linux-alsa: Add ALSA audio input plugin (linux)

Closes jp9000/obs-studio#494

plugins/CMakeLists.txt

@@ -21,6 +21,7 @@ elseif("${CMAKE_SYSTEM_NAME}" MATCHES "Linux")
 	add_subdirectory(linux-pulseaudio)
 	add_subdirectory(linux-v4l2)
 	add_subdirectory(linux-jack)
+	add_subdirectory(linux-alsa)
 	add_subdirectory(decklink/linux)
 elseif("${CMAKE_SYSTEM_NAME}" MATCHES "FreeBSD")
 	add_subdirectory(linux-capture)

plugins/linux-alsa/CMakeLists.txt

@@ -0,0 +1,34 @@
+project(linux-alsa)
+
+if(DISABLE_ALSA)
+	message(STATUS "ALSA support disabled")
+	return()
+endif()
+
+find_package(ALSA)
+if(NOT ALSA_FOUND AND ENABLE_ALSA)
+	message(FATAL_ERROR "ALSA not found but set as enabled")
+elseif(NOT ALSA_FOUND)
+	message(STATUS "ALSA not found, disabling ALSA plugin")
+	return()
+endif()
+
+include_directories(
+	SYSTEM "${CMAKE_SOURCE_DIR}/libobs"
+	${ALSA_INCLUDE_DIR}
+)
+
+set(linux-alsa_SOURCES
+	linux-alsa.c
+	alsa-input.c
+)
+
+add_library(linux-alsa MODULE
+	${linux-alsa_SOURCES}
+)
+target_link_libraries(linux-alsa
+	libobs
+	${ALSA_LIBRARY}
+)
+
+install_obs_plugin_with_data(linux-alsa data)

