AVAssetExportSession总是失败

Question

当我组合两个m4a音频文件并导出这个文件时，这总是会给我失败。我在这里得到了同样的问题，我尝试了每个人的答案，但没有一个对我有效。

NSString* documentsDirectory= [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];

    NSString* myDocumentPath= [documentsDirectory stringByAppendingPathComponent:@"merge_audio.mp4"];

    NSURL *url = [NSURL fileURLWithPath:myDocumentPath];//[[NSURL alloc] initFileURLWithPath: myDocumentPath];
    NSLog(@"%@",url);
    //Check if the file exists then delete the old file to save the merged video file.
    if([[NSFileManager defaultManager]fileExistsAtPath:myDocumentPath])
    {
        [[NSFileManager defaultManager]removeItemAtPath:myDocumentPath error:nil];
    }

AVAssetExportSession *exporter=[[AVAssetExportSession alloc] initWithAsset:composition presetName:AVAssetExportPresetAppleM4A];
    exporter.outputURL=url;
    exporter.outputFileType=AVFileTypeAppleM4A;
    [exporter exportAsynchronouslyWithCompletionHandler:^{
        switch([exporter status])
        {
            case AVAssetExportSessionStatusFailed:
                NSLog(@"Failed to export audio");
                break;
            case AVAssetExportSessionStatusCancelled:
                NSLog(@"export cancelled");
                break;
            case AVAssetExportSessionStatusCompleted:
                //Here you go you have got the merged video :)
                NSLog(@"Merging completed");

                break;
            default:
                break;
        }
}];

Answer 1

您可以在AVAssetExportSession的error property中找到所需的解释，只需记录下来即可。