There’s been quite a bit of grumbling about the PlayStation 4’s implementation of PlayStation 2 “backwards compatibility.” Mostly, there’s a lot of moaning about how those who’ve purchased the available games before, will have to pay form the again to play their up-scaled emulated versions.
The thing is, I can understand why. There’s a proper reason to moan about the implementation though, particularly those who live in PAL territories.
Here’s the thing. If you played PAL console games in the 8, 16 and even 32-bit days (and for a while, beyond!) you’ll know that because our TV system runs at 50hz, so did our games. That means that games were hardcoded to run slightly slower than the ones our American chums played, as their NTSC system ran at 60Hz (sacrificing a bit of resolution and colour reproduction, but I digress). It’s especially noticeable in games like Contra (released in Europe as Probotector), where the European versions are slightly easier to play through, because enemy bullets travel slower.
But it’s something that carried on through, right up to the PlayStation 2. Games released in PAL territories ran at 50hz, while the American ones ran at 60hz. With the PlayStation 4’s emulation allowing things to run at 1080p and at 60 fps, you’d imagine that Sony would opt for American versions of the games; with the 60 frame per second fitting so neatly in the 60hz refresh rate.
Instead, the PlayStation 4 version of PlayStation 2 games are based on the European versions, implemented a nasty bit of frame blending to make the games run at 60fps.
We’ve been looking at more PlayStation 2 titles running under emulation on PlayStation 4, and it now seems clear that all the UK code we’ve tested is running at 50Hz with a crude frame-blending ‘upscale’ to the 60Hz output. We made an error in the original analysis below – GTA San Andreas under emulation does have some frame-pacing issues, but much of the judder we encountered is actually a result of the frame-blending, registering to our eyes (and our analysis tools) as unique frames when in fact they are simply the interpolated results of two images – we did think that it may be an artefact of the emulator working with PS2’s original motion blur effect, but this is definitely not the case.
Credit goes to commenter Malek86 for noting that his copy of Twisted Metal Black is definitely European code, albeit outputting at 60Hz – a situation we have also confirmed with Dark Cloud. This was originally a 60fps game in NTSC territories, running at 50fps on the PS4 emulator, then frame-blended back up to 60fps. As you may imagine, this is not ideal.
The issue of course isn’t that they’re 50hz version, but rather that the implementation of frame blending leads to frame pacing issues It means that US emulation is smoother than the stuff we’d get here.
Last Updated: December 9, 2015