What is QRT?
QRT is a real-time soundfile mixing application modeled vaguely along the same lines as ProTools, at least in terms of visual editing of sound placement. It is also a scripted system, with variable-argument-count text commands representing each soundfile mixing event or other changes to the mix. These scripts are read and written by QRT to save and restore the detailed specifications of the mix. In addition to mixing, a growing subset of simple sound processing algorithms are also available, such as gain and pitch curves.
QRT is a port of Paul Lansky's Rt, which he created early 1990's as a NeXTStep application, then ported to the SGI platform in the mid to late 1990's. Rt's last incarnation was as a Linux application based upon a no-longer-public Linux port of SGI's Motify X library, ViewKit. I was actively involved in this port, and eventually abandoned it due to possible difficulties with ViewKit, most especially the lack of a port to the MacOSX platform. QRT is based upon the GPL QT GUI library from TrollTech, hence the name: QT + Rt == QRT. QRT runs under X86 Linux as an X application and under MacOSX as a native app.