Meanwhile a wide variety of digital video systems and codecs exist. Anyway, the importance of the Quicktime system seems to be decreasing in the last time. AVI finally is another large collection of codecs, for example Indeo codecs.
Details see below.
But don't be afraid, it's only needed for recording, not for playing. On all other systems you have simply to consider above preconditions. Generally speaking, you need sufficient fast hardware to make use of it. For playing the lower limit is either a 300 MHz Intel Pentium II or equivalent with simple graphics adapter without acceleration or a 200 MHz Intel MMX with a good accerated graphics adapter. This has nothing to do with OS, but with the high compression, which requires a lot of uncompressing work.