[Live-devel] RTP over TCP bugs

[Ralf Globisch]

Hi Ross,

We use the LIVE555 Streaming Media library to implement a live streaming server
(on Ubuntu) and a windows media player RTSP client streaming RTP over
TCP only.
We have run into a complicated set of problems recently:

1) When a client with a *bad* internet connection joins the RTSP
server, the server
becomes unresponsive (to new RTSP connections) and connected clients
are dropped.
Enabling the DEBUG processor directive showed that many writes fail in
RTPInterface::sendRTPOverTCP before the server finally hangs. After searching
the mailing list for any similar problems, I came across this post:
http://lists.live555.com/pipermail/live-devel/2010-June/012226.html
which seems to
indicate that using the new asynchronous RTSP client resolves that issue?

Could you please clarify this a bit? If I understand correctly, we
must therefore upgrade
both our server and client code to use the latest live media version
to avoid the server
hanging? Or would updating the client code to use the new async
RTSPClient code suffice?

2) We are aware that you only support the latest version so we
recently upgraded the live555 version.
We then ran into another issue: while the stream is playing back, CPU
usage is negligible.
Then, once network problems occur, the CPU usage spikes to 100%.
Matt's post (http://lists.live555.com/pipermail/live-devel/2011-June/013521.html)
could be related.
However commenting out the adding of dummy socket to fWriteSet and
fExceptionSet as you
advised in your response to Matt didn't solve the problem. Upgrading
our WMP client to use the
new asynchronous interface didn't help either. Finally, we were able
to replicate the problem using
only openRTSP.

Here's a short summary of the steps taken so far:

LiveMedia 2010.04.09 - synchronous - WMP RTSPClient - no problems with CPU usage
LiveMedia 2011.03.14 - synchronous - WMP RTSPClient - same CPU usage problem
LiveMedia 2011.03.14 - asynchronous - WMP RTSPClient - same CPU usage problem
LiveMedia 2011.03.14 - asynchronous - openRTSP - same CPU usage problem
LiveMedia 2011.07.15 - asynchronous - openRTSP - same CPU usage problem

Ways to replicate the problem:
- One method that has worked to trigger the problem is to start
running openRTSP and then restarting our ADSL router once the stream
is active.

Could this have anything to do with "the Windows bug that forced me to
add "dummySocket" in the first place"?

We are currently piloting the project and these errors are critical
for the success of the pilot.
Any pointers/advice would be greatly appreciated.

Best regards,
Ralf