What tools can I use to a text overlay to a video?

You can use Openshot or Kdenlive to achieve this effect.

Click here to install Openshot:

Openshot

To add text to your video, go to

• Title→New Title

or

• Title→New Animated Title

in the menu. You can add effects and transitions to Titles as you would to any other component of the video.

Click here to install Kdenlive:*

Kdenlive

You can add a title clip (text) to your video by going to:

• Project→Add Title Clip

Or you can do it by right clicking on the project tree and clicking "Add Title Clip".

As with Openshot, you can add effects and transitions to Title Clips.

**Kdenlive will pull in some KDE dependencies.*

You can also use gstreamer directly to do this.

Here's an example:

gst-launch filesrc location="<Filepath>" ! textoverlay text="Title : Hello" valign=top halign=left ! xvimagesink

There are also lot of other configurable options that you can use.

Hope this helps.