The old YouTube embed code allowed you to specify start and end times (that the viewer can override, but otherwise it'll play only the segment you had in mind).
Let's see if that can be made to work with the new embed code, which is supposed to be faster and more compatible with more devices and browsers....
If heaven really existed...
(trying a too-big player to see if it automagically resizes)
Playing around in the sandbox:
I've seen a bug in resizing: even if I write <iframe width="475" height="267">foo</iframe> as regular text (not in HTML mode) the code will still get triggered. Trying variations:<br/ _origwidth="1280">Height first: <iframe height="267" width="475">foo</iframe><br/ _origwidth="1280">No brackets: iframe width="475" height="267"<br/ _origwidth="1280">No quotes: <iframe width=475 height=267>foo</iframe><br/ _origwidth="475" _origwidth="475">more variations: iframe stuff width=475 stuff height=266
IfRaMe WiDtH=475 hEiGhT=266
width=1280 height=900 iframe
height=900 width=1280 iframe
width=1280 iframe height=900
height=900 iframe width=1280
iframe width=foo height=bar
heh ...Back to our regularly scheduled useful stuff.
anyway, the way to specify start and end points is to add parameters inside the "src" URL inside the "embed". I posted about it in "How to Do It".
Here I modified the embed code like this:
<iframe width="475" height="267" src="//www.youtube.com/embed/dMaK6k4oZ20?start=75&end=87" frameborder="0" allowfullscreen></iframe>
"start" and "end" times are in seconds. You can give just one, or both. The question mark goes before the first parameter, and & goes before each additional parameter. (Parameters are also used for things like unchecking "Show suggested videos when the video finishes".)
An example of unintended consequences in elections: