AVAssetWriter在Swift中錄製視頻？

Question

我已成功設置AVAssetWriter以將視頻錄製並保存到相機膠捲。唯一的問題是錄製的視頻的第一幀是空白的白框。有沒有辦法解決這個問題？到底是怎麼回事？

Answer 1

你對視頻幀有任何操縱嗎？在我的情況下，我正在調整視頻幀的大小，然後再編寫它們。在這種情況下，首先寫入音頻幀，在幾幀後寫入視頻幀。由於這個原因，前幾幀在預覽中顯示爲白色。但它在視頻播放中幾乎不明顯。

解決方案：

跳過寫音頻幀，直到你使用avasssetwriter

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推薦代碼captureoutput

func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection!) { 

    if CMSampleBufferDataIsReady(sampleBuffer) == false 
    { 
     // Handle error 
     return; 
    } 
    startTime = CMSampleBufferGetPresentationTimeStamp(sampleBuffer) 

    if videoWriter.status == AVAssetWriterStatus.Unknown { 
       videoWriter.startWriting() 
       videoWriter.startSessionAtSourceTime(startTime) 
       return 
     } 

    if videoWriter.status == AVAssetWriterStatus.Failed { 
     // Handle error here 
     return; 
    } 

    // Here you collect each frame and process it 

    if(recordingInProgress){ 

    if let _ = captureOutput as? AVCaptureVideoDataOutput { 

     if videoWriterInput.isReadyForMoreMediaData{ 
      videoWriterInput.append(sampleBuffer) 
      video_frames_written = true 
     } 
    } 
    if let _ = captureOutput as? AVCaptureAudioDataOutput { 
      if audioWriterInput.isReadyForMoreMediaData && video_frames_written{ 
       audioWriterInput.append(sampleBuffer) 
      } 

     } 

    } 

}