How to edit MP4 files

Anyone got a solid recommendation for free MP4 video editing software? Mostly just looking to overlay one video onto another, trim clips, wipe out existing text, and slap on some new text... I don't mean subtitles, just actual text overlays appearing on the screen.

You can handle basic tasks like nesting videos or trimming clips using iMovie.
You could likely add text overlays too, provided they weren't there originally (not subtitles, just text on screen).

As for the latter, I'm not entirely certain; you’d probably have to get creative (some sort of workaround—using iMovie alongside a graphics editor... since iMovie lacks layers, it would be an unnecessary headache and a total waste of time).

But you also mentioned removing text from a video.
That isn't a simple process, and it’s hardly "worth it" considering the effort involved compared to (usually) the final result.

Even with those more advanced (better) video editing suites, it isn't that easy.

It's much like standard graphic design, using something like Microsoft Photoshop for example:
it's easy enough to compose an image using various elements or text, but once that work is saved in a format that flattens all those ('layers') into a single plane (into one layer), no sane person is going to try and tinker with it hoping to produce something visually decent or high quality.

coppersailor28 said:..., then even God wouldn't dream of messing with it hoping for a result, yeah...

I was referring to a video, not a still image.
Essentially, you take a single saved file from photoshop, tweak it, say 23 times (for 23 frames per second) and repeat that cycle for every single second of the scene (assuming it’s dynamic, obviously) that we actually intend to edit.