(a) In all felony cases, other than cases involving capital felonies, in which defendants have been bound over to the superior court, are confined in jail or released on bond pending a commitment hearing, or are in jail having waived a commitment hearing, the district attorney shall have authority to prefer accusations, and such defendants shall be tried on such accusations, provided that defendants going to trial under such accusations shall, in writing, waive indictment by a grand jury.
(b) Judges of the superior court may open their courts at any time without the presence of either a grand jury or a trial jury to receive and act upon pleas of guilty in misdemeanor cases and in felony cases, except those punishable by death or life imprisonment, when the judge and the defendant consent thereto. The judge may try the issues in such cases without a jury upon an accusation filed by the district attorney where the defendant has waived indictment and consented thereto in writing and counsel is present in court representing the defendant
either by virtue of his employment or by appointment by the court.