[Live-devel] Starting and stopping video within MediaSessions

[Dave McMordie]

We are using Live555 to stream (unicast) short bursts of video (currently
MJPG, soon to be H.264) and metadata as objects are tracked throughout a
scene.  For a given tracked object , we have information about the object
(id, location, etc), which we send as XML meta data in a MediaSubsession.
Each video/metadata sequence has a start and an end, and multiple (up to
25) of these sequences may be active at one time (think of each as coming
from a separate camera trained on a separate subject).



Currently the way we are doing this (just as a proof of concept) is to use
a single SMS containing one MJPG stream and one XML stream, with each video
sequence multiplexed into this single image/metadata channel.  In this
model, the MJPG stream has the frames tagged with a serial number and put
into correspondence with the XML stream in a buffer on the receiving end.



This is very clunky, and will not scale to better video codecs due to the
uncorrelated (multiplexed) sequence of frames.  We would like to move
toward a model where we have a single session open, but each video/metadata
sequence is dynamically added/removed from that session as objects appear
and disappear.



Is this possible using Live555?  Is this something that can’t be done due
to limitations in RTSP/RTCP?



If this can be done, at what level can we dynamically add “streams” to an
open session?  Can we simply add a new ServerMediaSessions after the
Unicast session has begun?



Any guidance on the “right way” to tackle this would be much appreciated.



Best regards,


Dave McMordie



*[image: Description: cid:image001.jpg at 01C94FAF.E4535F30]*

*David McMordie*
*CTO*

1751 Richardson, Suite 8.123

Montreal, QC H3K 1G6
mcmordie at viionsystems.com
www.viionsystems.com



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