我正在使用PryntTrimmerView修剪视频文件。我的代码用于导出修整视频文件并生成视频缩略图：
func prepareAssetComposition() throws {
guard let asset = trimmerView.asset, let videoTrack = asset.tracks(withMediaType: AVMediaTypeVideo).last else {
return
}
let size = videoTrack.naturalSize.applying(videoTrack.preferredTransform)
print(CGSize(width: fabs(size.width), height: fabs(size.height)))
let assetComposition = AVMutableComposition()
let start = trimmerView.startTime?.seconds
let end = trimmerView.endTime?.seconds
let startTime = CMTime(seconds: Double(start ?? 0), preferredTimescale: 1000)
let endTime = CMTime(seconds: Double(end ?? 0), preferredTimescale: 1000)
let trackTimeRange = CMTimeRange(start: startTime, end: endTime)
let compositionTrack = assetComposition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: kCMPersistentTrackID_Invalid)
try compositionTrack.insertTimeRange(trackTimeRange, of: videoTrack, at: kCMTimeZero)
var url: URL!
if self.state == .Left {
url = URL(fileURLWithPath: "\(NSTemporaryDirectory())TrimmedMovie1.mp4")
}else if state == .Right {
url = URL(fileURLWithPath: "\(NSTemporaryDirectory())TrimmedMovie3.mp4")
}else if state == .Center {
url = URL(fileURLWithPath: "\(NSTemporaryDirectory())TrimmedMovie2.mp4")
}
try? FileManager.default.removeItem(at: url)
let exportSession = AVAssetExportSession(asset: assetComposition, presetName: AVAssetExportPresetHighestQuality)
if UIDevice.current.userInterfaceIdiom == .phone {
exportSession?.outputFileType = AVFileTypeQuickTimeMovie
}else {
exportSession?.outputFileType = AVFileTypeQuickTimeMovie
}
exportSession?.shouldOptimizeForNetworkUse = true
exportSession?.outputURL = url
exportSession?.exportAsynchronously(completionHandler: {
DispatchQueue.main.async {
if let url = exportSession?.outputURL, exportSession?.status == .completed {
var thump: UIImage?
var vData: Data?
if let asset = self.trimmerView.asset {
if let img = asset.videoThumbnail {
thump = img
}
}
if let videoData = NSData(contentsOf: url) {
vData = videoData as Data
}
if let delegate = self.delegate {
delegate.setVideoFromPath(path: url.path, thump: thump, videoData: vData)
self.dismiss(animated: true, completion: nil)
}
} else {
let error = exportSession?.error
print("error exporting video \(String(describing: error))")
}
}
})
}
extension AVAsset{
var videoThumbnail:UIImage?{
let assetImageGenerator = AVAssetImageGenerator(asset: self)
var time = self.duration
time.value = min(time.value, 2)
do {
let imageRef = try assetImageGenerator.copyCGImage(at: time, actualTime: nil)
let thumbNail = UIImage.init(cgImage: imageRef)
print("Video Thumbnail genertated successfuly")
return thumbNail
} catch {
print("error getting thumbnail video")
return nil
}
}
}
有时，导出的视频和缩略图会旋转为横向旋转，这很可能在将视频记录在移动相机上时发生。 如何解决这个问题。并迫使资产导向走向纵向？ 感谢所有答复。
答案 0 :(得分：0)
我找到了解决方案。有我的Swift 3.2代码
func prepareAssetComposition() throws {
guard let asset = trimmerView.asset, let videoTrack = asset.tracks(withMediaType: AVMediaTypeVideo).first else {
return
}
let assetComposition = AVMutableComposition()
let start = trimmerView.startTime?.seconds
let end = trimmerView.endTime?.seconds
let startTime = CMTime(seconds: Double(start ?? 0), preferredTimescale: 1000)
let endTime = CMTime(seconds: Double(end ?? 0), preferredTimescale: 1000)
let trackTimeRange = CMTimeRange(start: startTime, end: endTime)
let videoCompositionTrack = assetComposition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: kCMPersistentTrackID_Invalid)
try videoCompositionTrack.insertTimeRange(trackTimeRange, of: videoTrack, at: kCMTimeZero)
if let audioTrack = asset.tracks(withMediaType: AVMediaTypeAudio).first {
let audioCompositionTrack = assetComposition.addMutableTrack(withMediaType: AVMediaTypeAudio, preferredTrackID: kCMPersistentTrackID_Invalid)
