I've got a more formal draft of the format I described earlier up for review and consider it developed enough that it's ready for comment: http://wiki.xiph.org/index.php/OggYUV#John.27s_Draft I feel that it addresses the comments received to date, and more importantly can describe some formats in common use that the OggYUV does not, without (hopefully) being over generalized. My intention is to have mencoder/mplayer support at least one image type in this format next week. Comments and criticisms welcome. John