If you know the look, sound and feel of a gait, you can usually tell what a horse is doing without slow motion video to pick out each step. Don't be distracted by the length of step or speed of a gait. Those may be aspects of the quality of a gait, but they are not necessary to define a gait. Remember that some of the body language of gaits can be artificially produced. A horse can be made to nod his head in a rack or a hard trot to confuse people who rely on that sign of a running walk or fox trot.
Some relaxed horses flop their ears in time with their gait.
Others simply can't hold them still because of human intervention. A quick step may be a sign of a good paso corto, or it may result from worn feet on hard ground. The gait is what the legs, feet and body of the horse determine it to be, the rest of these clues to a gait are mainly frosting on the cake.