s-video carry the video signal

the yellow cable (we call it composite) also carry the video signal but combine all the RGB into a single cable, where s-video split the signal into 2-channel hence better color separation.

component are 2 RCA cable carries R, G & B signal each (which ASTRO decoder don't have) and their highest bandwidth can be up to 1080i (without HDCP)

use the s-video for ASTRO and no need the yellow cable, u will only need the red/white for audio.