pulseaudio and adder stream latency

lsmithso at hare.demon.co.uk lsmithso at hare.demon.co.uk
Sun Feb 2 08:42:20 PST 2014

Hi: I'm using gstreamer 0.10.  liveadder made no difference at all. I
 tried all kinds of combinations of the clock-source, do-timestamp and
 latency properties , but it made no difference.  I don't really
 understand the clocking stuff, so this wasn't very scientific.

I also tried mixing both streams on to themselves. It wasn't perfectly
in sync, butt it wasn't bad, and it certainly didn't drift by

I tried swapping devices around, but I got the following error.

ERROR: from element /GstPipeline:pipeline0/GstAudioConvert:audioconvert0: not negotiated
Additional debug info:
gstbasetransform.c(2525): gst_base_transform_handle_buffer (): /GstPipeline:pipeline0/GstAudioConvert:audioconvert0:
not negotiated

Is there a clue there. Recording works if the  1st element device is
the output monitor, and the second is the mic. The above error happens
when the 1st element is the mic and the 2nd the  output monitor.

Stefan Sauer 
 > On 01/31/2014 09:49 AM, lsmithso at hare.demon.co.uk wrote:
 > >
 > > Hi:
 > >
 > > I'm trying to record headphone output and mic input  simultaneously to
 > > a single file, using pulseaudio streams and the adder plugin.
 > >
 > > The problem is that the recording of the sink rapidly lags behind the
 > > source, eventually by several seconds. The result is that the
 > > headphone and mic recording are completely out of sync.
 > >
 > > Any idea of what causes this and how to fix it? Here's the pipeline:
 > >  
 > >
 > >
 > > gst-launch -q -e pulsesrc device=2 ! adder name=mix ! audioconvert ! vorbisenc ! oggmux  ! filesink location=r.ogg pulsesrc device=3 ! mix.
 > >
 > >
 > Hi,
 > is this with gst-0.10 or 1.X? Btw. it is not latency that your are
 > seeing, sounds more like clock drift perhaps. I wonder which of both
 > sources is providing the clock. Can you swap device=2/3 and retry?
 > Stefan
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 > gstreamer-devel at lists.freedesktop.org
 > http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel

Les Smithson

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