问题
As you may know Samsung Galaxy s4 has the capability to capture both front and back cameras at the same time. Now I need to capture both of them in my application. Should I download something?
I tried to open both of them but It wasn't successful! I'm using API level 17.
回答1:
As far as I know, this is the only phone which supports both the cameras working. This being said, your application may be applicable to this phone only by far.
Unfortunatelly I don't know of any API which is released so far that can work the things out and believe me I turned the Internet upside down. Samsung claims that on the S4 you can capture videos from both the cameras at the same time, but they never explained (or at least I didn't see it) what this "same time" means. This could be something in the hardware, which is controlled only by the Samsung's application or it can be achieved only by software, which is controlled by the same application - who knows.
I've read a lot of posts of how those two cameras can be put to work together on the other phones (by switching the cameras on an interval, but those are expensive operations and this will probably not work). Other thing I can think of (which I didn't see anywhere as a suggestion) is to start both cameras in separate processes (with or without using the AsyncTask class) and put them to work at the same time practically, but I didn't test such a solution (you can try this one if you like, I'm interested in the result actually).
To sum the things up: So far - no luck with Galaxy S4 API, but maybe there are going to be some leaks of the technology and/or a way of achieving this.
来源：https://stackoverflow.com/questions/17061045/how-to-capture-both-front-and-back-cameras-in-galaxy-s4-simultaneously