Video Communication system

This is A Video Communication System with Encoding, Modulation & Channel models

This system implements the video communication system using Simulink blocks from Communication Blockset & blocks from Video Processing blockset, based on MPEG-1 demo & DVB demo, it goes from Source Encoding, to Channel Encoding (RS Encoder, Convolutional Encoder) Modulation (QAM, OFDM), channel & then the reverse of the entire process, at the receiver side
HOWEVER, THERE IS A PROBLEM, WHERE THE OUTPUT OF THE VIDEO SOURCE ENCODER GOES TO THE CHANNEL ENCODER, WHEN RUNNING THE SYSTEM, AN ERROR OCCURS, STATING THAT THE INPUT OF THE RS-ENCODER IS NOT CORRECT, THIS INPUT PROBLEM I THINK WITH THE COMING VIDEO OUTPUT
I WOULD APRRECIATE YOUR HELP ABOUT THIS PROBLEM & WHAT SHOULD BE THE INPUT SIZE OF THE RS-ENCODER?
CAUSE THIS IS MY MASTERS THESIS DEISGN & I MUST COMPLETE IT CORRECTLY
ANY HELP YOU GIVE, MAY BENEFIT FROM, SO I APPRECIATE YOUR CONCERN ..