[mythtv] Audio for a second tuner [was: no video with mythtv]
Sat, 07 Dec 2002 04:59:57 -0800
Harondel J. Sibble wrote:
> I have my two cards in the machine and they both work fine with Xawtv.
> However, in Mythtv I don't seem to get anything when I hit V to bring up the
> PiP window. I know something is getting written to the ringbuf2.nuv file as
> it has a time/date stamp of earlier today when I was playing with it.
> Also wondering on what sound devices to use as both cards go through my
> SBLive! My AverMedia TVPhone goes in the rear bracket line-in while my ATI
> TV Wonder goes internally to the auxilliary connector. When running setup, I
> used /dev/dsp for audio for both cards as that seemed most appropriate. Is
> there a better way of doing thso
You need separate DSP devices for each tuner card. You can
either use the DSPs of two sound cards (which is what I did)
or use the btaudio kernel module (which I haven't done).
I use an SB card instead of the on board sound. When I added
a second bttv card, I plugged the audio jack into the on board
line in and configured the ALSA driver for it as card-1.
# ALSA portion
alias char-major-116 snd
alias snd-card-0 snd-ens1371 # sound blaster
alias snd-card-1 snd-via82xx # on board audio
# 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
"alsamixer -c 1" to set line as the capture device and to
set the volume for line and capture. So now my /dev/dsp1
is the audio device for /dev/video1 .
This worked for me but perhaps ignorance is bliss as I now
assume that btaudio is supposed to be the right way.
From the kernel Configure.help:
BT878 audio DMA
Audio DMA support for bt878 based grabber boards. As you might have
already noticed, bt878 is listed with two functions in /proc/pci.
Function 0 does the video stuff (bt848 compatible), function 1 does
the same for audio data. This is a driver for the audio part of
the chip. If you say 'Y' here you get a oss-compatible dsp device
where you can record from. If you want just watch TV you probably
don't need this driver as most TV cards handle sound with a short
cable from the TV card to your sound card's line-in.
This driver is available as a module called btaudio.o ...
Hope this helps,