[Pc_Support] HDTV Video Input -- WAS: GeForce 7900GT w/VIVO

[Bryan J. Smith]

Davie wrote:
> Was thinking too far down the line.

Yeah, sorry for doing that.  I guess I suggested such when I mentioned
video-in.  I really meant overlay-only, like from a HD DVR or cable
box already.

> Saw this as an opportunity to create a HD TiVO (through the use of
> the MythTV software and this card)...was forgetting that I'd need
> something to tune the channels.

Yeah.  All this thing gives you is the "raw analog" signal.  It works
fine for a video overlay.  But at 1280x720 at 60Hz (720p) = 55,296,000
pixels/second or 1920x1080 at 30Hz (1080i) = 62,208,000 pixels/second,
that's a _lot_ of data to capture "raw" (mulitple by 2 for 16-bit
color, 3 for 24-bit color).

> As it'll probably be DirecTV's HD signal...it'll already be in mpeg compression
> ......looks like I'll just need to get a DirecTV - DVR to do their HD - then hack that
> to pull the content off.

Yep, their QAM (19.2Mbps -> 2.4MBps), proprietary.

There are many ways to input HD video:

Analog:  "raw" 55.3-62.2Mpixel/second (as above) for 720p-1080i
Coax/HDMI:  Digital HDTV QAM format (HDMI with additional copy protect)

QAM format is basically implemented as follows (political-wise):
- Terrestrial Broadcast:  Unencrypted, with optional "Broadcast flag"
- Terrestrial Cable:  Encrypted, with mandatory CableCard (decrypt smartcard)
- Extraterrestrial Satellite:  Encrypted, proprietary