plugins/linux-alsa/alsa-input.c

@@ -0,0 +1,599 @@
+/*
+Copyright (C) 2015. Guillermo A. Amaral B. <[email protected]>
+
+Based on Pulse Input plugin by Leonhard Oelke.
+
+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 <util/bmem.h>
+#include <util/platform.h>
+#include <util/threading.h>
+#include <obs-module.h>
+
+#include <alsa/asoundlib.h>
+#include <alsa/pcm.h>
+
+#include <pthread.h>
+
+#define blog(level, msg, ...) blog(level, "alsa-input: " msg, ##__VA_ARGS__)
+
+#define NSEC_PER_SEC  1000000000LL
+#define NSEC_PER_MSEC 1000000L
+#define STARTUP_TIMEOUT_NS (500 * NSEC_PER_MSEC)
+#define REOPEN_TIMEOUT 1000UL
+#define SHUTDOWN_ON_DEACTIVATE false
+
+struct alsa_data {
+	obs_source_t *source;
+#if SHUTDOWN_ON_DEACTIVATE
+	bool active;
+#endif
+
+	/* user settings */
+	char *device;
+
+	/* pthread */
+	pthread_t listen_thread;
+	pthread_t reopen_thread;
+	os_event_t *abort_event;
+	volatile bool listen;
+	volatile bool reopen;
+
+	/* alsa */
+	snd_pcm_t *handle;
+	snd_pcm_format_t format;
+	snd_pcm_uframes_t period_size;
+
+	unsigned int channels;
+	unsigned int rate;
+	unsigned int sample_size;
+	uint8_t *buffer;
+	uint64_t first_ts;
+};
+
+static const char * alsa_get_name(void *);
+static obs_properties_t * alsa_get_properties(void *);
+static void * alsa_create(obs_data_t *, obs_source_t *);
+static void alsa_destroy(void *);
+static void alsa_activate(void *);
+static void alsa_deactivate(void *);
+static void alsa_get_defaults(obs_data_t *);
+static void alsa_update(void *, obs_data_t *);
+
+struct obs_source_info alsa_input_capture = {
+	.id             = "alsa_input_capture",
+	.type           = OBS_SOURCE_TYPE_INPUT,
+	.output_flags   = OBS_SOURCE_AUDIO,
+	.create         = alsa_create,
+	.destroy        = alsa_destroy,
+#if SHUTDOWN_ON_DEACTIVATE
+	.activate       = alsa_activate,
+	.deactivate     = alsa_deactivate,
+#endif
+	.update         = alsa_update,
+	.get_defaults   = alsa_get_defaults,
+	.get_name       = alsa_get_name,
+	.get_properties = alsa_get_properties
+};
+
+static bool _alsa_try_open(struct alsa_data *);
+static bool _alsa_open(struct alsa_data *);
+static void _alsa_close(struct alsa_data *);
+static bool _alsa_configure(struct alsa_data *);
+static void _alsa_start_reopen(struct alsa_data *);
+static void _alsa_stop_reopen(struct alsa_data *);
+static void * _alsa_listen(void *);
+static void * _alsa_reopen(void *);
+
+static enum audio_format _alsa_to_obs_audio_format(snd_pcm_format_t);
+static enum speaker_layout _alsa_channels_to_obs_speakers(unsigned int);
+
+/*****************************************************************************/
+
+void * alsa_create(obs_data_t *settings, obs_source_t *source)
+{
+	struct alsa_data *data = bzalloc(sizeof(struct alsa_data));
+
+	data->source   = source;
+#if SHUTDOWN_ON_DEACTIVATE
+	data->active   = false;
+#endif
+	data->buffer   = NULL;
+	data->device   = NULL;
+	data->first_ts = 0;
+	data->handle   = NULL;
+	data->listen   = false;
+	data->reopen   = false;
+	data->listen_thread = 0;
+	data->reopen_thread = 0;
+
+	data->device = bstrdup(obs_data_get_string(settings, "device_id"));
+	data->rate = obs_data_get_int(settings, "rate");
+
+	if (os_event_init(&data->abort_event, OS_EVENT_TYPE_MANUAL) != 0) {
+		blog(LOG_ERROR, "Abort event creation failed!");
+		goto cleanup;
+	}
+
+#if !SHUTDOWN_ON_DEACTIVATE
+	_alsa_try_open(data);
+#endif
+	return data;
+
+cleanup:
+	if (data->device)
+		bfree(data->device);
+
+	bfree(data);
+	return NULL;
+}
+
+void alsa_destroy(void *vptr)
+{
+	struct alsa_data *data = vptr;
+
+	if (data->handle)
