>I checked it on Xubuntu: running Pulseaudio as an audio submixer
>through JACK . In Pulseaudio's mixer GUI (which is the default mixer
>in Xubuntu's panel), JACK can be selected as destination for an
>application's audio output, but only when the application is indeed
>delivering audio. For example, when a video is playing in Firefox, the
>audio interface option boxes appear.

So when you pause the video does the option box go away?

>Setting up the connections manually is time-consuming. But, since JACK
>adds some latency to Pd, I would not use it as default (autostart)
>setup. The lowest practical roundtrip latency through Pd I could get
>in the JACK-with-Pulseaudio setup was measured 50 ms, 32 ms more than
>directly through ALSA.

Hm...
http://jackaudio.org/no_extra_latency

I'm talking about running PulseAudio on top of JACK and not the other
way around.  Is that what you're doing?

>Is there not another way to play sound files or tutorial video's
>together with Pd? I found one nice alternative: make VLC JACK-aware
>and use it to play media files and network streams through JACK. To
>prepare the setup:

>- install vlc package (multimedia player and streamer) if it's not
>already installed
>- install vlc-plugin-jack package
>- in VLC preferences, set audio output to JACK

>A Youtube video can be played in VLC via menu Media >> Open Network
>Stream. It should be possible for other streams as well but I still
>have to find out how to do Vimeo or Soundcloud. The VLC/JACK route
>would not be most convenient to watch internet video clips on a
>regular basis. However for incidental use, the advantage is that VLC
>connection is quickly made in JACK.

I''ve done that before to port youtube audio into Pd.  While it's certainly
handy it's a lot of work just to get a GNU/Linux machine to behave with
one other general audio use-case.

-Jonathan