< Guidelines and HOWTOs | Debugging Contents 1 Environment Variables 1.1 Phonon-GStreamer debugging 1.1.1 Drawing a dot diagram 1.1.2 Even more verbose output 1.1.3 Pulseaudio 1.1.4 Recreating the phonon-gst pipeline 2 Building Phonon from source 2.1 Get Dependencies 2.2 Install git 2.3 Install ccache to speed up compilation 2.4 Define the PATH and local environment 2.5 Make KDE aware of Phonon’s location 2.6 Install locally 2.7 Build locally from a tarball Environment Variables In general, there is one easy way to give Phonon devs all the information they need to help fix your problem. Set these environment variables: export PHONON_DEBUG=5 export PHONON_BACKEND_DEBUG=5 export PHONON_SUBSYSTEM_DEBUG=2 export PHONON_PULSEAUDIO_DEBUG=5 export PHONON_VLC_DEBUG=5 export PHONON_GST_DEBUG=5 Then run your program. The terminal will fill up with gobs of debugging output. Phonon-GStreamer debugging Drawing a dot diagram $ export GST_DEBUG_DUMP_DOT_DIR=/tmp $ # run your program $ dot -Tpng -oimage.png < /tmp/one-of-the-dot-files.dot Even more verbose output Phonon-gst has some fancier debug options available. In addition to PHONON_GST_DEBUG, there is PHONON_GST_GST_DEBUG. Setting it to 8 or so will cause the gstreamer libraries to produce copious quantities of debug output. We're talking thousands of lines of what seems to be useless noise. Roughly 1% of it is useful, but the phonon-gst devs can easily decipher it and drill down to the important bits. Pulseaudio Pulseaudio and phonon try their hardest to get along. Sometimes, it doesn't work. Luckily, there is a way to test gstreamer and pulseaudio to see who is at fault. $ gst-launch filesrc location=/usr/share/sounds/KDE-Sys-Log-In.ogg ! decodebin2 ! audioresample ! audioconvert ! pulsesink $ gst-launch filesrc location=/usr/share/sounds/KDE-Sys-Log-In.ogg ! decodebin2 ! audioresample ! audioconvert ! alsasink If they both work flawlessly, blame Phonon-GStreamer. If the first works but the second doesn't, you might have an exotic sound setup that involves tweaking the alsasink parameters to reflect what pulseaudio does to alsa. If the second works but the first doesn't, you can blame pulseaudio. Another way to confirm this is by setting the PHONON_GST_AUDIOSINK environment variable. Setting it to e.g. "pulsesink" uses the pulseaudio sink. Recreating the phonon-gst pipeline Phonon-GStreamer creates predicable pipelines. In general, they look like this: filesrc -> decodebin2 -> queue -> audioresample -> audioconvert -> pulsesink \ -> ffmpegcolorspace -> queue -> xvimagesink If the input stream isn't coming from a file, it is likely coming in via KIO which pipes it into an abstractmediastream. If pulseaudio isn't used, then replace pulsesink with something of alsasink, osssink, or somesuch. Recreating the playback stream of some video file can be done as such: $ gst-launch filesrc location=/path/to/video ! decdebin2 name=dec ! audioresample ! audioconvert ! pulsesink \ dec. ! ffmpegcolorspace ! xvimagesink DVD playback is a bit different: (subpicture stream) /--->---\ rsndvdbin -> dvdspu -> ffmpegcolorspace -> queue -> xvimagesink \-> queue -> audioresample -> audioconvert -> pulsesink This is built with the following: $ gst-launch rsndvdbin ! dvdspu ! ffmpegcolorspace ! queue ! xvimagesink \ rsndvdbin0 ! dvdspu0.subpicture \ rsndvdbin0 ! queue ! audioresample ! audioconvert ! pulsesink Building Phonon from source If you want to have a newer Phonon build than 4.4.3 which is currently shipped by most distributions in KDE 4.6, you can build from source (git). Phonon is now located on git.kde.org. Get Dependencies Deb-based distros, run sudo apt-get build-dep phononto be sure you have all dependencies installed. OpenSuSE: sudo zypper si -d phonon Install git In Kubuntu, Debian, etc.:sudo apt-get install git-core In Archlinux:sudo pacman -Sy git In Gentoo:sudo emerge -av dev-util/git In OpenSuSE:sudo zypper install git Install ccache to speed up compilation Install the package from your distribution and set the size of the cache to 2 GB with the commandccache -M 2G This will take 2Gb of space in your local directory. Enable the use of ccache by adding it to your local .bashrc, described below. Define the PATH and local environment Append the following to $HOME/.bashrc: export PATH=$HOME/kde/bin:$PATH export PATH=/usr/lib/ccache:$PATH export LD_LIBRARY_PATH=$HOME/kde/lib:$LD_LIBRARY_PATH Reload your edited .bashrc: source $HOME/.bashrc NOTE: if you are not using the bash shell, edit your proper shell config file (~/.zshrc or ~/.tcshrc or whatever it may be). Make KDE aware of Phonon’s location echo 'export KDEDIR=$HOME/kde' >> $HOME/.kde/env/myenv.sh echo 'export KDEDIRS=$KDEDIR' >> $HOME/.kde/env/myenv.sh Some distributions call the above folder $HOME/.kde4/, such as OpenSuSE. Install locally Install in your $HOME dir): mkdir $HOME/kde && cd kde && mkdir src && cd src git clone git://anongit.kde.org/phonon cd phonon && mkdir build && cd build cmake -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=debugfull $HOME/kde/src/phonon sudo make install To update your build, it's even easier: cd ~/kde/src/phonon git pull cd build && sudo make install Build locally from a tarball This is 4.4.4 for example: cd ~/kde/src/ wget http://download.kde.org/download.php?url=stable/phonon/4.4.4/src/phonon-4.4.4.tar.bz2 tar xf phonon-4.4.4.tar.bz2 cd phonon-4.4.4 && mkdir build && cd build cmake -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=debugfull $HOME/kde/src/phonon-4.4.4 sudo make install Retrieved from "https://community.kde.org/index.php?title=Guidelines_and_HOWTOs/Debugging/Phonon&oldid=53526" This page was last edited on 11 March 2016, at 12:31. Content is available under Creative Commons License SA 4.0 unless otherwise noted.