pa_context_set_state_callback(pulseaudio_context,
+			pulseaudio_context_state_changed, NULL);
+
+	pa_context_connect(pulseaudio_context, NULL, PA_CONTEXT_NOAUTOSPAWN,
+			NULL);
+	pa_proplist_free(p);
+
+	pulseaudio_unlock();
+}
+
+/**
+ * wait for context to be ready
+ */
+static int_fast32_t pulseaudio_context_ready()
+{
+	pulseaudio_lock();
+
+	if (!PA_CONTEXT_IS_GOOD(pa_context_get_state(pulseaudio_context))) {
+		pulseaudio_unlock();
+		return -1;
+	}
+
+	while (pa_context_get_state(pulseaudio_context) != PA_CONTEXT_READY)
+		pulseaudio_wait();
+
+	pulseaudio_unlock();
+	return 0;
+}
+
+int_fast32_t pulseaudio_init()
+{
+	pthread_mutex_lock(&pulseaudio_mutex);
+
+	if (pulseaudio_refs == 0) {
+		pulseaudio_mainloop = pa_threaded_mainloop_new();
+		pa_threaded_mainloop_start(pulseaudio_mainloop);
+
+		pulseaudio_init_context();
+	}
+
+	pulseaudio_refs++;
+
+	pthread_mutex_unlock(&pulseaudio_mutex);
+
+	return 0;
+}
+
+void pulseaudio_unref()
+{
+	pthread_mutex_lock(&pulseaudio_mutex);
+
+	if (--pulseaudio_refs == 0) {
+		pulseaudio_lock();
+		if (pulseaudio_context != NULL) {
+			pa_context_disconnect(pulseaudio_context);
+			pa_context_unref(pulseaudio_context);
+			pulseaudio_context = NULL;
+		}
+		pulseaudio_unlock();
+
+		if (pulseaudio_mainloop != NULL) {
+			pa_threaded_mainloop_stop(pulseaudio_mainloop);
+			pa_threaded_mainloop_free(pulseaudio_mainloop);
+			pulseaudio_mainloop = NULL;
+		}
+	}
+
+	pthread_mutex_unlock(&pulseaudio_mutex);
+}
+
+void pulseaudio_lock()
+{
+	pa_threaded_mainloop_lock(pulseaudio_mainloop);
+}
+
+void pulseaudio_unlock()
+{
+	pa_threaded_mainloop_unlock(pulseaudio_mainloop);
+}
+
+void pulseaudio_wait()
+{
+	pa_threaded_mainloop_wait(pulseaudio_mainloop);
+}
+
+void pulseaudio_signal(int wait_for_accept)
+{
+	pa_threaded_mainloop_signal(pulseaudio_mainloop, wait_for_accept);
+}
+
+void pulseaudio_accept()
+{
+	pa_threaded_mainloop_accept(pulseaudio_mainloop);
+}
+
+int_fast32_t pulseaudio_get_source_info_list(pa_source_info_cb_t cb,
+		void *userdata)
+{
+	if (pulseaudio_context_ready() < 0)
+		return -1;
+
+	pulseaudio_lock();
+
+	pa_operation *op = pa_context_get_source_info_list(
+			pulseaudio_context, cb, userdata);
+	if (!op) {
