我正在研究Video中基于Application的{{1}}。根据要求，我必须从Swift中选择多个Videos，为每个Device Gallery设置不同的CIFilter效果和Volume，然后合并所有{ {1}}，并且必须保存Video Asset。作为输出，当我播放Videos时，Final Video声音Final Video应该相应地改变。
我已经将所有选定的Video合并为具有不同volume效果的一个，但是我的问题是，当我尝试为每个Video Assets设置CIFilter时，不工作。我的Volume得到了默认的Video Clips。这是我的代码：
Volume此后，我再次使用一种方法来使用Final Video合并所有func addFilerEffectAndVolumeToIndividualVideoClip(_ assetURL: URL, video: VideoFileModel, completion : ((_ session: AVAssetExportSession?, _ outputURL : URL?) -> ())?){
let videoFilteredAsset = AVAsset(url: assetURL)
print(videoFilteredAsset)
createVideoComposition(myAsset: videoFilteredAsset, videos: video)
let documentDirectory = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
let url = URL(fileURLWithPath: documentDirectory).appendingPathComponent("\(video.fileID)_\("FilterVideo").mov")
let filePath = url.path
let fileManager = FileManager.default
do {
if fileManager.fileExists(atPath: filePath) {
print("FILE AVAILABLE")
try fileManager.removeItem(atPath:filePath)
} else {
print("FILE NOT AVAILABLE")
}
} catch _ {
}
let composition: AVMutableComposition = AVMutableComposition()
let compositionVideo: AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: CMPersistentTrackID())
let compositionAudioVideo: AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID())
//Add video to the final record
do {
try compositionVideo.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoFilteredAsset.duration), of: videoFilteredAsset.tracks(withMediaType: AVMediaTypeVideo)[0], at: kCMTimeZero)
} catch _ {
}
//Extract audio from the video and the music
let audioMix: AVMutableAudioMix = AVMutableAudioMix()
var audioMixParam: [AVMutableAudioMixInputParameters] = []
let assetVideoTrack: AVAssetTrack = videoFilteredAsset.tracks(withMediaType: AVMediaTypeAudio)[0]
let videoParam: AVMutableAudioMixInputParameters = AVMutableAudioMixInputParameters(track: assetVideoTrack)
videoParam.trackID = compositionAudioVideo.trackID
//Set final volume of the audio record and the music
videoParam.setVolume(video.videoClipVolume, at: kCMTimeZero)
//Add setting
audioMixParam.append(videoParam)
//Add audio on final record
do {
try compositionAudioVideo.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoFilteredAsset.duration), of: assetVideoTrack, at: kCMTimeZero)
} catch _ {
assertionFailure()
}
//Fading volume out for background music
let durationInSeconds = CMTimeGetSeconds(videoFilteredAsset.duration)
let firstSecond = CMTimeRangeMake(CMTimeMakeWithSeconds(0, 1), CMTimeMakeWithSeconds(1, 1))
let lastSecond = CMTimeRangeMake(CMTimeMakeWithSeconds(durationInSeconds-1, 1), CMTimeMakeWithSeconds(1, 1))
videoParam.setVolumeRamp(fromStartVolume: 0, toEndVolume: video.videoClipVolume, timeRange: firstSecond)
videoParam.setVolumeRamp(fromStartVolume: video.videoClipVolume, toEndVolume: 0, timeRange: lastSecond)
//Add parameter
audioMix.inputParameters = audioMixParam
// Export part, left for facility
let exporter = AVAssetExportSession(asset: videoFilteredAsset, presetName: AVAssetExportPresetHighestQuality)!
