从视频文件中删除音频 [英] Remove audio from a video file

问题描述

我正在尝试从手机资料库中的MOV类型视频中删除音轨.我知道我可以在播放时使音频静音，但是我计划上传用户视频，将音频取出并减小文件大小是很有意义的.

I'm trying to remove the audio track from a MOV type video in my phone's library. I know I can mute the audio on playback, but I plan to upload user videos and it would just make sense to take the audio out and reduce file size.

我已尝试从 转换obj-c代码这个答案 很快，但我要么搞砸了转换，要么只是不从文件中取出音频.

I've tried converting obj-c code from THIS ANSWER to swift, but I either messed up with conversion or it just doesn't take out the audio from the file.

任何帮助将不胜感激.

推荐答案

最受好评的答案对我不起作用+我在视频轮播方面遇到问题.我最终通过添加参数muteSound: Bool修改了我的视频压缩方法.

The top upvoted answer didn't work for me + I had issues with video rotation. I ended up modifying the video compression method I had by adding a parameter muteSound: Bool.

我使用比特率2300000来使视频看起来不错，但其大小是原始视频的3-4倍.

I use a bitrate of 2300000 to keep the video looking good but 3-4 times smaller in size than original.

我将保持开放性，并在大多数情况下将标记为正确的问题标记为正确.也许有人可以提出更简单的建议.

I'll keep the question open and mark most upvoted one as correct. Maybe someone can come up with something simpler.

func compressVideo(inputURL: NSURL, outputURL: NSURL, bitRate: Int, muteSound: Bool, onDone: () -> ()) {
  let videoAsset = AVURLAsset(URL: inputURL, options: nil)
  let videoTrack = videoAsset.tracksWithMediaType(AVMediaTypeVideo)[0]
  let videoSize = videoTrack.naturalSize
  let videoWriterCompressionSettings = [
    AVVideoAverageBitRateKey: bitRate
  ]

  let videoWriterSettings:[String : AnyObject] = [
    AVVideoCodecKey : AVVideoCodecH264,
    AVVideoCompressionPropertiesKey : videoWriterCompressionSettings,
    AVVideoWidthKey : Int(videoSize.width),
    AVVideoHeightKey : Int(videoSize.height)
  ]

  let videoWriterInput = AVAssetWriterInput(mediaType: AVMediaTypeVideo, outputSettings: videoWriterSettings)
  videoWriterInput.expectsMediaDataInRealTime = true
  videoWriterInput.transform = videoTrack.preferredTransform
  let videoWriter = try! AVAssetWriter(URL: outputURL, fileType: AVFileTypeQuickTimeMovie)
  videoWriter.addInput(videoWriterInput)

  let videoReaderSettings:[String : AnyObject] = [
    kCVPixelBufferPixelFormatTypeKey as String: Int(kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange)
  ]

  let videoReaderOutput = AVAssetReaderTrackOutput(track: videoTrack, outputSettings: videoReaderSettings)
  let videoReader = try! AVAssetReader(asset: videoAsset)
  videoReader.addOutput(videoReaderOutput)

  let audioWriterInput = AVAssetWriterInput(mediaType: AVMediaTypeAudio, outputSettings: nil)
  audioWriterInput.expectsMediaDataInRealTime = false
  videoWriter.addInput(audioWriterInput)

  let audioTrack = videoAsset.tracksWithMediaType(AVMediaTypeAudio)[0]
  let audioReaderOutput = AVAssetReaderTrackOutput(track: audioTrack, outputSettings: nil)
  let audioReader = try! AVAssetReader(asset: videoAsset)
  if muteSound == false {
    audioReader.addOutput(audioReaderOutput)
  }
  videoWriter.startWriting()

  videoReader.startReading()
  videoWriter.startSessionAtSourceTime(kCMTimeZero)
  let processingQueue = dispatch_queue_create("processingQueue1", nil)
  videoWriterInput.requestMediaDataWhenReadyOnQueue(processingQueue, usingBlock: {() -> Void in
    while videoWriterInput.readyForMoreMediaData {
      let sampleBuffer:CMSampleBuffer? = videoReaderOutput.copyNextSampleBuffer()
      if videoReader.status == .Reading && sampleBuffer != nil {
        videoWriterInput.appendSampleBuffer(sampleBuffer!)
      } else {
        videoWriterInput.markAsFinished()
        if videoReader.status == .Completed {
          if muteSound {
            // return without sound
            videoWriter.finishWritingWithCompletionHandler({() -> Void in
              onDone()
            })
          } else {
            audioReader.startReading()
            videoWriter.startSessionAtSourceTime(kCMTimeZero)
            let processingQueue = dispatch_queue_create("processingQueue2", nil)

            audioWriterInput.requestMediaDataWhenReadyOnQueue(processingQueue, usingBlock: {() -> Void in
              while audioWriterInput.readyForMoreMediaData {
                let sampleBuffer:CMSampleBufferRef? = audioReaderOutput.copyNextSampleBuffer()
                if audioReader.status == .Reading && sampleBuffer != nil {
                  audioWriterInput.appendSampleBuffer(sampleBuffer!)
                } else {
                  audioWriterInput.markAsFinished()
                  if audioReader.status == .Completed {
                    videoWriter.finishWritingWithCompletionHandler({() -> Void in
                      onDone()
                    })
                  }
                }
              }
            })
          }
        }
      }
    }
  })
}

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