This issue looks similar to bug 1201865 - Upstart is being spammed by the upstart-udev-bridge which itself is being spammed by all the SUBSYSTEM=platform udev events from the kernel.
I cannot recreate the issue you are seeing on my nexus 7, so that coupled with the fact that the event are udev-related suggests a kernel bug.
Please could you create the system job below, play your mp4 and see what's in /var/log/upstart/bug-1234743.log
$ cat <<EOT | sudo tee /etc/init/bug-1234743.conf
start on platform-device-changed
exec env
EOT
Hi Colin,
This issue looks similar to bug 1201865 - Upstart is being spammed by the upstart-udev-bridge which itself is being spammed by all the SUBSYSTEM=platform udev events from the kernel.
I cannot recreate the issue you are seeing on my nexus 7, so that coupled with the fact that the event are udev-related suggests a kernel bug.
Please could you create the system job below, play your mp4 and see what's in /var/log/upstart/bug-1234743.log
$ cat <<EOT | sudo tee /etc/init/bug-1234743.conf device- changed
start on platform-
exec env
EOT