CMBlockBuffer創建內存管理

Question

我有一些代碼創建CMBlockBuffers，然後創建一個CMSampleBuffer並將其傳遞給AVAssetWriterInput。

什麼是內存管理這裏的交易嗎？根據Apple文檔，anything you use with 'Create' in the name should be released with CFRelease。

但是，如果我使用CFRelease，那麼我的應用程序將終止'malloc：*錯誤對象0xblahblah：被釋放的指針未被分配。

CMBlockBufferRef tmp_bbuf = NULL; 
CMBlockBufferRef bbuf = NULL; 
CMSampleBufferRef sbuf = NULL; 
status = CMBlockBufferCreateWithMemoryBlock(
              kCFAllocatorDefault, 
              samples, 
              buflen, 
              kCFAllocatorDefault, 
              NULL, 
              0, 
              buflen, 
              0, 
              &tmp_bbuf); 

if (status != noErr || !tmp_bbuf) { 
    NSLog(@"CMBlockBufferCreateWithMemoryBlock error"); 
    return -1; 
} 
// Copy the buffer so that we get a copy of the samples in memory. 
// CMBlockBufferCreateWithMemoryBlock does not actually copy the data! 
// 
status = CMBlockBufferCreateContiguous(kCFAllocatorDefault, tmp_bbuf, kCFAllocatorDefault, NULL, 0, buflen, kCMBlockBufferAlwaysCopyDataFlag, &bbuf); 
//CFRelease(tmp_bbuf); // causes abort?! 
if (status != noErr) { 
    NSLog(@"CMBlockBufferCreateContiguous error"); 
    //CFRelease(bbuf); 
    return -1; 
} 


CMTime timestamp = CMTimeMake(sample_position_, 44100); 

status = CMAudioSampleBufferCreateWithPacketDescriptions(
    kCFAllocatorDefault, bbuf, TRUE, 0, NULL, audio_fmt_desc_, 1, timestamp, NULL, &sbuf); 

sample_position_ += n; 
if (status != noErr) { 
    NSLog(@"CMSampleBufferCreate error"); 
    return -1; 
} 
BOOL r = [audioWriterInput appendSampleBuffer:sbuf]; // AVAssetWriterInput 
//memset(&audio_buf_[0], 0, buflen); 
if (!r) { 
    NSLog(@"appendSampleBuffer error"); 
} 
//CFRelease(bbuf); 
//CFRelease(sbuf); 

所以，在這段代碼中，我應該用任何東西CFRelease？

Answer 1

的關鍵是blockAllocator參數CMBlockBufferCreateWithMemoryBlock：

分配器用於分配MemoryBlock中，如果MemoryBlock中是 NULL。如果MemoryBlock中的非NULL，該分配器將用於如果提供它 解除分配。傳遞NULL將導致默認 分配器（如設定在通話時）使用。 通過 如果不需要重新分配，kCFAllocatorNull。

既然你不想要的「樣本」當你釋放CMBlockBuffer被釋放嗎，你想在kCFAllocatorNull通過像這樣的第四個參數：

status = CMBlockBufferCreateWithMemoryBlock(
              kCFAllocatorDefault, 
              samples, 
              buflen, 
              kCFAllocatorNull, 
              NULL, 
              0, 
              buflen, 
              0, 
              &tmp_bbuf); 

Answer 2

CMAudioSampleBufferCreateWithPacketDescriptions(kCFAllocatorDefault, bbuf, TRUE, 0, NULL, audio_fmt_desc_, 1, timestamp, NULL, &sbuf); 

這應該是：

CMAudioSampleBufferCreateWithPacketDescriptions(kCFAllocatorDefault, bbuf, TRUE, 0, NULL, audio_fmt_desc_, 1024, timestamp, NULL, &sbuf);