+		_alsa_close(data);
+
+	os_event_destroy(data->abort_event);
+	bfree(data->device);
+	bfree(data);
+}
+
+#if SHUTDOWN_ON_DEACTIVATE
+void alsa_activate(void *vptr)
+{
+	struct alsa_data *data = vptr;
+
+	data->active = true;
+	_alsa_try_open(data);
+}
+
+void alsa_deactivate(void *vptr)
+{
+	struct alsa_data *data = vptr;
+
+	_alsa_stop_reopen(data);
+	_alsa_close(data);
+	data->active = false;
+}
+#endif
+
+void alsa_update(void *vptr, obs_data_t *settings)
+{
+	struct alsa_data *data = vptr;
+	const char *device;
+	unsigned int rate;
+	bool reset = false;
+
+	device = obs_data_get_string(settings, "device_id");
+	if (strcmp(data->device, device) != 0) {
+		bfree(data->device);
+		data->device = bstrdup(device);
+		reset = true;
+	}
+
+	rate = obs_data_get_int(settings, "rate");
+	if (data->rate != rate) {
+		data->rate = rate;
+		reset = true;
+	}
+
+#if SHUTDOWN_ON_DEACTIVATE
+	if (reset && data->handle)
+		_alsa_close(data);
+
+	if (data->active && !data->handle)
+		_alsa_try_open(data);
+#else
+	if (reset) {
+		if (data->handle)
+			_alsa_close(data);
+		_alsa_try_open(data);
+	}
+#endif
+}
+
+const char * alsa_get_name(void *unused)
+{
+	UNUSED_PARAMETER(unused);
+	return obs_module_text("AlsaInput");
+}
+
+void alsa_get_defaults(obs_data_t *settings)
+{
+	obs_data_set_default_string(settings, "device_id", "default");
+	obs_data_set_default_int(settings, "rate", 44100);
+}
+
+obs_properties_t * alsa_get_properties(void *unused)
+{
+	void **hints;
+	void **hint;
+	char *name = NULL;
+	char *descr = NULL;
+	char *io = NULL;
+        char *descr_i;
+	obs_properties_t *props;
+	obs_property_t *devices;
+	obs_property_t *rate;
+
+	UNUSED_PARAMETER(unused);
+
+	props = obs_properties_create();
+
+	devices = obs_properties_add_list(props, "device_id",
+	    obs_module_text("Device"), OBS_COMBO_TYPE_LIST,
+	    OBS_COMBO_FORMAT_STRING);
+
+	obs_property_list_add_string(devices, "Default", "default");
+
+	rate = obs_properties_add_list(props, "rate",
+	    obs_module_text("Rate"), OBS_COMBO_TYPE_LIST,
+	    OBS_COMBO_FORMAT_INT);
+
+	obs_property_list_add_int(rate, "32000 Hz", 32000);
+	obs_property_list_add_int(rate, "44100 Hz", 44100);
+	obs_property_list_add_int(rate, "48000 Hz", 48000);
+
+	if (snd_device_name_hint(-1, "pcm", &hints) < 0)
+		return props;
+
+	hint = hints;
+	while (*hint != NULL) {
+		/* check if we're dealing with an Input */
+		io = snd_device_name_get_hint(*hint, "IOID");
+		if (io != NULL && strcmp(io, "Input") != 0)
+			goto next;
+
+		name = snd_device_name_get_hint(*hint, "NAME");
+		if (name == NULL || strstr(name, "front:") == NULL)
+			goto next;
+
+		descr = snd_device_name_get_hint(*hint, "DESC");
+		if (!descr)
+			goto next;
+
+		descr_i = descr;
+		while (*descr_i) {
+			if (*descr_i == '\n') {
+			    *descr_i = '\0';
+			    break;
+			}
+			else ++descr_i;
+		}
+
+		obs_property_list_add_string(devices, descr, name);
+
+	next:
+		if (name != NULL)
+			free(name), name = NULL;
+
+		if (descr != NULL)
+			free(descr), descr = NULL;
+
+		if (io != NULL)
+			free(io), io = NULL;
+
+		++hint;
+	}
+	snd_device_name_free_hint(hints);
+
+	return props;
+}
+
+/*****************************************************************************/
+
+bool _alsa_try_open(struct alsa_data *data)
+{
+	_alsa_stop_reopen(data);
+
+	if (_alsa_open(data))
+		return true;
+
+	_alsa_start_reopen(data);
+
+	return false;
+}
+
+bool _alsa_open(struct alsa_data *data)
+{
+	pthread_attr_t attr;
+	int err;
+
+	err = snd_pcm_open(&data->handle, data->device,
+	    SND_PCM_STREAM_CAPTURE, 0);
+	if (err < 0) {
