Как освободить память, добавленный AVAsset

Question

У меня возникла проблема с моим кодом при чтении и уменьшении песни из моей музыкальной библиотеки, она заняла около 20 мб до предупреждения и сбоя памяти. я не видел, чтобы найти, что пошло не так, я понимаю, что когда я назову код ниже, размер памяти приложения увеличится.

Получу любые комментарии по моим кодам.

if ([self exportAudio:[AVAsset assetWithURL:songURL] toFilePath:savedPath]) 
     { 
      // [self performSelector:@selector(sendSongForUpload:) withObject:subStringPath afterDelay:1]; 
      [self sendRequest:2 andPath:subStringPath andSongDBItem:songVar]; 
     } 

конвертировано песни на более низкой скорости передачи данных и сохранить в папке приложения док

- (BOOL)exportAudio:(AVAsset *)avAsset toFilePath:(NSString *)filePath 
{ 
    CMTime assetTime = [avAsset duration]; 
    Float64 duration = CMTimeGetSeconds(assetTime); 
    if (duration < 40.0) return NO; 

    // get the first audio track 
    NSArray *tracks = [avAsset tracksWithMediaType:AVMediaTypeAudio]; 
    if ([tracks count] == 0) return NO; 


    NSError *readerError = nil; 
    AVAssetReader *reader = [[AVAssetReader alloc] initWithAsset:avAsset error:&readerError]; 
    AVAssetReaderOutput *readerOutput = [AVAssetReaderAudioMixOutput 
             assetReaderAudioMixOutputWithAudioTracks:avAsset.tracks 
             audioSettings: nil]; 

    if (! [reader canAddOutput: readerOutput]) 
    { 
     NSLog (@"can't add reader output... die!"); 
     return NO; 
    } 
    else 
    { 
     [reader addOutput:readerOutput]; 
    } 

    // writer 
    NSError *writerError = nil; 
    AVAssetWriter *writer = [[AVAssetWriter alloc] initWithURL:[NSURL fileURLWithPath:filePath] 
                 fileType:AVFileTypeAppleM4A 
                 error:&writerError]; 
    NSLog(@"writer %@",writer); 

    AudioChannelLayout channelLayout; 
    memset(&channelLayout, 0, sizeof(AudioChannelLayout)); 
    channelLayout.mChannelLayoutTag = kAudioChannelLayoutTag_Stereo; 

    // use different values to affect the downsampling/compression 
    // NSDictionary *outputSettings = [NSDictionary dictionaryWithObjectsAndKeys: 
    //         [NSNumber numberWithInt: kAudioFormatMPEG4AAC], AVFormatIDKey, 
    //         [NSNumber numberWithFloat:16000.0], AVSampleRateKey, 
    //         [NSNumber numberWithInt:2], AVNumberOfChannelsKey, 
    //         [NSNumber numberWithInt:128000], AVEncoderBitRateKey, 
    //         [NSData dataWithBytes:&channelLayout length:sizeof(AudioChannelLayout)], AVChannelLayoutKey, 
    //         nil]; 

    NSDictionary *outputSettings = @{AVFormatIDKey: @(kAudioFormatMPEG4AAC), 
            AVEncoderBitRateKey: @(8000), 
            AVNumberOfChannelsKey: @(1), 
            AVSampleRateKey: @(8000)}; 

    AVAssetWriterInput *writerInput = [[AVAssetWriterInput alloc] initWithMediaType:AVMediaTypeAudio outputSettings:outputSettings]; 
    [writerInput setExpectsMediaDataInRealTime:NO]; 

    //\Add inputs to Write 
    NSParameterAssert(writerInput); 
    NSAssert([writer canAddInput:writerInput], @"Cannot write to this type of audio input"); 

    if ([writer canAddInput:writerInput]) 
    { 
     [writer addInput:writerInput]; 
    } 
    else 
    { 
     NSLog (@"can't add asset writer input... die!"); 
     return NO; 
    } 
    [writer startWriting]; 
    [writer startSessionAtSourceTime:kCMTimeZero]; 
    [reader startReading]; 

    __block UInt64 convertedByteCount = 0; 
    __block BOOL returnValue; 
    dispatch_queue_t mediaInputQueue = dispatch_queue_create("mediaInputQueue", NULL); 

    [writerInput requestMediaDataWhenReadyOnQueue:mediaInputQueue usingBlock:^{ 

     // NSLog(@"Asset Writer ready : %d", writerInput.readyForMoreMediaData); 

     while (writerInput.readyForMoreMediaData) 
     { 
      CMSampleBufferRef nextBuffer = [readerOutput copyNextSampleBuffer]; 

      if (nextBuffer) 
      { 
       [writerInput appendSampleBuffer: nextBuffer]; 
       convertedByteCount += CMSampleBufferGetTotalSampleSize (nextBuffer); 
       //NSNumber *convertedByteCountNumber = [NSNumber numberWithLong:convertedByteCount]; 
       //NSLog (@"writing"); 
      } 
      else 
      { 
       [writerInput markAsFinished]; 

       [writer finishWritingWithCompletionHandler:^{ 

        if (AVAssetWriterStatusCompleted == writer.status) 
        { 
         NSLog(@"Writer completed"); 
         //[writer cancelWriting]; 
         //[reader cancelReading]; 
         returnValue = YES; 

         dispatch_async(mediaInputQueue, ^{ 
          dispatch_async(dispatch_get_main_queue(), ^{ 
           // add this to the main queue as the last item in my serial queue 
           // when I get to this point I know everything in my queue has been run 

          }); 

         }); 

        } 
        else if (AVAssetWriterStatusFailed == writer.status) 
        { 
         [writer cancelWriting]; 
         [reader cancelReading]; 
         NSLog(@"Writer failed"); 
         return; 
        } 
        else 
        { 
         NSLog(@"Export Session Status: %d", writer.status); 
        } 
       }]; 
       break; 
      } 
     } 
    }]; 
    writer = nil; 
    writerInput = nil; 
    reader = nil; 
    readerOutput=nil; 

    return returnValue; 
    //return YES; 
} 

Answer 1

https://developer.apple.com/library/mac/documentation/AVFoundation/Reference/AVAssetReaderOutput_Class/Reference/Reference.html#//apple_ref/occ/instm/AVAssetReaderOutput/copyNextSampleBuffer

Основной Фонд не освобождает от АРК в соответствии с «создания правил» в управлении памятью Руководство по программированию для Core Foundation. Я должен освободить CMSampleBufferRef, полученный из - (CMSampleBufferRef) copyNextSampleBuffer, или я получу утечку памяти.

if (nextBuffer) 
{ 
    [writerInput appendSampleBuffer: nextBuffer]; 
    convertedByteCount += CMSampleBufferGetTotalSampleSize (nextBuffer); 
    //NSLog (@"writing"); 
    CFRelease(nextBuffer); 
}