Video ok, but no audio on RTMPT connections

[dirk_eismann]

One of our customers uses LCCS from behind a corporate proxy (Squid) which only allows http connections, so no RTMFP or pure RTMP connections, only RTMPT works for them.

Interestingly, while video streaming works for them (the app we created for them is a 1:1 scenario), audio streaming does not. They do have microphones on their machines, the mics get correctly identified in the Flash Player Settings tab and the input level meter also responds / peaks when they test the mic in the Settings tab. However, no single audio chunk ever gets transferred... which is pretty strange as probably both the audio and video signal travel on the same NetStream internally (guessing here). In a non-LCCS environment (pure Flash and FMS application) the audio streaming works btw, so it must be somehow related to LCCS.

We use AudioPublisher and WebCamPublisher and their corresponding counterparts. And of course, the app works just fine on our side

Any ideas what could be the cause for this?

Thanks,

Dirk.

[Raff_]

The way RTMP tunnelling work is that a new HTTP request is created for every message pushed to the server (there are some optimizations to collapse multiple requests sent in a short time but this is the general idea) and receiving data is done by "polling" the HTTP endpoint (you receive data on the HTTP response to your request, and if there are no pending requests you send a polling request).

So, by nature RTMPT is much slower than regular RTMP (and RTMPTS is even slower because of the SSL overhead). In theory this still should cause the problem you are seeing but what may be happening is that audio gets so far behind that the player drops it.

One thing that you could try is to see where the "data" gets lost. If you can retrieve the "bandwith" used on the transmitter and the receiver side you should see if it seems that the server is dropping packets or the client is. In theory FMS should drop video packets before dropping audio and if this is true you should see the receiving client reporting a similar bandwidth usage as the server.

Something that would be really useful to us is to know more about the proxy configuration your client is using so that we can try to reproduce the problem internally.

[dirk_eismann]

Thanks. We're still investigating this with the customer. Funny side note is that audio works fine when doing legacy audio streaming via FMS and also when doing a connect session, even though they can only use RTMPT.

Btw, there is nothing like RTMPTS as far as I know, RTMPT is RTMP tunneled through http and RTMPS is just the same as RTMPT but tunneled through https of course.

Dirk.