[mythtv-users] Probably a FAQ Question (HD, MythTV, Cable Card, and Comcast)
Rod Smith
mythtv at rodsbooks.com
Wed Apr 11 01:49:56 UTC 2007
On Tuesday 10 April 2007 20:40, David Frascone wrote:
>
> Two last (I hope) questions:
>
> 1) What is the most popular tuner for analog & digital? (Popular for
> price / performance, features, and reliability)
By "analog & digital," do you mean a tuner that will do both? If so, probably
the pcHDTV cards. The latest model is the 5500. I must caution, however, that
I own a couple of pcHDTV 3000 cards, and my opinion of them is very low,
particularly for digital cable (QAM) reception -- they seem to work OK for
some people, but they've got signal lock problems for others, apparently
because of (very common) compatibility problems with random pieces or
combinations of hardware. I don't know if the 5500 improves matters. Also,
most (perhaps all) cards that do both digital and analog use framegrabber
analog tuners, which means that the CPU must encode the video into the
desired format (MPEG-4 or RTJpeg for MythTV). This increases CPU load, which
can be a problem if your CPU is marginal (3GHz and below is "marginal" for an
HD setup) and you want to record multiple channels or record analog while
playing back HD content. HD recording is actually light on the CPU, since the
card just sends a precompressed digital signal down the bus, which imposes
very little CPU load.
For digital-only, the HDHomerun and AVerMedia AVerTVHD A180 both seem to be
reasonably popular, but there are others, too. I replaced one of my pcHDTV
cards with an A180 and it's like night and day; the A180 produces clean video
with just an occasional minor digital "blip," whereas the pcHDTV 3000
produces recordings that are literally unwatchable; they're missing so much
data that MythTV usually reports them as half or less the show's length.
For analog-only, the Hauppauge product line, and particularly the
PVR-150/250/350/500, seems popular. These cards support MPEG-2 hardware
encoding, which greatly reduces CPU load. Other hardware-encoding cards
exist, but they seem less popular. I happen to have an AVerMedia AVerTV
M150-D, which is a bit finicky but can be made to work reasonably well
(although perhaps not for channel surfing). I've also got a Hauppauge
PVR-USB2, which is a USB-interfaced MPEG-2 encoder card that works reasonably
well, except that it doesn't respond to MythTV's bitrate-setting commands, so
all recordings have the same bitrate.
Check the wiki for information on quite a few video capture cards:
http://www.mythtv.org/wiki/index.php/Video_capture_card
http://www.mythtv.org/wiki/index.php/Category:Video_capture_cards
> 2) In regard to firewire -- how does that work? Does it just constantly
> transmit what's playing? So mythTV would change channels on the STB,
> and then store the stream to disk? If so, shouldn't I do this before
> even buying a tuner card?
If you've got an STB with a Firewire port, it's certainly worth trying this
approach before buying a separate card. AFAIK, there's nothing preventing you
from using both an STB/Firewire setup and separate digital and/or analog
tuners, so you can add to or replace your STB/Firewire configuration if you
like.
I've never actually used a Firewire input for MythTV, so I can't give you much
in the way of details about how it works.
--
Rod Smith
http://www.rodsbooks.com
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