Comment 14 for bug 452059

No, behaviour in Lucid is completely different.
When you add the files, Brasero gives an error prompt for each file in the list, then prompts for missing codecs, providing a list of downloadable ones, gstreamer0.10-ffmpeg, gstreamer0.10-fluendo-mp3, gstreamer0.10-plugins-ugly; (no crashes)

case 1: you accept to download the files.
           - Brasero downloads the codecs and dependencies, and terminates saying that the downloaded plugins are not enough to proceed.
           - Start another project, add files, and everything works.

case 2: you refuse to download the files.
            - You're stuck (of course)!
            - Start another project, add files, and Brasero won't ask you again to download the codecs, and you're stuck again.
            - If you close Brasero and then open it, it will correctly prompt for codecs again.

In general, if you should later uninstall one or more of the needed packages, eg. gstreamer0.10-plugins-ugly, Brasero won't anymore realize that it's missing, and it will never prompt for codecs again, returning the error prompt for each file in list.