AVFoundation框架解析（十七）—— 一個簡單示例之播放、錄制以及混合視頻之源碼及效果展示（二）

版本記錄

版本號 時間
V1.0 2018.08.18

前言

AVFoundation框架是ios中很重要的框架，所有與視頻音頻相關(guān)的軟硬件控制都在這個框架里面，接下來這幾篇就主要對這個框架進行介紹和講解。感興趣的可以看我上幾篇。
1. AVFoundation框架解析（一）—— 基本概覽
2. AVFoundation框架解析（二）—— 實現(xiàn)視頻預(yù)覽錄制保存到相冊
3. AVFoundation框架解析（三）—— 幾個關(guān)鍵問題之關(guān)于框架的深度概括
4. AVFoundation框架解析（四）—— 幾個關(guān)鍵問題之AVFoundation探索（一）
5. AVFoundation框架解析（五）—— 幾個關(guān)鍵問題之AVFoundation探索（二）
6. AVFoundation框架解析（六）—— 視頻音頻的合成（一）
7. AVFoundation框架解析（七）—— 視頻組合和音頻混合調(diào)試
8. AVFoundation框架解析（八）—— 優(yōu)化用戶的播放體驗
9. AVFoundation框架解析（九）—— AVFoundation的變化（一）
10. AVFoundation框架解析（十）—— AVFoundation的變化（二）
11. AVFoundation框架解析（十一）—— AVFoundation的變化（三）
12. AVFoundation框架解析（十二）—— AVFoundation的變化（四）
13. AVFoundation框架解析（十三）—— 構(gòu)建基本播放應(yīng)用程序
14. AVFoundation框架解析（十四）—— VAssetWriter和AVAssetReader的Timecode支持（一）
15. AVFoundation框架解析（十五）—— VAssetWriter和AVAssetReader的Timecode支持（二）
16. AVFoundation框架解析（十六）—— 一個簡單示例之播放、錄制以及混合視頻（一）

源碼

首先我們看一下工程組織結(jié)構(gòu)。

下面就一起看一下源碼。

1. HomeViewController.swift

import UIKit

class HomeViewController: UIViewController {

}

2. MergeVideoViewController.swift

import UIKit
import MobileCoreServices
import MediaPlayer
import Photos

class MergeVideoViewController: UIViewController {
  var firstAsset: AVAsset?
  var secondAsset: AVAsset?
  var audioAsset: AVAsset?
  var loadingAssetOne = false
  
  @IBOutlet var activityMonitor: UIActivityIndicatorView!
  
  func savedPhotosAvailable() -> Bool {
    guard !UIImagePickerController.isSourceTypeAvailable(.savedPhotosAlbum) else { return true }
    
    let alert = UIAlertController(title: "Not Available", message: "No Saved Album found", preferredStyle: .alert)
    alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.cancel, handler: nil))
    present(alert, animated: true, completion: nil)
    return false
  }
    
  func exportDidFinish(_ session: AVAssetExportSession) {
    
    // Cleanup assets
    activityMonitor.stopAnimating()
    firstAsset = nil
    secondAsset = nil
    audioAsset = nil
    
    guard session.status == AVAssetExportSessionStatus.completed,
    let outputURL = session.outputURL else { return }
    
    let saveVideoToPhotos = {
      PHPhotoLibrary.shared().performChanges({ PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: outputURL) }) { saved, error in
        let success = saved && (error == nil)
        let title = success ? "Success" : "Error"
        let message = success ? "Video saved" : "Failed to save video"
        
        let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.cancel, handler: nil))
        self.present(alert, animated: true, completion: nil)
      }
    }
    
    // Ensure permission to access Photo Library
    if PHPhotoLibrary.authorizationStatus() != .authorized {
      PHPhotoLibrary.requestAuthorization({ status in
        if status == .authorized {
          saveVideoToPhotos()
        }
      })
    } else {
      saveVideoToPhotos()
    }
  }
  
  @IBAction func loadAssetOne(_ sender: AnyObject) {
    if savedPhotosAvailable() {
      loadingAssetOne = true
      VideoHelper.startMediaBrowser(delegate: self, sourceType: .savedPhotosAlbum)
    }
  }
  
