目標C/IOS - AVAsset - 錯誤

Question

我嘗試使用下面的代碼保存音頻的片斷從URL流（例如，一個電臺廣播）：

float vocalStartMarker = 0.0; 
    float vocalEndMarker = 20.0; 

    NSURL *audioFileInput = [[NSURL alloc] initWithString: @"http://streamedaudio.mp3"]; 


    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString *documentsPath = [paths objectAtIndex:0]; //Get the docs directory 
    NSString *filePath = [documentsPath stringByAppendingPathComponent:@"TestName.m4a"]; //Add the file name 
    //[audioFileInput writeToFile:filePath atomically:YES]; //Write the file 
    NSURL *audioFileOutput = [[NSURL alloc] initWithString: filePath]; 
    NSLog(@"%@", audioFileOutput); 

    if (!audioFileInput || !audioFileOutput) 
    { 
     return NO; 
    } 

    [[NSFileManager defaultManager] removeItemAtURL:audioFileOutput error:NULL]; 
    AVAsset *asset = [AVAsset assetWithURL:audioFileInput]; 

    AVAssetExportSession *exportSession = [AVAssetExportSession exportSessionWithAsset:asset 
                      presetName:AVAssetExportPresetAppleM4A]; 

    if (exportSession == nil) 
    { 
     return NO; 
    } 

    CMTime startTime = CMTimeMake((int)(floor(vocalStartMarker * 100)), 100); 
    CMTime stopTime = CMTimeMake((int)(ceil(vocalEndMarker * 100)), 100); 
    CMTimeRange exportTimeRange = CMTimeRangeFromTimeToTime(startTime, stopTime); 

    exportSession.outputURL = audioFileOutput; 
    exportSession.outputFileType = AVFileTypeAppleM4A; 
    exportSession.timeRange = exportTimeRange; 

    [exportSession exportAsynchronouslyWithCompletionHandler:^ 
    { 
     if (AVAssetExportSessionStatusCompleted == exportSession.status) 
     { 
      // It worked! 
     } 
     else if (AVAssetExportSessionStatusFailed == exportSession.status) 
     { 
       NSLog(@"%@", exportSession.error); 
      return; 
     } 
    }]; 

我得到以下錯誤：

2015-12-26 14：17：11.523 SaveURL [4135：24621] Error Domain = AVFoundationErrorDomain Code = -11838「Operation Stopped」UserInfo = {NSLocalizedDescription = Operation停止，NSLocalizedFailureReason =該操作不支持這個媒體。}

這是因爲我試圖轉換MP3到M4A？

在此先感謝您的幫助。

Answer 1

應用程序傳輸安全性將請求限制爲HTTPS，除非您明確允許。