Bundling codecs with browsers is akin to bundling fonts with browsers. For type, the pragmatic, effective approach is enhancing the APIs to OS and Web accessible fonts via CSS @font-face, enabling the potential of rich typography on the Web.
Open the API and the OS system and browser plug-in developers will compete to fill the codec implementation opportunities. Meanwhile publishers presentation code is unaffected; Publishers may add media encodings as the market innovates and ultimately self-corrects.
FWIW, Songbird has done a lot of heavy lifting to bring the LGPL’d GStreamer framework + wrappers for Windows Media and Quicktime media cores to the Mozilla stack. =)