What are the key differences between Android, iOS and Blackberry OS in terms of level of accessibility by application developers (i.e. access to the video input, sound input, phone functionalities, to which extent, etc.)?
PS: Assume latest version of each OS.
EDIT: Can someone turn this into a wiki so we can compile answers from people that don”t necessarily have experience in all 3 plaforms.
I’m not familiar with BlackBerry, but on Android and iOS you can access just about anything. Until recently iOS had some restrictions about camera access (see this), but I belive those have been solved. Because Android is open-source, you can theoretically go as deep as you want as far as accessing the hardware, but you may or may not be able to get any deeper through the standard Android API than you can through the iOS API.
On Android, you can do a lot more to override default functionality. For example, you can create your own launcher screen or phone application. The iOS approval process wouldn’t allow these kinds of applications.
API hardware access really isn’t an issue on either platform, the bigger concern is overriding default software (almost never possible in iOS) and what types of applications iOS allows.