audiomixer gaps

[jim nualart]

Hi Matt,
I tried that as well. I get the same result .. gaps every 5 seconds.

If I remove is-live (with or without do-timestamp), then there are no gaps.
However, in this case, I also get a much larger, and longer, file; which I
don't understand.

And again, if I use an adder (vs audiomixer), I get no gaps (with is-live
and do-timestamp both true). And if I remove the adder, same ... no gaps.

I'm trying not to get hung up on audiotestsrc itself as it is simply a way
for me to demonstrate what I see with my pipeline using alsasrc and an
audiomixer.

I suppose I don't really understand what audiomixer is doing. Another
oddity (I think) is that if instead of running the sample pipeline for a
set time (using the timeout command), I instead use num-buffers=1000 (in
audiotestsrc), I get different resulting file sizes:
- with an adder, I get a file with 10.884s of audio and a size of 960056
bytes.
- with an audiomixer, I get a file with 10.920s of audio and a size
of 1926332 bytes.

Any chance someone is willing to run the same test and compare results?
export TESTSOURCE1="audiotestsrc wave=0 volume=0.8 is-live=true
do-timestamp=true samplesperbuffer=480"
export SINK="wavenc ! filesink location=test.wav"
timeout 60 gst-launch-1.0 $TESTSOURCE1 blocksize=960 ! audiomixer ! $SINK

The gaps go away if I use an adder, as does my actual problem in my "real"
pipeline, but I'd like to understand why.

thanks in advance,
-jim


> Date: Tue, 8 Dec 2020 19:05:25 +1100
> From: Matthew Waters <ystreet00 at gmail.com>
>
> Don't use 'do-timestamp=true' with audiotestsrc.? It will not do the
> right thing.
>
> Cheers
> -Matt
>
> On 8/12/20 5:12 pm, jim nualart wrote:
> > Hi,
> > Hoping that someone can shed some light on this...
> >
> > The following pipeline results in a file with gaps every 5 seconds:
> > export TESTSOURCE1="audiotestsrc wave=0 volume=0.8 is-live=true
> > do-timestamp=true samplesperbuffer=480"
> > export SINK="wavenc ! filesink location=test.wav"
> > timeout 60 gst-launch-1.0 $TESTSOURCE1 ! audiomixer ! $SINK
> >
> > If you open the resulting wav file (e.g., in audacity), there are gaps
> > every 5 seconds.
> >
> > If you remove the audiomixer?from the pipeline, there are no gaps. If
> > you use an adder (instead of the audiomixer), there are no gaps.
> >
> > I've looked at logs (GST_DEBUG=audiomixer:6), and there are no obvious
> > errors/warnings/etc.
> >
> > I realize that the audiotestsrc is not really a live-source and I'm
> > not sure how well it behaves as such. But I am actually
> > troubleshooting a similar issue using an alsasrc instead. I am hoping
> > that if I understand what's going on here, it will help on the other
> > issue. (For the issue with the alsasrc, I've gone so far as to write
> > the data to files; one at the src of the element feeding the
> > audiomixer, and one at the src of the audiomixer itself -- the first
> > shows no gaps, while the later does show gaps.)
> >
> > Many thanks in advance to any advice.
> > -jim
> >
> > _______________________________________________
> > gstreamer-devel mailing list
> > gstreamer-devel at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
>

>
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