Ensure the file extension is truly .mp4 (MPEG-4 video). If it is a disguised file type, it might not play.
Use a versatile media player that supports a wide range of codecs, such as VLC Media Player .
However, based on typical scenarios where files are named with "g" and a number, Guide to "g030.mp4"
Without the actual "g030.mp4" video file or more context about its content (e.g., is it a tutorial, a security video, a video game clip, or a product demo?), it is impossible to create a specific guide.
Look for clues within the video, such as on-screen text, logos, or distinct objects to understand the context.
(A screen recording, security camera footage, etc.)