revid/revid.go: added handling for FileFPS var from vidgrind

revid/revid.go

@@ -859,6 +859,13 @@ func (r *Revid) Update(vars map[string]string) error {
 				break
 			}
 			r.cfg.MOGHistory = uint(v)
+		case "FileFPS":
+			v, err := strconv.Atoi(value)
+			if err != nil {
+				r.cfg.Logger.Log(logger.Warning, pkg+"invalid FileFPS var", "value", value)
+				break
+			}
+			r.cfg.FileFPS = v
 		case "mode":
 			r.cfg.Loop = false
 			if value == "Loop" {