libobs: Log monitoring audio deduplication

The commit adds a log line to inform the user that deduplication is
being applied. The info is displayed whenever deduplication first
occurs.

Signed-off-by: pkv <pkv@obsproject.com>

libobs/obs-audio.c

@@ -63,6 +63,11 @@ static inline void check_audio_output_source_is_monitoring_device(obs_source_t *
 			if (strcmp(dev_id, audio->monitoring_device_id) == 0) {
 				audio->prevent_monitoring_duplication = true;
 				audio->monitoring_duplicating_source = s;
+				if (!audio->monitoring_duplication_prevented_on_prev_tick)
+					blog(LOG_INFO,
+					     "Device for 'Audio Output Capture' source is also used for audio"
+					     " monitoring:\nDeduplication logic is being applied to all monitored"
+					     " sources.\n");
 			}
 			obs_data_release(settings);
 		}
@@ -577,6 +582,7 @@ bool audio_callback(void *param, uint64_t start_ts_in, uint64_t end_ts_in, uint6
 
 	da_resize(audio->render_order, 0);
 	da_resize(audio->root_nodes, 0);
+	audio->monitoring_duplication_prevented_on_prev_tick = audio->prevent_monitoring_duplication;
 	audio->prevent_monitoring_duplication = false;
 	audio->monitoring_duplicating_source = NULL;
 

libobs/obs-internal.h

@@ -462,6 +462,7 @@ struct obs_core_audio {
 
 	volatile bool prevent_monitoring_duplication;
 	struct obs_source *monitoring_duplicating_source;
+	bool monitoring_duplication_prevented_on_prev_tick;
 };
 
 /* user sources, output channels, and displays */

libobs/obs.c

@@ -899,6 +899,7 @@ static bool obs_init_audio(struct audio_output_info *ai)
 
 	audio->monitoring_device_name = bstrdup("Default");
 	audio->monitoring_device_id = bstrdup("default");
+	audio->monitoring_duplication_prevented_on_prev_tick = false;
 
 	errorcode = audio_output_open(&audio->audio, ai);
 	if (errorcode == AUDIO_OUTPUT_SUCCESS)