我正在录制屏幕，我想将麦克风音频和应用程序音频中的声音合并为具有一个立体声音频轨道的视频。使用AVAssetWriter设置，它会创建一个具有两个单独音轨的视频文件；一个立体声轨道用于设备音频，一个单声道轨道用于麦克风音频。这不好。
我还尝试使用生成的视频文件并使用AVAssetTrack s AVMutableCompositionTrack函数将单独的音频insertTimeRange( s合并为一个，并重建新的视频文件下面。但这并不会合并音轨，无论我如何尝试，它都只是将它们串联起来（按顺序，没有覆盖在另一个轨道上）。
请有人告诉我如何用AVAssetWriter录制合并的曲目。或者稍后如何将它们合并在一起。网上没有任何东西可以讨论并完成它。许多文章都提到了insertTimeRange(的使用，但是此功能会合并曲目。请帮忙。
到目前为止我正在使用的代码：
func startRecording(withFileName fileName: String, recordingHandler: @escaping (Error?) -> Void) {
let sharedRecorder = RPScreenRecorder.shared()
currentlyRecordingURL = URL(fileURLWithPath: CaptureArchiver.filePath(fileName))
guard currentlyRecordingURL != nil else { return }
desiredMicEnabled = RPScreenRecorder.shared().isMicrophoneEnabled
assetWriter = try! AVAssetWriter(outputURL: currentlyRecordingURL!, fileType: AVFileType.mp4)
let appAudioOutputSettings = [
AVFormatIDKey : kAudioFormatMPEG4AAC,
AVNumberOfChannelsKey : 2,
AVSampleRateKey : 44100.0,
AVEncoderBitRateKey: 192000
] as [String : Any]
let micAudioOutputSettings = [
AVFormatIDKey : kAudioFormatMPEG4AAC,
AVNumberOfChannelsKey : 1,
AVSampleRateKey : 44100.0,
AVEncoderBitRateKey: 192000
] as [String : Any]
let adjustedWidth = ceil(UIScreen.main.bounds.size.width/4)*4
let videoOutputSettings: Dictionary<String, Any> = [
AVVideoCodecKey : AVVideoCodecType.h264,
AVVideoWidthKey : adjustedWidth,
AVVideoHeightKey : UIScreen.main.bounds.size.height
]
let audioInput_app = AVAssetWriterInput(mediaType: AVMediaType.audio, outputSettings: appAudioOutputSettings)
audioInput_app.expectsMediaDataInRealTime = true
if assetWriter.canAdd(audioInput_app) { assetWriter.add(audioInput_app) }
self.audioInput_app = audioInput_app
let audioInput_mic = AVAssetWriterInput(mediaType: AVMediaType.audio, outputSettings: micAudioOutputSettings)
audioInput_mic.expectsMediaDataInRealTime = true
if assetWriter.canAdd(audioInput_mic) { assetWriter.add(audioInput_mic) }
self.audioInput_mic = audioInput_mic
let videoInput = AVAssetWriterInput(mediaType: AVMediaType.video, outputSettings: videoOutputSettings)
videoInput.expectsMediaDataInRealTime = true
if assetWriter.canAdd(videoInput) { assetWriter.add(videoInput) }
self.videoInput = videoInput
RPScreenRecorder.shared().startCapture(handler: { [unowned self] (sample, bufferType, error) in
if CMSampleBufferDataIsReady(sample) {
DispatchQueue.main.async { [unowned self] in
if self.assetWriter.status == AVAssetWriter.Status.unknown {
self.assetWriter.startWriting()
#if DEBUG
let status = self.assetWriter.status
log(self, message: "LAUNCH assetWriter.status[\(status.rawValue)]:\(String(describing: self.readable(status)))")
#endif
self.assetWriter.startSession(atSourceTime: CMSampleBufferGetPresentationTimeStamp(sample))
} else if self.assetWriter.status == AVAssetWriter.Status.failed {
recordingHandler(error)
return
} else {
switch bufferType {
case .audioApp:
if let audioInput_app = self.audioInput_app {
if audioInput_app.isReadyForMoreMediaData { audioInput_app.append(sample) }
}
case .audioMic:
if let audioInput_mic = self.audioInput_mic {
if audioInput_mic.isReadyForMoreMediaData { audioInput_mic.append(sample) }
}
case .video:
if let videoInput = self.videoInput {
if videoInput.isReadyForMoreMediaData { videoInput.append(sample) }
}
@unknown default:
fatalError("Unknown RPSampleBufferType:\(bufferType)")
}
}
}
}
}) { [unowned self] (error) in
recordingHandler(error)
if error == nil && self.desiredMicEnabled == true && RPScreenRecorder.shared().isMicrophoneEnabled == false {
self.viewController.mic_cap_denied = true
} else {
self.viewController.mic_cap_denied = false
}
}
}
func mergeAudioTracksInVideo(_ videoURL: URL, completion: @escaping ((Bool) -> Void)) {
