在此处使用本教程:http://www.musicalgeometry.com/?p=1297我已经使用 AVCaptureSession
创建了自定义叠加层和图像捕获。
我试图让用户在前置和后置摄像头之间切换。这是我在 CaptureSessionManager
中切换摄像头的代码:
- (void)addVideoInputFrontCamera:(BOOL)front {
NSArray *devices = [AVCaptureDevice devices];
AVCaptureDevice *frontCamera;
AVCaptureDevice *backCamera;
for (AVCaptureDevice *device in devices) {
//NSLog(@"Device name: %@", [device localizedName]);
if ([device hasMediaType:AVMediaTypeVideo]) {
if ([device position] == AVCaptureDevicePositionBack) {
//NSLog(@"Device position : back");
backCamera = device;
}
else {
//NSLog(@"Device position : front");
frontCamera = device;
}
}
}
NSError *error = nil;
if (front) {
AVCaptureDeviceInput *frontFacingCameraDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:frontCamera error:&error];
if (!error) {
if ([[self captureSession] canAddInput:frontFacingCameraDeviceInput]) {
[[self captureSession] addInput:frontFacingCameraDeviceInput];
} else {
NSLog(@"Couldn't add front facing video input");
}
}
} else {
AVCaptureDeviceInput *backFacingCameraDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:backCamera error:&error];
if (!error) {
if ([[self captureSession] canAddInput:backFacingCameraDeviceInput]) {
[[self captureSession] addInput:backFacingCameraDeviceInput];
} else {
NSLog(@"Couldn't add back facing video input");
}
}
}
}
现在在我的自定义覆盖 Controller 中,我在 viewDidLoad
中初始化所有内容:
[self setCaptureManager:[[CaptureSessionManager alloc] init]];
[[self captureManager] addVideoInputFrontCamera:NO]; // set to YES for Front Camera, No for Back camera
[[self captureManager] addStillImageOutput];
[[self captureManager] addVideoPreviewLayer];
CGRect layerRect = [[[self view] layer] bounds];
[[[self captureManager] previewLayer] setBounds:layerRect];
[[[self captureManager] previewLayer] setPosition:CGPointMake(CGRectGetMidX(layerRect),CGRectGetMidY(layerRect))];
[[[self view] layer] addSublayer:[[self captureManager] previewLayer]];
[[_captureManager captureSession] startRunning];
切换相机按钮连接到名为 switchCamera
的方法。我试过这个:
- (void)switchCameraView:(id)sender {
[[self captureManager] addVideoInputFrontCamera:YES]; // set to YES for Front Camera, No for Back camera
}
调用它时,我从 CaptureSessionManager
收到错误 NSLog
并且我无法弄清楚原因。在viewDidLoad
中,如果我将fontCamera
设置为YES
,它会显示前置摄像头但不能切换到后置,反之亦然。
关于如何让它正确切换的任何想法?
最佳答案
您首先需要从 AVCaptureSession 中删除现有的 AVCameraInput,然后将新的 AVCameraInput 添加到 AVCaptureSession。以下对我有用(在 ARC 下):
-(IBAction)switchCameraTapped:(id)sender
{
//Change camera source
if(_captureSession)
{
//Indicate that some changes will be made to the session
[_captureSession beginConfiguration];
//Remove existing input
AVCaptureInput* currentCameraInput = [_captureSession.inputs objectAtIndex:0];
[_captureSession removeInput:currentCameraInput];
//Get new input
AVCaptureDevice *newCamera = nil;
if(((AVCaptureDeviceInput*)currentCameraInput).device.position == AVCaptureDevicePositionBack)
{
newCamera = [self cameraWithPosition:AVCaptureDevicePositionFront];
}
else
{
newCamera = [self cameraWithPosition:AVCaptureDevicePositionBack];
}
//Add input to session
NSError *err = nil;
AVCaptureDeviceInput *newVideoInput = [[AVCaptureDeviceInput alloc] initWithDevice:newCamera error:&err];
if(!newVideoInput || err)
{
NSLog(@"Error creating capture device input: %@", err.localizedDescription);
}
else
{
[_captureSession addInput:newVideoInput];
}
//Commit all the configuration changes at once
[_captureSession commitConfiguration];
}
}
// Find a camera with the specified AVCaptureDevicePosition, returning nil if one is not found
- (AVCaptureDevice *) cameraWithPosition:(AVCaptureDevicePosition) position
{
NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
for (AVCaptureDevice *device in devices)
{
if ([device position] == position) return device;
}
return nil;
}
关于ios - 使用 avcapturesession 切换摄像头,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/20864372/