I embeded a youtube video via iframe but &modestbranding=1 does not work if &controls is set to 0.
If you are using showinfo=0
to remove the title from the top of the embedded
video, modestbranding=1
will not work, and the logo will appear.
<iframe style="display: block; margin: auto;" width="560" height="315" src="https://www.youtube.com/embed/9dUdfY7op6M" modestbranding=1 frameborder="0" allowfullscreen></iframe>