I need to parse a H.264 stream to collect only NAL's needed to form a complete image, of only one frame. I'm reading the H.264 standard, but it's confuse and hard to read. I made some experiments but, did not worked. For example, i extracted an access unit with primary_pic_type == 0 containing only slice_type == 7 (I-Slice), it should give me a frame, but i tried to extract from ffmpeg, it did not work. But, when i append the next access_unit, containing only slice_type == 5 (P-Slice) it worked. Maybe i need to extract POC information, but i think not, because i only need extract one frame, but i'm not sure. Someone have some tip of how get only NAL's i need to form one complete image?
Just in case someone has the same problem, i solved it. I go until i find an AUD of primary_pic_type == 0. So i extract the AUD and the next one (when it's a field), send the two AUD to the server, and decode the frame using ffmpeg to generate a JPG image.