How to use MPP decoding to play MP4 format files

I use your armsom-w3 development board to perform encoding and decoding operations of the mpp library. I can successfully pull the rtsp stream, but I cannot play MP4 format files. How can I hard decode MP4 format files?

mpp can only decode encoding formats such as H.265/H.264/H.263/VP9/VP8, but cannot decode these encapsulated format files. You first need to decapsulate these files, obtain the encoding format supported by mpp, and then send them to the mpp decoder for decoding.

Understand, it seems that I first need to extract the H264 encoding information from the MP4 file, and then use mpp to decode it. I’ll try it first