Re: Launching Rygel on headless server

[Jens Georg <mail jensge org>]

> Finally I have success. The following command line proves that there's
> an issue with VLC, since the following direct request to the
> introspected UPnP-published stream...
> 
> curl http://192.168.1.128:36483/GstLaunch/i/bXlwdWxzZWF1ZGlvc2luaw%3D%3D
> | pacat -p
> 
> ...plays audio fine with no breaks, though a big delay. In VLC the
> same stream apparently plays, but stalls at 00:00 and no audio comes
> out.

If you don't define an encoder and use raw PCM data, you have to code the
parameters of the stream in the mime type. For a "normal" PC audio stream that
would be "audio/L16;rate=44100;channels=2". If you don't have much encoding
power, try adding wavenc which just wraps the raw data in a container.  If you
have the encoding power I'd try FLAC. That also reduces latency a bit. IIRC using
MP3 or Vorbis will increase the latency even more.

> I'll investigate other UPnP client options, or figure out a mime type
> configuration which media clients will accept in order to decode this
> format. This direct call to Pulseaudio is not a bad way to use Rygel
> actually, although I was hoping for family and other home network
> users to be able to do UPnP browsing through some kind of nice
> interface, like VLC or Rhythmbox, perhaps I can just write a simple

UPnP Browsing in VLC 2.x should work with Rygel. VLC 1.x has a semi-broken
UPnP implementation.

> GUI to connect desktops/etc to various systems around the house using
> curl and pacat, assuming I can figure out how to get the corresponding
> HTTP URLs for each source via some kind of UPnP library. Suggestions
> for a simple (console?) tool to query available UPnP trees to find the
> "Gst Launch" node?

I've a half-finished implementation of something like that on github:

https://github.com/phako/upnp-browse/

But I don't claim that there aren't better tools.

> 
> I might be able to use this for audio connectivity from microphones
> too, now I've figured it out, save buying a new baby alarm! Can I get
> any control through Rygel to minimise buffering and hence reduce audio
> delay?

I've not yet investigated what causes the delay there. Could you file an
enhancement bug about that against the GstLaunch plugin? Thanks.

> Congratulations on the release!

Thanks.