I have audio but no video in Movie Player and VLC Player. It fails for .flv, .mp4, and .VOB files. Avidemux works for .VOB; didn't try it for the others.
I believe the problem was caused by a poorly conceived update attempt. Faced with a broken Pitivi that I needed to fix, I figured I would update it from the PPA. (I have Oneiric, which does not have the latest version.)
I executed the following command, which I got from http://www.pitivi.org/?go=download :
sudo add-apt-repository ppa:gstreamer-developers/ppa && sudo apt-get update
Here's the relevant excerpt from /var/log/apt/history.log:
Commandline: aptdaemon role='role-commit-packages' sender=':1.68'
Install: libspandsp2:i386 (0.0.6~pre18-2)
Upgrade: gstreamer0.10-alsa:i386 (0.10.36-1~natty2, 0.10.36-1~oneiric1), libpurple0:i386 (2.10.0-0ubuntu2.1, 2.10.0-0ubuntu2.2), gstreamer0.10-x:i386 (0.10.36-1~natty2, 0.10.36-1~oneiric1), gstreamer0.10-plugins-base-doc:i386 (0.10.35-1, 0.10.36-1~oneiric1), libgstreamer0.10-0:i386 (0.10.36-1~natty1, 0.10.36-1~oneiric1), gstreamer0.10-plugins-ugly:i386 (0.10.19-1~natty2, 0.10.19-1~oneiric1), gir1.2-gstreamer-0.10:i386 (0.10.36-1~natty1, 0.10.36-1~oneiric1), gstreamer0.10-gconf:i386 (0.10.31-1~natty2, 0.10.31-1~oneiric1), pidgin-data:i386 (2.10.0-0ubuntu2.1, 2.10.0-0ubuntu2.2), gstreamer0.10-plugins-good:i386 (0.10.31-1~natty2, 0.10.31-1~oneiric1), gstreamer0.10-plugins-good-doc:i386 (0.10.30-1ubuntu7.1, 0.10.31-1~oneiric1), gstreamer0.10-pulseaudio:i386 (0.10.31-1~natty2, 0.10.31-1~oneiric1), gstreamer0.10-plugins-bad:i386 (0.10.23-1~natty3, 0.10.23-1~oneiric1), libgstreamer-plugins-bad0.10-0:i386 (0.10.23-1~natty3, 0.10.23-1~oneiric1), gstreamer0.10-doc:i386 (0.10.35-1, 0.10.36-1~oneiric1), libpurple-bin:i386 (2.10.0-0ubuntu2.1, 2.10.0-0ubuntu2.2), pidgin:i386 (2.10.0-0ubuntu2.1, 2.10.0-0ubuntu2.2), gstreamer0.10-plugins-base-apps:i386 (0.10.36-1~natty2, 0.10.36-1~oneiric1), gstreamer0.10-gnomevfs:i386 (0.10.36-1~natty2, 0.10.36-1~oneiric1), gstreamer0.10-plugins-base:i386 (0.10.36-1~natty2, 0.10.36-1~oneiric1), libgstreamer-plugins-base0.10-0:i386 (0.10.36-1~natty2, 0.10.36-1~oneiric1), transmission-common:i386 (2.33-0ubuntu2, 2.33-0ubuntu2.1), gstreamer0.10-tools:i386 (0.10.36-1~natty1, 0.10.36-1~oneiric1), transmission-gtk:i386 (2.33-0ubuntu2, 2.33-0ubuntu2.1)
This is a little mysterious. I have no idea why those natty packages are mentioned. The system was updated months ago from Natty, and it was fully up to date. I don't know how they could have been installed, if they were. What do I have to do to get this working? Ideas?