Comment 3 for bug 1201739

On Wed, 11 Sep 2013, Bill Kirkpatrick wrote:

> I also have a now sound problem with an NVidia card. Here's where I
> am....
>
> 1) PulseAudio is disabled. (Not shown in ps ax, and volume control
> reports it cannot connect to the server)

ok

> 2) Moved KDE settings away from alsa device hw:2.7

not sure what that would(n't) do as I am not too familiar with kde,but it
makes sense.

> 3) mplayer will use alsa device hw:2.7 and plays just fine.

> 4) if I start jackd on alsa hw:2.7 while mplayer is using it, jackd
> reports device is in use.

good.

> 5) If I start jackd without mplayer running, jackd starts just fine and
> mplayer then reports the device is in use.

good.

> 6) jackd creates a system playback sink.

Not quite the terminology I am used to with jack, but assuming same as
pulse, good.

Question: how are you starting jack? Are you running jackd or jackdbus?
(both are shipped in the jackd2 package) What do the logs say? How are you
seeing the logging output of jack?

> 7) Now, with 'mplayer -ao jack x.mp3' jack creates a mplayer source and
> maps it to the system sink.

How are you seeing the system sink? with what command or application?

> 8) No sound. Alsamixer reports no applications are playing audio.

The alsamixer I know does not report if sound is being played or not, only
control levels. Alsa itself does not report connections. What application
are you using to see this? If you have disabled pulse, the output level
may be down. If you run alsamixer in a terminal can you turn all the
levels up, are any channels muted?

> 9) if I run qjackrec, jackd will map the mplayer source to both the
> system and qjackreq sinks. qjackreq captures the audio into a .wav file
> just fine, but still no audio output. After jackd is shutdown, mplayer
> will play qjackrec's .wav file (via alsa, again on hw:2.7).

So it appears, audio is getting to jack just fine and jack is sending the
signal on. However jack does not control output levels, that has to be
done manually. Running alsamixer from a terminal is the most surefire way
of knowing you are dealing with the right controls. Use F6 to select your
hw:2.7 sounds card.

> 10) All the while jackd is running, including the period mplayer is
> playing into jack, alsamixer reports that no applications are playing
> sound.

Alsamixer does not report connections like pulse does or pavucontrol or
the kde mixer (also a pulse controler).

Sent via email for easier quoting.