SVF and STAPL players are very different, but both can be used to program CPLDS:
SVF (serial vector format) is a file format used by in-circuit testers. The programming data and algorithm for a CPLD can be written into SVF format so in-circuit testers can program CPLDs via JTAG during in-circuit test flow. An SVF player/interpreter, as it pertains to PCs, would "play" the SVF file's algorithm and program the device through a PC's parallel port during prototype. The problems with SVF is that was not created for programming CPLDs but rather for in-circuit test. SVF does not support branching in its language constructs resulting in longer programming times for CPLDs. It’s also sequential text file format - it does not support loops, resulting in very large sequential based files. As a whole SVF would really only be used for CPLDs if you were planning to production program CPLD devices through in-circuit testers. Altera® MAX PLUS® II and Quartus® II software support generation of SVF files but do not support "playing" or running SVF files.
STAPL (Standard Test and Programming Language) is a high level language designed specifically for CPLD ISP programming. STAPL is the JEDEC standardized version of the original Jam Language created by Altera. Jam/STAPL supports branching - which means faster programming times. A CPLDs programming algorithm and data is stored in ASCII STAPL or compressed byte code STAPL format. STAPL language also supports loops (e.g. FOR). This combined with compressed byte code means very small files. This is ideal for embedded programming where an intelligent host or microprocessor can use the STAPL player/interpreter to ISP program CPLDs. The STAPL player is also available to play through DOS executable or through Altera's MAX PLUS II or Quartus tools in windows or UNIX environment. The Altera MAX PLUS II or Quartus software Programmer Tools support "playing" and generation of Jam/STAPL files.