Basic info about twin tuner HDTV capture cards

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Davo26
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Basic info about twin tuner HDTV capture cards

Post by Davo26 » Sun Mar 09, 2008 11:00 pm

Do I need 2 signal feeds with these cards?

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Re: Basic info about twin tuner HDTV capture cards

Post by hnzw_rui » Mon Mar 10, 2008 12:32 am

No, you don't. But unless you can get it for cheaper or just a tiny bit more expensive than a single tuner card, why buy a twin if you're only using one connection? As it stands, dual HDTV tuners cost the same as two single tuner cards so if you don't need the functionality right away, you could save money now and just buy another tuner card when the need arises.
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Re: Basic info about twin tuner HDTV capture cards

Post by Davo26 » Mon Mar 10, 2008 1:14 am

I want to record 2 shows at once....I already have a single HDTV card, but I wasn't sure whether you need another input.
Does PQ degrade when you record 2 at once...?

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Re: Basic info about twin tuner HDTV capture cards

Post by DaIceMan » Mon Mar 10, 2008 4:19 am

Davo26 wrote:I want to record 2 shows at once....I already have a single HDTV card, but I wasn't sure whether you need another input.
Does PQ degrade when you record 2 at once...?
Picture Quality depends on the spec of your machine. From what I've seen/read, you need 1Ghz and 1GB of ram for each signal you are recording. Thus, if you use 2 cards (or a dual card) you will need at least 2.0Ghz and 2GB of ram. Of course, I'm only going from what I've read. I haven't built the box yet, but I'm planning to build an HTPC/MythTV (or equivalent) box in the next few months, so I've started to do a little research on it. I'm certain someone will correct me if my information is inaccurate.
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Re: Basic info about twin tuner HDTV capture cards

Post by Davo26 » Mon Mar 10, 2008 5:41 am

DaIceMan wrote:
Davo26 wrote:I want to record 2 shows at once....I already have a single HDTV card, but I wasn't sure whether you need another input.
Does PQ degrade when you record 2 at once...?
Picture Quality depends on the spec of your machine. From what I've seen/read, you need 1Ghz and 1GB of ram for each signal you are recording. Thus, if you use 2 cards (or a dual card) you will need at least 2.0Ghz and 2GB of ram. Of course, I'm only going from what I've read. I haven't built the box yet, but I'm planning to build an HTPC/MythTV (or equivalent) box in the next few months, so I've started to do a little research on it. I'm certain someone will correct me if my information is inaccurate.
Fair enough, but how does the card utilize one input, it must split the signal, so i'm wondering if one recording will suffer :shock:

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Re: Basic info about twin tuner HDTV capture cards

Post by hnzw_rui » Mon Mar 10, 2008 9:15 am

Davo26 wrote:I want to record 2 shows at once....I already have a single HDTV card, but I wasn't sure whether you need another input.
Does PQ degrade when you record 2 at once...?

Fair enough, but how does the card utilize one input, it must split the signal, so i'm wondering if one recording will suffer :shock:
If you want two shows at the same time, then you need two separate signal feeds, one for each. So that means a separate antenna for OTA or an RF splitter if you're recording unencrypted QAM (cable). Sorry for that misunderstanding. Digital broadcast is all or nothing. You don't get noise like you do in analog channels, but if your signal's not good enough, then you get freeze frames or no picture at all. For OTA, I don't think it would matter. For unencrypted QAM where each split suffers a signal loss, it might, depending on how strong your signal is.
DaIceMan wrote:Picture Quality depends on the spec of your machine. From what I've seen/read, you need 1Ghz and 1GB of ram for each signal you are recording. Thus, if you use 2 cards (or a dual card) you will need at least 2.0Ghz and 2GB of ram. Of course, I'm only going from what I've read. I haven't built the box yet, but I'm planning to build an HTPC/MythTV (or equivalent) box in the next few months, so I've started to do a little research on it. I'm certain someone will correct me if my information is inaccurate.
I think the system requirements you're quoting are for real-time encoding of analog feeds (for analog tuner cards w/o hardware encoding). If you're just recording HDTV and not watching it, and you're using a decent program to do so, then you don't really need that much processing power. HDTV feeds are already in compressed form (currently MPEG2 in the US) so all that's needed is to save the stream to the hard drive. If you're watching, though, then you would need a beefy system. If your graphics card can't do hardware assisted decoding, I don't think 1GHz is enough.

I've only got one tuner currently, the oldish ATI HDTV Wonder, and using the silent record feature in WatchHDTV, CPU usage on a Sempron 3200+ w/1GB DDR 400 SDRAM was just 8%. Forget about watching 1080i on that PC, though.

Looking into getting an HD Homerun (or two). I've run out of empty PCI slots. It supports ATSC & unencrypted QAM, and reportedly works out of the box with MythTV. Too bad it doesn't have analog. Hopefully, wifi throughput at home is decent enough so I can use it with my laptop, too.
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Re: Basic info about twin tuner HDTV capture cards

Post by Davo26 » Mon Mar 10, 2008 7:10 pm

Thanks for clearing that up hnzw :supz:

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Re: Basic info about twin tuner HDTV capture cards

Post by hnzw_rui » Sun Mar 16, 2008 2:03 pm

I stand corrected. Just read on another site that you can divide the signal coming from an antenna using an RF splitter like you would for cable. Same as with cable, signal deteriorates with every split.

Guess I never really thought of it as an option since all our TVs had their own antenna prior to switching to cable.
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Re: Basic info about twin tuner HDTV capture cards

Post by Davo26 » Sun Mar 16, 2008 9:43 pm

hnzw_rui wrote:I stand corrected. Just read on another site that you can divide the signal coming from an antenna using an RF splitter like you would for cable. Same as with cable, signal deteriorates with every split.

Guess I never really thought of it as an option since all our TVs had their own antenna prior to switching to cable.
I wonder if the twin tuner card would bundle this item....I might join a dedicated HDTV forum or whatever and see what I can come up with.

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Re: Basic info about twin tuner HDTV capture cards

Post by hnzw_rui » Sun Mar 16, 2008 11:11 pm

Bundle what? The splitter? I seriously doubt it. They're relatively cheap, though. If you've got a good enough signal, then even the $1 splitters from your local Walmart might work. If not, then get something better. My signal's already bad so if I get another ATSC tuner, it's gonna get its own antenna (renting so can't mount a good antenna on roof).
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