Question

我制作了一个使用OpenAL播放许多声音的iphone应用程序。这些声音是mp3，非常重（超过1百万），我流式传输（每个声音2个缓冲区），以便使用更少的内存。要管理中断，我使用以下代码：

在OpenALSupport.c文件中：

  //used to disable openAL during a call
    void openALInterruptionListener ( void   *inClientData, UInt32 inInterruptionState) 
    {
        if (inInterruptionState == kAudioSessionBeginInterruption) 
        {
            alcMakeContextCurrent (NULL);
        }
    }

    //used to restore openAL after a call
    void restoreOpenAL(void* a_context)
    {
        alcMakeContextCurrent(a_context);
    }

在我的SoundManager.m文件中：

 - (void) restoreOpenAL
    {
        restoreOpenAL(mContext);
    }

    //OPENAL initialization
    - (bool) initOpenAL
    {   
        // Initialization
        mDevice = alcOpenDevice(NULL);
        if (mDevice) {
    ...

            // use the device to make a context
            mContext=alcCreateContext(mDevice,NULL);
            // set my context to the currently active one
            alcMakeContextCurrent(mContext);

            AudioSessionInitialize (NULL, NULL, openALInterruptionListener, mContext);

            NSError *activationError = nil;
            [[AVAudioSession sharedInstance] setActive: YES error: &activationError];

            NSError *setCategoryError = nil;

            [[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryAmbient error: &setCategoryError];

            ...
    }

最后在我的AppDelegate中：

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    [[CSoundManager getInstance] restoreOpenAL];
    ...
}

使用此方法，声音在通话后恢复，但流似乎是随机播放的。是否有一种特定的方法来管理流媒体声音的中断？我没有找到任何关于此的文章。

感谢您的帮助。

Answer 1

好的，我回答了我自己的问题。

我通过管理流媒体方法的错误解决了这个问题：

- (void) updateStream
{
ALint processed;    
alGetSourcei(sourceID, AL_BUFFERS_PROCESSED, &processed);

while(processed--)
{
    oldPosition = position;

    NSUInteger buffer;

    alSourceUnqueueBuffers(sourceID, 1, &buffer);

    ////////////////////
    //code freshly added
    ALint err = alGetError();
    if (err != 0) 
    {
        NSLog(@"Error Calling alSourceUnQueueBuffers: %d",err);
        processed++;
        //restore old position for the next buffer
        position = oldPosition;
        usleep(10000);
        continue;
    }
    ////////////////////    

    [self stream:buffer];

    alSourceQueueBuffers(sourceID, 1, &buffer);

    ////////////////////
    //code freshly added
    err = alGetError();
    if (err != 0) 
    {
        NSLog(@"Error Calling alSourceQueueBuffers: %d",err);
        processed++;
        usleep(10000);
        //restore old position for the next buffer 
        position = oldPosition;
    }
    ///////////////////
}

}

openAL流媒体＆amp;中断

1 个答案: