mp3 decoding using ffmpeg API (Header missing)

I think i found my answer, the avpkt.data must have a header in front, without any garbage or previous frame bytes, or may be initial mp3 file data (name, gender, year ... etc).

so a little parser must be wrote, this is a useful link for mp3 headers (just search for the correct bytes in within the file, and increase avpkt.data pointer to match):

http://www.mp3-tech.org/programmer/frame_header.html