This'll be the last, definitive article from me on this subject for a while, I promise, but I wrote such a good summary on the Theora/H.264 controversy and the new
Silverlight Theora player on
Slashdot that I must put it up here as well (with some tweaks and updates).
1) The main point of the Silverlight player is that you can now relatively easily deploy Web video in Theora without sacrificing much potential user base. Firefox and Chrome users are covered, and Opera will be, but especially Internet Explorer is an important holdout (Safari also lacks support, but see below).
1a) It might not yet come preinstalled with the Internet Explorer, at least all versions, but MS is actively pushing Silverlight on Windows users, so the installed base is already fairly large and growing.
1b) There is Silverlight for MacOS X as well, though it's being pushed less. Mac OS X does include Java support out of the box though so the pre-existing
Cortado player can be used as a fallback for Safari users there.
1c) One might not like the proprietary nature of the Silverlight framework much, but in this case it's clearly being used for good, to enable the use of another free technology.
2) No, H.264 won't die a gruesome death now at the hands of Theora.
2a) Yes yes, we all know H.264 is better technically, it doesn't matter, it still can't be a common baseline Web codec because it cannot be freely used.
2b) Though Theora doesn't offer the best in quality per bit, you can make the quality of any codec better by using more bits. Bits are only going to get cheaper. H.264 can get much more expensive at the whim of the MPEG-LA, even if you don't put a price tag on freedom.
2c) Yes, some industry players, especially those with vested interest in the MPEG-LA racket and in excluding smaller competitors, will almost certainly use H.264 on the web for a long time to come.
2d) Isn't it nice though that a widely deployable option exists that
probably has already played a hand in how much money the MPEG-LA can squeeze from you if you do decide to go with H.264 anyway?
3) H.264 isn't as unified as you might think.
3a) Much of the material on the web incidentally doesn't use the very advanced features of H.264, because many players are limited in what profile or subset of H.264 they support (thus also reducing the quality advantage to Theora).
3b) Some material (like HD offerings and pirated stuff that cares neither for copyrights or patents) will use more of the bells and whistles, but then you may well be stuck with having to transcode for your mobile player even if everything does "H.264".
3c) Such conversions can be relatively well automated when needed while keeping the original not to incur generation loss (though improvement in user-friendly tools is always called for). Some need for transcoding persisting thus isn't a huge deal in either case, except of course to the extent that working with H.264 without a license might be illegal depending on jurisdiction and circumstance.
4) Yep, not much "hardware" (DSP) decoding support for Theora at this point on mobile devices.
4a) Modern mobile devices have enough oomph to decode it anyway in small resolutions that usually suffice for mobile use (Theora is lighter than H.264, too). Depending on device, might not be able to sneak in a sufficiently performant player as transparently as on a desktop browser, though; may require user installation of software.
4b) Yes, battery life will probably suffer somewhat from having to decode on the CPU, but that doesn't make it useless.
4c) Some DSP work
has already been done on Theora, though it can use some improvement (and support for more DSPs). The user would probably have to install it separately in the short term as well.
4d) Mobile device vendors may well be inclined to include such support out of the box, though, if Theora use becomes more common through the already existing deployability improvements. Especially if they get a free web browser in the deal as well:
Fennec, Mozilla's mobile version of Firefox, [
update] has apparently been released at least on Nokia's Maemo platform. (In fact, Mozilla has sponsored the above Theora DSP work with Fennec and mobile devices in mind.)
Hope this summary will clarify things somewhat.