using audiofirfilter from gst-launch-1.0

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using audiofirfilter from gst-launch-1.0

Charlie Laub

I’m currently investigating how I can modify an existing audio processing application to include the audiofirfilter plugin. The application uses gst-launch-1.0 to create pipelines. While I have a suite of IIR filters that I can implement using LADSPA, some users might want to implement FIR filters as well.


The online documentation for audiofirfilter only provides an example of how to implement it in code, however, using gst-inspect it seems that I should be able to implement it using gst-launch as well. The main issue I have encountered is how to specify the kernel. The docs say is should be of type GValueArray, however, this may now be deprecated and GArray used instead – not sure. For more info, see:

Can I provide an exlicit list of values for the kernel as a GArray? The number of data points used to define the kernel might range from under a thousand to over 10 thousand in some cases. Can I specify these inline as part of the gst-launch pipeline commands? Can gst-launch accept input of this length?


Just as a test I tried doing something like:

gst-launch-1.0 fakesrc ! audiofirfilter latency=3 kernel=”0 0 1 0 0” ! fakesink


I tried various ways to specify the kernel values (comma delimited, space deliminted, real values, inside double quotes, single quotes, curly braces, etc.) and each time I received the message:

“WARNING: erroneous pipeline: could not set property “kernel” in element “audiofirfilter0” to …


How can I provide the kernel to audiofirfilter when using gst-launch?

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