Bug#665732: reopen: vlc: GUI latency/unresponsiveness to clicks on control options

[Dirk Griesbach]

reopen 665732
Package: vlc
Version: 2.0.1-4+b2

I reopened the bug because it's not just about a minimal latency or a
long standing behavior. Under certain circumstances, the delay is in the
range of 10th of seconds and this definitely wasn't the case with pre
2.0 vlc. I found a report[1] in the vlc forum which sounds like the same
problem so we should try to find the culprit.

My observation so far:

* I absolutely can not recognize any delay with ogg audio files.
* volume change while playing wav or mp3 introduces a variable delay of
  multiple seconds - I even had the 30 second experience like in the
  linked forum thread.
* This is not only related to the volume change but the whole GUI is
  stalled. No reaction on menu or button press actions.
* With some other cpu load, the delay will vanish (or at least be
  minimized). E.g. playing another file in one instance and playing the
  delaying mp3 in another instance (no dbus invoked); or simple do a
  `cat /dev/zero > /dev/null`
* If the system is idling again (apart from playing mp3), the delay is
  back again, too.
* Doing some click-e-di-click on the desktop while waiting for the GUI and
  sound to respond causes the GUI to react and the volume to change.
* No remarkable delay with the vlc web interface
* and last but not least: Pause the song, change volume, resume playing.
  No delay except for the pause-play part. ;-)

For me it looks like some event/timer stuff isn't working as it should
be and maybe it's just only the Qt-interface?

Regards,
Dirk

[1] http://forum.videolan.org/viewtopic.php?f=13&t=98180&p=327950#p327950

-- System Information:
Debian Release: wheezy/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: i386 (i686)

Kernel: Linux 3.2.0-2-686-pae (SMP w/2 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages vlc depends on:
ii  libaa1                    1.4p5-39
ii  libavcodec53              6:0.8.2-1
ii  libavutil51               6:0.8.2-1
ii  libc6                     2.13-32
ii  libfreetype6              2.4.9-1
ii  libfribidi0               0.19.2-3
ii  libgcc1                   1:4.7.0-8
ii  libgl1-mesa-glx [libgl1]  8.0.2-2
ii  libice6                   2:1.0.8-2
ii  libqtcore4                4:4.8.1-1
ii  libqtgui4                 4:4.8.1-1
ii  libsdl-image1.2           1.2.12-2
ii  libsdl1.2debian           1.2.15-3
ii  libsm6                    2:1.2.1-2
ii  libstdc++6                4.7.0-8
ii  libtar0                   1.2.11-8
ii  libva-x11-1               1.0.15-4
ii  libva1                    1.0.15-4
ii  libvlccore5               2.0.1-4+b2
ii  libx11-6                  2:1.4.99.901-2
ii  libxcb-composite0         1.8.1-1
ii  libxcb-keysyms1           0.3.8-1
ii  libxcb-randr0             1.8.1-1
ii  libxcb-render0            1.8.1-1
ii  libxcb-shape0             1.8.1-1
ii  libxcb-shm0               1.8.1-1
ii  libxcb-xfixes0            1.8.1-1
ii  libxcb-xv0                1.8.1-1
ii  libxcb1                   1.8.1-1
ii  libxext6                  2:1.3.1-2
ii  libxinerama1              2:1.1.2-1
ii  libxpm4                   1:3.5.10-1
ii  ttf-freefont              20100919-1
ii  vlc-nox                   2.0.1-4+b2
ii  zlib1g                    1:1.2.7.dfsg-1

Versions of packages vlc recommends:
ii  vlc-plugin-notify  <none>
ii  vlc-plugin-pulse   <none>
ii  xdg-utils          1.1.0~rc1+git20111210-6

Versions of packages vlc suggests:
pn  videolan-doc  <none>

-- no debconf information