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Several problems occur when running The PS1 gamesused some rendering shortcuts to make the most of the hardware available at the time, and they which cause some quirks that become even more noticeable at resolutions higher than native when rendering with an increased internal resolution when using plugins which can increase it like Edgbla's GpuBladesoft, Pete's OpenGL2 and GSDX. Though they're still apparent at native, the low resolution's aliasing and blurriness kills almost any visibility, hiding the issues.
wanted to format →Emulation issues: 's headlines; ended up rewriting it
==Emulation issues==
===Rendering Quirks===
[[File:Cheryl_compared.png|thumb|350px|Left showing native resolution and unblended dithering. Right showing HD and no dithering.]]
[[File:Ps1_jitter.gif|thumb|left|Example of jittering in PS1 games, which is more noticeable when emulating at higher internal resolutions. (Click to play)]]
Jittering polygons are caused by low-precision fixed-point (to the native resolution) math. Plugins can attempt to fix this (This issue is mostly unnoticeable at native resolutions. [[Mednafen|Mednafen-libretro]] and some [[Recommended_PSX_Plugins#Video|GTE Accuracyplugins]])can attempt to fix this, but it often creates holes in seams.
The PS1 hardware didn't have a [https://en.wikipedia.org/wiki/Z-buffering z-buffer]. The lack of a z-buffer causes things like polygons popping over others. Tekken character limbs are a good example to see that. It's theoretically possible to implement z-buffer in PS1 emulators/GPU plugins.<ref>[https://translate.google.com/translate?sl=ru&tl=en&u=http://forum.emu-russia.net/viewtopic.php?p=17237 gpuBladeSoft discussion]</ref>
No texture perspective correction causes distortion to texture angles textures at certain viewing angles, notably at the bottom near the camera. This could be mitigated Along with modern texture filtering methods along with perspectivelow-precision math, this is a major factor in the apparent jitteryness of PS1 games. Perspective-correct texture mapping if could be implemented into PS1 emulators/GPU plugins, and actually already has been in an unreleased version of GPUBladeSoft([https://youtu.be/zGnLRR9kyvc video]).
On real hardware, many PS1 games displayed dithering to varying degrees due to a low color depth. This dithering would blend on most TVs to make new colors and smooth gradients. Most hardware-rendered plugins use 32-bit color depth, which removes dithering, while software-rendered plugins and emulators tend to retain it. While higher color depth can be considered an enhancement, since it results in less noise and smooth gradients, some think of dithering as seen on real hardware as added shading and texture, especially on untextured polygons. A few software-rendered emulators, such as PCSX-reARMed and the [[Mednafen|Mednafen-libretro fork of Mednafen]], are capable of increasing internal resolution while still retaining dithering, which keeps the shading/texturing aspect while making it more subtle by making the dithering artifacts smaller.
===CD format===
PSX games use the CD-ROM XA (eXtended Architecture) format which is based on CDi and allows developers to use both CD-ROM and CD-DA (audio) tracks on the same disc.