+		blog(LOG_ERROR, "Failed to open '%s': %s",
+			data->device, snd_strerror(err));
+		return false;
+	}
+
+	if (!_alsa_configure(data))
+		goto cleanup;
+
+	if (snd_pcm_state(data->handle) != SND_PCM_STATE_PREPARED) {
+		blog(LOG_ERROR, "Device not prepared: '%s'",
+			data->device);
+		goto cleanup;
+	}
+
+	/* start listening */
+
+	err = snd_pcm_start(data->handle);
+	if (err < 0) {
+		blog(LOG_ERROR, "Failed to start '%s': %s",
+			data->device, snd_strerror(err));
+		goto cleanup;
+	}
+
+	/* create capture thread */
+
+	pthread_attr_init(&attr);
+	pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
+
+	err = pthread_create(&data->listen_thread, &attr, _alsa_listen, data);
+	if (err) {
+		pthread_attr_destroy(&attr);
+		blog(LOG_ERROR,
+			"Failed to create capture thread for device '%s'.",
+			data->device);
+		goto cleanup;
+	}
+
+	pthread_attr_destroy(&attr);
+	return true;
+
+cleanup:
+	_alsa_close(data);
+	return false;
+}
+
+void _alsa_close(struct alsa_data *data)
+{
+	if (data->listen_thread) {
+		os_atomic_set_bool(&data->listen, false);
+		pthread_join(data->listen_thread, NULL);
+		data->listen_thread = 0;
+	}
+
+	if (data->handle) {
+		snd_pcm_drop(data->handle);
+		snd_pcm_close(data->handle), data->handle = NULL;
+	}
+
+	if (data->buffer)
+		bfree(data->buffer), data->buffer  = NULL;
+}
+
+bool _alsa_configure(struct alsa_data *data)
+{
+	snd_pcm_hw_params_t *hwparams;
+	int err;
+	int dir;
+
+	snd_pcm_hw_params_alloca(&hwparams);
+
+	err = snd_pcm_hw_params_any(data->handle, hwparams);
+	if (err < 0) {
+		blog(LOG_ERROR,
+			"snd_pcm_hw_params_any failed: %s",
+			snd_strerror(err));
+		return false;
+	}
+
+	err = snd_pcm_hw_params_set_access(data->handle, hwparams,
+		SND_PCM_ACCESS_RW_INTERLEAVED);
+	if (err < 0) {
+		blog(LOG_ERROR,
+			"snd_pcm_hw_params_set_access failed: %s",
+			snd_strerror(err));
+		return false;
+	}
+
+	data->format = SND_PCM_FORMAT_S16;
+	err = snd_pcm_hw_params_set_format(data->handle, hwparams,
+		data->format);
+	if (err < 0) {
+		blog(LOG_ERROR,
+			"snd_pcm_hw_params_set_format failed: %s",
+			snd_strerror(err));
+		return false;
+	}
+
+	err = snd_pcm_hw_params_set_rate_near(data->handle, hwparams,
+		&data->rate, 0);
+	if (err < 0) {
+		blog(LOG_ERROR,
+			"snd_pcm_hw_params_set_rate_near failed: %s",
+			snd_strerror(err));
+		return false;
+	}
+	blog(LOG_INFO, "PCM '%s' rate set to %d", data->device, data->rate);
+
+	err = snd_pcm_hw_params_get_channels(hwparams, &data->channels);
+	if (err < 0)
+		data->channels = 2;
+
+	err = snd_pcm_hw_params_set_channels_near(data->handle, hwparams,
+		&data->channels);
+	if (err < 0) {
+		blog(LOG_ERROR,
+			"snd_pcm_hw_params_set_channels_near failed: %s",
+			snd_strerror(err));
+		return false;
+	}
+	blog(LOG_INFO, "PCM '%s' channels set to %d",
+		data->device, data->channels);
+
+	err = snd_pcm_hw_params(data->handle, hwparams);
+	if (err < 0) {
+		blog(LOG_ERROR, "snd_pcm_hw_params failed: %s",
+			snd_strerror(err));
+		return false;
+	}
+
+	err = snd_pcm_hw_params_get_period_size(hwparams, &data->period_size,
+		&dir);
+	if (err < 0) {
+		blog(LOG_ERROR,
+			"snd_pcm_hw_params_get_period_size failed: %s",
+			snd_strerror(err));
+		return false;
+	}
+
+	data->sample_size = (data->channels
+		* snd_pcm_format_physical_width(data->format)) / 8;
+
+	if (data->buffer)
+		bfree(data->buffer);
+	data->buffer = bzalloc(data->period_size * data->sample_size);
+
+	return true;
+}
+
+void _alsa_start_reopen(struct alsa_data *data)
+{
+	pthread_attr_t attr;
+	int err;
+
+	if (os_atomic_load_bool(&data->reopen))
