[Libav-user] H264 Nal type Unspecified and Undefined filtered?

[Indio]

Hi all,
this is my first post in the list and i'm quite new to libav and ffmpeg.

For an experimental project i'm developing an RTSP client and server using
live555 for server and libav/ffmpeg as client.
The server treams live video from a webcam.

After each IDR frame we are sending a checksum in the NAL stream using
unspecified and undefined NAL types. From client side the expected
behaviuor is to read the checksum un the av_read_frame function.

We tried Nal type 30 but libav discard it with message "Undefined type
(30)" which happen in the demuxer in the h264_handle_packet function.
Looking at this function we tried to ne NAL type 0 because the comment says
"undefined, but pass them through". The problem is that the packet seems to
be discarded somewhere ad never arrive to be read in the av_read_frame.

So are those NALU filtered? Ho could i embed in the H264 stream a NAL
packet with user data?
Thanks in advance
Indio
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