Videos Blocky at beginning/end or loop last 2ish seconds

Hello,

I have many videos uploaded to the meural cloud  account that play fine when sent to the canvas, but when I put the exact same videos on the SD card, they are very blocky/digitized at the very beginning and end of the video where it loops.

I re-encoded several videos to troubleshoot and added them to a different playlist folder on the SD card and now the videos play fine the first play, but when it goes to loop, it just loops the last two seconds of the video over and over on multiple re-encoded videos.

So what exactly happens when I upload video to the mueral site?  Is it re-encoded there?  What exaclty do I need to get the appropriate video playback on the canvas using the SD card?  What encoder?  I was using 15fps and 10mbps for the re-encodes as that was listed on the support site, but it doesn't work correclty.  

Also, this is for vertical videos ie 1080x1920, not 1920x1080.