Encode H264 per frame

[leacape]

Hi,

I don't have any prior knowledge in video and using FFmpeg.
For streaming purposes, I need to encode each frame (containing textures) to H264, the sample code is encoding from a video mp4 input, in my case, it is not.
I don't know how I can convert each frame containing textures to AVFrame, some says to use AVPicture, but AVPicture is not available in this library.

Hoping for your reply!
Thank you