使用 AVMutableComposition 难以合并两个视频
Difficulty Merging Two Videos Using AVMutableComposition
我正在做一个项目，我试图使用 AVMutableComposition 将两个 AVAssets（视频文件）合并在一起。我的视频文件保存到我的相机胶卷时，都完全符合预期。他们的 URL 是有效的，但我的最终导出产品只显示第一个视频，而不是第二个合并的视频。这是我正在使用的代码：
// Setup video asset
let videoAsset: AVAsset = AVAsset( url: clip1 )
// Setup composition
let composition = AVMutableComposition()
// Get video track
let vtrack = videoAsset.tracks(withMediaType: AVMediaType.video)
// Setup the first video track as asset track
let videoTrack: AVAssetTrack = vtrack[0]
// Setup the video timerange
let vid_timerange = CMTimeRangeMake(kCMTimeZero, videoAsset.duration)
// Setup the composition video track
let compositionvideoTrack:AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaType.video, preferredTrackID: kCMPersistentTrackID_Invalid)!
// Insert expected time range
do {
try compositionvideoTrack.insertTimeRange(vid_timerange, of: videoTrack, at: kCMTimeZero)
} catch {
print("An error occurred")
}
// Setup second video asset
let reversedAsset: AVAsset = AVAsset( url: clip2 )
// Setup the video track
let vtrack1 = reversedAsset.tracks(withMediaType: AVMediaType.video)
// Setup the video track
let videoTrack1: AVAssetTrack = vtrack1[0]
// Setup the video time range
let vid1_timerange = CMTimeRangeMake(kCMTimeZero, reversedAsset.duration)
// Setup the second composition video track
let secondCompositionVideoTrack:AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaType.video, preferredTrackID: kCMPersistentTrackID_Invalid)!
// Insert time range
do {
try secondCompositionVideoTrack.insertTimeRange(vid1_timerange, of: videoTrack1, at: videoAsset.duration)
} catch {
print("An error occurred")
}
// Setup the folder path
let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
// Setup documents directory
let documentsDirectory = paths[0] as String
// Setup the last path component
let lastPath = clip1.lastPathComponent
// Setup the reverse string
let reverseString = "loop-" + lastPath
// Setup desired full path
let fullPath: String = "\(documentsDirectory)/\(reverseString)"
// Setup reverse destination URL
let reverseURL = URL(fileURLWithPath: fullPath)
// Export
let exportSession = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetHighestQuality)!
// Setup the destination for output
exportSession.outputURL = reverseURL
// Setup the file type
exportSession.outputFileType = AVFileType.mp4
exportSession.exportAsynchronously(completionHandler: {
if exportSession.status == .completed {
// Send completion on main queue
DispatchQueue.main.async(execute: {
PHPhotoLibrary.shared().performChanges({PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: reverseURL)
}) { saved, error in
if saved {
print("save of potentially looped video succesful")
}
}
// Send completion handler
completionHandler(reverseURL)
})
return
} else if exportSession.status == .failed {
print("Loop Export failed - \(String(describing: exportSession.error))")
completionHandler(nil)
}
completionHandler(nil)
return
})
保存到我的相机胶卷的只是第一个片段，看不到第二个片段的迹象。任何帮助将不胜感激。谢谢！
我写了下面的代码来合并视频。这工作正常。我还在需要的代码行上方写了注释。
let videoAssets1 = AVAsset(url: videoUrl1)
let videoAssets2 = AVAsset(url: videoUrl2)
let mixComposition = AVMutableComposition()
// Create composition track for first video
let firstCompositionTrack = mixComposition.addMutableTrack(withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid)
do {
try firstCompositionTrack?.insertTimeRange(CMTimeRange(start: kCMTimeZero, end: videoAssets1.duration), of: videoAssets1.tracks(withMediaType: .video)[0], at: kCMTimeZero)
} catch {
print("Error = \(error.localizedDescription)")
}
// Create composition track for second video
let secondCompositionTrack = mixComposition.addMutableTrack(withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid)
do {
try secondCompositionTrack?.insertTimeRange(CMTimeRange(start: kCMTimeZero, end: videoAssets2.duration), of: videoAssets2.tracks(withMediaType: .video)[0], at: kCMTimeZero)
} catch {
print("Error = \(error.localizedDescription)")
}
//See how we are creating AVMutableVideoCompositionInstruction object.This object will contain the array of our AVMutableVideoCompositionLayerInstruction objects.You set the duration of the layer.You should add the lenght equal to the lingth of the longer asset in terms of duration.
let mainInstruction = AVMutableVideoCompositionInstruction()
mainInstruction.timeRange = CMTimeRange(start: kCMTimeZero, duration: videoAssets1.duration)
// We will be creating 2 AVMutableVideoCompositionLayerInstruction objects.
