IOS 捕获 12 MP 视频（IPhone 6 秒）产生 1000x750

Question

根据https://forums.developer.apple.com/thread/21694

Both iPhone 6s and 6s Plus can capture 12 megapixel photos (4032x3024) on the rear-facing camera via the AVCaptureStillImageOutput, and can deliver up to 30 fps 12 MP frames to your process via AVCaptureVideoDataOutput. When you use AVCaptureSessionPresetPhoto as your AVCaptureSession’s -sessionPreset, the 12 megapixel ‘420f’ format is chosen by default.

所以我尝试使用以下代码来实现：

self.captureSession.sessionPreset = AVCaptureSessionPresetPhoto;
AVCaptureVideoDataOutput*   videoOutput = [[AVCaptureVideoDataOutput alloc] init];
videoOutput.alwaysDiscardsLateVideoFrames = YES;
[videoOutput setSampleBufferDelegate:self queue:dispatch];
[self.captureSession addOutput:videoOutput];

我的设备的活动格式设置为：

device format: AVCaptureDeviceFormat: 0x12c684630 'vide'/'420f' 4032x3024, { 3- 30 fps}, fov:57.716, max zoom:189.00 (upscales @1.00), AF System:2, ISO:23.0-1840.0, SS:0.000013-0.333333

看起来不错。

但是，我在 captureOutput 回调中添加了以下代码：

CVPixelBufferLockBaseAddress(imageBufferRef,0);
size_t width = CVPixelBufferGetWidth(imageBufferRef);
size_t height = CVPixelBufferGetHeight(imageBufferRef);
CVPixelBufferUnlockBaseAddress(imageBufferRef,0);
NSLog(@"ImageCameraSource:\n   width:%zu\n   height:%zu\n", width, height);

它输出

ImageCameraSource: width:1000 height:750

为什么回调中的分辨率不是 4032x3024？

Answer 1

尝试使用AVCaptureSessionPreset3840x2160实时获取最高分辨率帧

self.captureSession.sessionPreset = AVCaptureSessionPreset3840x2160;
AVCaptureVideoDataOutput*   videoOutput = [[AVCaptureVideoDataOutput alloc] init];
videoOutput.alwaysDiscardsLateVideoFrames = YES;
[videoOutput setSampleBufferDelegate:self queue:dispatch];
[self.captureSession addOutput:videoOutput];