MediaInfo class
===============

It might be nice to have a class that gives information about MediaSource
objects without having to use MediaObject for it. Something like QFileInfo for
QFile. MediaObject could also return a list of MediaInfo objects for all the
MediaSource objects in the queue.

Rationale: The app then can get info about length and substreams so that it can
set up everything correctly for the next "file" in the queue.


- on hotplug of a USB audio/video device:
  1. If the device is plugged in for the first time
    Check whether the backend now provides new device selections. If yes, open
    up central config with the page that allows selection of the default
    devices. Tell the user what new options are available.
    Allow the user to set preference of devices: If device USB-Headset is
    available use that, else use builtin speakers.

 device info persistence
=========================
On device selections: should the user be presented with options that are
currently not available? It might actually be confusing to select a device that
is not usable at the moment.

Some situations:
(device A is always available)
- user plugs device B
- selects device B as default
next day: device B unplugged
- phonon falls back to device A as B is not available and shows a passive popup
  informing the user about the fallback
- user opens config dialog
- device B still shows up as default
- selects device A, closes dialog
- opens dialog again
- device B is gone...
- user plugs device B
- device B reappears

The Backend has to provide the information about devices. Those can map directly
to hardware or a soundserver or some other virtual device. The Backend has to
have some unique identifier. For example the ALSA devices could be identified
using the ALSA device names (either hw:0, hw:1 or aliases from asoundrc). OSS
devices could be identified using /dev/dsp, /dev/dsp1 and so on.
=> the backend internal uid is a string
In the Frontend all that is needed is a name and a description of the device
(both translated to the current locale) and a unique identifier to talk to the
backend. This identifier could be the same as used internally by the Backend,
but doesn't have to be.

 "lowlevel" audio I/O
======================
ByteStream is a buffered stream, and as therefore completely useless for cases
where an application wants to write audio data to the soundcard/-system with low
latency.
=> PcmInStream and PcmOutStream


============================================================================
= Ideas for "useless but nice" things (until somebody can convince me that =
= they're useful)                                                          =
============================================================================

 Video Output
==============
Add another VideoOutput that can be used directly with QGraphicsView by creating
a QGraphicsItem subclass.