我一直在尝试按照here指令序列化本地音频文件,而不仅仅是将数据包直接馈送到AudioQueBuffer,我想使用GKSession通过蓝牙/ wifi将其发送。我收到EXC_BAD_ACCESS错误:

- (void)broadcastServerMusicWithSession:(GKSession *)session playerName:(NSString *)name clients:    (NSArray *)clients
{
    self.isServer = YES;

    _session = session;
    _session.available = NO;
    _session.delegate = self;
    [_session setDataReceiveHandler:self withContext:nil];

    CFURLRef     fileURL = (__bridge CFURLRef)[[NSBundle mainBundle] URLForResource:@"mozart"                                                                       withExtension:@"mp3"]; // file URL
    AudioFile *audioFile = [[AudioFile alloc] initWithURL:fileURL];

    //no we start sending the data over
    #define MAX_PACKET_COUNT    4096
    SInt64 currentPacketNumber = 0;
    UInt32 numBytes;
    UInt32 numPacketsToRead;
    AudioStreamPacketDescription    packetDescriptions[MAX_PACKET_COUNT];

    NSInteger bufferByteSize = 4096;
    if (bufferByteSize < audioFile.maxPacketSize) bufferByteSize = audioFile.maxPacketSize;
    numPacketsToRead = bufferByteSize/audioFile.maxPacketSize;
    UInt32 numPackets = numPacketsToRead;

    BOOL isVBR = ([audioFile audioFormatRef]->mBytesPerPacket == 0) ? YES : NO;

// this should be in a do while (numPackets < numPacketsToRead) loop..
// but i took it out just to narrow down the problem

    NSMutableData *myBuffer = [[NSMutableData alloc] initWithCapacity:numPackets * audioFile.maxPacketSize];

    AudioFileReadPackets (
                          audioFile.fileID,
                          NO,
                          &numBytes,
                          isVBR ? packetDescriptions : 0,
                          currentPacketNumber,
                          &numPackets,
                          &myBuffer
                          );

    NSError *error;
    if (![session sendDataToAllPeers:packetData withDataMode:GKSendDataReliable error:&error])
    {
        NSLog(@"Error sending data to clients: %@", error);
    }

我知道事实上是AudioFileReadPackets调用破坏了代码,因为如果我注释掉它,它可以正常运行

我试过使用xcode 4.3进行Zombies profiling,但是它只是崩溃..当代码崩溃并使用gdb控制台输出错误代码时,我得到的一个有用的调试tip中断了。这就是我得到的:
(lldb) po [$eax className] NSException
error: warning: receiver type 'unsigned int' is not 'id' or interface pointer, consider casting it to 'id'
warning: declaration does not declare anything
error: expected ';' after expression
error: 1 errors parsing expression

但我不能做太多..任何帮助吗?

最佳答案

原来上述代码有两个问题:

  • [audioFile audioFormatRef]-> mBytesPerPacket == 0
    如果您引用定义了audioFormatRef的code,它会返回一个指向具有mBytesPerPacket字段的格式结构的指针。.我不知道为什么上面的语法虽然
  • 不起作用
  • 我不应该为AudioFileReadPackets函数(类型mistmach)提供myBuffer。我应该做这样的事情:
    NSMutableData *myBuffer = [[NSMutableData alloc] initWithCapacity:numPackets * audioFile.maxPacketSize];
    const void *buffer = [myBuffer bytes];
    AudioFileReadPackets (
                          audioFile.fileID,
                          NO,
                          &numBytes,
                          isVBR ? packetDescriptions : 0,
                          currentPacketNumber,
                          &numPackets,
                          buffer
                          );
    

  • 这也有效
    void *buffer = [myBuffer mutablebytes];
    

    阅读this帖子以解释这两个选项之间的区别

    10-06 00:08