AVMutableAudioMixInputParameters：setVolume() 不适用于 iOS 9 的音频文件
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【中文标题】AVMutableAudioMixInputParameters：setVolume() 不适用于 iOS 9 的音频文件【英文标题】：AVMutableAudioMixInputParameters: setVolume() doesn't work with audio file iOS 9 【发布时间】：2015-10-26 13:41:27 【问题描述】：我尝试将视频记录与设备 iPod 库中的音频文件混合。
我想设置每个音频（视频的音频和音频文件的音频）的音量。
我尝试将AVMutableAudioMixInputParameters 对象与setVolume() 方法一起使用。
我对视频的音量没有任何问题，但最终录制的音频文件的音量总是设置为最大。我尝试更改音频文件以使用视频进行测试，并仅获取该视频的音轨，并且效果很好。
import UIKit
import AVFoundation
class AVTools: NSObject
/**
volume: between 1.0 and 0.0
*/
class func mergeVideoAndMusicWithVolume(videoURL: NSURL, audioURL: NSURL, startAudioTime: Float64, volumeVideo: Float, volumeAudio: Float, complete: (NSURL?) -> Void) -> Void
//The goal is merging a video and a music from iPod library, and set it a volume
//Get the path of App Document Directory
let dirPaths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
let docsDir = dirPaths[0] as String
//Create Asset from record and music
let assetVideo: AVURLAsset = AVURLAsset(URL: videoURL)
let assetMusic: AVURLAsset = AVURLAsset(URL: audioURL)
let composition: AVMutableComposition = AVMutableComposition()
let compositionVideo: AVMutableCompositionTrack = composition.addMutableTrackWithMediaType(AVMediaTypeVideo, preferredTrackID: CMPersistentTrackID())
let compositionAudioVideo: AVMutableCompositionTrack = composition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID())
let compositionAudioMusic: AVMutableCompositionTrack = composition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID())
//Add video to the final record
do
try compositionVideo.insertTimeRange(CMTimeRangeMake(kCMTimeZero, assetVideo.duration), ofTrack: assetVideo.tracksWithMediaType(AVMediaTypeVideo)[0], atTime: kCMTimeZero)
catch _
//Extract audio from the video and the music
let audioMix: AVMutableAudioMix = AVMutableAudioMix()
var audioMixParam: [AVMutableAudioMixInputParameters] = []
let assetVideoTrack: AVAssetTrack = assetVideo.tracksWithMediaType(AVMediaTypeAudio)[0]
let assetMusicTrack: AVAssetTrack = assetMusic.tracksWithMediaType(AVMediaTypeAudio)[0]
let videoParam: AVMutableAudioMixInputParameters = AVMutableAudioMixInputParameters(track: assetVideoTrack)
videoParam.trackID = assetVideoTrack.trackID
let musicParam: AVMutableAudioMixInputParameters = AVMutableAudioMixInputParameters(track: assetMusicTrack)
musicParam.trackID = assetMusicTrack.trackID
//Set final volume of the audio record and the music
videoParam.setVolume(volumeVideo, atTime: kCMTimeZero)
musicParam.setVolume(volumeAudio, atTime: kCMTimeZero) // <----- This doesn't work on audio file
//Add setting
audioMixParam.append(musicParam)
audioMixParam.append(videoParam)
//Add audio on final record
//First: the audio of the record and Second: the music
do
try compositionAudioVideo.insertTimeRange(CMTimeRangeMake(kCMTimeZero, assetVideo.duration), ofTrack: assetVideoTrack, atTime: kCMTimeZero)
catch _
assertionFailure()
do
try compositionAudioMusic.insertTimeRange(CMTimeRangeMake(CMTimeMake(Int64(startAudioTime * 10000), 10000), assetVideo.duration), ofTrack: assetMusicTrack, atTime: kCMTimeZero)
catch _
assertionFailure()
//Add parameter
audioMix.inputParameters = audioMixParam
//Remove the previous temp video if exist
let filemgr = NSFileManager.defaultManager()
do
if filemgr.fileExistsAtPath("\(docsDir)/movie-merge-music.mov")
try filemgr.removeItemAtPath("\(docsDir)/movie-merge-music.mov")
else
catch _
//Exporte the final record’
let completeMovie = "\(docsDir)/movie-merge-music.mov"
let completeMovieUrl = NSURL(fileURLWithPath: completeMovie)
let exporter: AVAssetExportSession = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetHighestQuality)!
