Actually, using ffmpeg's libavformat and linking it with Classilla could do some very interesting things... for a start, HTML 5 has ogg format as its native embeddable media format, and IIRC ffmpeg can decode Theora and Vorbis using libavformat
You know, if they got on that they might actually beat Firefox/Seamonkey to the punch! Oh man that would be a victory for 68k Macs everywhere - "Our dedicated geeks beat your pansy programmers at supporting the very latest web specs!" :cc: