I want to display a text over a video. However, the video may include any color from white to black. What is the best text effect (color/stroke/shadow/glow ... etc) that can be applied on the text so that it will be very clear on any background color.
The classic internet answer, at least for static images (and I imagine it would work for video as well), is "White text with black outline can be read on any color."
You need to make the background immediately behind your text contrast with your text color.
A very wide subtle soft white glow or spotlight will lighten the background adding contrast to make your black text (making it pop), same goes for a black glow behind white text (or any pair of contrasting colors). This method allows you to have a crisp/clean/sharp and minimal text style, however you can always add a dropshadow or stroke if you like to bring the text forward.
Personally I think adding a little bit of many effects looks better than a hard stroke or really dark dropshadow (unless you are doing for that more aggressive kind of look).
it's depend on Video subject, for example in a long time movie may choosing mostly white text with shadow is best choose (because of eye tiredness), but in a sport video choosing yellow text with shadow is best choose (because most sports have green field). but in most case i prefer "mostly white text" and a "little amount of shadow" beneath it.