【swift3.0】【一秒就懂】【切换镜头】

最新推荐文章于 2025-09-05 15:31:08 发布

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最新推荐文章于 2025-09-05 15:31:08 发布

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文章标签： swift xcode

原文链接：https://my.oschina.net/shengbingli/blog/793403

本文介绍了如何在iOS应用中实现视频采集，并提供了具体的代码示例来演示如何切换前后摄像头。涉及AVFoundation框架的使用，包括配置视频和音频输入输出、启动和停止采集等关键步骤。

为什么80%的码农都做不了架构师？>>>

贡献作者 -【XJDomain】
博客XJ: https://my.oschina.net/shengbingli/blog
GitHub: https://github.com/lishengbing/XJQRCodeToolDemo

第三讲：采集中

>切换镜头

@IBAction func switchScene() {
        // 1:获取之前的镜头
        guard var position = videoInput?.device.position else { return }
        
        // 2:获取当前显示的镜头
        position = position == .front ? .back : .front
        
        // 3:根据当前镜头创建新的device
        let devices = AVCaptureDevice.devices(withMediaType: AVMediaTypeVideo) as? [AVCaptureDevice]
        guard let device = devices?.filter({$0.position == position}).first else { return }
        
        // 4: 根据新的device创建新的input
        guard let videoInput = try? AVCaptureDeviceInput(device: device) else { return }
        
        // 4:在session中切换input
        session.beginConfiguration()
        session.removeInput(self.videoInput)
        if session.canAddInput(videoInput) {
           session.addInput(videoInput)
        }
        session.commitConfiguration()
        self.videoInput = videoInput
    }

范例：

//
//  ViewController.swift
//  视频采集
//
//  Created by 李胜兵 on 2015/11/23.
//  Copyright © 2015年 付公司. All rights reserved.
//

import UIKit
import AVFoundation

class ViewController: UIViewController {
    
   

    fileprivate lazy var videoQueue = DispatchQueue.global()
    fileprivate lazy var audioQueue = DispatchQueue.global()
    
    fileprivate lazy var session : AVCaptureSession = AVCaptureSession()
    fileprivate lazy var previewLayer : AVCaptureVideoPreviewLayer = AVCaptureVideoPreviewLayer(session: self.session)
    
    fileprivate var videoInput : AVCaptureDeviceInput?
    fileprivate var videoOutput : AVCaptureVideoDataOutput?
    
}

// MARK: - 视频的开始采集和停止采集&切换镜头
extension ViewController {
    
    @IBAction func switchScene() {
        // 1:获取之前的镜头
        guard var position = videoInput?.device.position else { return }
        
        // 2:获取当前显示的镜头
        position = position == .front ? .back : .front
        
        // 3:根据当前镜头创建新的device
        let devices = AVCaptureDevice.devices(withMediaType: AVMediaTypeVideo) as? [AVCaptureDevice]
        guard let device = devices?.filter({$0.position == position}).first else { return }
        
        // 4: 根据新的device创建新的input
        guard let videoInput = try? AVCaptureDeviceInput(device: device) else { return }
        
        // 4:在session中切换input
        session.beginConfiguration()
        session.removeInput(self.videoInput)
        if session.canAddInput(videoInput) {
           session.addInput(videoInput)
        }
        session.commitConfiguration()
        self.videoInput = videoInput
    }
    
    @IBAction func starCapture() {
        stopCapture()
        
        // 1:设置音频的输入 && 输出
        setupVideo()
        
        // 2:设置音频的输入 && 输出
        setupAudio()
        
        // 2:给用户一个预览图层（可选）
        previewLayer.frame = view.bounds
        view.layer.insertSublayer(previewLayer, at: 0)
        
        // 3:开始采集
        session.startRunning()
    }
    
    @IBAction func stopCapture() {
        print("停止采集...")
        session.stopRunning()
        previewLayer.removeFromSuperlayer()
    }
}


extension ViewController {
    
    // 需要配置视频key info.plist  : NSCameraUsageDescription
    fileprivate func setupVideo() {
        
        // 1:给捕捉会话设置输入源(摄像头)
        guard let devices = AVCaptureDevice.devices(withMediaType: AVMediaTypeVideo) as? [AVCaptureDevice] else {
            print("摄像头不可用")
            return
        }
        
        /* 获取摄像头设备方式1
         let device = devices.filter { (device : AVCaptureDevice) -> Bool in
         return device.position == .front
         }.first
         */
        
        // 2:获取摄像头设备方式2
        guard let device = devices.filter({$0.position == .back}).first else { return }
        guard let vedioInput = try? AVCaptureDeviceInput(device: device) else { return }
        self.videoInput = vedioInput
        if session.canAddInput(vedioInput) {
            session.addInput(vedioInput)
        }

        // 3:给捕捉会话设置输出源
        let videoOutput = AVCaptureVideoDataOutput()
        videoOutput.setSampleBufferDelegate(self, queue: videoQueue)
        if session.canAddOutput(videoOutput) {
            session.addOutput(videoOutput)
        }
        
        // 4:获取video对应的connection
        //connection = videoOutput.connection(withMediaType: AVMediaTypeVideo)
        self.videoOutput = videoOutput
    }
    
    
    // 需要配置音频key info.plist : NSMicrophoneUsageDescription
    fileprivate func setupAudio() {
        // 1:设置音频的输入(话筒)
        // 1.1获取话筒设备
        let device = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeAudio)
        
        // 1.2根据device创建AVCaptureDeviceInput
        guard let audioInput = try? AVCaptureDeviceInput(device: device) else { return }
        if session.canAddInput(audioInput) {
           session.addInput(audioInput)
        }
        
        
        // 2:给会话设置音频输出源
        let audioOutput = AVCaptureAudioDataOutput()
        audioOutput.setSampleBufferDelegate(self, queue: audioQueue)
        if session.canAddOutput(audioOutput) {
           session.addOutput(audioOutput)
        }
        
    }

}

extension ViewController : AVCaptureVideoDataOutputSampleBufferDelegate, AVCaptureAudioDataOutputSampleBufferDelegate {
    func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {
        if connection == self.videoOutput?.connection(withMediaType: AVMediaTypeVideo) {
            print("采集到-视频=画面")
        }else {
            print("采集到-音频-画面")
        }
    }
}

转载于:https://my.oschina.net/shengbingli/blog/793403