I think for tv tuner card pinacle is the best
I have not read this article fully but might be it may prove useful to you.
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Interface: Internal or External
The first choice to make after deciding to go with a digital TV tuner card is figuring out whether you want to opt for an internal or external solution. Digital TV tuners are available as both internal cards that fit into a PCI slot or as external USB devices.
An internal card requires a spare PCI slot, as well as a desire to open your computer up to install it. This isn't technically challenging, just a little daunting if you've never done it. PCI Express models are also due out later this year to take advantage of the PCI Express bus found on newer motherboards. These will be functionally similar to the internal PCI models, though they'll be designed to fit the PCI Express slot instead. Internal cards tend to be cheaper than their external brethren, but they're a little less flexible.
Internal cards start around $140 and go up to $250. Generally, a basic model will include a card, some tuner software, and little else. The card will include a coaxial aerial connector, but you'll have to go shopping for coaxial cable yourself, and if you're serious about watching TV from a distance you'll also have to add a third-party USB or Serial infrared remote control. These cards are generally adequate for recording shows though, and if your primary goal is to be able to watch TV while sitting at a PC this solution is ideal. Higher-end models will generally include more cabling, a wider range of connectors, a remote control, richer software bundle, as well as extra filters to clean the image. As a result, they'll offer a slightly superior picture to less expensive models, but the difference isn't enormous.
Some high-end tuners will even include analog inputs, allowing the user to record footage from a VCR. This sort of device can do double duty: it can be used to receive and record broadcast TV and also for converting old VHS, Super 8 or Beta tapes into a digital format.
An external device is the only viable solution for notebook users, also favouring those that don't want to mess around opening their computers. Better yet, they're portable. You're generally looking at a slight price premium to move from an internal to external solution. When buying an external tuner, the best bet is to go for a USB 2.0 or Firewire model. This is because the limited bandwidth of USB 1.1 (11Mbps) isn't adequate for the data passing between the tuner and the PC, leading to playback glitches. Firewire and USB 2.0 offer 400Mbs and 480Mbps bandwidth respectively, which is plenty to cover the demands of a digital TV tuner. External tuners start at around $160 and go up to $300. Like their internal counterparts, the more expensive models feature extra software, cabling and often ship with a remote control.
Chipset
One of the key features to keep an eye out for when shopping around is the chipset employed by the tuner. The chipset refers to the manufacturer of the decoder that receives the digital signal; this can be a good indicator of the quality of the image that you get out of the tuner as well as software support. It's always best to go for a popular chipset if possible, as this will increase the number of compatible software packages that will work with the card. In particular, keep an eye out for cards with chipsets manufactured by Philips. The chipset a tuner employs is generally listed on the packaging, so do a little shopping around before committing to a purchase. If you're shopping at a larger store, ask the shop staff for a demo of the product in operation. This way, you can judge for yourself if the display quality is adequate.
Technically, there are two types of digital TV broadcasts: Standard Definition (SD) and High Definition (HD). SD is broadcast at a resolution of 576 lines x 720 pixels, while HD supports up to a massive display resolution of 1920 lines x 1080 pixels (as a comparison, most computer screens run at a resolution of 1024 x 768 pixels). Because HD is broadcasting much more information than SD, the decoding requirements are higher, but the broadcast image is astonishingly clear and crisp. Many channels offer separate analog, SD and HD broadcasts simultaneously, but it will still be a while before HD takes over.
Availability
Though the rollout has been slower than many would like, digital TV is available across most of Australia. Standard definition is available in capitals and most regional centres (for a chart detailing what's available where, see
www.dba.org.au/index.asp?sectionID=22). All major channels are currently available in SD, so there's very little reason to opt for a regular analog tuner these days.
If you live in a metropolitan centre like Sydney or Melbourne, you may want to consider picking up a High Definition (HD) digital tuner. Remember that it'll be a couple of years before all the broadcasters make all their content available in HD, so check out what you want to watch before making the switch.
Software
One consideration that many overlook when shopping for digital TV tuner hardware is the software packages to drive the tuner. Because the hardware is next to useless without software, it's important to include the software that comes with the card as part of the buying decision. Poor software will make the tuner difficult to use, and a stable, full-featured and well-designed package will improve the TV viewing experience. Some of the features to look out for are time-shifting, scheduling (programming the tuner to record either a set show or for a set time period) and integration of an Electronic Program Guide (EPG). Some even include the ability to burn recorded TV directly to CD or DVD, which can be a massive time saver for serious users.
Time-shifting
Time-shifting is another compelling reason to go digital. Quite simply, time-shifting allows the viewer to pause a live TV broadcast and then resume it later on. Imagine you're watching a show and the phone rings. You press pause and answer the phone, but the computer keeps receiving the digital content while the show is paused. This information is written to the hard disk until you press pause again and continue playback. At this point, the recording will continue to buffer to the hard disk while you catch up. Using time-shifting, you can sit down to watch a half-hour show ten minutes after it started, and then press fast-forward to speed through all the advertisements while you're watching.
Time shifting also allows you to record shows and watch them later, and because digital TV is broadcast as an MPEG-2 stream, the computer only needs to decode the broadcast if it's playing it back. So, if you're not watching while you're recording, the PC can simply save the stream directly to the hard disk, which requires relatively little processing power. Bear in mind that this takes a large amount of hard disk space (approximately 1MBps for an SD stream), so you'll want to regularly archive any recorded footage by burning it to CD or DVD.
Electronic Program Guides
One issue that has stifled the uptake of digital tuners in Australia is the slow offering of an Electronic Program Guide (EPG). An EPG allows the user to schedule recordings based on the show listings. Instead of setting up a VCR to record a certain channel at a certain time, as in the bad old days, you can set the software to record a certain show every day of the week. The software can be configured to start recording when the show comes on, and then turn off when the show finishes.
The program information is broadcast over the air as binary information that can be received by the software, or as a video stream that can be read by the user. A few commercial web sites like Ice TV (
www.icetv.com.au) list EPG information for Australia, so you can also use this in conjunction with the tuner software to schedule recordings.
