14.04 w/Brasero asking for GStreamer mplex

I've recently upgraded to Ubuntu 14.04 (64-bit).
I'm trying to burn a multi-file DVD readable by a TV/DVD. I can start Brasero, import the files, and hit <Burn...>, and then receive two pop-up windows:
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Installing packages by files isn't supported
This method hasn't yet been implemented.
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All required applications and libraries are not installed.
Please install the follwing manually and try again:
mplex(GStreamer plugin)
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I have installed all the Gstreamer options Ubuntu Software Center will display, as well as uninstalling and reinstalling Brasero and checking that Ubuntu Restricted Extras was installed. I also added mjpegtools.

That did not fix the problem. So I went to Terminal and did sudo apt-get refreshes, updates, installs, cleans, fixes, etc of all packages, including these specificaly. (Although apt-get does not find a gstreamer or a GStreamer package.)

Am I beating a dead horse here? Is Brasero on 14.04 dead at last?