Question

我正在尝试在后台录制。当我使用audiounit技术时，我在背景中看到一个红色条。但是，当我使用AV Foundation框架（AVAudioRecorder）时，我看不到红条。我在所需的背景模式下有“App播放音频”。以下是AudioSession的代码片段

[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryRecord error:&error];
[[AVAudioSession sharedInstance] setActive:YES error:&error];

与AVAudioRecorder相对应的代码

// ... url, recordSettings initialized properly
recorder = [[ AVAudioRecorder alloc] initWithURL:url settings:recordSettings error:&error];
if([recorder record] == YES)
    NSLog(@"Started recording");

与音频单元对应的代码

// Describe audio component
AudioComponentDescription desc;
desc.componentType = kAudioUnitType_Output;
desc.componentSubType = kAudioUnitSubType_RemoteIO;
desc.componentFlags = 0;
desc.componentFlagsMask = 0;
desc.componentManufacturer = kAudioUnitManufacturer_Apple;

// Get component
AudioComponent inputComponent = AudioComponentFindNext(NULL, &desc);

// Get audio units
oserr = AudioComponentInstanceNew(inputComponent, &m_audioUnit);
checkStatus(oserr);

// Enable IO for recording
UInt32 flag = 1;
oserr = AudioUnitSetProperty(m_audioUnit,
                             kAudioOutputUnitProperty_EnableIO,
                             kAudioUnitScope_Input,
                             1,
                             &flag,
                             sizeof(flag));
checkStatus(oserr);

UInt32 enableOutput        = 0;    // to disable output
AudioUnitElement outputBus = 0;

// Disable output
oserr = AudioUnitSetProperty (
                              m_audioUnit,
                              kAudioOutputUnitProperty_EnableIO,
                              kAudioUnitScope_Output,
                              outputBus,
                              &enableOutput,
                              sizeof (enableOutput)
                              );
checkStatus(oserr);

oserr = AudioUnitInitialize(m_audioUnit);

oserr = AudioOutputUnitStart(m_audioUnit);

我在iOS 6，iPhone 5上运行它。我不清楚为什么在使用AVAudioRecorder时看不到录制状态栏。有关如何获得它的任何建议？

使用AVAudioRecorder在后台录制时无法看到红色状态栏

0 个答案: