/* filter_mapping
         *      The `filter_mapping` setting determines whether or not to use
         *      the "PeOPS" implementation of the SPU filter, or my own.
         *
         *      The "PeOPS" implementation is faster, but lacks many effects,
         *      and is not an accurate recreation of audio from a PSX.
         *      Additionally, it can't produce proper 5.1 audio like the PSX
         *      SPU does (but UPSE does not yet support 5.1 output).
         *
         *      However, if you have been a pirate all of your life, you will
         *      probably want "PeOPS" here because it is probably what you are
         *      used to (as it's used in most emulators).
         *
         *      The "upse-ps2" implementation is theoretically bit-exact
         *      output comparable to an actual PS2 SPU. This includes the
         *      full PSX filter.
         *
         *      Note that PSF2 support is not presently emulated due to too many
         *      undocumented instructions in both the BIOS and PS2 HAL.
         */
        filter_mapping = upse-ps2;