我正在开发一个 iPhone 应用程序。在那里,需要暂停和恢复相机。所以我用AVFoundation
它而不是使用UIImagePickerController
.
我的代码是:
- (void) startup :(BOOL)isFrontCamera
{
if (_session == nil)
{
NSLog(@"Starting up server");
self.isCapturing = NO;
self.isPaused = NO;
_currentFile = 0;
_discont = NO;
// create capture device with video input
_session = [[AVCaptureSession alloc] init];
AVCaptureDevice *cameraDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if(isFrontCamera)
{
NSArray *videoDevices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
AVCaptureDevice *captureDevice = nil;
for (AVCaptureDevice *device in videoDevices)
{
if (device.position == AVCaptureDevicePositionFront)
{
captureDevice = device;
break;
}
}
cameraDevice = captureDevice;
}
cameraDevice=[AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
AVCaptureDeviceInput* input = [AVCaptureDeviceInput deviceInputWithDevice:cameraDevice error:nil];
[_session addInput:input];
// audio input from default mic
AVCaptureDevice* mic = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
AVCaptureDeviceInput* micinput = [AVCaptureDeviceInput deviceInputWithDevice:mic error:nil];
[_session addInput:micinput];
// create an output for YUV output with self as delegate
_captureQueue = dispatch_queue_create("uk.co.gdcl.cameraengine.capture", DISPATCH_QUEUE_SERIAL);
AVCaptureVideoDataOutput* videoout = [[AVCaptureVideoDataOutput alloc] init];
[videoout setSampleBufferDelegate:self queue:_captureQueue];
NSDictionary* setcapSettings = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange], kCVPixelBufferPixelFormatTypeKey,
nil];
videoout.videoSettings = setcapSettings;
[_session addOutput:videoout];
_videoConnection = [videoout connectionWithMediaType:AVMediaTypeVideo];
[_videoConnection setVideoOrientation:AVCaptureVideoOrientationPortrait];
NSDictionary* actual = videoout.videoSettings;
_cy = [[actual objectForKey:@"Width"] integerValue];
_cx = [[actual objectForKey:@"Height"] integerValue];
AVCaptureAudioDataOutput* audioout = [[AVCaptureAudioDataOutput alloc] init];
[audioout setSampleBufferDelegate:self queue:_captureQueue];
[_session addOutput:audioout];
_audioConnection = [audioout connectionWithMediaType:AVMediaTypeAudio];
[_session startRunning];
_preview = [AVCaptureVideoPreviewLayer layerWithSession:_session];
_preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
}
}
当我将相机更改为前置时,我遇到了这个问题。当我通过将相机更改为前置来调用上述方法时,预览层被卡住并且没有预览。我的疑问是“我们可以在捕获会话中间更改捕获设备吗?”。请指导我哪里出错(或)建议我提供有关如何在录制时在前后摄像头之间导航的解决方案。
提前致谢。