The YCbCr texture extension works now that bytes_per_pixel() returns the correct value for YUV textures. Yay! I'm still cheering for Ryan's pixel shader instead, since once it works different shaders can handle all the YUV formats.

/*
 *  jumphack.h
 *  SDLiPhoneOS
 *
 */

#ifndef _jumphack_h
#define _jumphack_h

#include "setjmp.h"

/* see SDL_uikitevents.m for more info */

extern jmp_buf *jump_env();

#endif