I'm trying to hide the YouTube logo that appears in the bottom right had corner of an embed. For some reason modestbranding=1 is not working:
<iframe class="gtms-intro" style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;" width="1280" height="720" src="https://www.youtube.com/embed/ywFGJecodxQ?rel=0&controls=0&showinfo=0&autoplay=1&loop=1&modestbranding=1&playlist=ywFGJecodxQ" frameborder="0"></iframe>
Problem is with how you added the parameters. Inside the link you are supposed to add parameters like so:
"http://www.myLink.com?first_param=1&second_param=0&third_param=3"
No amp; in between.
As a result, your iFrame is supposed to look like this:
<iframe class="gtms-intro" style="position: absolute; top: 0; left: 0; width: 100%; height: 100%;" width="1280" height="720" src="https://www.youtube.com/embed/ywFGJecodxQ?rel=0&controls=0&showinfo=0&autoplay=1&loop=1&modestbranding=1&playlist=ywFGJecodxQ" frameborder="0"></iframe>
Hope it helped.