1. Legitimacy of audio-visual materials. We can judge whether it is legal from the act of taking evidence itself, which requires that the collected audio-visual materials cannot violate the prohibitive provisions of the law.
 2. Authenticity of audio-visual materials. If the parties have any objection to the authenticity of audio-visual materials, they need to remind the parties to apply for judicial expertise to identify the authenticity, and inform the parties that they may bear adverse consequences if they do not apply.
 3. The proof power of audio-visual materials. When audio-visual materials are single evidence, it is necessary to prompt the parties to provide other evidence, such as witness testimony.
 [Legal basis] According to Article 63 of the Civil Procedure Law, evidence includes:
 （1） Statement of the parties;
 （2） Documentary evidence;
 （3） Physical evidence;
 （4） Audio-visual materials;
 （5） Electronic data;
 （6） Witness testimony;
 （7） Appraisal opinions;
 （8） Record of inspection. Evidence must be verified before it can be used as the basis for ascertaining facts.