// Each for our 2 AVMutableCompositionTrack.
// Here we are creating AVMutableVideoCompositionLayerInstruction for out first track.
// See how we make use of CGAffineTransform to move and scale our First Track.
// So it is displayed at the bottom of the screen in smaller size.
// (First track in the one that remains on top).
let firstLayerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: firstCompositionTrack!)
let firstScale : CGAffineTransform = CGAffineTransform(scaleX: 1, y: 1)
let firstMove: CGAffineTransform = CGAffineTransform(translationX: 0, y: 0)
firstLayerInstruction.setTransform(firstScale.concatenating(firstMove), at: kCMTimeZero)
// Here we are creating AVMutableVideoCompositionLayerInstruction for second track.
// See how we make use of CGAffineTransform to move and scale our second Track.
let secondLayerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: secondCompositionTrack!)
let secondScale : CGAffineTransform = CGAffineTransform(scaleX: 1, y: 1)
let secondMove : CGAffineTransform = CGAffineTransform(translationX: (firstCompositionTrack?.naturalSize.width)! + CGFloat(20), y: 0)
secondLayerInstruction.setTransform(secondScale.concatenating(secondMove), at: kCMTimeZero)
//Now we add our 2 created AVMutableVideoCompositionLayerInstruction objects to our AVMutableVideoCompositionInstruction in form of an array.
mainInstruction.layerInstructions = [firstLayerInstruction, secondLayerInstruction]
// Get the height and width of video.
let height = (Float((firstCompositionTrack?.naturalSize.height)!) > Float((secondCompositionTrack?.naturalSize.height)!)) ? firstCompositionTrack?.naturalSize.height : secondCompositionTrack?.naturalSize.height
// height will be larger in both and width is total of both video.
let width = CGFloat((Float((firstCompositionTrack?.naturalSize.width)!) + Float((secondCompositionTrack?.naturalSize.width)!))) + CGFloat(20)
//Now we create AVMutableVideoComposition object.
//We can add mutiple AVMutableVideoCompositionInstruction to this object.
//We have only one AVMutableVideoCompositionInstruction object in our example.
//You can use multiple AVMutableVideoCompositionInstruction objects to add multiple layers of effects such as fade and transition but make sure that time ranges of the AVMutableVideoCompositionInstruction objects don't overlap.
let mainCompositionInst = AVMutableVideoComposition()
mainCompositionInst.instructions = [mainInstruction]
mainCompositionInst.frameDuration = CMTime(value: CMTimeValue(1), timescale: CMTimeScale(30))
mainCompositionInst.renderSize = CGSize(width: width, height: height!)
// Create the export session with the composition and set the preset to the highest quality.
let exporter = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality)
// Set the desired output URL for the file created by the export process.
exporter?.outputURL = URL(fileURLWithPath: self.getVideoPath(name: "videoCompose"))
exporter?.videoComposition = mainCompositionInst
// Set the output file type to be a mp4 movie.
exporter?.outputFileType = AVFileType.mp4
exporter?.shouldOptimizeForNetworkUse = true
exporter?.exportAsynchronously(completionHandler: {() -> Void in
DispatchQueue.main.async(execute: {() -> Void in
if exporter?.status == .completed {
do {
let videoData = try Data(contentsOf: exporter!.outputURL!)