  @IBAction func loadAssetTwo(_ sender: AnyObject) {
    if savedPhotosAvailable() {
      loadingAssetOne = false
      VideoHelper.startMediaBrowser(delegate: self, sourceType: .savedPhotosAlbum)
    }
  }
  
  @IBAction func loadAudio(_ sender: AnyObject) {
    let mediaPickerController = MPMediaPickerController(mediaTypes: .any)
    mediaPickerController.delegate = self
    mediaPickerController.prompt = "Select Audio"
    present(mediaPickerController, animated: true, completion: nil)
  }
    
  @IBAction func merge(_ sender: AnyObject) {
    guard let firstAsset = firstAsset, let secondAsset = secondAsset else { return }
    
    activityMonitor.startAnimating()
    
    // 1 - Create AVMutableComposition object. This object will hold your AVMutableCompositionTrack instances.
    let mixComposition = AVMutableComposition()
    
    // 2 - Create two video tracks
    guard let firstTrack = mixComposition.addMutableTrack(withMediaType: .video,
                                                          preferredTrackID: Int32(kCMPersistentTrackID_Invalid)) else { return }
    do {
      try firstTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, firstAsset.duration),
                                     of: firstAsset.tracks(withMediaType: .video)[0],
                                     at: kCMTimeZero)
    } catch {
      print("Failed to load first track")
      return
    }
    
    guard let secondTrack = mixComposition.addMutableTrack(withMediaType: .video,
                                                           preferredTrackID: Int32(kCMPersistentTrackID_Invalid)) else { return }
    do {
      try secondTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, secondAsset.duration),
                                      of: secondAsset.tracks(withMediaType: .video)[0],
                                      at: firstAsset.duration)
    } catch {
      print("Failed to load second track")
      return
    }
    
    // 2.1
    let mainInstruction = AVMutableVideoCompositionInstruction()
    mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, CMTimeAdd(firstAsset.duration, secondAsset.duration))
    
    // 2.2
    let firstInstruction = VideoHelper.videoCompositionInstruction(firstTrack, asset: firstAsset)
    firstInstruction.setOpacity(0.0, at: firstAsset.duration)
    let secondInstruction = VideoHelper.videoCompositionInstruction(secondTrack, asset: secondAsset)
    
    // 2.3
    mainInstruction.layerInstructions = [firstInstruction, secondInstruction]
    let mainComposition = AVMutableVideoComposition()
    mainComposition.instructions = [mainInstruction]
    mainComposition.frameDuration = CMTimeMake(1, 30)
    mainComposition.renderSize = CGSize(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
    
    // 3 - Audio track
    if let loadedAudioAsset = audioAsset {
      let audioTrack = mixComposition.addMutableTrack(withMediaType: .audio, preferredTrackID: 0)
      do {
        try audioTrack?.insertTimeRange(CMTimeRangeMake(kCMTimeZero, CMTimeAdd(firstAsset.duration, secondAsset.duration)),
                                        of: loadedAudioAsset.tracks(withMediaType: .audio)[0] ,
                                        at: kCMTimeZero)
      } catch {
        print("Failed to load Audio track")
      }
    }
    
    // 4 - Get path
    guard let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else { return }
    let dateFormatter = DateFormatter()
    dateFormatter.dateStyle = .long
    dateFormatter.timeStyle = .short
    let date = dateFormatter.string(from: Date())
    let url = documentDirectory.appendingPathComponent("mergeVideo-\(date).mov")
    
    // 5 - Create Exporter
    guard let exporter = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality) else { return }
    exporter.outputURL = url
    exporter.outputFileType = AVFileType.mov
    exporter.shouldOptimizeForNetworkUse = true
    exporter.videoComposition = mainComposition
    
    // 6 - Perform the Export
    exporter.exportAsynchronously() {
      DispatchQueue.main.async {
        self.exportDidFinish(exporter)
      }
    }
  }
  
