AVCaptureVideoDataOutput 和设置 kCVPixelBufferWidthKey & kCVPixelBufferHeightKey

我正在尝试捕获特定尺寸的帧AVCaptureVideoDataOutput通过设置kCVPixelBufferWidthKey & kCVPixelBufferHeightKey.
问题是缓冲区的宽度和高度永远不会改变，它们总是会回来852x640

这是我的代码：

// Add the video frame output   
    self.videoOutput = [[AVCaptureVideoDataOutput alloc] init];
    [videoOutput setAlwaysDiscardsLateVideoFrames:YES];
// Use RGB frames instead of YUV to ease color processing
[videoOutput setVideoSettings:[NSDictionary dictionaryWithObjectsAndKeys:
                               [NSNumber numberWithFloat:320.0], (id)kCVPixelBufferWidthKey,
                               [NSNumber numberWithFloat:320.0], (id)kCVPixelBufferHeightKey,
                               [NSNumber numberWithInt:kCVPixelFormatType_32BGRA],(id)kCVPixelBufferPixelFormatTypeKey,
                                                              nil]];
 [videoOutput setSampleBufferDelegate:self queue:dispatch_get_main_queue()];   

编辑：来自 iOS AVCaptureOutput.h：目前，唯一支持的键是 kCVPixelBufferPixelFormatTypeKey。

有人知道设置输出缓冲区宽度/高度的工作方法吗？

来自 iOS AVCaptureOutput.h：Currently, the only supported key is kCVPixelBufferPixelFormatTypeKey.

总结如下。