9 Apr 2010 ensonic   » (Master)

buzztard

I will give a talk about "Writing audio applications using gstreamer" at the Linux Audio Conference 2010. Naturally quite some time went for writing the article. Now that it has been accepted, I need to start working on the slides and demos.

In buzztard I've tried to make the life of people that use jack or pulse a bit easier. The problem here is that the player is only visible in jack/pulse when it is actually playing. I have now some code that keeps the sink alive (in GST_STATE_READY). This allows e.g. changing the volume in pulse or routing the output in QJackCtrl even if the app is not playing. Unfortunately it only works after the sink was in playing once. I need to confirm my theory of what wrong still.

I recently brought a netbook (MSI L1300) and thus wanted to try buzztard on this machine. I have installed moblin 2.1 on it to play with moblin. As usual, installing own software on a new linux distro/machine always brings up something. After a few rounds of configure maintenance and dependency trimming I am set and having it running. Performance seems to be okay even for complex songs. Yay!

Besides that, I fixed a few more bugs and wrote more tests.

gtk-doc, xslt and profiling

As part of the endless journey of getting gtk-doc to spit out the docs faster I managed to get xsltproc from libxslt to output full callgraphs. The output is compatibe with oprofile and thus the same tools to rendering can be used (e.g. gprof2dot). Bit sadly me profiles hit a python assertion in the above code which I have to disable to run it, buug filed but dormant since 1 month. Same for the xsltproc patch, the patch and an example image is here but no reviews so far.

Now the way to make gtk-doc faster would be to make the xslt faster and as I can see from the profile, this could be done, by preprocessing the xsl with some variables set. Right now I have not too high hopes on this as libxslt seems quite dormant and this is not so straight forward :/

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