Every person accused of crime shall have the right to meet the witnesses produced against him or her face to face: PROVIDED, That whenever any witness whose deposition shall have been taken pursuant to law by a magistrate, in the presence of the defendant and his or her counsel, shall be absent, and cannot be found when required to testify upon any trial or hearing, so much of such deposition as the court shall deem admissible and competent shall be admitted and read as evidence in such case.