A few lines of code looks different，it seems the 4th generation iPhone will be able to record high definition (HD) videos. According to Macrumore, the preset values in iPhone OS 4 beta 3 SDK, the new OS version able to record videos at 1280×720 HD resolution instead of the 640×480 VGA resolution possible in iPhone 3GS.

AVCaptureSessionPreset640x480
AVCaptureSessionPreset1280x720

This will open the door to developers to create some new apps, and could be one of the reason why Apple might name its fourth generation iPhone - iPhone HD. Do you think this will be the killer features of the next-gen iPhone? When iPhone OS 4 and the new iPhone become available to the public we'll find out.