未能在苹果示例代码"AVCaptureToAudioUnit“中设置音频文件

Question

我不熟悉目标C和audioUnit。

我想要做的iOS应用程序，可以保存声音信号从麦克风通过一些audioUnit效果，在设备中的声音。因此，现在我正在尝试研究苹果的示例代码"AVCaptureToAudioUnit“

https://developer.apple.com/library/ios/samplecode/AVCaptureToAudioUnit/Introduction/Intro.html (使用Xcode 6.1和仿真器iphone5构建)

但是它暴露了下面的错误

AudioStreamBasicDescription: 0 ch,0 Hz,'lpcm' (0x0000000E) 16-bit signed integer

2015-03-17 13:44:56.589 AVCaptureToAudioUnit[1462:151210] Failed to setup audio file! (29759)

这些日志是用下面的CaptureSessionController.mm方法编写的

- (void)startRecording
{
 if (!self.isRecording) {
    OSErr err = kAudioFileUnspecifiedError;
    @synchronized(self) {
        if (!extAudioFile) {
            /*
             Start recording by creating an ExtAudioFile and configuring it with the same sample rate and
             channel layout as those of the current sample buffer.
            */

            // recording format is the format of the audio file itself
            CAStreamBasicDescription recordingFormat(currentInputASBD.mSampleRate,
                                                     currentInputASBD.mChannelsPerFrame,
                                                     CAStreamBasicDescription::kPCMFormatInt16,
                                                     true);
            recordingFormat.mFormatFlags |= kAudioFormatFlagIsBigEndian;

            NSLog(@"Recording Audio Format:");
            recordingFormat.Print();

            err = ExtAudioFileCreateWithURL(_outputFile,
                                            kAudioFileAIFFType,
                                            &recordingFormat,
                                            currentRecordingChannelLayout,
                                            kAudioFileFlags_EraseFile,
                                            &extAudioFile);
            if (noErr == err)
                // client format is the output format from the delay unit
                err = ExtAudioFileSetProperty(extAudioFile,
                                              kExtAudioFileProperty_ClientDataFormat,
                                              sizeof(graphOutputASBD),
                                              &graphOutputASBD);

            if (noErr != err) {
                if (extAudioFile) ExtAudioFileDispose(extAudioFile);
                extAudioFile = NULL;
            }
        }
    } // @synchronized

    if (noErr == err) {
        self.recording = YES;
        NSLog(@"Recording Started");
    } else {
        NSLog(@"Failed to setup audio file! (%ld)", (long)err);
    }
}
}

"currentInputASBD“的提取似乎不起作用，但我无法为自己找到解决方案。如果有人知道如何解决这个问题，并分享它，我非常感谢。

诚挚的问候。

杜布玉

Answer 1

AudioStreamBasicDescription: 0 ch,0 Hz,'lpcm' (0x0000000E) 16-bit signed integer

一个问题是您没有指定通道数(请参阅0 ch)。所以你需要指定它。

您应该看到类似于：

AudioStreamBasicDescription: 1 ch, 44100 Hz, 'lpcm' (0x0000000E) 16-bit signed integer