libobs: Prevent video cache clear on first frame

Fix a bug where when a source first starts up its async cache, it
unintentionally resets its cache, which means that the first few frames
would be lost.

libobs/obs-source.c

@@ -196,6 +196,9 @@ obs_source_t *obs_source_create(enum obs_source_type type, const char *id,
 
 	source->flags = source->default_flags;
 
+	/* prevents the source from clearing the cache on the first frame */
+	source->async_reset_texture = true;
+
 	if (info && info->type == OBS_SOURCE_TYPE_TRANSITION)
 		os_atomic_inc_long(&obs->data.active_transitions);
 	return source;
@@ -1474,11 +1477,14 @@ static inline struct obs_source_frame *cache_video(struct obs_source *source,
 	pthread_mutex_lock(&source->async_mutex);
 
 	if (async_texture_changed(source, frame)) {
+		/* prevents the cache from being freed on the first frame */
+		if (!source->async_reset_texture)
+			free_async_cache(source);
+
 		source->async_width         = frame->width;
 		source->async_height        = frame->height;
 		source->async_format        = frame->format;
 		source->async_reset_texture = true;
-		free_async_cache(source);
 	}
 
 	for (size_t i = 0; i < source->async_cache.num; i++) {