[Live-devel] Need to implement Pan Tilt Zoom (PTZ) control over RTSP or RTP
matt at schuckmannacres.com
Fri Oct 3 17:17:51 PDT 2008
I'm working on a pan tilt zoom (PTZ) type video server application and
the corresponding viewer application .
I'm using the Live555 library for RTSP and RTP, and I must it is great,
thank you very much,
Anyway I need to implement the control back channel for controlling the
PTZ from the viewer and I'm trying to figure out the best way to do it
within the RTSP/RTP/RTCP and Live555 framework.
The way I figure it I can go 1 of 3 ways.
1. Use the SET_PARAMETER command for RTSP to send back the commands that
I've defined (things like pan=5 or tilt=+10, etc) using the sessionID to
associate the command with the session. However, it appears that the
Live555 library doesn't support the SET_PARAMETER command so I'd have to
go about implementing it (if I did I'd submit my implementation back to
the library) but I don't know how difficult or trivial it will be to do
2. Use the APP packet type for the RTCP channel to send my custom
formated commands. This seems reasonable but I don't know if this is
what the APP packet types in RTCP where meant for or if there would be
any pitfalls. Also I haven't gotten deep enough into Live555 to
determine if there is a way to send APP packets through the RTCP channel.
3. Open another RTP/RTCP connection pair with my own MIME type strictly
dedicated to controlling the PTZ. Seems kind of overkill but it might
make it easy to fit into the Live555 RTP sink and source framework.
I've tried to look around to see if anybody else has gone any of these
routes but I haven't found much; the RTSP RFC does mention something
about using the SET_PARAMETER method for PTZ control but it doesn't go
into any great detail. Any comments or suggestions from the experts out
there would be most appreciated.
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