[mythtv] Possible playback scenarios for the iPhone

Keith Cremer mythtv at keithandjill.com
Sat Jul 19 00:08:54 UTC 2008

On Jul 18, 2008, at 5:58 PM, Chase Douglas wrote:

> I am interested in developing a frontend for the iPhone with live tv
> playback, but there are two hurdles along the way:
> 1. Content is encoded in the format coming from the tuner device, and
> as far as I am aware, no tuning device outputs an iPhone compatible
> format
> 2. The iPhone SDK (I'm trying to keep this under Apple's terms as
> well) has no streaming video support. At best, it can take a static
> file and stream that from a URL, but there's no support for streaming
> mutable content like an rtsp:// stream. A further complication is
> Apple's insistence that developers cannot access the framebuffer.
> The first issue could be remedied through live transcoding before
> streaming to the device. This isn't implemented yet, but is possible.
> The second issue is a much higher hurdle. Without the ability to play
> streaming content within the SDK, the only way this could work is
> through software decoding and playback through either a quartz
> graphics layer or an opengl layer. I've never written any rendering
> software but I know it's possible. My question is: would the iPhone be
> powerful enough for a reasonably encoded stream to be played back? By
> reasonable, I'm thinking standard mpeg-2 or the mpeg-4 encoding, but
> keeping in mind that I'll have no access to the hardware acceleration
> already present on the iPhone.

I would assume your best bet would be on the fly transcoding by the  
backend into something the iPhone likes.  Like h.264.  I think you can  
use hardware acceleration for that in the SDK, but I'm not 100% sure.   
If not, you should look at the BBC iPlayer and how they got video  
working :

Keith C

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