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

[andrea zambon <zamby ing gmail com>]

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

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
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