[mythtv-users] Intro & question

Chad masterclc at gmail.com
Sat Jul 29 01:33:30 UTC 2006


> I called WOW and they offer nearly identical service for nearly
> identical price.  They use two different models of HD STB: 1) SA3250HD;
> and, 2) Pace 551HD.  I was told I could not request a specific model and
> of course they were clueless what firewire was and said their cable
> boxes had component out but if I provided a DVI or HDMI cable, the
> installer would use it if I asked.  A friend of mine who works in the
> cable industry also told me the Pace box would likely be a PoS.
>
> I keep thinking if I could guarantee an SA3250 I'd just switch to them,
> but since they won't guarantee it, I'm on the fence.  No matter what I
> do, I realize I'll have to bypass my MythTV box if I want to watch HBO-
> HD (and probably ESPN-HD as well) which really sucks.

I don't know if I'd switch either, it's probably personal preference
at this point.

> > The problem you'll face when you do get to the point of figuring out
> > if HBO-HD is encrypted or not is that if it is, the only way to get it
> > run *through* MythTV is to use a PVR-x50's analog inputs.  It'll
> > downgrade to a 720x480 signal, but will give you the ability to
> > pause/rewind/record the movies that are broadcast on it at their best
> > quality.  I'm sure you know this, but encryption needs to be
> > decrypted, and the only thing currently capable of that (legally) is
> > your STB that your cable company sends you.  If they choose to encrypt
> > a channel, and don't decrypt it over firewire, then... well your
> > choice is listed above ;)
> >
>
> If HBO-HD is encrypted over firewire, it sounds as if you're saying I
> have to go with an S-Video or such connection to an analog tuner card
> (like the PVR-x50s) and watch/record it at 720x480. But it still would
> be a broadcast NTSC signal, right?  Not only interlaced, but not even
> truly 720x480.  A few more questions:

Answer to your question below, and a generic response to the PVRx50 info:

You'll be feeding into a PVR-x50 over S-Video, yes.  The resolution is
probably not downscaled beyond 720x480 to feed it out of your cable
box, so your PVR-x50 will be receiving a 720x480 signal (probably).
As for interlaced vs. progressive, that will probably be up to your
box, or possibly the station.  I'm not sure what HBO-HD shoots their
stuff out at (1920x1080i or 1280x720p) but that will probably be what
your box shoots it out at, it probably only resizes to a 720x480
resolution and doesn't change whether it's progressive or interlaced.
MythTV has a built in deint option you can use if it ends up being
interlaced.  The PVR is capable of a 720x480 resolution encoding, so
that's probably going to give you a good 1:1-ish capture.

> 1) if the signal coming into the S-Video port on a PVR-x50 card is NTSC
> broadcast quality (not DTV 480i), it's not 720x480 is it?  It's
> something roughly equivalent to 440x480, is it not?  I mean, it's analog
> with 480 scan lines interlaced, but how much data is really there in the
> horizontal?  I'm going off stuff I read on wikipedia, so I know there's
> no guarantee it's 100% accurate info.  Still, even if it's not actually
> a 720x480 signal, I can set MythTV to record it that way?  Will it de-
> interlace on the fly, or do I record it interlaced and then run a
> process on it after the fact to convert it to de-interlaced?
>
> 2) Does anybody know: if an HD signal is encrypted over the firewire
> stream at its full resolution, could it still be down-sampled and sent
> from the cable box at 720x480 (DTV 480p) in unencrypted form?  That's
> DVD quality and good enough for me.  (Somehow I doubt it's doable
> though.)

Well, that would seem appropriate.  If not, how would they make money?  ;-)

> 3) What's with S-Video anyway?  I thought it used 6 pins but it seems
> most S-Video devices (and cables) are only 4-pin.  Anybody got the scoop
> on that?



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