Canon EOS REBEL T2I Instruction Manual page 48

Shooting Movies
Set the Mode DiaJ to <%_,> to
shoot movies. The movie
recording format wiJJbe MOb'.
Cards which can record movies
When shooting movies, use a large-capacity SD card rated SD
Speed Class 6 "c_z,_s@" or higher.
_fyou use a slow-writing card when shooting movies, the movie
might not be recorded properly. An.:{ if you playback a movie on a
caro navlng a slow reading speeo, the movie might not piayback
properly,
To check the card's read/write speed, refer to the cara
manufacturer's Web site.
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