exporter.videoComposition = videoFilterComposition
exporter.outputURL = url
exporter.outputFileType = AVFileTypeQuickTimeMovie
exporter.audioMix = audioMix
exporter.exportAsynchronously(completionHandler: { () -> Void in
completion!(exporter, url)
})
}
，在这里我没有设置任何Video Clips。
AVAssetExportSession当我使用AudioMixInputParameters Note:以最终合并方法设置音量时，AVAssetExportSession's会变成完整AudioMixInputParameters的更改。
我的问题：是否可以为每个Volume设置多个Video。请提出建议。谢谢！
答案 0 :(得分：2)
这是我的问题的可行解决方案：
func addVolumeToIndividualVideoClip(_ assetURL: URL, video: VideoFileModel, completion : ((_ session: AVAssetExportSession?, _ outputURL : URL?) -> ())?){
//Create Asset from Url
let filteredVideoAsset: AVAsset = AVAsset(url: assetURL)
video.fileID = String(video.videoID)
//Get the path of App Document Directory
let documentDirectory = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
let url = URL(fileURLWithPath: documentDirectory).appendingPathComponent("\(video.fileID)_\("FilterVideo").mov")
let filePath = url.path
let fileManager = FileManager.default
do {
if fileManager.fileExists(atPath: filePath) {
print("FILE AVAILABLE")
try fileManager.removeItem(atPath:filePath)
} else {
print("FILE NOT AVAILABLE")
}
} catch _ {
}
let composition: AVMutableComposition = AVMutableComposition()
let compositionVideo: AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: CMPersistentTrackID())
let compositionAudioVideo: AVMutableCompositionTrack = composition.addMutableTrack(withMediaType: AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID())
//Add video to the final record
do {
try compositionVideo.insertTimeRange(CMTimeRangeMake(kCMTimeZero, filteredVideoAsset.duration), of: filteredVideoAsset.tracks(withMediaType: AVMediaTypeVideo)[0], at: kCMTimeZero)
} catch _ {
}
//Extract audio from the video and the music
let audioMix: AVMutableAudioMix = AVMutableAudioMix()
var audioMixParam: [AVMutableAudioMixInputParameters] = []
let assetVideoTrack: AVAssetTrack = filteredVideoAsset.tracks(withMediaType: AVMediaTypeAudio)[0]
let videoParam: AVMutableAudioMixInputParameters = AVMutableAudioMixInputParameters(track: assetVideoTrack)
videoParam.trackID = compositionAudioVideo.trackID
//Set final volume of the audio record and the music
videoParam.setVolume(video.videoVolume, at: kCMTimeZero)
//Add setting
audioMixParam.append(videoParam)
//Add audio on final record
//First: the audio of the record and Second: the music
do {
try compositionAudioVideo.insertTimeRange(CMTimeRangeMake(kCMTimeZero, filteredVideoAsset.duration), of: assetVideoTrack, at: kCMTimeZero)
} catch _ {
assertionFailure()
}
//Fading volume out for background music
let durationInSeconds = CMTimeGetSeconds(filteredVideoAsset.duration)
let firstSecond = CMTimeRangeMake(CMTimeMakeWithSeconds(0, 1), CMTimeMakeWithSeconds(1, 1))
let lastSecond = CMTimeRangeMake(CMTimeMakeWithSeconds(durationInSeconds-1, 1), CMTimeMakeWithSeconds(1, 1))
videoParam.setVolumeRamp(fromStartVolume: 0, toEndVolume: video.videoVolume, timeRange: firstSecond)
videoParam.setVolumeRamp(fromStartVolume: video.videoVolume, toEndVolume: 0, timeRange: lastSecond)
//Add parameter
audioMix.inputParameters = audioMixParam
//Remove the previous temp video if exist
let filemgr = FileManager.default
do {
if filemgr.fileExists(atPath: "\(video.fileID)_\("FilterVideo").mov") {
try filemgr.removeItem(atPath: "\(video.fileID)_\("FilterVideo").mov")
} else {
}
} catch _ {
}
//Exporte the final record’
let exporter: AVAssetExportSession = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetHighestQuality)!
exporter.outputURL = url
exporter.outputFileType = AVFileTypeMPEG4
exporter.audioMix = audioMix
exporter.exportAsynchronously(completionHandler: { () -> Void in
completion!(exporter, url)
// self.saveVideoToLibrary(from: filePath)
})
}
答案 1 :(得分：1)
我发现，导出预设为AVAssetExportPresetPassthrough的资产不会影响输出量。当我尝试使用AVAssetExportPresetLowQuality时，成功应用了音量更改。
我希望更好地记录在某处：（
工作代码：
// Assume we have:
let composition: AVMutableComposition
var inputParameters = [AVAudioMixInputParameters]()
// We add a track
let trackComposition = composition.addMutableTrack(...)
// Configure volume for this track
let inputParameter = AVMutableAudioMixInputParameters(track: trackComposition)
inputParameter.setVolume(desiredVolume, at: startTime)
// It works even without setting the `trackID`
// inputParameter.trackID = trackComposition.trackID
inputParameters.append(inputParameter)
// Apply gathered `inputParameters` before exporting
let audioMix = AVMutableAudioMix()
audioMix.inputParameters = inputParameters
// I found it's not working, if using `AVAssetExportPresetPassthrough`,
// so try `AVAssetExportPresetLowQuality` first
let export = AVAssetExportSession(..., presetName: AVAssetExportPresetLowQuality)
export.audioMix = audioMix
对同一 compositionTrack 的多个 assetTrack 插入进行了测试，为每个插入设置了不同的音量。似乎正在工作。