[mythtv-users] pcHDTV with PVR-350 for output

Dan Lanciani ddl5 at danlan.com
Sat Oct 23 05:31:54 UTC 2004


Jarod Wilson <jcw at wilsonet.com> wrote:

|On Friday 22 October 2004 21:56, Dan Lanciani wrote:
|> I've been trying to send ATSC programming from a pcHDTV card through the
|> MPEG decoder in a PVR-350 using MythTV 0.16.  It seemed that the
|> configuration setting to use the PVR-350's output was just being ignored.=
|=20
|> (I could run an X server on the 350 and then of course everything display=
|ed
|> on the TV, but through the dumb framebuffer interface.)  There were no
|> error messages or anything else to indicate that the PVR-350 was being
|> accessed at all.
|>
|> Finally I had the thought to try using the PVR-350's own analog tuner as a
|> source rather than the pcHDTV.  The PVR-350's output then came to life,
|> turned on and off by the configuration option in Playback Settings just as
|> it should be.  Is something in MythTV deciding that the PVR-350's MPEG
|> decoder can't handle the ATSC stream?  Or is there some interdependence
|> between PVR-350 capture and output (which would seem to defeat the purpose
|> of MythTV's distributed architecture)?

|=46irst off, the 350's decoder is set up for NTSC or PAL sized mpeg2 frames=
|, not=20
|ATSC sized frames. I don't think the hardware is physically capable of=20
|handling something that big.

So does something in the MythTV code know this and simply refuse to try?  Is
this documented anywhere?

|Second, why on earth would you want to output=
|=20
|HDTV content through an SVideo connection that is 720x480, interlaced?

Because I don't care about "H"DTV.  I just want ATSC reception converted
to NTSC.

|You'=
|d=20
|effectively be down-sampling the ATSC signal back down to NTSC,

Yes, that's exactly what I want.

|so why even=
|=20
|bother?

Because analog will eventually go away and even now ATSC offers me a picture
with less ghosting and interference.

|For HDTV, you really need to be outputting to your TV via VGA, DVI =
|or=20
|component for it to be worthwhile.

Well, clearly this is a matter of opinion (as suggested by the existence of
set top boxes that receive ATSC and downconvert to NTSC as necessary).  My TVs
do not have VGA, DVI, or component inputs.

It's possible that I misunderstood the generality of the MythTV model.  I
thought that the pcHDTV card was just another source of input and the PVR-350
just another output device.

|This has all been discussed before, plea=
|se=20
|search the archives if you want more insight.

I've searched extensively and I found nothing to answer my question.  Could
you point me to the specific discussion of PVR-350 output used with the
pcHDTV as source?

				Dan Lanciani
				ddl at danlan.*com


More information about the mythtv-users mailing list