[theora-dev] Theora on iPhone

Steven Woolley woobert at gmail.com
Tue Oct 7 10:56:50 PDT 2008

I posted a while back "complaining" about lack of a theora player on the
iPhone.  Porting the code for libtheora (and libogg/libvorbis) was
(relatively) painless, and appears to be working.  I'm up against a tougher
challenge now... rendering the video!
I tried using the brand-new SOC-funded SDL port to iphone to get the
"player_example.c" code up and running, but ran into a major roadblock:

The SDL port to iphone uses an opengl-es driver and opengl drivers for SDL
don't support YUV overlay's!  So the problem (at least for now) is how I can
get the YUV encoded frames from a theora movie rendered on the iPhone?

The options I've considered are:
a) convert from YUV to RGB in code (this probably won't work for realtime
b) convert from YUV to RGB using pixel shading (If it sounds like I don't
know what I'm talking about, that's correct... I've simply seen smarter
people talk about doing the conversion on the GPU using pixel shading???)
c) convert the frames to still images in a format that the iphone can
display natively (doesn't jpeg use the same YUV encoding that theora does?)
and render them as a series of images (I have no clue if this is feasible or
not, or if the conversion/decoding would be worse than just doing a or b
d) something else?
e) give up!

So any feedback would be great!
On a positive note, the iphone sdk's NDA should be lifted very soon..
On a negative note, the guy that ported vlc to iphone (google vlc4iphone)
hasn't released any of the source... so I can't even cheat to see how he's
doing it... and asking him directly hasn't worked.
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