There are several strumming patterns that encompass most songs, they are what we shall call strum #1 ,2, and 3.
Strum #1 (D Du uDu )
Strum #2 (D__Ddu uDd)
Strum #3 (D__Ddu )
This is by no means every strum that is out there but these are the 3 most common. The way I have been able to recognize which one is being used is to listen to the sounds of which end of the strings are being played. As you can see they all start with a down-stroke, the second part is also a down-stroke but can be a bit different also based on a small rest before you hit the next one. That rest is key to identifying the strumming pattern, if it is not there you have pattern #1, if it is then you have to listen a bit longer and check for the signatures of pattern 2 and 3.
Strum 2 and 3 are almost identical with strum 3 being easily identifiable by listening to the accent strum or the first down-stroke. If the first down-stroke always lands on a new note anytime there is a chord change you know you have strum #3. Strum #2 also has an extra uDd on the end. Pattern 2 can also have an extra ud at the very end lengthening it even more. I hope this helps, learning this info has helped me a ton in identifying strumming patterns of my favorite songs.
God said to Abraham, “Kill me a son”
Abe says, “Man, you must be puttin’ me on”
God say, “No.” Abe say, “What?”
God say, “You can do what you want Abe, but
The next time you see me comin’ you better run”
Well Abe says, “Where do you want this killin’ done?”
God says, “Out on Highway 61”
cm