[mythtv-users] Capture card with best tuner - BT8x8, SA713x or PVR-250?

[Joe V]

For the record I'm using RTJPEG as well.  The machine
is quite capable of MPEG-4, but until I get the
problems worked out with RTJPEG, I'm sticking with it.

It's possible that the OS is doing something else, I
suppose, but I boot into run-level 3 and start MythTV
from there (using a .xinitrc).  I've removed as many
of the services as I could using ntsysv (Red Hat 9).

The pictures that I took, those were of the TV.  It
was like that before I even started building the
MythTV box.

The video clip was also taken on the TV, and just to
show the diagonal lines running through the screen. 
Any stutter (or the black bars running up the screen)
are likely because the camera was capturing at a
different frame rate than the TV was displaying at. 
So, I would think that is normal (my TV doesn't
stutter that I can tell when using it).

I'll try unhooking my XBox (which is connected vias
S-Video), since I wanted to hook up the MythBox via
S-Video anyway.

As for the capture card, I've used two different ones
- a LeadTek Winfast 2000 XP Deluxe (which seemed to be
pretty bad), as well as a Pinnacle PCTV Rave, which
seems to be a bit better.  That's why I was asking
what kinds of cards/tuners people are using.  Fry's
has a SAA7130-based card (the LifeView FlyVideo 2000)
for $45-$50, but it's mono (like my current card).  I
bought the Leadtek because it was stereo (and returned
it because I was having problems).

One thing that could be a cause of the problem is that
on both the Leadtek and the Pinnacle cards the coax
barrel connector isn't part of the tuner itself, it
connects to the tuner (it's a slide-on connector,
looks like a composite connector).  I'm thinking that
this might have something to do with it, but I don't
know how many cards actually are like this.

Maybe I'll pick up the FlyVideo card today at Fry's
and see how it works.  I've been wanting to get some
testing with an SAA713x chipset to see if the picture
quality really is better.

Now then, one final question for you...  If you look
at the console, do you see any "rebuffering (X,Y)"
messages (where X and Y are numbers)?  Depending on
the channel I'm watching, I see these messages
anywhere from every 10 seconds to every 10 minutes
(sometimes I get a few of them every 10 seconds and
then they go away for 5-10 minutes).  In order to keep
track of the times, I modified the RingBuffer.cpp file
to print out the date/time.

-- Joe

--- Richard Lee-Morlang <rick at webtownis.bc.ca> wrote:
> On Sat, 2003-08-23 at 02:54, Joe V wrote:
> 
> 
> > Now that I've dropped the capture resolution down
> to
> > 352x480, the pauses (when one actually happens)
> are
> > only a couple of seconds long (not as bad as
> before). 
> 
> 
> Even at 720x480 (only tried with RTJPEG, mind you) I
> get no frameloss
> unless something extreme is happening with the video
> or there's
> something else going on in the OS. 
> 
> 
> > The only interference I can think of is that the
> PC is
> > next to the TV, and has it's side panels off. 
> That's
> > because it's a temporary case, and I don't have
> proper
> > cooling in it.
> 
> 
> I assume your cable picture looked much the same
> before you setup your
> computer anyway? 
> 
> 
> > Anybody who wants to look at the images can go to
> > http://www.vulturesnest.net/catv.html.  I have
> enough
> > of a transfer cap that plenty of people can look
> at
> > them.  Feel free to check out the rest of the site
> > too.  :)
> 
> 
> Your picture quality isn't that far different from
> my worst channels,
> though for me it's more like random noise/static and
> less like a regular
> interference pattern as yours appears. In any case,
> I don't get stutter
> problems like what I see in your video clip unless
> I've got something
> disk or interrupt intensive going on in another
> thread.
> 
> If a point of reference would be useful, I can put
> up some screen
> captures for you to compare with. At this point, if
> I were you, I might
> try buying a different capture card from a store
> that will accept
> returns without too much hassle. It might be worth
> taking a closer look
> at your video card, motherboard, and X setup too. Of
> course, maybe the
> culprit is your signal, so perhaps you'd be better
> off leaning on the
> powers that be to get it improved. 
> 
> The only other thing I can suggest is if you've got
> more than one
> video/audio signal coming into the back of your TV,
> disconnect
> everything except the signal from your computer and
> see if that helps. I
> doubt it would clear up the stutter problem, but in
> my case it
> significantly cleaned up the picture. Might also be
> worthwhile trying
> some different cables out. I've got one S-Video
> cable that picks up
> noise like crazy...
> 
> But if your picture quality using the TV tuner alone
> straight from the
> wall is about the same as it is with the setup you
> have now (excepting
> the stutter) then none of that will make any
> difference. :-(
> 
> I don't know what else to suggest, but I wish you
> good luck.
> 
> Rick
> 
> 
> 
> 
> 
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>
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> 


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