问题
I want to merge the AVAsset-arrayVideos into one single video and save it on camera roll. Raywenderlich.com has a great tutorial where two videos are merged into one. I've created the following code, however the video that I get after exporting to camera roll includes only the first and the last video from the array (excluding the rest of the videos in the middle of arrayVideos). Am I missing something here?
var arrayVideos = [AVAsset]() //Videos Array
var atTimeM: CMTime = CMTimeMake(0, 0)
var lastAsset: AVAsset!
var layerInstructionsArray = [AVVideoCompositionLayerInstruction]()
var completeTrackDuration: CMTime = CMTimeMake(0, 1)
var videoSize: CGSize = CGSize(width: 0.0, height: 0.0)
func mergeVideoArray(){
let mixComposition = AVMutableComposition()
for videoAsset in arrayVideos{
let videoTrack = mixComposition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
do {
if videoAsset == arrayVideos.first{
atTimeM = kCMTimeZero
} else{
atTimeM = lastAsset!.duration
}
try videoTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration), of: videoAsset.tracks(withMediaType: AVMediaTypeVideo)[0], at: atTimeM)
videoSize = videoTrack.naturalSize
} catch let error as NSError {
print("error: \(error)")
}
completeTrackDuration = CMTimeAdd(completeTrackDuration, videoAsset.duration)
let videoInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: videoTrack)
if videoAsset != arrayVideos.last{
videoInstruction.setOpacity(0.0, at: videoAsset.duration)
}
layerInstructionsArray.append(videoInstruction)
lastAsset = videoAsset
}
let mainInstruction = AVMutableVideoCompositionInstruction()
mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, completeTrackDuration)
mainInstruction.layerInstructions = layerInstructionsArray
let mainComposition = AVMutableVideoComposition()
mainComposition.instructions = [mainInstruction]
mainComposition.frameDuration = CMTimeMake(1, 30)
mainComposition.renderSize = CGSize(width: videoSize.width, height: videoSize.height)
let documentDirectory = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
let dateFormatter = DateFormatter()
dateFormatter.dateStyle = .long
dateFormatter.timeStyle = .short
let date = dateFormatter.string(from: NSDate() as Date)
let savePath = (documentDirectory as NSString).appendingPathComponent("mergeVideo-\(date).mov")
let url = NSURL(fileURLWithPath: savePath)
let exporter = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality)
exporter!.outputURL = url as URL
exporter!.outputFileType = AVFileTypeQuickTimeMovie
exporter!.shouldOptimizeForNetworkUse = true
exporter!.videoComposition = mainComposition
exporter!.exportAsynchronously {
PHPhotoLibrary.shared().performChanges({
PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: exporter!.outputURL!)
}) { saved, error in
if saved {
let alertController = UIAlertController(title: "Your video was successfully saved", message: nil, preferredStyle: .alert)
let defaultAction = UIAlertAction(title: "OK", style: .default, handler: nil)
alertController.addAction(defaultAction)
self.present(alertController, animated: true, completion: nil)
} else{
print("video erro: \(error)")
}
}
}
}
回答1:
You need to track the total time for all of the assets and update it for each video.
The code in your question was rewriting the atTimeM with the current video. That's why only the first and last got included.
It will look something like this:
...
var totalTime : CMTime = CMTimeMake(0, 0)
func mergeVideoArray() {
let mixComposition = AVMutableComposition()
for videoAsset in arrayVideos {
let videoTrack =
mixComposition.addMutableTrack(withMediaType: AVMediaTypeVideo,
preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
do {
if videoAsset == arrayVideos.first {
atTimeM = kCMTimeZero
} else {
atTimeM = totalTime // <-- Use the total time for all the videos seen so far.
}
try videoTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration),
of: videoAsset.tracks(withMediaType: AVMediaTypeVideo)[0],
at: atTimeM)
videoSize = videoTrack.naturalSize
} catch let error as NSError {
print("error: \(error)")
}
totalTime += videoAsset.duration // <-- Update the total time for all videos.
...
You can remove the use of lastAsset.
回答2:
Swift 4
Use like
MeargeVide.mergeVideoArray(arrayVideos: arrayAsset) { (urlMeargeVide, error) in
debugPrint("url",urlMeargeVide ?? "")
debugPrint("error",error ?? "")
}
Complete class with orientation and merge multiple clip in single.
class MeargeVide {
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: .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
}
class func mergeVideoArray(arrayVideos:[AVAsset], callBack:@escaping (_ urlGet:URL?,_ errorGet:Error?) -> Void){
var atTimeM: CMTime = CMTimeMake(0, 0)
var lastAsset: AVAsset!
var layerInstructionsArray = [AVVideoCompositionLayerInstruction]()
var completeTrackDuration: CMTime = CMTimeMake(0, 1)
var videoSize: CGSize = CGSize(width: 0.0, height: 0.0)
var totalTime : CMTime = CMTimeMake(0, 0)
let mixComposition = AVMutableComposition.init()
for videoAsset in arrayVideos{
let videoTrack = mixComposition.addMutableTrack(withMediaType: AVMediaType.video, preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
do {
if videoAsset == arrayVideos.first {
atTimeM = kCMTimeZero
} else {
atTimeM = totalTime // <-- Use the total time for all the videos seen so far.
}
try videoTrack?.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration),
of: videoAsset.tracks(withMediaType: AVMediaType.video)[0],
at: completeTrackDuration)
videoSize = (videoTrack?.naturalSize)!
} catch let error as NSError {
print("error: \(error)")
}
totalTime = CMTimeAdd(totalTime, videoAsset.duration)
completeTrackDuration = CMTimeAdd(completeTrackDuration, videoAsset.duration)
let firstInstruction = self.videoCompositionInstruction(videoTrack!, asset: videoAsset)
firstInstruction.setOpacity(0.0, at: videoAsset.duration)
layerInstructionsArray.append(firstInstruction)
lastAsset = videoAsset
}
let mainInstruction = AVMutableVideoCompositionInstruction()
mainInstruction.layerInstructions = layerInstructionsArray
mainInstruction.timeRange = CMTimeRangeMake(kCMTimeZero, completeTrackDuration)
let mainComposition = AVMutableVideoComposition()
mainComposition.instructions = [mainInstruction]
mainComposition.frameDuration = CMTimeMake(1, 30)
mainComposition.renderSize = CGSize(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
let documentDirectory = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
let dateFormatter = DateFormatter()
dateFormatter.dateStyle = .long
dateFormatter.timeStyle = .short
let date = dateFormatter.string(from: NSDate() as Date)
let savePath = (documentDirectory as NSString).appendingPathComponent("mergeVideo-\(date).mov")
let url = NSURL(fileURLWithPath: savePath)
let exporter = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality)
exporter!.outputURL = url as URL
exporter!.outputFileType = AVFileType.mp4
exporter!.shouldOptimizeForNetworkUse = true
exporter!.videoComposition = mainComposition
exporter!.exportAsynchronously {
DispatchQueue.main.async {
callBack(exporter?.outputURL, exporter?.error)
}
}
}
}
回答3:
You don't need atTimeM at all, since you are simply marching completeTrackDuration along it is where the next piece should be added. So replace
if videoAsset == arrayVideos.first{
atTimeM = kCMTimeZero
} else{
atTimeM = lastAsset!.duration
}
try videoTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration), of: videoAsset.tracks(withMediaType: AVMediaTypeVideo)[0], at: atTimeM)
with
try videoTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration), of: videoAsset.tracks(withMediaType: AVMediaTypeVideo)[0], at: completeTrackDuration)
来源：https://stackoverflow.com/questions/38972829/swift-merge-avasset-videos-array