HTTP tunneling (of RTP) for cameras

Question

My company is developing a system that interfaces with several network cameras. The way we stream video from the cameras is over HTTP (mainly because of camera limitations combined with the fact that we want it to be able to supply plug-and-play behavior). I noticed that when I use the streaming of rtp over http option, the way rtp is streamed is
| X | | RTP |
|-4-| |-------|

where X is a 4-byte header which starts with "24 00" in hexa, and the other 2 bytes are the length of the RTP packet (and afterwards the RTP packet comes).

Now I can't for the life of me figure out what the X protocol is. I have witnessed this same behavior in two camera brands already - Panasonic and Edimax, which suggests it's not some kind of proprietary protocol.

Does anyone have any idea what kind of protocol this is? Maybe some sort of HTTP tunneling protocol?

Thanks,
Tomer

Answer 1

Section Data Streamed Over TCP of this document may help: "The RTP or RDT packets are encapsulated by an ASCII dollar sign (24 hexidecimal), followed by a one-byte binary channel identifier, followed by the length of the encapsulated binary data as a binary, two-byte integer in network byte order, followed by the upper-layer protocol layer and stream data."

Yes, it is a part (10.12) of the RTSP protocol as stated by the above document.