Older blog entries for ensonic (starting at number 98)


I went over pending bugs and fixed a couple more parser errors. The testsuite is definitely helping. The I also had a stab on one feature request - print warnings for failed xrefs. This would be helpful to fix typos in the doc comments that were intended as links, but don't become ones. It was easy to add the warnings, but unfortunately it produced lots of false positives. This is mainly because gtk-doc also creates implicit links. Almost one week later I had most of them under control and now the amount of false positives is quite low. I pushed my ohloh score by fixing the found issues already in gstreamer core/base and in buzztard. You can do the same in other libs. If noone complains any further I intend to release gtk-doc 1.12 this year still :)


I made a nice change to the pipeline graph builder - It now uses a fixed internal format (float 32bit). This allows us to avoid plugging audioconvert elements in wires and machines. Now we plug them only if the machine cannot support the internal format. This gives 7 -> 1 sec speedup for load & play of e.g. Aenathron.bmx.

In general also plain to wav rendering is now quite fast. On my AMD64 @ 1.8GHz the 11:45 min. song renders in 45 sec. and on my Intel Core 2 Duo @ 2.0GHz it takes 28 sec..

The rest of the month I spent a lot of time on project maintenance, improving the api-docs and writing more test. Regarding the latter, I got the test coverage improved a lot. Writing automated tests for some areas is quite tough though.

Then I also made a small change in the UI. All context menus can now be invoked via a popup menu button in the toolbar above (machine, pattern and sequence view), this makes it more usable on touchscreen devices.

upstream hacking

I started the month with upstream bugs work. First I looked into #581873, made a fix and two days later realized that my git checkout was on a stale branch and its already fixed in gtk+-2.18. Next I looked at the mime matching issue that is already plaguing me for a while (#541236). I also have a patch for that and hope that I get green light for it or a review how it should be fixed instead.


In buzztard I implemented copy and paste in sequence. I also found our what I did wrong in my clipboard handling code (see my previous post). Dunno what wrong with the old code, but this change made it work:

GtkClipboard *cb

Next I finally got rid of the gnomevfs hard dependency. It is only needed if you have a quite old gtk to get help working. While testing I noticed that some translations disappear during run time. I made some i18n handling fixes regarding to initialisation and libraries.

I am probably the last one to figure that one has to draw with the 0.5 px offset in cairo to get non blurry gfx. After Matthias post I looked at my vu-meters and voila, I was doing it wrong. Fixes are in svn together with some small optimizations.


After a release it is always not so easy for me to pick what I will work on next. I decided to look into copy'n'paste as this is crippling usability right now. This sounds like a trivial thing to implement, but its not. Its partially difficult because the gtk documentation on that matter leaves a lot to answer. With the help of the sources I got it implemented for patterns. One thing that worries me right now is that I use GDK_SELECTION_SECONDARY instead of GDK_SELECTION_CLIPBOARD (which seems to be the recommended one). In my case I have a custom widget to edit structured data. I serialize the data in a textual form, but use an own mime-type for copying, as its kind of pointless to paste it into e.g. your editor. The mime type thing works. To debug it, I can also provide the data as text and then I can paste it in some text editors. What puzzles me is that if GDK_SELECTION_CLIPBOARD is used, gtk+ seemingly randomly post a GDK_SELECTION_CLEAR in gtk_widget_event_internal() and that clear my copy before I have a chance to paste the data. It has something to do with a "selection-clear-event", but again that's only partially documented and the other related events are not documented at all.

Besides a few bug fixes, I also did more optimisations on song-loading. There are still a few candidates for more optimizations, but some of them require quite substantial refactorings. Some of the improvements I already did were on the gstreamer side and they are now in the official tree (some already in 0.10.25 release and some in the next one).


The buzztard team has released version 0.5.0 "crown of thorns" of its buzz-alike music composer. All modules got extensive improvements over the last release from almost a year ago. Give it a try, join hacking and report bugs.

[project-page] [screenshots] [downloads]


After all the thinking last month regarding the saves and handling external files, I finally found time at GUADEC to finish the implementation. I can do a quick copy from the old file to the new one on save and create wav files on the fly when e.g.. saving a buzz song in buzztards own format.

During the month I did a lot of real world testing. I recorded children songs as I had scores from my sons kindergarden :), but also just played around. I had the app running under gdb with G_DEBUG="fatal_warnings". Obviously I did not got far with making music on the first evenings. A couple of days later we have a lot bugs less.

My talk at GCDS about "multimedia in your pocket" went fine. I showed short demos of running pitivi, jokosher and buzztard on a omap3 device using maemo 5. I hope the slides will be available soon. For the demo I did some more performance tuning. Using GTK_DEBUG=updates was very helpful to improve the UI to do less redraws.

I also spend some more time on the user manual again. Much less FIXME paragraphs left :)


Also did some hacking on gtk-doc. I can haz pdfs now! Try the git version and report please. I should make a release. I also hacked a bit on the migratetmpl script. It's now trying to patch tmpl docs into sources. I uses ctags to locate the positions. It needs more work still, but I see that as the only way to get e.g. gtk+ converted. If you want to try it talk to me on #gtkdoc, don't run it on a dirty work tree!


