How to decode a live stream encoded using FFMPEG?

Question

I am not very proficient with C programming and working on live streaming using FFMPEG. Basically, I want to put a watermark on a live streaming video.

Using FFMPEG, I have been able to record a video from webcam, encode it and send to some ip:port using UDP. Now, my receiver(written in Java) is receiving the data in packets but I don't know how to decode it for editing or play it. If I use ffplay, it plays it automatically. I referred some links:
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Could anyone please tell, how can I proceed for the solution. Any hints would be appreciable.

1. How the data is encoded. Is it some FFMPEG format or generic format?
2. If a live stream is coming, then what information does each packet contains? Whether it is a complete video itself or a portion of complete video file?

Answer 1

ffmpeg -f dshow -i video="Integrated Webcam" -c:v rawvideo -pix_fmt yuv420p -window_size qcif -f sdl "SDL output"

在Windows上，此FFMPEG命令对我有效。