If you doubt this, by all means try it out yourself. If you do, be aware that you have to start charging for the U1 before you even hit cr.MK. So you press MK at [down-back] after having quickly gone to [forward] to buffer the fireball input.
If you did this fast enough you will still be able to cancel it into the ex.fireball. Also, after the fireball connects you have to wait as long as possible then, about the time Chun-Li is able to move, input [forward,back,forward+KKK] hella fast (the timing is really tight).
Don't think it works on everyone but try it out against any of the characters shown. It felt slightly easier against Honda but that might just be because I did that clip last and I was more used to the timing by then.
