![]() ![]() PAL GPU cycles in a PAL line: (53.203425 MHz)/(15.625 kHz) ~= 3405.0192 cycles per lineįield rate = (GPU clock)/(Lines per field * GPU cycles per line) This all gets thrown out if a console is specifically modded so I'll ignore that specific case for now.ĭisclaimer: calculated values in this section are liable to be inaccurate and I make no guarantees for their accuracy. I'm not very confident about these calculations and it seems like results might even wildly differ depending on console revision. (15.625 kHz)/312.5 ~= 50.00 Hz Non-matching content and console clocks The PS1 NTSC/PAL line timings are fairly standard and empirically measured values should lie within some small tolerance of the nominal values.įield rate = (Line rate)/(Lines per field) I'm working backwards from nominal values listed above rather than via primitives like oscillators. PAL line rate (horizontal frequency) is 15.625 kHz (64 us per line) Field rate calculations Matching content and console clocks PS1 outputs 312.5 scanlines per field for PAL interlaced PS1 outputs 314 scanlines per field for PAL non-interlaced PS1 outputs 262.5 scanlines per field for NTSC interlaced PS1 outputs 263 scanlines per field for NTSC non-interlaced NTSC GPU clock is nominally 53.693175 MHz Hopefully the calculations below put some of the discussion from this issue thread and the forum thread to rest. The values calculated out in the matching content and clocks section below should be what we use in pretty much all cases since the Beetle core doesn't currently allow the video mode of a game to be set to something different from the disc region. ![]() We could implement the fps switching pretty easily but without any guarantees this might result in bad behavior for some frontends, especially for many games that switch between non-interlaced and interlaced frequently. RetroArch won't perform a driver reinit on fps changes anymore after e8c027c but the libretro API has no guarantees for this. Currently the way to report the proper frame rate to the frontend is through RETRO_ENVIRONMENT_SET_SYSTEM_AV_INFO. ![]()
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