When I am editing and rendering videos that have picture-in-picture using Premiere Elements 11, the videos (once they've been uploaded to YouTube) have these thick black margins above and below the picture-in-picture images/videos. These margins are not visible when the videos are viewed using Premiere Elements but then they appear when the video is on YouTube. How can I prevent this? Is this a format issue? Thanks.
Welcome to the forum.
Can you tell us exactly how you created your PiP, please?
Knowing the specs. of both your background Video (and your Project Settings), plus the specs. of the Video used in the PiP, will likely be useful.
Also, seeing a screen-cap of your Timeline, at the point of the PiP, might be useful too.