I am working on Application that combines the multiple videos along with background audio track. It also need to set different audio level for different videos.
Following is the code for AssetItem class & AssetManager Class
// AssetItem Class
class AssetItem : NSObject {
var asset : Asset!
var assetEffect : AssetEffectType! // Enum
var assetSceneType : SceneType! // Enum
var videoLength : CMTime!
var animationLayer : AnyObject?
var volumeOfVideoVoice : Float = 0.0
var volumeOfBGMusic : Float = 0.0
override init() {
super.init()
}
}
// AssetManager Class implementation
class AssetManager{
var assetList = [AssetItem]()
var composition : AVMutableComposition! = AVMutableComposition()
var videoComposition : AVMutableVideoComposition? = AVMutableVideoComposition()
var audioMix : AVMutableAudioMix = AVMutableAudioMix()
var transitionDuration = CMTimeMakeWithSeconds(1, 600) // Default transitionDuration is 1 sec
var compositionTimeRanges : [NSValue] = [NSValue]()
var passThroughTimeRangeValue : [NSValue] = [NSValue]()
var transitionTimeRangeValue : [NSValue] = [NSValue]()
var videoTracks = [AVMutableCompositionTrack]()
var audioTracks = [AVMutableCompositionTrack]()
// MARK: - Constructor
override init() {
super.init()
let compositionTrackA = self.composition.addMutableTrackWithMediaType(AVMediaTypeVideo, preferredTrackID: CMPersistentTrackID(kCMPersistentTrackID_Invalid))
let compositionTrackB = self.composition.addMutableTrackWithMediaType(AVMediaTypeVideo, preferredTrackID: CMPersistentTrackID(kCMPersistentTrackID_Invalid))
let compositionTrackAudioA = self.composition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID(kCMPersistentTrackID_Invalid))
let compositionTrackAudioB = self.composition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID(kCMPersistentTrackID_Invalid))
self.videoTracks = [compositionTrackA, compositionTrackB]
self.audioTracks = [compositionTrackAudioA, compositionTrackAudioB]
}
func buildCompositionTrack(forExport : Bool ){
// This is the Method to Build Compositions
}
}
FOllowing is the Method for BuildingCompositions
func buildCompositionTrack(forExport : Bool) {
var cursorTIme = kCMTimeZero
var transitionDurationForEffect = kCMTimeZero
// Create a mutable composition instructions object
var videoCompositionInstructions = [AVMutableVideoCompositionInstruction]()
var audioMixInputParameters = [AVMutableAudioMixInputParameters]()
let timeRanges = calculateTimeRangeForAssetLayer()
self.passThroughTimeRangeValue = timeRanges.passThroughTimeRangeValue
self.transitionTimeRangeValue = timeRanges.transitionTimeRangeValue
let defaultMuteSoundTrackURL: NSURL = bundle.URLForResource("30sec", withExtension: "mp3")!
let muteSoundTrackAsset = AVURLAsset(URL: defaultMuteSoundTrackURL, options: nil)
let muteSoundTrack = muteSoundTrackAsset.tracksWithMediaType(AVMediaTypeAudio)[0]
for (index,assetItem) in self.assetsList.enumerate() {
let trackIndex = index % 2
let assetVideoTrack = assetItem.asset.movieAsset.tracksWithMediaType(AVMediaTypeVideo)[0]
let timeRange = CMTimeRangeMake(kCMTimeZero, assetItem.videoLength)
do {
try self.videoTracks[trackIndex].insertTimeRange(timeRange, ofTrack: assetVideoTrack, atTime: cursorTime)
} catch let error1 as NSError {
error = error1
}
if error != nil {
print("Error: buildCompositionTracks for video with parameter index: %@ and VideoCounts: %@ error: %@", ["\(index)", "\(self.assetsList.count)", "\(error?.description)"])
error = nil
}
if assetItem.asset.movieAsset.tracksWithMediaType(AVMediaTypeAudio).count > 0 {
let clipAudioTrack = assetItem.asset.movieAsset.tracksWithMediaType(AVMediaTypeAudio)[0]
do {
try audioTracks[trackIndex].insertTimeRange(timeRange, ofTrack: clipAudioTrack, atTime: cursorTime)
} catch let error1 as NSError {
error = error1
}
}else {
do {
try audioTracks[trackIndex].insertTimeRange(timeRange, ofTrack: muteSoundTrack, atTime: cursorTime)
}catch let error1 as NSError {
error = error1
}
}
// The end of this clip will overlap the start of the next by transitionDuration.
