It seems like it's pretty easy to consume HTTP Live Streaming content in an iOS app. Unfortunately, I need to consume media from an RTSP server. It seems to me that this is a very similar thing, and that all of the underpinnings for doing it ought to be present in iOS, but I'm having a devil of a time figuring out how to make it work without doing a lot of programming.
For starters, I know that there are web-based services that can consume an RTSP stream and rebroadcast it as an HTTP Live Stream that can be easily consumed by the media players in iOS. This won't work for me because my application needs to function in an environment where there is no internet access (it's on a private Wifi network where the only other thing on the network is the device that is serving the RTSP stream).
Having read everything I can get my hands on and exploring third-party and open-source solutions, I've compiled the following list of ideas:
1. Using an iOS build of the open-source ffmpeg library, which supports RTSP, I've come up with a test app that can receive the RTSP packets, decode them, create UIImages out of the frames, and display those frames on-screen. This provides a crude player, but performance is poor, most likely because ffmpeg can't take advantage of any hardware acceleration. It also doesn't provide me with any way to integrate the video stream into AVFoundation, so I'm on my own as far as saving the stream to a file, transcoding it, etc.
2. I know that the AVURLAsset class doesn't directly support the RTSP scheme. Since I have access to the undecoded RTSP packets via ffmpeg, I've thought it should be possible to implement RTSP support myself via a custom NSURLProtocol, essentially fooling AVFoundation into reading those packets as if they originated in a file. I'm not sure if this would work, since the raw packets coming from the RTSP server might lack the headers that would otherwise be present in data being read from a file. I'm not even sure if AVFoundation would recognize my custom protocol.
3. If a protocol doesn't work, I've considered that I might be able to implement my own local HTTP Live Streaming server that converts the RTSP packets into an HTTP stream that the media players can read. This sounds like a terribly convoluted solution to the problem, at best, and very difficult at worst.
4. Going back to solution (1), if I could speed up the decoding by using some iOS CoreVideo function instead of ffmpeg, this solution might be okay. However, I can't find any documentation for CoreVideo on iOS (Apple only documents it for OS X).
5. I'm certainly willing to license a third-party solution if it works well and provides good performance. Unfortunately, everything I've found so far is pretty crummy and mostly just leverages ffmpeg and/or VLC. What is most disappointing to me is that nobody seems to be able or willing to provide a solution that neatly integrates with AVFoundation. I really want to make my RTSP stream available as an AVAsset so I can use it with AVFoundation players and other classes -- I don't want to build an app that relies on custom third-party code for everything.
Any ideas, tips, advice would be greatly appreciated.