Objective - C，我如何裁剪 .caf 文件？

Posted 2023-02-25

【中文标题】Objective - C，我如何裁剪 .caf 文件？

【英文标题】：Objective - C, how do I crop .caf file?

【发布时间】：2013-03-01 10:03:49

【问题描述】：

我已使用 AVAudioRecorder 将声音录制到 .caf 文件中。 我想剪切/修剪这个文件的前 2 秒。怎么做？ （我花了好几个小时才找到解决方案，但是不走运）

【参考方案1】：

您可以使用 AVAssetExportSession.. 来做到这一点。

试试这个代码..

float vocalStartMarker = 0.0f;
float vocalEndMarker = 2.0f;

NSURL *audioFileInput = @"input filePath"; // give your audio file path

NSString *docsDirs;
NSArray *dirPath;
dirPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDirs = [dirPath objectAtIndex:0];
NSString *destinationURLs = [docsDirs stringByAppendingPathComponent:@"trim.caf"];
audioFileOutput = [NSURL fileURLWithPath:destinationURLs];

if (!audioFileInput || !audioFileOutput)

    return NO;

[[NSFileManager defaultManager] removeItemAtURL:audioFileOutput error:NULL];
AVAsset *asset = [AVURLAsset URLAssetWithURL:audioFileInput options:nil];
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!
             NSLog(@"DONE TRIMMING.....");
             NSLog(@"ouput audio trim file %@",audioFileOutput);
      
     else if (AVAssetExportSessionStatusFailed == exportSession.status)
     
         // It failed...
             NSLog(@"FAILED TRIMMING.....");
     
 ];