California Code of Civil Procedure
(a) The deposition officer shall put the deponent under oath or affirmation.
(b) Unless the parties agree or the court orders otherwise, the testimony, as well as any stated objections, shall be taken stenographically. If taken stenographically, it shall be by a person certified pursuant to Article 3 (commencing with Section 8020) of Chapter 13 of Division 3 of the Business and Professions Code.
(c) The party noticing the deposition may also record the testimony by audio or video technology if the notice of deposition stated an intention also to record the testimony by either of those methods, or if all the parties agree that the testimony may also be recorded by either of those methods. Any other party, at that party’s expense, may make an audio or video record of the deposition, provided that the other party promptly, and in no event less than three calendar days before the date for which the deposition is scheduled, serves a written notice of this intention to make an audio or video record of the deposition testimony on the party or attorney who noticed the deposition, on all other parties or attorneys on whom the deposition notice was served under Section 2025.240, and on any deponent whose attendance is being compelled by a deposition subpoena under Chapter 6 (commencing with Section 2020.010). If this notice is given three calendar days before the deposition date, it shall be made by personal service under Section 1011.
(d) Examination and cross-examination of the deponent shall proceed as permitted at trial under the provisions of the Evidence Code.
(e) In lieu of participating in the oral examination, parties may transmit written questions in a sealed envelope to the party taking the deposition for delivery to the deposition officer, who shall unseal the envelope and propound them to the deponent after the oral examination has been completed.