我是 iOS 和多媒体开发的新手,我正在尝试从 iPhone 的相机捕捉视频并将其显示在屏幕上,而不将其保存在内存中。
到目前为止,我在网上的示例代码的帮助下编写了以下代码:
头文件:
// ViewController.h
#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
@class AVCamCaptureManager, AVCamPreviewView, AVCaptureVideoPreviewLayer;
@interface ViewController : UIViewController <UIImagePickerControllerDelegate>
@property (weak, nonatomic) IBOutlet UIView *previewView;
- (IBAction)StartCapture:(id)sender;
- (void)setCaptureSession;
@end
实施文件
// ViewController.m
#import "ViewController.h"
@interface ViewController ()
@property (nonatomic, strong) AVCaptureSession *captureSession;
@property (nonatomic, strong) AVCaptureMovieFileOutput *captureOutput;
@property (nonatomic, weak) AVCaptureDeviceInput *activeVideoInput;
@property (nonatomic, strong) AVCaptureVideoPreviewLayer *previewLayer;
@end
@implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)StartCapture:(id)sender
{
if ([sender isSelected])
{
[sender setSelected:NO];
[self.captureOutput stopRecording];
}
else
{
[sender setSelected:YES];
if (!self.captureOutput)
{
self.captureOutput = [[AVCaptureMovieFileOutput alloc] init];
[self.captureSession addOutput:self.captureOutput];
}
[self.captureSession startRunning];
}
}
- (void)setCaptureSession
{
self.captureSession = [[AVCaptureSession alloc] init];
NSError *error;
// Set up hardware devices
AVCaptureDevice *videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if (videoDevice)
{
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:&error];
if (input)
{
[self.captureSession addInput:input];
self.activeVideoInput = input;
}
}
AVCaptureDevice *audioDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
if (audioDevice) {
AVCaptureDeviceInput *audioInput = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:&error];
if (audioInput) {
[self.captureSession addInput:audioInput];
}
}
// Start running session so preview is available
[self.captureSession startRunning];
// Set up preview layer
dispatch_async(dispatch_get_main_queue(), ^{
self.previewLayer = [AVCaptureVideoPreviewLayer layerWithSession:self.captureSession];
self.previewLayer.frame = self.previewView.bounds;
self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
//[[self.previewLayer connection] setVideoOrientation:[self currentVideoOrientation]];
[self.previewView.layer addSublayer:self.previewLayer];
});
}
// Re-enable capture session if not running currently
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
if (![self.captureSession isRunning])
{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[self.captureSession startRunning];
});
}
}
// Stop running capture session when this view disappears
- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
if ([self.captureSession isRunning])
{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[self.captureSession stopRunning];
});
}
}
@end
请告诉我应该在 IBAction 方法中写什么(按下捕获视频按钮时调用该方法)以及如何使用 AVCaptureVideoPreviewLayer 使正在捕获的视频显示在屏幕上。
谢谢。