May passed quickly. I was testing a lot and as usual this brings bugs to day- light. I noticed one particular problem, that I still have to solve. Buzztard songs are actually zip file containing the songs.XML file and references files like samples. When the song is save the externals are copied from its original location into the zip. First there is a chance that the file becomes unavailable between loading it and saving the song (e.g. if the files where loaded some a sample CD) and then of course if those songs are given to someone then the zip is all there is. I see two ways to handle it - a) if the file is not available, save the raw-pcm as a wave-file, b) when loading new files samples, copy these somewhere and keep the file open and when loading a song, copy this somewhere and keep it open (somewhere = local file system). One thing I already have implemented is save saving, that is rename the old file, save and in the case of failure roll back.

There were also a couple of bugfixes in the UI. I had a long session to fix object destruction and detaching related signal handlers - too bad that the limitations in g_signal_connect_object() still render it pretty useless.

In the beginning of the month I continued with the work on the buzzmachines module. I rewrote one effect from scratch and its pretty compatible. I also added more presets and demo-songs.

While testing more buzz songs I realized two long standing issues. On the buzz song loader I got one detail wrong from the reverse-engineering - I was loading polyphonic pattern with voices and time swapped. That was easy to fix and make many songs sound proper. I made a few other compatibility fixes and improvements on the song load too. The other problem was actually much more work - the buzzmachine emulation had a big flaw. When I instantiated a plugin I was loading the dll/so once for the class and created the machine instance at the same time. The emulation API only had a init(). That means for multiple instances I was "reusing" the class wide instance. It worked surprisingly well :) Now I did a big refactoring there. In class init the dll/so is loaded and for each gobject instance I create a instance of the wrapped machine.

Finally I got around implementing one feature in the GStreamer side. There are a couple of wrapper plugins in gstreamer that act as a bridge between different plugin APIs. The way this was done had quite a drawback. Whenever the plugin was loaded, it was re-registering all the element types. In order to do that it needed plugin specific metadata. So it was loading each of the bridged plugins and querying the features. It needed two patches to get that changed. Now gstreamer does not ref each element class of a loaded plugin during loading and the registry can cache plugin specific metadata. What does it mean practically? A typical buzz song now loads in a quarter of the time.


Lots of testing and small improvements again. Besides the usual valgind sessions I tried the LLVM/Clang Static Analyzer. There are some annoying warnings, but lots of correct one too. Most of them were nothing major, but this is a good tool to follow. I also got more feedback from the NetBSD packages and worked on my Maemo port. This resulted in a couple of portability fixes and dependency cleanups.

With the testing came also many small but nice fixes and improvements. E.g. stereo wavetable support was incomplete and is now working fine. The pattern editor got many improvements like entering wave-table numbers, note-off support. Finally "play notes" is fully done. Latency is a bit better also. With latest pulsesink in gst-plugins-good git its actually quite okay (thanks wtay!).

The buzzmachines module has more machines ported, I have started to add demo songs and preset files. This needed some update in the gstreamer plugin too. Under windows the plugins, presets and help is all crammed into one dir. I have split it to have docs and presets under share and not in lib.

Thanks for help on gobject-introspection irc channel, bindings start to work. I have a javascript example that plays songs. Major obstacle was to get the js syntax right. The python sample does still not work. I hope it will after this summer of code.

I also reviewed and extended the user-docs. This version finally becomes usable :) Will do the strings freeze and pre-release tarballs this month.


We're heading for a 0.5 release! Most planned features are done and thus its time for testing. I've added some more unit tests. Especially for the dynamic editing, which now finally seems to work quite fine.

I added more keyboard shortcuts to support the workflow people might know from buzz. There is one to start playback from cursor-position and several for cycling through the comboboxes in pattern editor. I started to work on the play-notes functionality in pattern editor too. One can play notes while editing if song is playing already. Need to play the song in a idle-loop otherwise. Also need to figure the horrible latency I get.

One feature that was missing compared to buzz, is that buzz also shows parameters (volume, panorama) of incoming connections in the parameter view. We have this now too.

I also refactored some code in the machines and made monitoring more flexible. As a result the level-meters in the toolbar are now post-gain. Means if you change the volume you see the level-changing accordingly.

Last change of the month is some eye candy. The icons in the machine view don't become blurry when zooming anymore. I also added some simple effects to show the state (desaturizing them or making them half transparent).

LJ has part two of the buzztard article</b> online. Its an interview and tells you all you never wanted to know a bout me and the project.


Yay. LJ has a nice online article about buzztard. While helping the author to get the code up & running, I mad several improvments to the configure stuff to make things more obvious, especially when installing not to /usr. I also updated the instructions on the wiki and waffel updated our jhbuild module- set.

The GStreamer buzzmachine plugin now supports an index.txt file in the search path. This is used in buzz to categorize machines. The wrapper plugin adds the categories to the GStreamer classification filed and buzztard-edit uses it to build a structured menu. This helps makes the menu a bit more useful again. Same stuff needed for ladspa (via rdf).

The whole machine graph handling is now getting into 2nd phase. I can already disconnect stuff while playing without breaking things. Adding sources still has issues :/

I also made a series of UI experiemnts. I now have some code for doing properly scaled svgs on gnome-canvas. Sofar the machine icons became blurry when zooming. This was quite noticable in the screenshots of the article. Speaking of those I am suprised that even today, browsers only do nearest neighbour scaling. As graphics is fun, I also hacked some pixbuf filter effect, so that I can get icon variants for selecting and disabling. This will hopefully be integrated in next month. Finally I replaced the VU meter code with the cairo variant from gbo #547490 and made some fixes/improvements.

make me happy again

If you are an ubuntu developer, please dedicate some minutes to this bug report. Not having a working oprofile is quite bad, especially if it looks like all that is needed is to rebuild the package against the right kernel. Thanks, a lot!

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