How-to enable jack in mplayer (Ubuntu Gutsy)

In my last how-to we played a multichannel video with surround audio (coded with ac3) using mplayer and jack. Jack (the audio server and router) is perfect to use with firewire audio interfaces. However, the Ubuntu Gutsy mplayer is not jack enabled by default.

To see the list of audio backends:

mplayer -ao help

However, it is very easy to compile a new mplayer .deb package jack enabled. First, create a temp dir (for example debs) and change to it. Install libjack with it’s development headers

sudo apt-get install libjack-dev

Install all the packages to build the mplayer-nogui package. This is done in a single command:

sudo apt-get build-dep mplayer-nogui

Now just get the source package and build it (the -b option is for build). This will take time.

sudo apt-get -b source mplayer-nogui

The mplayer build system automatically searches for libjack headers and when found configures its build system to use jack.

Finally install the new packages (dpkg complains with an error error processing mplayer which you can ignore):

sudo dpkg -i *.deb

To use it, choose the jack audio driver with -ao jack. A nice feature is that it automatically connects all the outputs to the physical device inputs.

mplayer -ao jack someaudiofile.mp3

If your file have more that 2 channels:

mplayer -ao jack -channels 5 surround.wav

As a final note, I’ve checked that debian (not ubuntu) package is jack enabled by default. The reason is that their packaging scripts differ a little bit (specifically debian/control file). The Ubuntu one don’t define the jack-dev build dependency.