Add option to use alternative timestamps

With this option enabled the plugin will generate timestamps
based on the system time instead of using the ones provided by
pulse audio. This might fix problems with audio desync and may
become the default/only option in the future.

plugins/linux-pulseaudio/pulse-input.c

@@ -15,6 +15,7 @@ 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/platform.h>
 #include <util/bmem.h>
 #include <obs.h>
 
@@ -34,6 +35,8 @@ struct pulse_data {
 	uint_fast32_t bytes_per_frame;
 
 	pa_stream *stream;
+
+	bool ostime;
 };
 
 static void pulse_stop_recording(struct pulse_data *data);
@@ -122,6 +125,7 @@ static void pulse_stream_read(pa_stream *p, size_t nbytes, void *userdata)
 		pa_stream_drop(data->stream);
 		goto exit;
 	}
+	pa_time = (!data->ostime) ? pa_time * 1000 : os_gettime_ns();
 
 	pulse_get_stream_latency(data->stream, &pa_latency);
 
@@ -131,7 +135,7 @@ static void pulse_stream_read(pa_stream *p, size_t nbytes, void *userdata)
 	out.format          = pulse_to_obs_audio_format(data->format);
 	out.data[0]         = (uint8_t *) frames;
 	out.frames          = bytes / data->bytes_per_frame;
-	out.timestamp       = (pa_time - pa_latency) * 1000;
+	out.timestamp       = pa_time - (pa_latency * 1000);
 	obs_source_output_audio(data->source, &out);
 
 	pa_stream_drop(data->stream);
@@ -285,6 +289,8 @@ static obs_properties_t pulse_properties(const char *locale, bool input)
 	pulse_get_source_info_list(cb, (void *) devices);
 	pulse_unref();
 
+	obs_properties_add_bool(props, "ostime", "Use OS timestamps");
+
 	return props;
 }
 
@@ -344,6 +350,8 @@ static void pulse_defaults(obs_data_t settings, bool input)
 	pulse_get_server_info(cb, (void *) settings);
 
 	pulse_unref();
+
+	obs_data_set_default_bool(settings, "ostime", false);
 }
 
 static void pulse_input_defaults(obs_data_t settings)
@@ -398,15 +406,24 @@ static void pulse_destroy(void *vptr)
 static void pulse_update(void *vptr, obs_data_t settings)
 {
 	PULSE_DATA(vptr);
+	bool restart = false;
 	char *new_device;
 
 	new_device = bstrdup(obs_data_getstring(settings, "device_id"));
-	if (data->device && strcmp(data->device, new_device) == 0)
-		return;
+	if (!data->device || strcmp(data->device, new_device) != 0) {
+		if (data->device)
+			bfree(data->device);
+		data->device = new_device;
+		restart = true;
+	}
 
-	if (data->device)
-		bfree(data->device);
-	data->device = new_device;
+	if (data->ostime != obs_data_getbool(settings, "ostime")) {
+		data->ostime = obs_data_getbool(settings, "ostime");
+		restart = true;
+	}
+
+	if (!restart)
+		return;
 
 	if (data->stream)
 		pulse_stop_recording(data);