On average, the ffmpeg mirror is updated every 4-6 months.

This is too long. Unfortunately the task of updating the mirror is very painful (ffmpeg changes API/ABI, new codecs appear, build process changes, you have to do gst-media tests to make sure the new mirror doesn't introduce regressions, ...).

We should bring down the mirror update frequency to 2 months at maximum, with a gst-ffmpeg release before updating that mirror.

To do this, the ffmpeg mirror updating process should be detailed enough to explain all the various steps you have to do:
* How to get the mirror and use quilt with it (almost complete)
* How to do a pre-analysis of the differences with ffmpeg svn (make notes of what new plugins/formats/codecids/formatids are available, what files have appeared, what files have gone/moved, what has changed in the build system, ...)
* How to properly copy over the new sources to the mirror
* Which quilt patches to update depending on what has changed
* What to update in gst-ffmpeg depending on the changes seen during pre-analysis
* What changes to do in the quilt autoconf patches depending on the changes seen during pre-analysis
* How to test with gst-media-test
* Update the ffmpeg mirror updating process document steps explained above if something has changed