try audioCompositionTrack.insertTimeRange(trackTimeRange, of: audioTrack, at: kCMTimeZero)
}
let size = videoTrack.naturalSize
let txf = videoTrack.preferredTransform
var recordType = ""
if (size.width == txf.tx && size.height == txf.ty){
recordType = "UIInterfaceOrientationLandscapeRight"
}else if (txf.tx == 0 && txf.ty == 0){
recordType = "UIInterfaceOrientationLandscapeLeft"
}else if (txf.tx == 0 && txf.ty == size.width){
recordType = "UIInterfaceOrientationPortraitUpsideDown"
}else{
recordType = "UIInterfaceOrientationPortrait"
}
if recordType == "UIInterfaceOrientationPortrait" {
let t1: CGAffineTransform = CGAffineTransform(translationX: videoTrack.naturalSize.height, y: -(videoTrack.naturalSize.width - videoTrack.naturalSize.height)/2)
let t2: CGAffineTransform = t1.rotated(by: CGFloat(Double.pi / 2))
let finalTransform: CGAffineTransform = t2
videoCompositionTrack.preferredTransform = finalTransform
}else if recordType == "UIInterfaceOrientationLandscapeRight" {
let t1: CGAffineTransform = CGAffineTransform(translationX: videoTrack.naturalSize.height, y: -(videoTrack.naturalSize.width - videoTrack.naturalSize.height)/2)
let t2: CGAffineTransform = t1.rotated(by: -CGFloat(Double.pi))
let finalTransform: CGAffineTransform = t2
videoCompositionTrack.preferredTransform = finalTransform
}else if recordType == "UIInterfaceOrientationPortraitUpsideDown" {
let t1: CGAffineTransform = CGAffineTransform(translationX: videoTrack.naturalSize.height, y: -(videoTrack.naturalSize.width - videoTrack.naturalSize.height)/2)
let t2: CGAffineTransform = t1.rotated(by: -CGFloat(Double.pi/2))
let finalTransform: CGAffineTransform = t2
videoCompositionTrack.preferredTransform = finalTransform
}
var url: URL!
if self.state == .Left {
url = URL(fileURLWithPath: "\(NSTemporaryDirectory())TrimmedMovie1.mp4")
}else if state == .Right {
url = URL(fileURLWithPath: "\(NSTemporaryDirectory())TrimmedMovie3.mp4")
}else if state == .Center {
url = URL(fileURLWithPath: "\(NSTemporaryDirectory())TrimmedMovie2.mp4")
}
try? FileManager.default.removeItem(at: url)
let exportSession = AVAssetExportSession(asset: assetComposition, presetName: AVAssetExportPresetHighestQuality)
if UIDevice.current.userInterfaceIdiom == .phone {
exportSession?.outputFileType = AVFileTypeQuickTimeMovie
}else {
exportSession?.outputFileType = AVFileTypeQuickTimeMovie
}
exportSession?.shouldOptimizeForNetworkUse = true
exportSession?.outputURL = url
exportSession?.exportAsynchronously(completionHandler: {
DispatchQueue.main.async {
if let url = exportSession?.outputURL, exportSession?.status == .completed {
let asset = AVAsset(url: url)
var thump: UIImage?
var vData: Data?
if let img = asset.videoThumbnail {
thump = img
if recordType == "UIInterfaceOrientationPortrait" {
if thump != nil {
let img = UIImage(cgImage: thump!.cgImage!, scale: CGFloat(1.0), orientation: .right)
thump = img
thump = thump?.fixedOrientation()
}
}else if recordType == "UIInterfaceOrientationLandscapeRight" {
if thump != nil {
let img = UIImage(cgImage: thump!.cgImage!, scale: CGFloat(1.0), orientation: .down)
thump = img
thump = thump?.fixedOrientation()
}
}else if recordType == "UIInterfaceOrientationPortraitUpsideDown" {
if thump != nil {
let img = UIImage(cgImage: thump!.cgImage!, scale: CGFloat(1.0), orientation: .left)
thump = img
thump = thump?.fixedOrientation()
}
}
}
if let videoData = NSData(contentsOf: url) {
vData = videoData as Data
}
if let delegate = self.delegate {
delegate.setVideoFromPath(path: url.path, thump: thump, videoData: vData)
self.dismiss(animated: true, completion: nil)
}
} else {
let error = exportSession?.error
print("error exporting video \(String(describing: error))")
}
}
})
}