+import sigrokdecode as srd
+
+# Concentrate all timing constraints of the IR protocol here in a single
+# location at the top of the source, to raise awareness and to simplify
+# review and adjustment. The tolerance is an arbitrary choice, available
+# literature does not mention any. The inter-frame timeout is not a part
+# of the protocol, but an implementation detail of this sigrok decoder.
+_TIME_TOL = 8 # tolerance, in percent
+_TIME_IDLE = 20.0 # inter-frame timeout, in ms
+_TIME_LC = 13.5 # leader code, in ms
+_TIME_RC = 11.25 # repeat code, in ms
+_TIME_ONE = 2.25 # one data bit, in ms
+_TIME_ZERO = 1.125 # zero data bit, in ms
+_TIME_STOP = 0.562 # stop bit, in ms