Phonon problems in Debian

[Colin Guthrie]

'Twas brillig, and Debian at 15/01/11 14:01 did gyre and gimble:
> Am 10.01.2011 12:07, schrieb Allan Sandfeld Jensen:
>>
>> Well, it should by default, but you an also choose different outputs 
>> in the Phonon configuration. There is some interaction there between 
>> Solid (hardware-detection) and Phonon backends there. I am not 
>> entirely sure how that works in details though.
>>
> 
> The problem is that nobody is really sure how it works. :-)

Just FYI, when PulseAudio is used underneath, the whole Solid detection
and backend device detection is completely bypassed and PA is used as
the sole source of audio device information. It has the handy side
effect of actually making the device list sensible and free from
confusing options.

Regardless of how you feel about PA, I don't think anyone has complained
about this tidy up!

> This is my main question and i hope someone can explain this.
> I will multiply my knowledge to the community then.

AFAICT the device detection stuff is done via a phonon "platform plugin"
it is this plugin that actually talks to Solid and (I think) uses
libkaudiodevice. I didn't personally look at this much because (as I
said above) I totally bypass the platform plugins when PA is used,
avoiding all the resulting issues therein!



>>>> If you go into System Settings -> Multimedia -> Phonon, you can select
>>>> the audio output to use and test the choices available.
>>> Of course i tried this.
>>> Sometimes there are some options grayed out (the one that would be
>>> correct)?

Typically if the option is greyed out, it is not currently present. e.g.
a USB device not currently plugged in.

>> Interesting. Have you tried different Phonon backends?
>>
> 
> What do you mean with phonon backend - the outputs that you can choose 
> in the setup?

No this is just the device list. The "backend" itself is one of
GStreamer, VLC or Xine (but Xine is more or less dead these days).

You can access these from the "Backend" tab under System Settings.

> I always tried all the possible outputs - but it never makes a 
> difference to get it working.
> 
> In the last week i worked on the PC with the onboard sound with a CM6501 
> (USB-)Chip.
> (Refer to PC2 from http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=609441)
> Here you can choose between "PNP Audio Device (USB Audio)" and "Jack 
> Audio Connection Kit".
> Only the PNP Audio Device is working.
> With this device i have the KDE system sound and i have sound with VLC, 
> Dragon Player and Amarok.
> Kaffeine and Flash-sound is not working?
> 
> I can't understand this.
> It is the right standard device but not all applications are working.
> This are the problems you can read often in the forums.
> The sound only works for some applications.
> Why?

If you do not use PulseAudio, the settings shown in System Settings
*only* apply to Phonon apps, which means basically Amarok, Dragon and a
handful of others.

Any other apps, (VLC, Adobe Flash, mplayer etc.) will use the ALSA
configuration.


When you use PulseAudio, the configuration set in System Settings
applies to all applications.


>> Btw. the greyed out options is as far as I know options that Solid has 
>> determined are no longer present. I have sometimes seen this after 
>> upgrading the linus kernel, leading to a new set of Solid devices, 
>> leaving the old ones no longer recognized as active.
>>
> 
> O.K.
> When i look at my PC1 i can see the fully working ENS1371 and the 
> deactivated onboard sound greyed out.
> So the chipset can be seen but not be used.

Not sure why they would be greyed out here. I've only really looked at
the PulseAudio case (the only time I look at non-PA usage in Phonon is
to make sure I've not broken it!)

All the best

Col

-- 

Colin Guthrie
gmane(at)colin.guthr.ie
http://colin.guthr.ie/

Day Job:
  Tribalogic Limited [http://www.tribalogic.net/]
Open Source:
  Mageia Contributor [http://www.mageia.org/]
  PulseAudio Hacker [http://www.pulseaudio.org/]
  Trac Hacker [http://trac.edgewall.org/]