exporter.outputURL = completeMovieUrl
exporter.outputFileType = AVFileTypeMPEG4
exporter.audioMix = audioMix
exporter.exportAsynchronouslyWithCompletionHandler(
switch exporter.status
case AVAssetExportSessionStatus.Failed:
print("failed \(exporter.error)")
complete(nil)
case AVAssetExportSessionStatus.Cancelled:
print("cancelled \(exporter.error)")
complete(nil)
default:
print("complete")
complete(completeMovieUrl)
)
【问题讨论】：
您找到解决方案了吗？！ 还没有...任何更新暂时修复它 这实际上不是我的问题。我只是忘记在exporter.audioMix = audioMix周围复制+粘贴代码时将混合添加到导出会话中@
【参考方案1】：
好的，我找到了问题所在。 问题是我分配了资产的 trackID 而不是组合的 trackID。 要修复它，只需替换：
let videoParam: AVMutableAudioMixInputParameters = AVMutableAudioMixInputParameters(track: assetVideoTrack)
videoParam.trackID = assetVideoTrack.trackID
let musicParam: AVMutableAudioMixInputParameters = AVMutableAudioMixInputParameters(track: assetMusicTrack)
musicParam.trackID = assetMusicTrack.trackID
到：
let videoParam: AVMutableAudioMixInputParameters = AVMutableAudioMixInputParameters(track: assetVideoTrack)
videoParam.trackID = compositionAudioVideo.trackID
let musicParam: AVMutableAudioMixInputParameters = AVMutableAudioMixInputParameters(track: assetMusicTrack)
musicParam.trackID = compositionAudioMusic.trackID
最终结果：
/**
volume: between 1.0 and 0.0
*/
class func mergeVideoAndMusicWithVolume(videoURL: NSURL, audioURL: NSURL, startAudioTime: Float64, volumeVideo: Float, volumeAudio: Float, complete: (NSURL?) -> Void) -> Void
//The goal is merging a video and a music from iPod library, and set it a volume
//Get the path of App Document Directory
let dirPaths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
let docsDir = dirPaths[0] as String
//Create Asset from record and music
let assetVideo: AVURLAsset = AVURLAsset(URL: videoURL)
let assetMusic: AVURLAsset = AVURLAsset(URL: audioURL)
let composition: AVMutableComposition = AVMutableComposition()
let compositionVideo: AVMutableCompositionTrack = composition.addMutableTrackWithMediaType(AVMediaTypeVideo, preferredTrackID: CMPersistentTrackID())
let compositionAudioVideo: AVMutableCompositionTrack = composition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID())
let compositionAudioMusic: AVMutableCompositionTrack = composition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID())
//Add video to the final record
do
try compositionVideo.insertTimeRange(CMTimeRangeMake(kCMTimeZero, assetVideo.duration), ofTrack: assetVideo.tracksWithMediaType(AVMediaTypeVideo)[0], atTime: kCMTimeZero)
catch _
//Extract audio from the video and the music
let audioMix: AVMutableAudioMix = AVMutableAudioMix()
var audioMixParam: [AVMutableAudioMixInputParameters] = []
let assetVideoTrack: AVAssetTrack = assetVideo.tracksWithMediaType(AVMediaTypeAudio)[0]
let assetMusicTrack: AVAssetTrack = assetMusic.tracksWithMediaType(AVMediaTypeAudio)[0]
let videoParam: AVMutableAudioMixInputParameters = AVMutableAudioMixInputParameters(track: assetVideoTrack)
videoParam.trackID = compositionAudioVideo.trackID
let musicParam: AVMutableAudioMixInputParameters = AVMutableAudioMixInputParameters(track: assetMusicTrack)
musicParam.trackID = compositionAudioMusic.trackID
//Set final volume of the audio record and the music
videoParam.setVolume(volumeVideo, atTime: kCMTimeZero)
musicParam.setVolume(volumeAudio, atTime: kCMTimeZero)
//Add setting
audioMixParam.append(musicParam)
audioMixParam.append(videoParam)
//Add audio on final record
//First: the audio of the record and Second: the music
do
try compositionAudioVideo.insertTimeRange(CMTimeRangeMake(kCMTimeZero, assetVideo.duration), ofTrack: assetVideoTrack, atTime: kCMTimeZero)
catch _
assertionFailure()
do
try compositionAudioMusic.insertTimeRange(CMTimeRangeMake(CMTimeMake(Int64(startAudioTime * 10000), 10000), assetVideo.duration), ofTrack: assetMusicTrack, atTime: kCMTimeZero)
catch _
assertionFailure()
//Add parameter
audioMix.inputParameters = audioMixParam
//Remove the previous temp video if exist
let filemgr = NSFileManager.defaultManager()
do
if filemgr.fileExistsAtPath("\(docsDir)/movie-merge-music.mov")
try filemgr.removeItemAtPath("\(docsDir)/movie-merge-music.mov")
else
catch _
//Exporte the final record’
let completeMovie = "\(docsDir)/movie-merge-music.mov"
let completeMovieUrl = NSURL(fileURLWithPath: completeMovie)
let exporter: AVAssetExportSession = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetHighestQuality)!
exporter.outputURL = completeMovieUrl
exporter.outputFileType = AVFileTypeMPEG4
exporter.audioMix = audioMix
exporter.exportAsynchronouslyWithCompletionHandler(
switch exporter.status
case AVAssetExportSessionStatus.Failed:
print("failed \(exporter.error)")
complete(nil)
case AVAssetExportSessionStatus.Cancelled:
print("cancelled \(exporter.error)")
complete(nil)
default:
print("complete")
complete(completeMovieUrl)
)
【讨论】：
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