Just one more point Bob, I would not consider a difference in burst pair timing (on/off times) of one clock time to be "dirty" (0018 vis 0019, 0030 vs 0031) the basic unit of timing in the Sony IR world is 600 microseconds with a timing of 2:1 or 1:1 between on vs off. (0x18= 24 decimal and 0x30=48 decimal) They actually represent the number of ticks or cycles of the IR frequency that is being flashed. In the Sony world IIRC this is 40khz or a cycle time of 25 microseconds. . Interested parties can do the math to verify. Most IR receivers will accept at least a 10% variant in timing, some as high as 25%.

Dirty is when really off values appear, or there are extraneous or extra bursts after or befor the message. If these extraneous or erroneous bursts appear inside the message the message will not be properly decoded by the receiver.