[mythtv-users] No video

mark fairlane at voyager.net
Wed Jul 9 01:30:49 EDT 2003


Perfect!!  Swapping the cards did the trick.  Everything works now, and 
I am moving on to tweaking things.  Thanks again!

Bruce Markey wrote:

> Shirley, Mark R wrote:
>
>> You were right Bruce, I made the changes I wanted to modules.conf
>> to correct the broken default install of ALSA, rebooted, and suddenly 
>> I had working video on Myth.  Now I need to get the recording of sound
>> sorted out.  I have two sound cards in this box, and the SBLive! is the
>> second card.  I am trying to work with the second card, and still 
>> haven't
>> gotten any sound out of myth yet.  When I run aplay /dev/dsp when 
>> myth is
>> running, I get nothing.  aplay /dev/dsp1 when myth is running, has a 
>> bitstream it's trying to play, but I can't hear it.  Is there a 
>> switch to change aplay's output to the second card?  I haven't had a 
>> chance to
>> dig into aplay's man page yet.  Also have been playing with alsamixer
>> to set the sound card inputs and outputs.  SBLive has a TON of mixer
>> sliders.
>> I'm not sure I'm getting the right ones.  I muted what I thought was
>> line-in,
>> and also set it to capture on that.  How can I be sure it's correct?
>
>
>
> I trust you will get this all working correctly but it can
> be difficult to communicate the details. Please forgive me
> if I misunderstand or misinterpret something you may have
> written.
>
> I do use two configured ALSA cards for dual tuner systems. For
> example, this is a system with an SB Live! and the on board
> sound which I use only for capturing /dev/dsp1 for the second
> tuner card.
>
> # ALSA portion
> alias char-major-116 snd
> # alias snd-card-0 snd-card-via686a
> alias snd-card-0 snd-emu10k1
> alias snd-card-1 snd-via82xx
>
> # OSS/Free portion
> alias char-major-14 soundcore
> alias sound-slot-0 snd-card-0
> alias sound-service-0-0 snd-mixer-oss
> alias sound-service-0-1 snd-seq-oss
> alias sound-service-0-3 snd-pcm-oss
> alias sound-service-0-8 snd-seq-oss
> alias sound-service-0-12 snd-pcm-oss
>
> alias sound-slot-1 snd-card-1
> alias sound-service-1-0 snd-mixer-oss
> alias sound-service-1-1 snd-seq-oss
> alias sound-service-1-3 snd-pcm-oss
> alias sound-service-1-8 snd-seq-oss
> alias sound-service-1-12 snd-pcm-oss
>
> "snd-card-0" I would refer to as the 'first card' and is the
> SB Live!. My speaker cord is plugged into the the speaker jack
> of this card. I also have the digital out wired to the digital
> input on my stereo receiver.
>
> "snd-card-1" I would refer to as the 'second card' and is the
> on board VIA sound chip. No speakers are attached to the green
> speaker jack on the motherboard.
>
> I have the /dev/video0 patch cord attached to line in of the
> SB card and the /dev/video1 patch cord to the on board blue Line-
> in jack.
>
> If I try "xawtv -c /dev/video0" and use "alsamixer" to unmute
> line-in, I hear the analog passthru audio. If I try
> "xawtv -c /dev/video1" and use "alsamixer -c 1" to unmute
> line-in, I hear nothing(!). Why? There are no speakers attached
> to the speaker out of that card.
>
> If I run "aplay /dev/dsp1" aplay captures from dsp1 and outputs
> to the default /dev/dsp so I do hear the slightly delayed recorded
> sound and know that it is ready for MythTV.
>
> So, if your "second card" is the SB Live! and the speakers are
> attached to the SB Live, you would need to tell aplay to output
> to /dev/dsp1 . I've never needed to do that and the man page is
> a little vague.
>
> I would suggest that life will be easier if your speakers are
> attached to "snd-card-0" so if you want to take advantage of
> the SB card, switch your modules.conf so that it is the first
> card.
>
>
> That being said, there is one other issue for capture on the
> SB Live! cards. Like other ALSA drivers, it is the "Capture"
> slider in "alsamixer" that sets the record level (and the Line-in
> level should have no impact on the record level). However, it
> also has separate sliders for different capture device types.
> One of these needs to be turned up also. I have "AC97 Cap" and
> "Wave Cap" turned up all the way. One of them affects the record
> level but I'm recording right now so I can't test to see which
> one it is ;-).
>
> One other tool that can be helpful is "record" that comes with
> xawtv. This has ASCII level meters. This can help determine if
> the problem is output (meters move but no sound) or recording
> (meters don't move or only show background noise). "-d" to
> specify the input device "record -d /dev/dsp1".
>
> --  bjm
>
>
>
>
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