The ShortCode format :
[video v=8ttSBO0SnsU columns=3]
Or, more simply :
[video v=8ttSBO0SnsU c=3]
Place multiple ShortCodes on the same line, without spaces between. Ideally, inside a div. For example :
<div>[video v=Wtgg6hDYfWs c=3][video v=hT3b8F2ka9w c=3]</div>