pulseaudio and adder stream latency

[Stefan Sauer]

On 02/02/2014 05:42 PM, lsmithso at hare.demon.co.uk wrote:
> 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.
The interesting properties are "provide-clock" and "slave-method". To
debug this one would need to figure which elements (sink, src1, src2)
provides the clock and why the others don't sync to that properly.

>
>
> 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
> seconds.
>
> 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
Ideally you use a "audioconvert ! audio/x-raw, ..." after both sources
to ensure you have the same format. adder does not convert.

Stefan
>
> 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
>  > _______________________________________________
>  > gstreamer-devel mailing list
>  > gstreamer-devel at lists.freedesktop.org
>  > http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>