[mythtv-users] recommend PCI DVB-T Tuner Card?

Devin Heitmueller dheitmueller at kernellabs.com
Thu May 6 12:51:02 UTC 2010

On Thu, May 6, 2010 at 8:26 AM, Lindsay Mathieson
<lindsay.mathieson at gmail.com> wrote:
> On Thu, 6 May 2010 10:14:57 pm Devin Heitmueller wrote:
>> nfortunately, the theoretical doesn't really match real life that
>> closely.  Given crappy driver optimization under Linux for most
>> boards, you're not likely to get more than two to stream HD reliably
>> at the same time.
> Bollocks. Utter bollocks. I regularly record 3-4 HD channels simultaneously. I
> once tried 14 channels at once (mix of HD & SD) with no problems.

Are you saying "bollocks" because I asserted that the driver
optimization under Linux is crappy?  I'm allowed to do that since I
wrote a bunch of the LinuxTV drivers.  ;-)

Your mileage may vary depending on which USB bridge is on the board
you selected.  I can tell you that many of them are not properly tuned
for more than a couple of streams (they don't setup their isoc
parameters correctly).  While it may work for you because you had the
luck to get one with a driver that is properly setup, I wouldn't
recommend it to others.

>> And be prepared to get a powered USB hub, since
>> even a single tuner draws pretty close to the 500ma limit while
>> streaming (thereby hitting the power limit on a single port).
> Same as above. I have 3 USB devices (2 single and one double tuner) running off
> the ports on my mobo.

You've probably got a motherboard that provides 500ma *per* port.
Again, you're lucky enough to have ended up with hardware that is well
designed.  You shouldn't assume that everyone will be so lucky.

All I'm getting at is you've had a positive experience because you
happened to end up with good hardware with good drivers, which is
great.  From that though, people shouldn't operate under the
assumption that they can get any USB capture device operating on any
motherboard and expect comparable results.

In other words:

I own a Honda and I've never gotten into an accident even once,
therefore it *must* be the safest car in the world!


Devin J. Heitmueller - Kernel Labs

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