// Here video will save in document directory path, you can use your requirement.
try videoData.write(to: URL(fileURLWithPath: self.getVideoPath(name: "videoCompose")), options: Data.WritingOptions.atomic)
} catch {
print("Failed to Save video ===>>> \(error.localizedDescription)")
}
}
})
})
希望对您有所帮助。
你的第二个剪辑在第一个剪辑的持续时间开始时从零开始：
let vid1_timerange = CMTimeRangeMake(videoAsset.duration, reversedAsset.duration)
我正在做一个项目，我试图使用 AVMutableComposition 将两个 AVAssets（视频文件）合并在一起。我的视频文件保存到我的相机胶卷时，都完全符合预期。他们的 URL 是有效的，但我的最终导出产品只显示第一个视频，而不是第二个合并的视频。这是我正在使用的代码：
// Setup video asset
let videoAsset: AVAsset = AVAsset( url: clip1 )
// Setup composition
let composition = AVMutableComposition()
// Get video track
let vtrack = videoAsset.tracks(withMediaType: AVMediaType.video)
// Setup the first video track as asset track
let videoTrack: AVAssetTrack = vtrack[0]
// Setup the video timerange
let vid_timerange = CMTimeRangeMake(kCMTimeZero, videoAsset.duration)
// Setup the composition video track
let compositionvideoTrack:AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaType.video, preferredTrackID: kCMPersistentTrackID_Invalid)!
// Insert expected time range
do {
try compositionvideoTrack.insertTimeRange(vid_timerange, of: videoTrack, at: kCMTimeZero)
} catch {
print("An error occurred")
}
// Setup second video asset
let reversedAsset: AVAsset = AVAsset( url: clip2 )
// Setup the video track
let vtrack1 = reversedAsset.tracks(withMediaType: AVMediaType.video)
// Setup the video track
let videoTrack1: AVAssetTrack = vtrack1[0]
// Setup the video time range
let vid1_timerange = CMTimeRangeMake(kCMTimeZero, reversedAsset.duration)
// Setup the second composition video track
let secondCompositionVideoTrack:AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaType.video, preferredTrackID: kCMPersistentTrackID_Invalid)!
// Insert time range
do {
try secondCompositionVideoTrack.insertTimeRange(vid1_timerange, of: videoTrack1, at: videoAsset.duration)
} catch {
print("An error occurred")
}
// Setup the folder path
let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
// Setup documents directory
let documentsDirectory = paths[0] as String
// Setup the last path component
let lastPath = clip1.lastPathComponent
// Setup the reverse string
let reverseString = "loop-" + lastPath
// Setup desired full path
let fullPath: String = "\(documentsDirectory)/\(reverseString)"
// Setup reverse destination URL
let reverseURL = URL(fileURLWithPath: fullPath)
// Export
let exportSession = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetHighestQuality)!
// Setup the destination for output
exportSession.outputURL = reverseURL
// Setup the file type
exportSession.outputFileType = AVFileType.mp4
exportSession.exportAsynchronously(completionHandler: {
if exportSession.status == .completed {
// Send completion on main queue
DispatchQueue.main.async(execute: {
PHPhotoLibrary.shared().performChanges({PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: reverseURL)
}) { saved, error in
if saved {
print("save of potentially looped video succesful")
}
}
// Send completion handler
completionHandler(reverseURL)
})
return
} else if exportSession.status == .failed {
print("Loop Export failed - \(String(describing: exportSession.error))")
completionHandler(nil)
}
completionHandler(nil)
return
})
保存到我的相机胶卷的只是第一个片段，看不到第二个片段的迹象。任何帮助将不胜感激。谢谢！
我写了下面的代码来合并视频。这工作正常。我还在需要的代码行上方写了注释。
let videoAssets1 = AVAsset(url: videoUrl1)
let videoAssets2 = AVAsset(url: videoUrl2)
let mixComposition = AVMutableComposition()
// Create composition track for first video
let firstCompositionTrack = mixComposition.addMutableTrack(withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid)
do {
try firstCompositionTrack?.insertTimeRange(CMTimeRange(start: kCMTimeZero, end: videoAssets1.duration), of: videoAssets1.tracks(withMediaType: .video)[0], at: kCMTimeZero)
} catch {
print("Error = \(error.localizedDescription)")
}
// Create composition track for second video
let secondCompositionTrack = mixComposition.addMutableTrack(withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid)
do {
try secondCompositionTrack?.insertTimeRange(CMTimeRange(start: kCMTimeZero, end: videoAssets2.duration), of: videoAssets2.tracks(withMediaType: .video)[0], at: kCMTimeZero)
} catch {
print("Error = \(error.localizedDescription)")
}
//See how we are creating AVMutableVideoCompositionInstruction object.This object will contain the array of our AVMutableVideoCompositionLayerInstruction objects.You set the duration of the layer.You should add the lenght equal to the lingth of the longer asset in terms of duration.
let mainInstruction = AVMutableVideoCompositionInstruction()
mainInstruction.timeRange = CMTimeRange(start: kCMTimeZero, duration: videoAssets1.duration)
// We will be creating 2 AVMutableVideoCompositionLayerInstruction objects.
