I hate you.
As a standalone statement, it seems quite aggressive. But words on a page, in a text message or in a video can often be ambiguous - put another way, they have different intentions.
Let's look at that phrase again: I hate you.
Most of the time it's used in its literal sense - to express strong dislike for somebody. But it's also used by, for example, victims of pranks - oh hahaha now I've got custard all over my head, I hate you - and doesn't carry any ill feeling whatsoever.
Context is important when interpreting the meaning of different types of media. Music can set the tone of a piece. Filmed footage gives immediate visual references to latch on to. But there are still occasions where context isn't so easy to recognise. If the sum of all the parts don't quite marry up, viewers or listeners can be left a bit confused and often they won't know why.
One of the jobs of a voice over artist is to give further context to a piece. I've created some ridiculous videos to highlight what I'm trying to say here.
Have a watch - when the words come on screen, think about them. What springs to mind? Where do they usually occur? What feelings appear? How does it sound in your head? Then when the words show up again, see if your pre-conceptions match up with the voice.
I'm also available for video production (I'm not).
Hopefully the videos showed that you can't always tell what the words are supposed to be doing (saying).
When you add the voice, you get the feeling and intention that can so often go missing. It can help the audience to make sense of a piece. Even if it already has visuals and music, the voice can take away some of the work for the viewer. Rather than having to process parts of it themselves, they can just soak it up.
From the perspective of a voice over artist, if you can't quite grasp the meaning of a piece, never be afraid to ask. After all, everybody wants to get it right. Ask for the music, ask for direction, ask what THEIR intention is for the piece. If you get a two word script that just says "I'm fine", there's so many ways that it can be taken. Yes, I actually am fine / I'm ok I guess, but I'm saying it in a way that I want attention / I am fiiiiiiine! (Just check out my photo in the header). Ha!
I'm not saying voice is needed in all productions, because it isn't. If it's not going to be adding identity, emotions, messages, details we don't know about, or (yes I'm going to use that word again) context, it's maybe superfluous to the project.
It's not just about regurgitating what's happening on screen, it's about filling in the gaps and most important of all (and I can't emphasise this enough (because the editor only gives me bold and italics)) helping the audience to understand.