code: func (self *Transcoder) Close() (err error) {
  	for _, stream := range self.streams {
  		if stream.aenc != nil {
  			stream.aenc.Close()
  			stream.aenc = nil
  		}
  		if stream.adec != nil {
  			stream.adec.Close()
  			stream.adec = nil
  		}
  	}
  	self.streams = nil
  	return
  }
docs: // Close transcoder, close related encoder and decoders.