Does a promise of immunity from prosecution in return for testimony from a witness in a criminal investigation constitute immunity?

Although immunity in a felony proceeding is usually granted by the court following application by the prosecution (Pen. Code, 1324), the same result is achieved where, as here, the prosecution has obtained testimony under a promise to withhold prosecution. (People v. Brunner (1973) 32 Cal.App.3d 908, 914-915 [district attorney's promise of immunity from prosecution in return for testimony in murder case].) Indeed, an application pursuant to Penal Code section 1324 would have been unavailing in the instant matter since the immunity statute has no application to matters other than felony proceedings or investigations before the court or the Grand Jury. (Ibid.)