[mythtv-users] New user setup questions?

[Jarod C. Wilson]

On Feb 16, 2004, at 18:43, Alex Van Deusen wrote:

> 1. I love the HD TV that is delivered from the Zenith HD DirectTV box. 
> ( I live directly across from NYC so I get all the HDTV channels 
> available)  I could never ever go back to standard TV watching if I 
> don't have to.   The guide  integrates the ATSC with Satellite 
> channels and is great for previewing TV while I watch other channels.
> a.  I know that I will not be able to capture HDTV from the HD 
> DirectTV,  so I will need to purchase the PCHDTV.  Will the guide be 
> integrated within Myth.  Will it remap channels (sub channels) ie CBS 
> is 56-1 to 2-1 etc.....  Can I choose to exclude channels that have no 
> signal?

You can exclude channels, you can get the guide data to line up by 
using the NTSC guide data with the corresponding ATSC channels. You 
have a bit of work to do there, but yes, all that can be done.

> b.  The quality for the main TV is paramount.  I know that DirecTV is 
> highly compressed so will I be able to capture that in at least 
> 720x480. ( I am sure the answer is yes). Can I scale that with FFDshow 
> or Dscaler.

MythTV has its own internal scaling mechanisms which will handle all 
that.

> c. For the HD broadcast will I be able to capture full 1080i for 
> 2,4,11 and 720p and 480p for ABC and Fox.

Yes, yes and yes.

> d. How does the sound work.  The Zenith has optical out and analog 
> out.  I have purchased a Mad Dog card with the Envy chipset and it has 
> optical in and out.  Do I need to even bother with the optical in to 
> get DD 5.1 for HD broadcast or Direct TV.  Will the capture card(s) 
> just send the data over the PCI bus?  Or would I need to plug the 
> optical in from the HD DirectTV into the soundcard in and route 
> optical out from my soundcard to my receiver?

The pcHDTV card tunes to an ATSC channel and then simply dumps the raw 
mpeg2 transport stream to disk. The audio is in the transport stream, 
no mucking with sound card (except for playback). You won't be able to 
interface the DirecTV HD box with Myth at all for HD content.

> e. I intend to build separate backends and front ends.  Therefore what 
> is the best configuration for this system.  I concerned that the PCI 
> bus won't be able to handle all this from a central mammoth server.  
> So I have different scenarios which would make more sense?
>
> Again image quality on the main RPTV is paramount.
>        i. build low end front end pII 333mhz  with a (new purchase) 
> PVR-350 that has Mpeg2 Hardware Encoder/Decoder and a PCHDTV for HDTV. 
>  I       would use a Radeon 9600xt or Geforce Ti200 for graphics card. 
>  I would use the Envy card for audio.  Lirc with a low speed data 
> serial connection.

A PII-333 is NOT going to cut it for a frontend capable of playing back 
HDTV content. Not even close by any stretch of the imagination. The 
recommendation is something in the ballpark of a 3GHz HT-P4.

>        ii. or I would need much more powerful front end 2.6 ghz 
> machine at least for HDTV.  Then I could run just a PVR 250 in a 
> backend.

Yes, the backend capture requirements are very minimal. All you're 
doing is dumping a data stream to disk, then streaming it off to a 
frontend. A 2.6GHz machine might make the grade if you're not using all 
the bells and whistles and couple it with XvMC.

>        iii dont need to run anything on frontend except graphics card, 
> so i could go lowend with a nic card and pull everything from the 
> backend of (2)       PVR-250s connected to (2)DirectTV's and a PCHDTV

Definitely can't go low-end on the frontend. Just an FYI, I have a 
pcHDTV card, and my frontend is an Athlon XP 3200.

>        iv.  does the slave backend need a graphics card?  Or could I 
> load up an old box that has scsi and ata 133 with multiple drives and 
> just the          capture cards.

The backend doesn't need to be much. Basically, the hard disks just 
need to be able to keep up. A single ATA/133 drive is plenty for a 
single HDTV stream. I'm not positive where it would start to bog down 
with the addition of the PVR-250s, but I believe one of the main pcHDTV 
guys has a single ATA/133 drive and can capture from 3 pcHDTV cards 
simultaneously, so you should be fine.

>        v.  can I even use the Wincast TV card.   It has composite 
> video out and analog out.  Coud I use this without a graphics card?  
> Will that be good enough on the 27" TV.

I know nothing about that card in particular, but that being the case, 
I doubt its outputs are supported for playback of MythTV content, so 
you'll need a video card to feed the TV.

>        vi.  If intend to build a frontend only for the 27" TV and the 
> bedroom small TV do I need anything except for graphics card and sound 
> cards in those machines with minimal drives (9 gigs).  What is the 
> minimum configs for front ends like this if I have a big backend with 
> (2)PVR 250 and PCHDTV?

So long as you don't intend to try playing back the HD content on those 
machines, you can get by with something fairly minimal. You're correct, 
you don't need much hard drive capacity (just the OS and apps need to 
get on there), but would need a graphics card and sound card. So far as 
processor specs go, I've had no problems with playback on an Athlon 800 
remote frontend myself (playing back PVR-250 captures from my backend), 
and others have reported gone with even less.

>        vii I like to channel surf and don't intend to completely 
> Timeshift all material.  So if I wanted to watch Direct TV in one room 
> while my wife records something on another TV and watches Live TV is 
> this possible. Or would I need to have three PVR-250 connected to 
> three DirectTV.    Same question for PCHDTV.  Would I need to have two 
> PCHDTV to watch LiveTV and record.

One capture card per stream. If you're watching something, your wife is 
watching something, and you've got something recording, you need 3 
capture cards. Same thing for the pcHDTV. Only one stream per card.

> Would that crush the PCI bus?

Four cards (two PVR-250 and two pcHDTV) might be getting close, but I'm 
not certain. Again, there's someone using 3 pcHDTV cards, so you might 
be okay...

> Does the box need to be superpowerful for dual PCHDTVs

Nope. Again, the big strain for HDTV is playback, not capture. Capture 
side considerations are mainly just PCI bus and hard drive throughput.

> Your thoughts are greatly appreciated...  Detailed responses are very 
> helpful.

Detailed enough? :-)

> I have been reading the boards for months.

Me too. ;-)

-- 
Jarod C. Wilson, RHCE

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