Cannot create a new pixel buffer adaptor with an asset writer input that has already started writing'

reason: '*** -[AVAssetWriterInputPixelBufferAdaptor initWithAssetWriterInput:sourcePixelBufferAttributes:] Cannot create a new pixel buffer adaptor with an asset writer input that has already started writing'

assetWriterInput.readyForMoreMediaData为NO

解决方法：

[self setupAVAssetWriterInputPixelBufferAdaptor];

[self.assetWriter startWriting];

在starWriting方法之前先创建好AVAssetWriterInputPixelBufferAdaptor对象