Recording videos with Jack and gtk-recordmydesktop

From Psychosynth

This tutorial is not fully translated into english. You can still visit the spanish version.

This tutorial explains how to use gtk and jack-recordmydesktop to record video with psychosynth using directly the output of the program, with much better quality than with a microphone and a video camera:)


Installing and jack-gtk recordmydesktop

The first step is to install these two programs. From a Debian-based distribution it can be done really simply:

apt-get install jackd gtk-recordmydesktop

If you have other Linux distribution you need to find and install right packages manually. See these homapages: jack and recordmydesktop.

Starting Jack

First let's explain briefly what the Jack is.

Jack is a sound system, which works both on GNU / Linux and MacOS X that is oriented to interconnect the sound signal between several applications. An application can use Jack's input and output, both audio and MIDI. When the Jack is installed, any application can use its inlets and outlets to send and receive information. We can also change connections between programs, using applications like qjackqtl.

What we want to do is to connect Psychosynth to a program that allows us to record videos of the desktop, so that it can capture the output of Psychosynth directly, without any noise from surrounding.

The first thing you have to do is to start Jack. You have to specify a system output with the '-d' option. To make everything work better, you should also adjust the sampling rate at which Psychosynth usually works with the '-r' option. We could also adjust Psychsynth's sampling rate, so it would match the Jack.

Thus, you can run:

jackd -d oss -r 44100

Or, alternatively:

jackd -d alsa -r 44100

Running Psychosynth sending the output to Jack

Now we have to launch Psychosynth so that is send output to Jack. We can do this in two ways:

Through the console

We'll use the "-r" option to specify the system output. Note the output system will change permanently, you'll have to switch to oss or to alsa in order to stop using Jack.

psynth3d -o jack

Through the graphical interface

That's really simple. First, click the 'Configure the program settings' button, to access Settings window. In field 'output' choose 'jack' and then press 'apply'. Ready :). Here's an image:


Recording the video with gtk-recordmydesktop

To record the video, run:


The first thing you have to do is to click on "advanced" button. Now, go to the Performance tab and then activate the option "full shots every frame", otherwise RecordMyDesctop won't be able to record properly the windows using OpenGL (like the Psychosynth).

Then you should...

(the translation is not finisched... check back soon.)