Problème cadre de rognage vidéo qui apparait

Hi Joe,

Thanks for your answer.

To clarify some points, here are my answers:

- If I use a different video, somehow I cannot replicate the behavior. 

- I've already used the option "adding the video from file" so this doesn't make difference.

- I'm working locally when previewing my project file. 

Unfortunately, I'm not allow by my company to share my project files. I can just send you a screen shot from a small part of a slide in private (through support case). 

To give you further information:

My vidéos are captured by Obs Studio from an old Flash module. At that point, no issues. Then, after uploading in Storyline, a frame appears all around all my videos but oddly it disappears when those videos start. I'm having troubles only when I use several "calque" (I don't know the word in english, sorry) and a different video in each "calque". In that case, the frame appears few seconds before disappearing. 

Thank you by advance for your help.

Amandine