[pulseaudio-discuss] redirecting audio from SAA7134 tv card.

Tanu Kaskinen tanuk at iki.fi
Thu Oct 1 08:06:18 PDT 2009

to, 2009-10-01 kello 09:14 -0500, Luca DELLA GHEZZA kirjoitti:
> I refer to this ticket http://www.pulseaudio.org/ticket/665
> As lennart said I tried to load module loopback with the command
> pactl load-module module-loopback
> it answers to me with   22   that I suppose is the number of devices
> found.

No, it's the index that was assigned to the newly loaded module.

> After that I found that from the speakers I could hear the sound from
> the mic integrated in my webcam, so the command had some effect. I muted
> the mic from Pulseaudio settings.

That means that the default source was the webcam mic instead of the tv 
card. The module documentation at


states that the source and sink parameters are mandatory. Apparently the
documentation is wrong, if you managed to load the module without those
parameters... Anyway, in order to use the tv card as the source, load
the module with command

load-module module-loopback source=SOURCE_NAME

SOURCE_NAME is the unique (and probably rather cryptic-looking)
identifier that pulseaudio assigns for the tv card. It can (hopefully -
I didn't test) be found with the following command:

LANG=C pactl list | grep -A2 'Source #' | grep 'Name: ' | cut -d" " -f2

That should list all sources available. If you can guess which of those
is the tv card, good (hint: it isn't any of those that end with
".monitor"). Otherwise run just "pactl list" and search from that
verbose output the correct source.

> I tried to listen my tv card audio, but no way. Tvtime was unable to
> connect to pulseaudio.
> i.e. launching tvtime like this
> tvtime --mixer=pcm:0
> the answer was:
> mixer: Can't open device pcm, mixer volume and mute unavailable.
> mixer: No such mixer channel '0', using channel 'line'.

Where did you get that "pcm:0" string? I haven't used tvtime, but
looking at its man page it looks like the part before the colon should
be a path to an OSS mixer device, e.g. /dev/mixer, and the part after
the colon should be one of a fixed set of strings, one of which is
"line". Pulseaudio isn't OSS, so it's questionable whether you can get
volume controls to work at all from tvtime.

I wouldn't bother with the mixer parameter at all before things work so
well that your top concern is that volume controlling doesn't work from
tvtime's own interface.

> I tried different devices, but the answer was always the same.
> After that I made a call with skype and on the other side the person
> could listen to my tv card audio instead of my voice coming from the
> mic.

Does Skype use pulseaudio for input? Are you running the newest release
of Skype that I hear finally works decently with pulseaudio?

> I tried different settings using Pavucontrol, but finally I rebooted the
> system and everything was back to the normality.
> Any suggestion?

I think I gave some suggestions :) I hope those help.

Tanu Kaskinen

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