There is a HOWTO: wunderkiste.gedankenstrudel.de/2011/05/21/building-showtime-with-psl1ght-v1/
Building Showtime with PSL1GHT v1
Showtime is a lightweight HTS (Home Theater System) for Windows, Linux, MacOS and even PS3 and Wii. Unfortunately it is impossible to build the recent git snapshots using newest PSL1GHT right after the merge with PSL1GHT v2 I patched the ps3toolchain making it possible to compile PSL1GHT v1 that is required by showtime.
This can take several minutes or several hours depending on your hardware. A core2duo should make it within 1,5 hours. There are 12 steps: compiling ppu-gcc, spu-gcc and several tools like gdb, binutils and newlib. I patched the toolchain scripts not to download the source code from the internet. Otherwise building the toolchain fails. Feel free to check the checksums. If it’s done, you get a fully functional environment ready for showtime.
Andreas Oman, you are dong an amazing job! Your homebrew allowed me for the first time to play mkv videos on my PS3! However, as i am sure you are aware, MP4 files do not work (H.264 video codec). Hopefully, you will make this media player the best by first fixing the playback issues for all existing formats, and then later on, add new features.