[FFmpeg-devel] Decoding H264 / RTP with ffmpeg

[Sergio Arroutbi]

Hello.

I am trying to decode images coming from a H264 Axis camera.

This camera is sending H.264 stream based on some information provided 
in SDP (sent via 200 Ok responses to RTSP DESCRIBE messages).

After sending RTSP requests, I start receiving the stream.

Once the stream is received, I dont know how to parse the RTP messages 
in order to be able to decode the

What i have is basically a socket that reads the RTP packets, get RTP 
payload and calls:

avcodec_decode_video(*context, *decoded_image, &got_picture, frame, 
frame_size)), where "frame" and "frame_size" are the RTP payload and RTP 
payload length. I continously get the error:

[h264 @ 0x99b7a20]no frame!

After investigating the issue, I guess that I have to parse  RTP payload 
in order to get "raw H264 frames". I discovered RFC3984 (that talks 
about this topic), but I believe ffmpeg library does already perform 
"RFC3984 performance", as it has some methods to parse the sdp, RTP, etc.

Which is the best method to decode the frames by calling 
avcodec_decode_video?

I guess I have to pass SDP information to AVContext*, but do not know 
how to do so.

Anyone could perform decoding of frames in a H.264 stream encapsulated 
in RTP?

Which is the best method to use?

Thanks a lot.

Sergio.


-- 
Sergio Arroutbi Braojos
Ingeniero de Desarrollo Software
Grupo GMIS
SEPSA