Re: [bump] rygel streaming live audio: low latency?

[Jens Georg <mail jensge org>]

On Di, 2012-06-12 at 21:24 +0200, andrea zambon wrote:
> I tried with Slackware, rygel 0.11 and alsa:
> 
> [GstLaunch]
> enabled=true
> launch-items=myaudiosink
> myaudiosink-title=Audio on @HOSTNAME@
> myaudiosink-mime=audio/x-wav
> myaudiosink-launch=alsasrc ! audioconvert ! wavpackenc

Wavpackenc does not create WAV. It creates wavpack which is a loss-less
but compressed audio format format similar to flac.

Try to set the proper mime-type audio/L16;rate=44100;channels=2 and no
encoding or use wavenc. 

Also not that this method is not really meant for pulse integration, it
just happened to be the only working way for several pulse and rygel
versions.

Using the "native" pulse integration gives you direct access to pulse's
HTTP stream.


> 
> I get 1-2 seconds delay.
> I not think that is a problem Rygel.
> You try to take the stream from rygel uri and listen to the delay.
> 
> Note:
> I work in a similar project (webcam), but I'm not using Rygel.
> I do experiments with a simple application and libsoup, I can send the
> raw audio of the microphone toward the TV:
> If I use 1 MB buffer, I get 10 seconds of delay.
> If I use 1 KB buffer, I get 1-2 second delay.
> 
> I think that is the best possible result with upnp/dlna media server.
> 
> Ciao.
> 
> 
> 
> 2012/6/12 Leonardo Gabrielli <l gabrielli univpm it>:
> > Sorry, for bumping...
> >
> > Dear rygel-list members,
> > I'm a phd student in Italy and I'm currently trying to stream live audio
> > with rygel to other devices. I succeded in doing this by following a method
> > using gstreamer input to rygel, here:
> > http://chemicaloliver.net/linux/streaming-audio-from-ubuntu-linux-to-a-dlna-player-blu-ray-or-ps3/
> > However my goal is to obtain a low latency stream. So far I get 10 seconds
> > delay from the live input (e.g. my voice speaking numbers to the microphone
> > on the rygel machine) to the renderer machine (another linux machine with
> > VLC). This is not related with network problems or other software layers
> > (sending audio with other systems I get milliseconds latency). My opinion is
> > that such a big delay is due to the connection mechanism which takes approx
> > 10 seconds: my idea:
> > - the media renderer connects to rygel
> > - rygel starts buffering the live audio at once
> > - in the meanwhile all the handshaking between rygel and the renderer begins
> > and takes some time
> > - when everything is ready rygel starts sending the audio to the renderer,
> > beginning from the start of the buffer, which is many seconds long now
> > - from the media renderer you can listen to an audio signal that is several
> > seconds old
> >
> > This could be fixed if rygel starts buffering when the connection is ready.
> > THe only latency then would be the one from the network and the one from the
> > *short* (128 to 1024 samples) buffer.
> >
> > I'm not very good in reading or writing code, and I'd like to ask you
> > developers if this makes sense to you or this is not the cause of the delay.
> >
> > Thanks & cheers
> >
> > --
> >
> > Leonardo Gabrielli, PhD student
> > A3Lab - Dept. Information Engineering
> > Università Politecnica delle Marche
> > via Brecce Bianche 31, 60131, Ancona, Italy
> >
> >
> >
> > --
> >
> > Dr. Leonardo Gabrielli, PhD student
> > A3Lab - Dept. Information Engineering
> > Università Politecnica delle Marche
> > via Brecce Bianche 31, 60131, Ancona, Italy
> > Skype: leonardo.gabrielli
> > _______________________________________________
> > rygel-list mailing list
> > rygel-list gnome org
> > https://mail.gnome.org/mailman/listinfo/rygel-list
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