}

extension MergeVideoViewController: UIImagePickerControllerDelegate {
  func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    dismiss(animated: true, completion: nil)
    
    guard let mediaType = info[UIImagePickerControllerMediaType] as? String,
      mediaType == (kUTTypeMovie as String),
      let url = info[UIImagePickerControllerMediaURL] as? URL
      else { return }
    
    let avAsset = AVAsset(url: url)
    var message = ""
    if loadingAssetOne {
      message = "Video one loaded"
      firstAsset = avAsset
    } else {
      message = "Video two loaded"
      secondAsset = avAsset
    }
    let alert = UIAlertController(title: "Asset Loaded", message: message, preferredStyle: .alert)
    alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.cancel, handler: nil))
    present(alert, animated: true, completion: nil)
  }
  
}

extension MergeVideoViewController: UINavigationControllerDelegate {
  
}

extension MergeVideoViewController: MPMediaPickerControllerDelegate {
  func mediaPicker(_ mediaPicker: MPMediaPickerController, didPickMediaItems mediaItemCollection: MPMediaItemCollection) {
    
    dismiss(animated: true) {
      let selectedSongs = mediaItemCollection.items
      guard let song = selectedSongs.first else { return }
      
      let url = song.value(forProperty: MPMediaItemPropertyAssetURL) as? URL
      self.audioAsset = (url == nil) ? nil : AVAsset(url: url!)
      let title = (url == nil) ? "Asset Not Available" : "Asset Loaded"
      let message = (url == nil) ? "Audio Not Loaded" : "Audio Loaded"
      
      let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
      alert.addAction(UIAlertAction(title: "OK", style: .cancel, handler:nil))
      self.present(alert, animated: true, completion: nil)
    }
  }
  
  func mediaPickerDidCancel(_ mediaPicker: MPMediaPickerController) {
    dismiss(animated: true, completion: nil)
  }
}

3. PlayVideoViewController.swift

import UIKit
import AVKit
import MobileCoreServices

class PlayVideoViewController: UIViewController {
  
  @IBAction func playVideo(_ sender: AnyObject) {
    VideoHelper.startMediaBrowser(delegate: self, sourceType: .savedPhotosAlbum)
  }
}

// MARK: - UIImagePickerControllerDelegate

extension PlayVideoViewController: UIImagePickerControllerDelegate {
  func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    
    guard let mediaType = info[UIImagePickerControllerMediaType] as? String,
      mediaType == (kUTTypeMovie as String),
      let url = info[UIImagePickerControllerMediaURL] as? URL
      else { return }
    
    dismiss(animated: true) {
      let player = AVPlayer(url: url)
      let vcPlayer = AVPlayerViewController()
      vcPlayer.player = player
      self.present(vcPlayer, animated: true, completion: nil)
    }
  }
}

// MARK: - UINavigationControllerDelegate

extension PlayVideoViewController: UINavigationControllerDelegate {
}

4. RecordVideoViewController.swift

import UIKit
import MobileCoreServices

class RecordVideoViewController: UIViewController {
  
  @IBAction func record(_ sender: AnyObject) {
    VideoHelper.startMediaBrowser(delegate: self, sourceType: .camera)
  }
  
  @objc func video(_ videoPath: String, didFinishSavingWithError error: Error?, contextInfo info: AnyObject) {
    let title = (error == nil) ? "Success" : "Error"
    let message = (error == nil) ? "Video was saved" : "Video failed to save"
    
    let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
    alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.cancel, handler: nil))
    present(alert, animated: true, completion: nil)
  }
  
}

// MARK: - UIImagePickerControllerDelegate

extension RecordVideoViewController: UIImagePickerControllerDelegate {
  func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    dismiss(animated: true, completion: nil)
    
    guard let mediaType = info[UIImagePickerControllerMediaType] as? String,
      mediaType == (kUTTypeMovie as String),
      let url = info[UIImagePickerControllerMediaURL] as? URL,
      UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(url.path)
      else { return }
    
    // Handle a movie capture
    UISaveVideoAtPathToSavedPhotosAlbum(url.path, self, #selector(video(_:didFinishSavingWithError:contextInfo:)), nil)
  }
  
