控制 iphone錄影 品質







在AVCaptureSession  Class裡面， 可以sessionPreset進行設定 改變錄影品質




sessionPreset

A constant value indicating the quality level or bitrate of the output.

@property(nonatomic, copy) NSString *sessionPreset

Discussion

You use this property to customize the quality level or bitrate of the output. For possible values ofsessionPreset, see “Video Input Presets.” The default value is AVCaptureSessionPresetHigh.

You can set this value while the session is running.

You can only set a preset if canSetSessionPreset: returns YES for that preset.

Availability

• Available in iOS 4.0 and later.

Declared In

AVCaptureSession.h




http://developer.apple.com/library/ios/#DOCUMENTATION/AVFoundation/Reference/AVCaptureSession_Class/Reference/Reference.html#//apple_ref/doc/c_ref/AVCaptureSessionPreset640x480Video Input Presets

Constants to define capture setting presets using the sessionPreset property.




AVCaptureSessionPresetLow

Specifies capture settings suitable for output video and audio bitrates suitable for sharing over 3G.

Available in iOS 4.0 and later.

Declared in AVCaptureSession.h.

AVCaptureSessionPreset640x480

Specifies capture settings suitable for VGA quality (640x480 pixel) video output.

Available in iOS 4.0 and later.

Declared in AVCaptureSession.h.

AVCaptureSessionPreset1280x720

Specifies capture settings suitable for 720p quality (1280x720pixel) video output.

Available in iOS 4.0 and later.

Declared in AVCaptureSession.h.