let sourceAsset = AVURLAsset(url: videoURL)
let sourceVideoTrack: AVAssetTrack = sourceAsset.tracks(withMediaType: AVMediaType.video)[0]
let sourceAudioTrackApp: AVAssetTrack = sourceAsset.tracks(withMediaType: AVMediaType.audio)[0]
let sourceAudioTrackMic: AVAssetTrack = sourceAsset.tracks(withMediaType: AVMediaType.audio)[1]
let comp: AVMutableComposition = AVMutableComposition()
guard let newVideoTrack: AVMutableCompositionTrack = comp.addMutableTrack(withMediaType: AVMediaType.video,
preferredTrackID: kCMPersistentTrackID_Invalid) else {
completion(false)
return
}
newVideoTrack.preferredTransform = sourceVideoTrack.preferredTransform
guard let newAudioTrack: AVMutableCompositionTrack = comp.addMutableTrack(withMediaType: AVMediaType.audio,
preferredTrackID: kCMPersistentTrackID_Invalid) else {
completion(false)
return
}
//THE MIXING //THIS STILL RESULTS IN TWO SEPARATE AUDIO TRACKS //LOOKS LIKE THIS IS MORE ABOUT VOLUME LEVELS
let mix = AVMutableAudioMix()
let audioMixInputParamsMic = AVMutableAudioMixInputParameters()
audioMixInputParamsMic.trackID = sourceAudioTrackMic.trackID
audioMixInputParamsMic.setVolume(1.0, at: CMTime.zero)
let audioMixInputParamsApp = AVMutableAudioMixInputParameters()
audioMixInputParamsApp.trackID = sourceAudioTrackApp.trackID
audioMixInputParamsApp.setVolume(1.0, at: CMTime.zero)
mix.inputParameters.append(audioMixInputParamsMic)
mix.inputParameters.append(audioMixInputParamsApp)
///////
let timeRange: CMTimeRange = CMTimeRangeMake(start: CMTime.zero, duration: sourceAsset.duration)
do {
try newVideoTrack.insertTimeRange(timeRange, of: sourceVideoTrack, at: CMTime.zero)
try newAudioTrack.insertTimeRange(timeRange, of: sourceAudioTrackMic, at: CMTime.zero)
try newAudioTrack.insertTimeRange(timeRange, of: sourceAudioTrackApp, at: CMTime.zero)
} catch {
completion(false)
return
}
let exporter: AVAssetExportSession = AVAssetExportSession(asset: comp, presetName: AVAssetExportPresetHighestQuality)!
exporter.audioMix = mix
exporter.outputFileType = AVFileType.mp4
exporter.outputURL = videoURL
removeFileAtURLIfExists(url: videoURL)
exporter.exportAsynchronously(completionHandler: {
switch exporter.status {
case AVAssetExportSession.Status.failed:
#if DEBUG
log(self, message: "1000000000failed \(String(describing: exporter.error))")
#endif
case AVAssetExportSession.Status.cancelled:
#if DEBUG
log(self, message: "1000000000cancelled \(String(describing: exporter.error))")
#endif
case AVAssetExportSession.Status.unknown:
#if DEBUG
log(self, message: "1000000000unknown\(String(describing: exporter.error))")
#endif
case AVAssetExportSession.Status.waiting:
#if DEBUG
log(self, message: "1000000000waiting\(String(describing: exporter.error))")
#endif
case AVAssetExportSession.Status.exporting:
#if DEBUG
log(self, message: "1000000000exporting\(String(describing: exporter.error))")
#endif
default:
#if DEBUG
log(self, message: "1000000000-----Mutable video exportation complete.")
#endif
}
completion(true)
})
}
答案 0 :(得分：1)
在此类中使用，并在以下功能中用于记录开始和结束后：
https://gist.github.com/mspvirajpatel/f7e1e258f3c1fff96917d82fa9c4c137
import AVFoundation
import ReplayKit
var rpScreenRecorder = RPScreenRecorder.shared()
var rpScreenWriter = RPScreenWriter()
func startRecord() {
rpScreenRecorder.isMicrophoneEnabled = true
rpScreenRecorder.startCapture(handler: { cmSampleBuffer, rpSampleBufferType, error in
if let error = error {
} else {
self.rpScreenWriter.writeBuffer(cmSampleBuffer, rpSampleType: rpSampleBufferType)
}
}) { error in
}
}
func stopRecording() {
rpScreenRecorder.stopCapture { error in
if let error = error {
} else {
self.rpScreenWriter.finishWriting(completionHandler: { url, error in
if let url = url {
print("\(url)")
}
})
}
}
}