Producing a "Blue Screen" is a complex undertaking, For plain Video, NTSC or Computer> for NTSC (Never the Same Color... twice) you only need to generate the horiz and vert sync signals and the color signal necessary for blue. That's easy,,, the trick is to re-insert the signals in place of the other "Crashed" one and do so in the same EXACT PHASE as the ones that created the original video signal that you are trying to "recover" without that you will totally corrupt the existing signal, which is corrupted already and why the picture is "Pixelated". It is time determinant and possible but nearly impossible in practice without studio type gear. Which is network time determinate already since now most major video feeds are locked to a standard atomic time clock. Good Luck in the Contest...
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