libobs: Deprecate service multitrack check

This isn't particularly needed, as a service with multiple tracks won't
be using multiple tracks to begin with anyway.  This might change later,
but for now just mark it deprecated.

libobs/obs-output.c

@@ -1018,27 +1018,10 @@ void obs_output_set_audio_conversion(
 	output->audio_conversion_set = true;
 }
 
-static inline bool service_supports_multitrack(const struct obs_output *output)
-{
-	const struct obs_service *service = output->service;
-
-	if (!service || !service->info.supports_multitrack) {
-		return false;
-	}
-
-	return service->info.supports_multitrack(service->context.data);
-}
-
 static inline size_t num_audio_mixes(const struct obs_output *output)
 {
 	size_t mix_count = 1;
 
-	if ((output->info.flags & OBS_OUTPUT_SERVICE) != 0) {
-		if (!service_supports_multitrack(output)) {
-			return 1;
-		}
-	}
-
 	if ((output->info.flags & OBS_OUTPUT_MULTI_TRACK) != 0) {
 		mix_count = 0;
 

libobs/obs-service.h

@@ -63,7 +63,7 @@ struct obs_service_info {
 	const char *(*get_username)(void *data);
 	const char *(*get_password)(void *data);
 
-	bool (*supports_multitrack)(void *data);
+	bool (*deprecated_1)();
 
 	void (*apply_encoder_settings)(void *data,
 				       obs_data_t *video_encoder_settings,

plugins/rtmp-services/rtmp-common.c

@@ -645,5 +645,4 @@ struct obs_service_info rtmp_common_service = {
 	.get_key = rtmp_common_key,
 	.apply_encoder_settings = rtmp_common_apply_settings,
 	.get_output_type = rtmp_common_get_output_type,
-	.supports_multitrack = supports_multitrack,
 };