+		return;
+
+	pthread_attr_init(&attr);
+	pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
+
+	err = pthread_create(&data->reopen_thread, &attr, _alsa_reopen, data);
+	if (err) {
+		blog(LOG_ERROR,
+			"Failed to create reopen thread for device '%s'.",
+			data->device);
+	}
+
+	pthread_attr_destroy(&attr);
+}
+
+void _alsa_stop_reopen(struct alsa_data *data)
+{
+	if (os_atomic_load_bool(&data->reopen))
+		os_event_signal(data->abort_event);
+
+	if (data->reopen_thread) {
+		pthread_join(data->reopen_thread, NULL);
+		data->reopen_thread = 0;
+	}
+
+	os_event_reset(data->abort_event);
+}
+
+void * _alsa_listen(void *attr)
+{
+	struct alsa_data *data = attr;
+	struct obs_source_audio out;
+
+	blog(LOG_DEBUG, "Capture thread started.");
+
+	out.data[0]  = data->buffer;
+	out.format   = _alsa_to_obs_audio_format(data->format);
+	out.speakers = _alsa_channels_to_obs_speakers(data->channels);
+	out.samples_per_sec = data->rate;
+
+	os_atomic_set_bool(&data->listen, true);
+
+	do {
+		snd_pcm_sframes_t frames = snd_pcm_readi(data->handle,
+			data->buffer, data->period_size);
+
+		if (!os_atomic_load_bool(&data->listen))
+			break;
+
+		if (frames <= 0) {
+			frames = snd_pcm_recover(data->handle, frames, 0);
+			if (frames <= 0) {
+				snd_pcm_wait(data->handle, 100);
+				continue;
+			}
+		}
+
+		out.frames = frames;
+		out.timestamp = os_gettime_ns()
+			- ((frames * NSEC_PER_SEC) / data->rate);
+
+		if (!data->first_ts)
+			data->first_ts = out.timestamp + STARTUP_TIMEOUT_NS;
+
+		if (out.timestamp > data->first_ts)
+			obs_source_output_audio(data->source, &out);
+	} while (os_atomic_load_bool(&data->listen));
+
+	blog(LOG_DEBUG, "Capture thread is about to exit.");
+
+	pthread_exit(NULL);
+	return NULL;
+}
+
+void * _alsa_reopen(void *attr)
+{
+	struct alsa_data *data = attr;
+	unsigned long timeout = REOPEN_TIMEOUT;
+
+	blog(LOG_DEBUG, "Reopen thread started.");
+
+	os_atomic_set_bool(&data->reopen, true);
+
+	while (os_event_timedwait(data->abort_event, timeout) == ETIMEDOUT) {
+		if (_alsa_open(data))
+			break;
+
+		if (timeout < (REOPEN_TIMEOUT * 5))
+			timeout += REOPEN_TIMEOUT;
+	}
+
+	os_atomic_set_bool(&data->reopen, false);
+
+	blog(LOG_DEBUG, "Reopen thread is about to exit.");
+
+	pthread_exit(NULL);
+	return NULL;
+}
+
+enum audio_format _alsa_to_obs_audio_format(snd_pcm_format_t format)
+{
+	switch (format) {
+	case SND_PCM_FORMAT_U8:       return AUDIO_FORMAT_U8BIT;
+	case SND_PCM_FORMAT_S16_LE:   return AUDIO_FORMAT_16BIT;
+	case SND_PCM_FORMAT_S32_LE:   return AUDIO_FORMAT_32BIT;
+	case SND_PCM_FORMAT_FLOAT_LE: return AUDIO_FORMAT_FLOAT;
+	default:                      break;
+	}
+
+	return AUDIO_FORMAT_UNKNOWN;
+}
+
+enum speaker_layout _alsa_channels_to_obs_speakers(unsigned int channels)
+{
+	switch(channels) {
+	case 1: return SPEAKERS_MONO;
+	case 2: return SPEAKERS_STEREO;
+	case 3: return SPEAKERS_2POINT1;
+	case 4: return SPEAKERS_SURROUND;
+	case 5: return SPEAKERS_4POINT1;
+	case 6: return SPEAKERS_5POINT1;
+	case 8: return SPEAKERS_7POINT1;
+	}
+
+	return SPEAKERS_UNKNOWN;
+}
+

plugins/linux-alsa/data/locale/en-US.ini

@@ -0,0 +1,2 @@
+AlsaInput="Audio Capture Device (ALSA)"
+Device="Device"

plugins/linux-alsa/linux-alsa.c

@@ -0,0 +1,29 @@
+/*
+Copyright (C) 2015. Guillermo A. Amaral B. <[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 <obs-module.h>
+
+OBS_DECLARE_MODULE()
+OBS_MODULE_USE_DEFAULT_LOCALE("linux-alsa", "en-US")
+
+extern struct obs_source_info alsa_input_capture;
+
+bool obs_module_load(void)
+{
+	obs_register_source(&alsa_input_capture);
+	return true;
+}
+