Bug#560762: Downgraded libavcodec52, libavformat52, libavutil50 to 11/01 versions

[Dominique Brazziel]

SUCCESS!  Note:  The 11/01 debs were on the backup machine
(in '/var/cache/apt/archives') which hadn't been updated in
awhile, and used the test machine to fetch upgrades via apt-cacher.
I copied the debs over to the test machine then apt-cacher-imported
them after purging the libav* packages from 11/29.  Using
'aptitude' to install the three packages went fetched and 
installed the latest (11/29) versions, so I had to purge again 
and install the debs with 'dpkg'.

Question:  How did you know that libavcodec52, et. al. were
at fault?  Did you deduce anything from the trace, or did
something else give you a clue?  From the trace I saw a lot
of waiting on FUTEX, but had no idea which component was doing
that.