[Live-devel] Receiving in multiple threads

[Rawling, Stuart]

Hi Guys,

I have an application that uses the RTSPServer code to send streams out to
clients.   The source of what it sends varies and is pluggable.  All of
these plugins end up writing to a unix pipe, which the RTSPServer code reads
and streams out.  Even tho the app and the plugins are multi threaded, I
have taken great care to protect the integrity and single threaded nature of
the live555 event loop.  And it works very well.

However, I am integrating with some new plugins that are also using live555
(they are restreaming existing rtsp streams) and I am seeing some strange
behaviours.  First of all sometimes I see the wrong video coming in the
wrong pipe.  I believe the cause of this is because although the plugins
have been written to instantiate their own usageenvironement and
taskscheduler, they are all using RTSP client.  I am theorizing that in some
circumstances, such as connecting to another RTSP server of the same type,
they are actually initiating streams being sent to the same port, and the 2
instances of the live555 event loops are competing over the incoming
packets.   Streaming a single source is fine, and mixing other streams from
plugins not based on live555 is fine too.

To address this I am looking at making these plugins share the same
usageenvironment and event loop.

Can you comment on 3 things:

1. My understanding is that so long as each instance of the library uses its
own usageenvironment and event loop, it is ok to have multiple instances in
multiple threads (although I agree this is really not advised).
2. My hypothesis about the RTSPClient initiating streams from similar
sources that stream to similar port numbers could be the cause of the above
issue, and my proposal would make sense.
3. Would it make sense to add an optional base port for the client to use,
similar to RTSPServer?


Thanks for any help provided.

Stuart


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