时间：2020年4月27日。

备注：Demo中已经完美解决，没什么问题。

原理：在即将播放声音时，释放声音资源

• 非网传的声波抵消
• 非截取视频流（像素差一些）

声波抵消时机不好掌握，一旦发生卡顿，极有可能播放两次声音，或者音频错位

注意：不适用StillImage

这种方式效果不佳，会产生奇怪的效果，而且API已经过时。

- (void)captureStillImageAsynchronouslyFromConnection:(AVCaptureConnection *)connection completionHandler:(void (^)(CMSampleBufferRef _Nullable imageDataSampleBuffer, NSError * _Nullable error))handler;

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完美解决：AVCapturePhotoCaptureDelegate

- (void)captureOutput:(AVCapturePhotoOutput *)output didFinishProcessingPhotoSampleBuffer:(CMSampleBufferRef)photoSampleBuffer previewPhotoSampleBuffer:(CMSampleBufferRef)previewPhotoSampleBuffer resolvedSettings:(AVCaptureResolvedPhotoSettings *)resolvedSettings bracketSettings:(AVCaptureBracketedStillImageSettings *)bracketSettings error:(NSError *)error;

- (void)captureOutput:(AVCapturePhotoOutput *)output willCapturePhotoForResolvedSettings:(AVCaptureResolvedPhotoSettings *)resolvedSettings{
   /// 释放声音
   AudioServicesDisposeSystemSoundID(1108);
}
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willCapturePhotoForResolvedSettings 时释放声音

AudioServicesDisposeSystemSoundID(1108);
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这样就可以了

我们来看看这个API

AudioServicesDisposeSystemSoundID(SystemSoundID inSystemSoundID)  
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/*!
    @function       AudioServicesDisposeSystemSoundID
    @abstract       Allows the System Sound server to dispose any resources needed for the provided
                    SystemSoundID.
    @discussion     Allows the application to tell the System Sound server that the resources for the
                    associated audio file are no longer required.
    @param          inSystemSoundID
                        A SystemSoundID that the application no longer needs to use.
*/
extern OSStatus 
AudioServicesDisposeSystemSoundID(SystemSoundID inSystemSoundID)                                    
                                                                API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0))
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A SystemSoundID that the application no longer needs to use.

应用程序不再需要使用的SystemSoundID。

其他：

1108 是非公开的音频ID，有可能被拒，但是有些竞品APP已经使用了这个，应该可以顺利上线。