+		pulseaudio_unlock();
+		return -1;
+	}
+	while (pa_operation_get_state(op) == PA_OPERATION_RUNNING)
+		pulseaudio_wait();
+	pa_operation_unref(op);
+
+	pulseaudio_unlock();
+
+	return 0;
+}
+
+int_fast32_t pulseaudio_get_source_info(pa_source_info_cb_t cb,
+		const char *name, void *userdata)
+{
+	if (pulseaudio_context_ready() < 0)
+		return -1;
+
+	pulseaudio_lock();
+
+	pa_operation *op = pa_context_get_source_info_by_name(
+			pulseaudio_context, name, cb, userdata);
+	if (!op) {
+		pulseaudio_unlock();
+		return -1;
+	}
+	while (pa_operation_get_state(op) == PA_OPERATION_RUNNING)
+		pulseaudio_wait();
+	pa_operation_unref(op);
+
+	pulseaudio_unlock();
+
+	return 0;
+}
+
+int_fast32_t pulseaudio_get_server_info(pa_server_info_cb_t cb, void *userdata)
+{
+	if (pulseaudio_context_ready() < 0)
+		return -1;
+
+	pulseaudio_lock();
+
+	pa_operation *op = pa_context_get_server_info(
+			pulseaudio_context, cb, userdata);
+	if (!op) {
+		pulseaudio_unlock();
+		return -1;
+	}
+	while (pa_operation_get_state(op) == PA_OPERATION_RUNNING)
+		pulseaudio_wait();
+	pa_operation_unref(op);
+
+	pulseaudio_unlock();
+	return 0;
+}
+
+pa_stream *pulseaudio_stream_new(const char *name, const pa_sample_spec *ss,
+		const pa_channel_map *map)
+{
+	if (pulseaudio_context_ready() < 0)
+		return NULL;
+
+	pulseaudio_lock();
+
+	pa_proplist *p = pulseaudio_properties();
+	pa_stream *s = pa_stream_new_with_proplist(
+			pulseaudio_context, name, ss, map, p);
+	pa_proplist_free(p);
+
+	pulseaudio_unlock();
+	return s;
+}
+
+int_fast32_t pulseaudio_connect_playback(pa_stream *s, const char *name,
+		const pa_buffer_attr *attr, pa_stream_flags_t flags)
+{
+	if (pulseaudio_context_ready() < 0)
+		return -1;
+
+	size_t dev_len = strlen(name) - 8;
+	char device[dev_len];
+	memcpy(device, name, dev_len);
+	device[dev_len] = '\0';
+
+	pulseaudio_lock();
+	int_fast32_t ret = pa_stream_connect_playback(s, device, attr, flags,
+			NULL, NULL);
+	pulseaudio_unlock();
+	return ret;
+}
+
+void pulseaudio_write_callback(pa_stream *p, pa_stream_request_cb_t cb,
+		void *userdata)
+{
+	if (pulseaudio_context_ready() < 0)
+		return;
+
+	pulseaudio_lock();
+	pa_stream_set_write_callback(p, cb, userdata);
+	pulseaudio_unlock();
+}

