The coroner shall cause the testimony given by any witness to be reduced to writing or recorded either in shorthand or by a mechanical recording device. It may, if recorded, at his discretion, be transcribed into typewriting by him or under his direction. He may employ a clerk or stenographer for the purpose. When the testimony is taken down by a stenographer, his duly certified transcription thereof constitutes the deposition of the witness. The compensation of the clerk or stenographer shall be the same as that allowed to stenographers in the superior court of the county and is a legal charge against the county.