// (Note: this arithmetic falls apart if timeRangeInAsset.duration < 2 * transitionDuration.)
if assetItem.assetEffect == FLIXAssetEffectType.Default {
transitionDurationForEffect = kCMTimeZero
let timeRange = CMTimeRangeMake(cursorTime, assetItem.videoLength)
self.compositionTimeRanges.append(NSValue(CMTimeRange: timeRange))
cursorTime = CMTimeAdd(cursorTime, assetItem.videoLength)
} else {
transitionDurationForEffect = self.transitionDuration
let timeRange = CMTimeRangeMake(cursorTime, CMTimeSubtract(assetItem.videoLength, transitionDurationForEffect))
self.compositionTimeRanges.append(NSValue(CMTimeRange: timeRange))
cursorTime = CMTimeAdd(cursorTime, assetItem.videoLength)
cursorTime = CMTimeSubtract(cursorTime, transitionDurationForEffect)
}
videoCompositionInstructions.appendContentsOf(self.buildCompositionInstructions( index, assetItem : assetItem))
}
if self.project.hasProjectMusicTrack() && self.backgroundMusicTrack != nil {
let url: NSURL = bundle.URLForResource("Music9", withExtension: "mp3")!
bgMusicSound = AVURLAsset(URL: url, options: nil)
backgroundAudioTrack = bgMusicSound.tracksWithMediaType(AVMediaTypeAudio)[0]
let compositionBackgroundTrack = self.composition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID(kCMPersistentTrackID_Invalid))
let soundDuration = CMTimeCompare(bgMusicSound.duration, self.composition.duration)
if soundDuration == -1 {
let bgMusicSoundTimeRange = CMTimeRangeMake(kCMTimeZero, bgMusicSound.duration)
let noOftimes = Int(CMTimeGetSeconds(self.composition.duration) / CMTimeGetSeconds(bgMusicSound.duration))
let remainingTime = CMTimeGetSeconds(self.composition.duration) % CMTimeGetSeconds(bgMusicSound.duration)
var musicCursorTime = kCMTimeZero
for _ in 0..<noOftimes {
do {
try compositionBackgroundTrack.insertTimeRange(bgMusicSoundTimeRange, ofTrack: backgroundAudioTrack, atTime: musicCursorTime)
} catch let error1 as NSError {
error = error1
}
musicCursorTime = CMTimeAdd(bgMusicSound.duration, musicCursorTime)
}
}
let backgroundMusciMixInputParameters = AVMutableAudioMixInputParameters(track: compositionBackgroundTrack)
backgroundMusciMixInputParameters.trackID = compositionBackgroundTrack.trackID
// setting up music levels for background music track.
for index in 0 ..< Int(self.compositionTimeRanges.count) {
let timeRange = self.compositionTimeRanges[index].CMTimeRangeValue
let scene = self.assetsList[index].assetSceneType
let volumeOfBGMusic = self.assetsList[index].volumeOfBGMusic
var nextvolumeOfBGMusic : Float = 0.0
if let nextAsset = self.assetsList[safe: index + 1] {
nextvolumeOfBGMusic = nextAsset.volumeOfBGMusic
}
backgroundMusciMixInputParameters.setVolume(volumeOfBGMusic, atTime: timeRange.start)
backgroundMusciMixInputParameters.setVolumeRampFromStartVolume(volumeOfBGMusic, toEndVolume: nextvolumeOfBGMusic, timeRange: CMTimeRangeMake(CMTimeSubtract(timeRange.end,CMTimeMake(2, 1)), CMTimeMake(2, 1)))
}
audioMixInputParameters.append(backgroundMusciMixInputParameters)
} // End of If for ProjectMusic Check
for (index, assetItem) in self.assetsList.enumerate(){
let trackIndex = index % 2
let timeRange = self.compositionTimeRanges[index].CMTimeRangeValue
let sceneType = assetItem.assetSceneType
let volumnOfVideoMusic = assetItem.volumeOfVideoVoice
let audioTrackParamater = AVMutableAudioMixInputParameters(track: self.audioTracks[trackIndex])
audioTrackParamater.trackID = self.audioTracks[trackIndex].trackID
audioTrackParamater.setVolume(0.0, atTime: kCMTimeZero ) // Statement 1
audioTrackParamater.setVolume(volumnOfVideoMusic, atTime: timeRange.start) // Statement 2
audioTrackParamater.setVolume(0.0, atTime: timeRange.end) // statement 3
audioMixInputParameters.append(audioTrackParamater)
}
self.audioMix.inputParameters = audioMixInputParameters
self.composition.naturalSize = self.videoRenderSize
self.videoComposition!.instructions = videoCompositionInstructions
self.videoComposition!.renderSize = self.videoRenderSize
self.videoComposition!.frameDuration = CMTimeMake(1, 30)
self.videoComposition!.renderScale = 1.0 // This is a iPhone only option.
}
In above code, Background Music Levels are set properly, but something is going wrong for audio levels of Video Tracks. I have added DebugView to help Debug Compositions, everything looks perfect in debug view, but other than Background Music Track, Audio of Video is no more audible. is there is something I am doing wrong?
If I remove Statement 1 from above code then its audible, but now they are all audible at level 1.0, and dont respect the levels set.
