While Video Post offers many useful functions and creative effects, invariably you will set up a queue that looks like it should work or even appears to render correctly only to give you an animation that does not include the desired effect. Here are some troubleshooting tips to reference when a queue just isn't doing what you expect.
There are two key things that can cause a Video Post queue to fail. The first is incorrect ordering and nesting of events in the queue. The second is faulty positioning and/or overlapping of the range bars.
When you come up again a problem, especially if you're attempting to set up a very complex queue, the best way to diagnose the problem is to create a new queue that should only result in the effect that is failing. If you can get the simplified queue to work, you can compare it to the structure of the failing queue to see what might be out of order.
Here are two very common scenarios that look like they should work but ultimately don't give you the result you expected. These examples are shown in their simplified state, but could very easily be buried in more complex queues.
The first example illustrates a problem where you expect the scene to render for fifteen frames before fading to black to finish the animation. However, at frame sixteen, the scene abruptly goes black.
This queue shows all the correct events in the proper order in the queue. The problem is the timing and positioning of the range bars. The most likely cause of this problem is using the when it's not necessary. In order for the Fade event to work properly, it needs to overlap the animation for the amount of time you want to fade to occur. You need to take into account the number of frames where the scene actually fades.
To fix this queue, you have to decide how many frames over which the fade will occur. Let's say you want the scene to fade to black over ten frames. You would need to drag the right end of the Perspective event range bar ten frames to the right to overlap the Fade event.
This second example is even more misleading than the first. The infuriating thing about this problem is that while the scene is rendering, the object in the scene shows the glow effect. When the resultant animation is played back, the Glow effect is not present.
Once again, this queue shows all the correct events, but the problem here is the ordering of the events in the queue. This problem is commonly caused when an event is selected while other events are being added. In this case, the Perspective event was select when the Lens Effects Glow and output events were added.
There are two ways to create this queue to give you the correct results. You can recreate the queue and add each event so there is no nesting, or you remove the current output event and add it again, making sure no other events are selected. The following images show the two ways this queue could be set up to successfully show the glowing object.