// Each for our 2 AVMutableCompositionTrack.
// Here we are creating AVMutableVideoCompositionLayerInstruction for out first track.
// See how we make use of CGAffineTransform to move and scale our First Track.
// So it is displayed at the bottom of the screen in smaller size.
// (First track in the one that remains on top).
let firstLayerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: firstCompositionTrack!)
let firstScale : CGAffineTransform = CGAffineTransform(scaleX: 1, y: 1)
let firstMove: CGAffineTransform = CGAffineTransform(translationX: 0, y: 0)
firstLayerInstruction.setTransform(firstScale.concatenating(firstMove), at: kCMTimeZero)
// Here we are creating AVMutableVideoCompositionLayerInstruction for second track.
// See how we make use of CGAffineTransform to move and scale our second Track.
let secondLayerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: secondCompositionTrack!)
let secondScale : CGAffineTransform = CGAffineTransform(scaleX: 1, y: 1)
let secondMove : CGAffineTransform = CGAffineTransform(translationX: (firstCompositionTrack?.naturalSize.width)! + CGFloat(20), y: 0)
secondLayerInstruction.setTransform(secondScale.concatenating(secondMove), at: kCMTimeZero)
//Now we add our 2 created AVMutableVideoCompositionLayerInstruction objects to our AVMutableVideoCompositionInstruction in form of an array.
mainInstruction.layerInstructions = [firstLayerInstruction, secondLayerInstruction]
// Get the height and width of video.
let height = (Float((firstCompositionTrack?.naturalSize.height)!) > Float((secondCompositionTrack?.naturalSize.height)!)) ? firstCompositionTrack?.naturalSize.height : secondCompositionTrack?.naturalSize.height
// height will be larger in both and width is total of both video.
let width = CGFloat((Float((firstCompositionTrack?.naturalSize.width)!) + Float((secondCompositionTrack?.naturalSize.width)!))) + CGFloat(20)
//Now we create AVMutableVideoComposition object.
//We can add mutiple AVMutableVideoCompositionInstruction to this object.
//We have only one AVMutableVideoCompositionInstruction object in our example.
//You can use multiple AVMutableVideoCompositionInstruction objects to add multiple layers of effects such as fade and transition but make sure that time ranges of the AVMutableVideoCompositionInstruction objects don't overlap.
let mainCompositionInst = AVMutableVideoComposition()
mainCompositionInst.instructions = [mainInstruction]
mainCompositionInst.frameDuration = CMTime(value: CMTimeValue(1), timescale: CMTimeScale(30))
mainCompositionInst.renderSize = CGSize(width: width, height: height!)
// Create the export session with the composition and set the preset to the highest quality.
let exporter = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality)
// Set the desired output URL for the file created by the export process.
exporter?.outputURL = URL(fileURLWithPath: self.getVideoPath(name: "videoCompose"))
exporter?.videoComposition = mainCompositionInst
// Set the output file type to be a mp4 movie.
exporter?.outputFileType = AVFileType.mp4
exporter?.shouldOptimizeForNetworkUse = true
exporter?.exportAsynchronously(completionHandler: {() -> Void in
DispatchQueue.main.async(execute: {() -> Void in
if exporter?.status == .completed {
do {
let videoData = try Data(contentsOf: exporter!.outputURL!)
// Here video will save in document directory path, you can use your requirement.
try videoData.write(to: URL(fileURLWithPath: self.getVideoPath(name: "videoCompose")), options: Data.WritingOptions.atomic)
} catch {
print("Failed to Save video ===>>> \(error.localizedDescription)")
}
}
})
})
希望对您有所帮助。
你的第二个剪辑在第一个剪辑的持续时间开始时从零开始：
let vid1_timerange = CMTimeRangeMake(videoAsset.duration, reversedAsset.duration)