[mythtv-users] ASUS DigiMatrix & mythTV

Joseph A. Caputo jcaputo1 at comcast.net
Tue Jun 1 17:07:37 EDT 2004


On Tuesday 01 June 2004 16:28, Ron Aldrich wrote:
> On May 31, 2004, at 11:26 PM, Steven Cruysberghs wrote:
> > Op ma 31-05-2004, om 00:33 schreef Ron Aldrich:
> >> Folks,
> >>
> >> I've spent the last couple of weeks trying to get an ASUS
> >> DigiMatrix working with mythTV, and have run into a bit of a snag.
> >>
> >> First, my system configuration:
> >>
> >> ASUS DigiMatrix, 512mb RAM, 2.4ghz P4.  The TV-in card is
> >> apparently not the same as was used in older DigiMatrix models -
> >> it's tuner bears the following legends:
> >>
> >>      LG INNOTEK
> >>      TALN-H250T
> >>      308B1406
> >>      NTSC
> >>
> >> RedHat linux (Fedora Core 2, kernel version 2.6.5-1.358).
> >>
> >> MythTV 0.15-38 (installed from ATrpms).
> >> saa7134 0.2.12-15 (Video4Linux, installed from ATrpms).
> >>
> >> In /etc/modprobe.conf
> >>
> >> alias /dev/v4l saa7134
> >> options saa7134 card=2 tuner=39 oss=1 dsp_nr=1 mixer_nr=1
> >>
> >> Now, on to the problem.
> >>
> >> I've gotten the TV-in card working well with xawtv (sound, s-video
> >> and television all work correctly), but when I try to use it with
> >> mythTV, I
> >> get no sound.
> >>
> >> Does anyone have any ideas?
> >>
> >> Thanks,
> >>
> >> Ron
> > (re)read the audio section in the mythtv docs. Maybe you didn't set
> > the mixer to record the right source? If you have a cable from
> > audio out of your tvcard to line in from you soundcard you have to
> > mute line-in and set it to record.
> >
> Actually, it turns out that I'm probably having a problem with the
> saa7134 driver - it registers /dev/dsp1, but aplay doesn't find any
> audio there (It doesn't get errors either - just doesn't play any
> sound).  It may be that the TV card just isn't fully supported by
> v4l2 yet.
>
> I may be able to get it working by moving the sound cable from the TV
> in to one of the shared audio connectors (subwoofer out/audio in),
> but that will break the tuner (not a problem for me, because I use an
> external tuner).
>
> Thanks,
>
> Ron
>


You may need to use an audio patch cable from the TV-card line-out to 
your sound card line-in.  Although you can in theory capture audio 
directly from your tuner card over the PCI bus using the btaudio 
module, very few tuner cards seem to actually work this way.  Just 
because a dsp* device is created doesn't mean the card is correctly 
wired to provide audio in this manner -- the driver creates the device 
node when it detects the sound chip on the tuner card, regardless of 
whether the chip is wired up on the card in such a way as to enable 
access to the audio stream.  The more common way to capture audio in 
Myth is to use the aforementioned patch cable.

If you have sound with xawtv, you should be able to get sound in Myth 
using the patch cable.

The issue now will be that your sound card & driver will need to support 
full duplex in order to do LiveTV, or any other simultaneous record + 
playback.

Search the list archives for 'btaudio' for more detailed descriptions of 
how/why btaudio works only with some cards.

-JAC


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