'Jazz a Vienne' is one of the world's most prestigious jazz festivals. Ever since 1981 it has attracted leading jazz artists, with many of them playing return engagements. Unsurprisingly, the festival's 2012 edition did not fall short of expectations: the lineup was filled with the biggest names in music. Among them was vocalist Gregory Porter transcends the jazz bubble. His magnificent, burnished baritone can sink into a lyric with luxurious ease, the melody gently sculpted into new shapes at every turn, with the rhythm tugging subtly back and forth across the bar line.