Description of problem:

If you attempt to burn a video disc project in brasero, you get an obscure error message.

Version-Release number of selected component (if applicable):
3.4.1-1.el.7

How reproducible:
100%

Steps to Reproduce:
1. Run brasero
2. Click the "Video Project / Create a video DVD or an SVCD" button.
3. Click the "+" button
4. In the file browser, select a video file.  I've been using /usr/share/gnome/help/evince/C/figures/synctex_screencast.ogv, but I get similar results with other files.
5. Project -> Burn...
  
Actual results:
"All required applications and libraries are not installed.

Please install the following manually and try again:
mplex (GStreamer plugin)
ffenc_mp2 (GStreamer plugin)
ffenc_ac3 (GStreamer plugin)
ffenc_mpeg2video (GStreamer plugin)
vcdimager (application)."

Expected results:
Good question; I was quite skeptical about whether it would work.  Perhaps the real question is how exactly it could be failing better.  The error message was probably written for end-users with the technical expertise to find "bad" apps and GStreamer plugins but I'm not sure it's a great idea for us to offer our users that advice, at the very least because it's not terribly user-friendly advice.  Might it be better to present a different error message? Dim and disable the Burn... option iff it's not supported?  Are there third-party vendors from whom users could buy codecs, in which case we could direct them to those vendors? 

Additional info:
Google suggests that Ubuntu users had similar problems.