如何釋放AVASSETEXPORTSESSION的iOS

Question

我寫的代碼像下面和我在行獲取內存泄漏：

AVAssetExportSession* _assetExport = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetPassthrough]; 

我的代碼是：

NSError *error; 
AVMutableComposition* mixComposition = [AVMutableComposition composition]; 


NSURL* audio_inputFileUrl = [_songPath valueForProperty:MPMediaItemPropertyAssetURL]; 

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES); 
NSString *documentsDirectory = ([paths count] > 0) ? [paths objectAtIndex:0] : nil; 

NSString *video_inputFilePath = [documentsDirectory stringByAppendingPathComponent:@"videoOutput1234videoOutput1234.mp4"]; 
NSLog(@"output url %@",video_inputFilePath); 

NSURL* video_inputFileUrl = [NSURL fileURLWithPath:video_inputFilePath]; 


NSArray *docPaths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *docPath=[docPaths objectAtIndex:0]; 
NSString* outputFilePath = [docPath stringByAppendingPathComponent:@"OutPut.mov"];//[[NSBundle mainBundle] pathForResource:@"OutPut" ofType:@"mov"]; 
NSURL* outputFileUrl = [NSURL fileURLWithPath:outputFilePath]; 

if ([[NSFileManager defaultManager] fileExistsAtPath:outputFilePath]) 
{ 
    [[NSFileManager defaultManager] removeItemAtPath:outputFilePath error:nil]; 
} 
else { 
    NSString *defaultPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"OutPut.mov"]; 
    [[NSFileManager defaultManager] copyItemAtPath:defaultPath toPath:outputFilePath error:&error]; 
    [[NSFileManager defaultManager] removeItemAtPath:outputFilePath error:nil]; 
} 



CMTime nextClipStartTime = kCMTimeZero; 

AVURLAsset* videoAsset = [[AVURLAsset alloc]initWithURL:video_inputFileUrl options:nil]; 
CMTimeRange video_timeRange = CMTimeRangeMake(kCMTimeZero,videoAsset.duration); 
AVMutableCompositionTrack *a_compositionVideoTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid]; 

[a_compositionVideoTrack insertTimeRange:video_timeRange ofTrack:[[videoAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0] atTime:nextClipStartTime error:nil]; 


AVURLAsset* audioAsset = [[AVURLAsset alloc]initWithURL:audio_inputFileUrl options:nil]; 
CMTimeRange audio_timeRange = CMTimeRangeMake(kCMTimeZero, audioAsset.duration); 
AVMutableCompositionTrack *b_compositionAudioTrack = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid]; 
[b_compositionAudioTrack insertTimeRange:audio_timeRange ofTrack:[[audioAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:nextClipStartTime error:nil]; 
if ([[NSFileManager defaultManager] fileExistsAtPath:outputFilePath]) 
    [[NSFileManager defaultManager] removeItemAtPath:outputFilePath error:nil]; 

AVAssetExportSession* _assetExport = [[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetPassthrough]; 
_assetExport.outputFileType = @"com.apple.quicktime-movie"; 
_assetExport.outputURL = outputFileUrl; 

if ([[NSFileManager defaultManager] fileExistsAtPath:outputFilePath]) 
    [[NSFileManager defaultManager] removeItemAtPath:outputFilePath error:nil]; 

[_assetExport exportAsynchronouslyWithCompletionHandler:^(void) {[self saveVideoToAlbum:outputFilePath]; }  ];  

[outputFileUrl release]; 
[videoAsset release]; 
[audioAsset release]; 
if (_assetExport.status == 2) { 
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Exporting to library is completed" message:nil delegate:nil cancelButtonTitle:nil otherButtonTitles:@"OK",nil]; 
    [alertView show]; 
    [alertView release]; 
    [mixComposition release]; 
} 

當我試圖釋放AVASSETEXPORTSESSION我應用程序崩潰，我不知道如何釋放這個

你能告訴我答案。

Answer 1

你並不需要釋放：

[outputFileUrl release]; 
[mixComposition release]; 

從代碼中刪除這些行。您需要這樣做，因爲您不擁有它們（未分配）。所以你不需要發佈他們。

然後它現在應該工作。

自動釋放：

AVAssetExportSession* _assetExport = [[[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetPassthrough] autorelease]; 

或發佈：

[_assetExport release];