Cal. CCP § 2025.620

At the trial or any other hearing in the action, any part or all of a deposition may be used against any party who was present or represented at the taking of the deposition, or who had due notice of the deposition and did not serve a valid objection under Section 2025.410, so far as admissible under the rules of evidence applied as though the deponent were then present and testifying as a witness, in accordance with the following provisions:

(a) Any party may use a deposition for the purpose of contradicting or impeaching the testimony of the deponent as a witness, or for any other purpose permitted by the Evidence Code.

(b) An adverse party may use for any purpose, a deposition of a party to the action, or of anyone who at the time of taking the deposition was an officer, director, managing agent, employee, agent, or designee under Section 2025.230 of a party. It is not ground for objection to the use of a deposition of a party under this subdivision by an adverse party that the deponent is available to testify, has testified, or will testify at the trial or other hearing.

(c) Any party may use for any purpose the deposition of any person or organization, including that of any party to the action, if the court finds any of the following:

(1) The deponent resides more than 150 miles from the place of the trial or other hearing.

(2) The deponent, without the procurement or wrongdoing of the proponent of the deposition for the purpose of preventing testimony in open court, is any of the following:

(A) Exempted or precluded on the ground of privilege from testifying concerning the matter to which the deponent’s testimony is relevant.

(B) Disqualified from testifying.

(C) Dead or unable to attend or testify because of existing physical or mental illness or infirmity.

(D) Absent from the trial or other hearing and the court is unable to compel the deponent’s attendance by its process.

(E) Absent from the trial or other hearing and the proponent of the deposition has exercised reasonable diligence but has been unable to procure the deponent’s attendance by the court’s process.

(3) Exceptional circumstances exist that make it desirable to allow the use of any deposition in the interests of justice and with due regard to the importance of presenting the testimony of witnesses orally in open court.

(d) Any party may use a video recording of the deposition testimony of a treating or consulting physician or of any expert witness even though the deponent is available to testify if the deposition notice under Section 2025.220 reserved the right to use the deposition at trial, and if that party has complied with subdivision (m) of Section 2025.340.

(e) Subject to the requirements of this chapter, a party may offer in evidence all or any part of a deposition, and if the party introduces only part of the deposition, any other party may introduce any other parts that are relevant to the parts introduced.

(f) Substitution of parties does not affect the right to use depositions previously taken.

(g) When an action has been brought in any court of the United States or of any state, and another action involving the same subject matter is subsequently brought between the same parties or their representatives or successors in interest, all depositions lawfully taken and duly filed in the initial action may be used in the subsequent action as if originally taken in that subsequent action. A deposition previously taken may also be used as permitted by the Evidence Code.