why dvb-t example has not any video input it has only random source?

i used commdv-t example,rtl-sdr is hardware sdr, how i can enter input video to this simulink example,it is very basic,for input i don't wont transmit random source i want to transmit video file but how?? example matlab is very basic and not practical?

is there a comprehensive example dvb-t in matlab?? thanks in advance best regards stackprogramer