[gst-devel] [gstreamer] Problem with pulling data from a sink pad

[Thomas Vander Stichele]

Hi,

> Thanks again.  I originally planned on implementing the analysis as a
> Gstreamer plugin, but the documentation on writing Gstreamer plugins
> is so sparse and partially incomplete.  I'll give it a shot if someone
> could point me to some examples or better documentation on Gstreamer
> plugins.

The docs on writing plugins are sparse, a known problem.  If you tell us
what it is you want to do as analysis, we can help you along.  If you
can't for some reason, we could point you at for example the level
plugin in gst-plugins, which does a simple level signalling of audio
flowing through.

Re: your other mail, for display of audio files; I think the best there
would be to
a) define a peak file format (or reuse an existing one that makes sense)
b) write a plug-in that analyzes the input stream and outputs a stream
in this peak file format
c) the app would then be able to generate a peak file using a pipeline
like filesrc location="..." ! peak ! application/x-gst-peak size=1024 !
filesink

In this pipeline, application/x-gst-peak would be the mime type of peak
data we define, and size would be a property of the media we are
defining, stating that the peak data is calculated per 1024 samples.
Other possibilities might be better, feel free to discuss.

If you have a good file format to use for peak files (or someone else,
iain ?) that we could use, I can easily implement this plug-in.

Thomas


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