I guess a lot of people that have to deal with integrating videos on a website for iPhone and iPad, will  - at some point - run into the problem that some videos simply won't play. In most cases embedding the video is the simple part: either we use the fantastic HTML5 specifcation or use some weird snippet for loading a Flash Video Player. But I don't want to look at that in this post, I want to dig a little deeper into the encoding problematics. But this is not about dealing with whether to use OGG Theora, VP8 or h264, or how to use them all at once. In this case I stumbled upon an iOS specific problem. So h264 would be the codec to look at, as this is the favourite on Apple devices.