obs_video_info: add a parent_ovi pointer

Add a parent_ovi pointer to obs_video_info so that when a new video_mix is created
within maybe_set_up_gpu_rescale() we can effectively reuse a canvas for
sceneItems since they had no knowledge of the new ovi* created for the encoder. Resolves issue
where we saw a black screen during Twitch enhanced streaming.

Author: sandboxcoder

frontend/widgets/OBSBasic.cpp

@@ -1505,6 +1505,7 @@ int OBSBasic::ResetVideo()
 	ovi.adapter = config_get_uint(App()->GetUserConfig(), "Video", "AdapterIdx");
 	ovi.gpu_conversion = true;
 	ovi.scale_type = GetScaleType(activeConfiguration);
+	ovi.parent_ovi = NULL;
 
 	if (ovi.base_width < 32 || ovi.base_height < 32) {
 		ovi.base_width = 1920;

libobs/obs-encoder.c

@@ -274,6 +274,8 @@ static void maybe_set_up_gpu_rescale(struct obs_encoder *encoder)
 	ovi->scale_type = encoder->gpu_scale_type;
 
 	ovi->gpu_conversion = true;
+	// Source items will be unaware of this new ovi* since it doesn't match their cached ptr. So we will set the parent ovi*
+	ovi->parent_ovi = current_mix->ovi;
 
 	mix = obs_create_video_mix(ovi);
 	if (!mix)

libobs/obs-scene.c

@@ -1086,9 +1086,13 @@ static void scene_video_render(void *data, gs_effect_t *effect)
 	gs_blend_state_push();
 	gs_reset_blend_state();
 
+	// Determine if there is another obs_video_info this scene item can render into
+	struct obs_video_info *parent_ovi =
+		obs_get_video_rendering_canvas() != NULL ? obs_get_video_rendering_canvas()->parent_ovi : NULL;
+
 	item = scene->first_item;
 	while (item) {
-		if (obs_get_video_rendering_canvas() != item->canvas &&
+		if (parent_ovi != item->canvas && obs_get_video_rendering_canvas() != item->canvas &&
 		    item->canvas != NULL) {
 			item = item->next;
 			continue;

libobs/obs.c

@@ -1967,6 +1967,7 @@ struct obs_video_info *obs_create_video_info()
 	ovi->scale_type = OBS_SCALE_BILINEAR;
 	ovi->adapter = 0;
 	ovi->gpu_conversion = true;
+	ovi->parent_ovi = NULL;
 
 	return ovi;
 }

libobs/obs.h

@@ -224,6 +224,7 @@ struct obs_video_info {
 	enum video_range_type range;      /**< YUV range (if YUV) */
 
 	enum obs_scale_type scale_type; /**< How to scale if scaling */
+	void* parent_ovi;               /**< Pointer to the source obs_video_info this was copied from */
 };
 
 /**