The common container for distributing soundtracks as sets of SPC save states is RSN, which is a RAR file that uses the solid archiving feature to compress out duplicate code and samples shared between files. But RAR is proprietary. Its compressor is payware, and its decompressor source code is available only under a license that prohibits understanding it. There exists an SPC2 container, but that allows matches only at 256-byte boundaries, which isn't so good for music engines that reuse samples but dynamically relocate them in SPC RAM depending on which samples a particular song uses. How hard would it be to add support for 7SN, which uses 7-Zip's similar solid archiving, to common SPC players?