Is there a way to convert a mjpeg stream to h264 video?

[SolskGaer]

I saw C.avformat_open_input(&this.avCtx, cfilename, nil, &options); in the source code. Now I have a mjpeg stream, which doesn't have filename but just the content of the image, since I have no experience in cgo or anything related to ffmpeg, so I have no idea how to use this repo to satisfy my need, how do I convert such a stream to video? Any suggestion is appreciated.