One ask. Two asks is a choice, and a choice presented at the end of a piece is reliably answered with neither. This is the most commonly ignored rule in commercial video, usually because two stakeholders each wanted something.
Placement should follow the argument rather than the runtime. If the strongest moment of belief is at sixty per cent, the ask belongs there, and the rest of the piece can continue afterwards. The convention of putting it last exists because it is tidy, not because it converts.
Specificity matters more than urgency. "Reply with the word audit" outperforms "get in touch today" because it names an action small enough to complete without a decision about how. Urgency without specificity is the shape of an ask nobody acts on.
Where should the call to action go?
At the point of maximum persuasion, which is often not the end. The convention of placing it last is tidy rather than effective.
How many calls to action should a video have?
One. Two asks constitute a choice, and a choice offered at the end of a piece is usually answered with neither.