The Cross Dissolve

Different from a fade to black, a cross dissolve is when a shot transitions to the next shot by lowering the opacity of the previous shot while raising the opacity of the next one. It's a bit more complicated than that, but in editing software it's typically the default transition effect; you also can do it with layering video clips, and keyframing the opacity of the second clip.

I bring this up because excessive use of dissolves in game trailers is frequently a pretty sure sign of an inexperienced editor; I see it A LOT.

In film language, dissolves traditionally have a very specific use case and meaning. The most typical example is using dissolves to indicate the passage of time. Imagine a static shot of a person in a doctor's office, then the shot fades and the person is in a different position or chair, fades again and they've moved somewhere else, and sometimes there's an analog clock on the wall to indicate how much time has passed. Dissolves can also indicate time passing just between two different shots.

Dissolves can also be used to "soften" edits and make a montage of shots feel more dreamy and ethereal. I've done this when the music track feels very flowing, grand, and sweeping. I think this stylistic choice is mostly me copying the cast montage in the middle of this Spider-Man 2 teaser cut by Phil Daccord who was a senior editor at the trailer house where I got started.

(I totally ripped off that montage in my Mass Effect 1 Femshep fan trailer). 

I'm sure there are many other effective uses for dissolves in trailers, but the main point is that dissolves are a tool like any other part of film language like a straight cut or a fade to black. When I see a game trailer which uses virtually nothing but dissolves to transition from one shot to another, what I see is usually not a series of calculated choices. What I see is a person who is using editing software for the first time, who discovered the transition effects and was excited to use them.

Don't get me wrong, I LOVE to see more and more people experimenting with editing software for the first time. I don't want to discourage anyone from making their own trailers. I just want to explain the history and utility of the tools and toys available. I think learning what a particular type of cut can do is fascinating and exciting, because there really is nothing quite like it in other media.

This trailer for Virginia does eventually use cuts, which makes me believe there is some intent behind the use of dissolves, but it still feels like a LOT of dissolves.

I also recognize dissolves-on-every-transition as a sign of inexperience because I know I certainly did it when I first got my hands on editing software. It was almost like the first time I could create real slow motion images using film, an iPhone or game capture via game clock manipulation debug options; I wanted to use it for EVERYTHING. It was the simplest form of film eye candy I could muster, and I thought that might make my pieces look cooler. 

The other reason I think it's good to very deliberately use dissolves, is that when it's on almost every transition, it becomes predictable; it draws attention to itself. A straight cut is so fundamental to film that no one is ever going to say "Geez, why are they using so many straight cuts!?" Straight cuts are also closer to how we ingest information as described by Walter Murch in his essential editing book In the Blink of an Eye. Our eyes dart around from point to point, they don't really pan like a camera does. 

As you can see, dissolves are a contentious topic in the trailer editing world (This is via the excellent trailer meme Instagram account RedbandGreenband)

This is why a cut is invisible, but a cross dissolve draws attention to itself. So a trailer where every transition point draws attention to itself is also somewhat shifting attention away from the content of the shots themselves. 

So before you add that cross dissolve effect to your cuts, ask yourself why you're adding it. What is the feeling or effect you're trying to create? If it's just there for eye candy, I'm telling you right now it's probably not worth it. Eye candy for the sake of eye candy is very difficult to pull off. Cross dissolves can feel very tentative and unconfident, so get in touch with your editing intentions and make sure you're not apologizing or trying to hide the footage. A trailer's editing style can say a lot about the person who made it, so be confident and edit with purpose!