PSX v220702
Game: Final Fantasy VII (USA, http://redump.org/disc/66/) with translation patch (https://traduccionesxt.blogspot.com/202 ... final.html). Packed into a chd (Final Fantasy VII (Disc 1).chd).
EDIT: tried with an official unpatched version, similar results.
BIOS tested (boot.rom):
- PSP 6.60 c53ca5908936d412331790f4426c6c33
- SCPH-1001 924e392ed05558ffdb115408c263dccf
- SCPH-7001 1e68c231d0896b7eadcad1d7d8e76129
Audio filter set to Internal.
Stereo Mix: None.
Audio sample taken from MiSTer through a Scarlett 2i2. Only recorded audio from the left channel (duplicated channels to hear in stereo).
This problem seems to not be present all the time, only in specific areas or audio tracks. The sample was recorded in No. 1 reactor, before the Guard Scorpion fight. On the fight, the audio track is different and the crackles are no longer there (or hard to notice). After the No. 1 reactor explosion, when meeting Aerith, the audio track has no audible crackles either. The victory fanfare has crackles too (hard to notice but audible).
Savestate attached.
SOLVED
Unfiltered analog audio output when the FPGA gets busy can produce the crackles heard. Using HDMI audio or plugging a mini-TOSLINK into a DAC (jack doubles as a mini-TOSLINK connector) can solve the issue.