Comment 12 for bug 751114

 ormat52 libpostproc51 libswscale0
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
  ffmpeg: Depends: libavcodec52 (>= 4:0.5.1-1ubuntu1.1) but it is not going to be installed or
                   libavcodec-extra-52 (>= 4:0.5.1-1ubuntu1.1) but 4:0.5.1-1ubuntu1+medibuntu1 is to be installed
          Depends: libavutil49 (>= 4:0.5.1-1ubuntu1.1) but it is not going to be installed or
                   libavutil-extra-49 (>= 4:0.5.1-1ubuntu1.1) but 4:0.5.1-1ubuntu1+medibuntu1 is to be installed
  libavdevice52: Depends: libavcodec52 (>= 4:0.5.1-1ubuntu1.1) but it is not going to be installed or
                          libavcodec-extra-52 (>= 4:0.5.1-1ubuntu1.1) but 4:0.5.1-1ubuntu1+medibuntu1 is to be installed
                 Depends: libavutil49 (>= 4:0.5.1-1ubuntu1.1) but it is not going to be installed or
                          libavutil-extra-49 (>= 4:0.5.1-1ubuntu1.1) but 4:0.5.1-1ubuntu1+medibuntu1 is to be installed
  libavfilter0: Depends: libavcodec52 (>= 4:0.5.1-1ubuntu1.1) but it is not going to be installed or
                         libavcodec-extra-52 (>= 4:0.5.1-1ubuntu1.1) but 4:0.5.1-1ubuntu1+medibuntu1 is to be installed
                Depends: libavutil49 (>= 4:0.5.1-1ubuntu1.1) but it is not going to be installed or
                         libavutil-extra-49 (>= 4:0.5.1-1ubuntu1.1) but 4:0.5.1-1ubuntu1+medibuntu1 is to be installed
  libavformat52: Depends: libavcodec52 (>= 4:0.5.1-1ubuntu1.1) but it is not going to be installed or
                          libavcodec-extra-52 (>= 4:0.5.1-1ubuntu1.1) but 4:0.5.1-1ubuntu1+medibuntu1 is to be installed
                 Depends: libavutil49 (>= 4:0.5.1-1ubuntu1.1) but it is not going to be installed or
                          libavutil-extra-49 (>= 4:0.5.1-1ubuntu1.1) but 4:0.5.1-1ubuntu1+medibuntu1 is to be installed
  libpostproc51: Depends: libavutil49 (>= 4:0.5.1-1ubuntu1.1) but it is not going to be installed or
                          libavutil-extra-49 (>= 4:0.5.1-1ubuntu1.1) but 4:0.5.1-1ubuntu1+medibuntu1 is to be installed
  libswscale0: Depends: libavutil49 (>= 4:0.5.1-1ubuntu1.1) but it is not going to be installed or
                        libavutil-extra-49 (>= 4:0.5.1-1ubuntu1.1) but 4:0.5.1-1ubuntu1+medibuntu1 is to be installed
E: Broken packages

I would think that various AV dependency trees may be messed up completely, and would prevent us from updating these packages.