}

// MARK: - UINavigationControllerDelegate

extension RecordVideoViewController: UINavigationControllerDelegate {
}

5. VideoHelper.swift

import UIKit
import MobileCoreServices
import AVFoundation

class VideoHelper {
  
  static func startMediaBrowser(delegate: UIViewController & UINavigationControllerDelegate & UIImagePickerControllerDelegate, sourceType: UIImagePickerControllerSourceType) {
    guard UIImagePickerController.isSourceTypeAvailable(sourceType) else { return }
    
    let mediaUI = UIImagePickerController()
    mediaUI.sourceType = sourceType
    mediaUI.mediaTypes = [kUTTypeMovie as String]
    mediaUI.allowsEditing = true
    mediaUI.delegate = delegate
    delegate.present(mediaUI, animated: true, completion: nil)
  }
  
  static func orientationFromTransform(_ transform: CGAffineTransform) -> (orientation: UIImageOrientation, isPortrait: Bool) {
    var assetOrientation = UIImageOrientation.up
    var isPortrait = false
    if transform.a == 0 && transform.b == 1.0 && transform.c == -1.0 && transform.d == 0 {
      assetOrientation = .right
      isPortrait = true
    } else if transform.a == 0 && transform.b == -1.0 && transform.c == 1.0 && transform.d == 0 {
      assetOrientation = .left
      isPortrait = true
    } else if transform.a == 1.0 && transform.b == 0 && transform.c == 0 && transform.d == 1.0 {
      assetOrientation = .up
    } else if transform.a == -1.0 && transform.b == 0 && transform.c == 0 && transform.d == -1.0 {
      assetOrientation = .down
    }
    return (assetOrientation, isPortrait)
  }
  
  static func videoCompositionInstruction(_ track: AVCompositionTrack, asset: AVAsset) -> AVMutableVideoCompositionLayerInstruction {
    let instruction = AVMutableVideoCompositionLayerInstruction(assetTrack: track)
    let assetTrack = asset.tracks(withMediaType: AVMediaType.video)[0]
    
    let transform = assetTrack.preferredTransform
    let assetInfo = orientationFromTransform(transform)
    
    var scaleToFitRatio = UIScreen.main.bounds.width / assetTrack.naturalSize.width
    if assetInfo.isPortrait {
      scaleToFitRatio = UIScreen.main.bounds.width / assetTrack.naturalSize.height
      let scaleFactor = CGAffineTransform(scaleX: scaleToFitRatio, y: scaleToFitRatio)
      instruction.setTransform(assetTrack.preferredTransform.concatenating(scaleFactor), at: kCMTimeZero)
    } else {
      let scaleFactor = CGAffineTransform(scaleX: scaleToFitRatio, y: scaleToFitRatio)
      var concat = assetTrack.preferredTransform.concatenating(scaleFactor)
        .concatenating(CGAffineTransform(translationX: 0, y: UIScreen.main.bounds.width / 2))
      if assetInfo.orientation == .down {
        let fixUpsideDown = CGAffineTransform(rotationAngle: CGFloat(Double.pi))
        let windowBounds = UIScreen.main.bounds
        let yFix = assetTrack.naturalSize.height + windowBounds.height
        let centerFix = CGAffineTransform(translationX: assetTrack.naturalSize.width, y: yFix)
        concat = fixUpsideDown.concatenating(centerFix).concatenating(scaleFactor)
      }
      instruction.setTransform(concat, at: kCMTimeZero)
    }
    
    return instruction
  }
  
}

下面看一下sb文件中的內(nèi)容。

1
2
3
4

效果展示

1. Select and Play Video - 選擇并播放視頻

效果展示如下所示：

2. Record and Save Video - 錄制和保存視頻

效果展示如下所示：

這里我錄制了兩次，第一次錄制的時候App會申請很多的權(quán)限，包括麥克風(fēng)什么的，這里不是第一次錄制了，所有不會有權(quán)限申請了。

3. Merge Video - 視頻合并

效果展示如下所示：

可見，兩個視頻以及背景音樂就這么合并到一起了。

后記

本篇主要講述了一個簡單示例之播放、錄制以及混合視頻的源碼和效果展示，感興趣的給個贊或者關(guān)注~~~

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