obs-ffmpeg: Add linear alpha setting

Allow proper linear treatment of alpha for authoring sanity.

plugins/obs-ffmpeg/data/locale/en-US.ini

@@ -41,6 +41,7 @@ ColorRange="YUV Color Range"
 ColorRange.Auto="Auto"
 ColorRange.Partial="Partial"
 ColorRange.Full="Full"
+LinearAlpha="Apply alpha in linear space"
 RestartMedia="Restart"
 SpeedPercentage="Speed"
 Seekable="Seekable"

plugins/obs-ffmpeg/obs-ffmpeg-source.c

@@ -43,6 +43,7 @@ struct ffmpeg_source {
 	uint8_t *sws_data;
 	int sws_linesize;
 	enum video_range_type range;
+	bool is_linear_alpha;
 	obs_source_t *source;
 	obs_hotkey_id hotkey;
 
@@ -109,6 +110,7 @@ static void ffmpeg_source_defaults(obs_data_t *settings)
 	obs_data_set_default_bool(settings, "looping", false);
 	obs_data_set_default_bool(settings, "clear_on_media_end", true);
 	obs_data_set_default_bool(settings, "restart_on_activate", true);
+	obs_data_set_default_bool(settings, "linear_alpha", false);
 	obs_data_set_default_int(settings, "reconnect_delay_sec", 10);
 	obs_data_set_default_int(settings, "buffering_mb", 2);
 	obs_data_set_default_int(settings, "speed_percent", 100);
@@ -163,8 +165,7 @@ static obs_properties_t *ffmpeg_source_getproperties(void *data)
 	dstr_free(&filter);
 	dstr_free(&path);
 
-	prop = obs_properties_add_bool(props, "looping",
-				       obs_module_text("Looping"));
+	obs_properties_add_bool(props, "looping", obs_module_text("Looping"));
 
 	obs_properties_add_bool(props, "restart_on_activate",
 				obs_module_text("RestartWhenActivated"));
@@ -215,6 +216,9 @@ static obs_properties_t *ffmpeg_source_getproperties(void *data)
 	obs_property_list_add_int(prop, obs_module_text("ColorRange.Full"),
 				  VIDEO_RANGE_FULL);
 
+	obs_properties_add_bool(props, "linear_alpha",
+				obs_module_text("LinearAlpha"));
+
 	obs_properties_add_bool(props, "seekable", obs_module_text("Seekable"));
 
 	return props;
@@ -229,13 +233,15 @@ static void dump_source_info(struct ffmpeg_source *s, const char *input,
 		"\tinput_format:            %s\n"
 		"\tspeed:                   %d\n"
 		"\tis_looping:              %s\n"
+		"\tis_linear_alpha:         %s\n"
 		"\tis_hw_decoding:          %s\n"
 		"\tis_clear_on_media_end:   %s\n"
 		"\trestart_on_activate:     %s\n"
 		"\tclose_when_inactive:     %s",
 		input ? input : "(null)",
 		input_format ? input_format : "(null)", s->speed_percent,
-		s->is_looping ? "yes" : "no", s->is_hw_decoding ? "yes" : "no",
+		s->is_looping ? "yes" : "no", s->is_linear_alpha ? "yes" : "no",
+		s->is_hw_decoding ? "yes" : "no",
 		s->is_clear_on_media_end ? "yes" : "no",
 		s->restart_on_activate ? "yes" : "no",
 		s->close_when_inactive ? "yes" : "no");
@@ -304,6 +310,7 @@ static void ffmpeg_source_open(struct ffmpeg_source *s)
 			.buffering = s->buffering_mb * 1024 * 1024,
 			.speed = s->speed_percent,
 			.force_range = s->range,
+			.is_linear_alpha = s->is_linear_alpha,
 			.hardware_decoding = s->is_hw_decoding,
 			.is_local_file = s->is_local_file || s->seekable,
 			.reconnecting = s->reconnecting,
@@ -425,6 +432,7 @@ static void ffmpeg_source_update(void *data, obs_data_t *settings)
 		obs_data_get_bool(settings, "restart_on_activate");
 	s->range = (enum video_range_type)obs_data_get_int(settings,
 							   "color_range");
+	s->is_linear_alpha = obs_data_get_bool(settings, "linear_alpha");
 	s->buffering_mb = (int)obs_data_get_int(settings, "buffering_mb");
 	s->speed_percent = (int)obs_data_get_int(settings, "speed_percent");
 	s->is_local_file = is_local_file;