Almost <i>nobody</i> builds Chromium without trivially linking in ffmpeg.<p>In the real world, Chromium supports <i>every</i> damn codec and container format. All of them. Safari has identical support with Perian installed, and Opera does too with gst-ffmpeg.<p>The official Chrome supports Theora, Vorbis, H.264, AAC, MP3, and WAV in all reasonable container formats. Mozilla only supports Theora and Vorbis in ogm containers, plus WAV/RIFF for &#60;audio&#62;.