What are the entire set of criteria that decide how 'b/v' are pronounced in Spanish?
I see here and here that 'b/v' are pronounced like the 'b' sound when it is the first letter of a word or when it follows a 'm' or 'b'.
However, the pronunciation of 'v' in 'vivo' is closer to 'v' than 'b' as seen here whereas it should be pronounced like 'bibo' based on the rule that I've mentioned above.
Is there any other rule that I may have missed?