It's pretty difficult to read/decode data with an oscilloscope. If you're sending one byte you can probably decipher it if you know the code/format (as long as you have a digital storage 'scope). I knew a guy who was pretty good at "reading" RS-232 as long as it was one or two bytes.
You could build a reader/analyzer with another Arduino... And by the time you're finished you'd be an expert on the WS2812! 
If you have an Arduino and the code (not some pre-made product) it should be easier to figure-out what the code is doing. 