libobs/audio-monitoring/pulse/pulseaudio-wrapper.h

@@ -0,0 +1,175 @@
+/*
+Copyright (C) 2014 by Leonhard Oelke <[email protected]>
+Copyright (C) 2017 by Fabio Madia <[email protected]>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <inttypes.h>
+#include <pulse/stream.h>
+#include <pulse/context.h>
+#include <pulse/introspect.h>
+
+#pragma once
+
+struct pulseaudio_default_output {
+	char *default_sink_name;
+};
+
+struct enum_cb {
+	obs_enum_audio_device_cb cb;
+	void *data;
+	int cont;
+};
+
+void get_default_id(char **id);
+
+bool devices_match(const char *id1, const char *id2);
+
+/**
+ * Initialize the pulseaudio mainloop and increase the reference count
+ */
+int_fast32_t pulseaudio_init();
+
+/**
+ * Unreference the pulseaudio mainloop, when the reference count reaches
+ * zero the mainloop will automatically be destroyed
+ */
+void pulseaudio_unref();
+
+/**
+ * Lock the mainloop
+ *
+ * In order to allow for multiple threads to use the same mainloop pulseaudio
+ * provides it's own locking mechanism. This function should be called before
+ * using any pulseaudio function that is in any way related to the mainloop or
+ * context.
+ *
+ * @note use of this function may cause deadlocks
+ *
+ * @warning do not use with pulseaudio_ wrapper functions
+ */
+void pulseaudio_lock();
+
+/**
+ * Unlock the mainloop
+ *
+ * @see pulseaudio_lock()
+ */
+void pulseaudio_unlock();
+
+/**
+ * Wait for events to happen
+ *
+ * This function should be called when waiting for an event to happen.
+ */
+void pulseaudio_wait();
+
+/**
+ * Wait for accept signal from calling thread
+ *
+ * This function tells the pulseaudio mainloop wheter the data provided to
+ * the callback should be retained until the calling thread executes
+ * pulseaudio_accept()
+ *
+ * If wait_for_accept is 0 the function returns and the data is freed.
+ */
+void pulseaudio_signal(int wait_for_accept);
+
+/**
+ * Signal the waiting callback to return
+ *
+ * This function is used in conjunction with pulseaudio_signal()
+ */
+void pulseaudio_accept();
+
+/**
+ * Request source information
+ *
+ * The function will block until the operation was executed and the mainloop
+ * called the provided callback function.
+ *
+ * @return negative on error
+ *
+ * @note The function will block until the server context is ready.
+ *
+ * @warning call without active locks
+ */
+int_fast32_t pulseaudio_get_source_info_list(pa_source_info_cb_t cb,
+		void *userdata);
+
+/**
+ * Request source information from a specific source
+ *
+ * The function will block until the operation was executed and the mainloop
+ * called the provided callback function.
+ *
+ * @param cb pointer to the callback function
+ * @param name the source name to get information for
+ * @param userdata pointer to userdata the callback will be called with
+ *
+ * @return negative on error
+ *
+ * @note The function will block until the server context is ready.
+ *
+ * @warning call without active locks
+ */
+int_fast32_t pulseaudio_get_source_info(pa_source_info_cb_t cb,
+		const char *name, void *userdata);
+
+/**
+ * Request server information
+ *
+ * The function will block until the operation was executed and the mainloop
+ * called the provided callback function.
+ *
+ * @return negative on error
+ *
+ * @note The function will block until the server context is ready.
+ *
+ * @warning call without active locks
+ */
+int_fast32_t pulseaudio_get_server_info(pa_server_info_cb_t cb, void *userdata);
+
+/**
+ * Create a new stream with the default properties
+ *
+ * @note The function will block until the server context is ready.
+ *
+ * @warning call without active locks
+ */
+pa_stream *pulseaudio_stream_new(const char *name, const pa_sample_spec *ss,
+		const pa_channel_map *map);
+
+/**
+ * Connect to a pulseaudio playback stream
+ *
+ * @param s pa_stream to connect to. NULL for default
+ * @param attr pa_buffer_attr
+ * @param name Device name. NULL for default device
+ * @param flags pa_stream_flags_t
+ * @return negative on error
+ */
+int_fast32_t pulseaudio_connect_playback(pa_stream *s, const char *name,
+		const pa_buffer_attr *attr, pa_stream_flags_t flags);
+
+/**
+ * Sets a callback function for when data can be written to the stream
+ *
+ * @param p pa_stream to connect to. NULL for default
+ * @param cb pa_stream_request_cb_t
+ * @param userdata pointer to userdata the callback will be called with
+ */
+void pulseaudio_write_callback(pa_stream *p, pa_stream_request_cb_t cb,
+		void *userdata);

libobs/obs.c

@@ -1903,7 +1903,7 @@ bool obs_set_audio_monitoring_device(const char *name, const char *id)
 	if (!obs || !name || !id || !*name || !*id)
 		return false;
 
-#ifdef _WIN32
+#if defined(_WIN32) || HAVE_PULSEAUDIO
 	pthread_mutex_lock(&obs->audio.monitoring_mutex);
 
 	if (strcmp(id, obs->audio.monitoring_device_id) == 0) {

libobs/obsconfig.h.in

@@ -17,3 +17,4 @@
 #define OBS_UNIX_STRUCTURE @OBS_UNIX_STRUCTURE@
 #define BUILD_CAPTIONS @BUILD_CAPTIONS@
 #define HAVE_DBUS @HAVE_DBUS@
+#define HAVE_PULSEAUDIO @HAVE_PULSEAUDIO@