[mythtv-users] More DirecTV/MythTV clarification

Henry A Harper III hah at alumni.rice.edu
Wed Jan 10 20:49:44 UTC 2007

>Good point. The cable boxes pre-compress the signal for you when outputting
>their firewire port. I guess this is why you would need the modified STB
from 169time
>as well as their "AVX1 processor"? To compress the uncompressed signal from
>STB into a format that MythTV could use? So it's like $1800 to get HD out
of a
>satellite box. Yikes.

If it's coming over firewire (400/800mbit/s), it can't really be
uncompressed HD (DVI/HDMI is 3gbit/s-ish?), more likely MPEG2 TS format
(19mbit/s for ATSC). The cable boxes probably just decrypt the (selected)
compressed-at-headend MPEG2 TS for firewire output, and the 169time solution
does the same thing by grafting a firewire output into the STB between
decryption step and MPEG2 decode step. It's unlikely that 169time will work
for DirecTV's new MPEG4 HD channels - the 169time modded boxes are older
MPEG2-HD units, all DirecTV's future HD channels will be MPEG4 on new
satellites/encoding systems that the older boxes can't feasibly be modified
to receive.

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