It looks like a fife and drum band, maybe military or militia related. The caps with the hackles/plumes would seem to indicate this.It doesn't look like the 12 July parade. Spectators are not dressed for July, trees lack leaves. Obviously an orange event, but cannot be the 12 July affair.
If you care the 2019 elfast parade is atOrange Order loved fifes and drums. To Irish Catholic ears, fifes and drums were 'Protestant music'.