How Does PS2 Emulation Work On The PS4?

PS2 emulation on PS4 is an intriguing move by Sony to expand its catalog of video games.

Posted By | On 21st, Nov. 2015 Under Article, Graphics Analysis | Follow This Author @GamingBoltTweet

A few days ago Sony officially confirmed emulation of PlayStation 2 games for the PS4. It’s an interesting strategy by the Japanese company which is most likely a reaction to Microsoft’s support for Xbox 360 games on the Xbox One via the backwards compatibility update that was released for free a few days ago. However, it seems that Sony will be taking a different approach regarding the business model of making their older catalog available for the PS4 by charging for digital downloads compared to the free model that Microsoft opted for. However this topic is for another day. The bigger question right now is: How does emulation work on the PlayStation 4?

The Basics:

ps3 super slim 2

Emulation of older games on new consoles is not a new idea. Most manufacturing companies opt for a software emulation or in some cases, a more expensive hardware emulation. Take the example of the PlayStation 3. The first batch of PS3 SKUs actually had the original PS2 Emotion Engine CPU embedded right into the console’s complicated C.E.L.L. architecture which allowed players to play most PlayStation 2 and PlayStation One games. Later on Sony completely removed hardware emulation and opted for software emulation by allowing players to buy PS2 games from the PlayStation Network store. So as you may have already guessed by now, the PlayStation 4 uses software emulation to run Sony’s old PlayStation 2 catalog of games.

PS2 Inside The PS4:

ps2 architecture

In order to understand how emulation works, one has to look back the architecture of the PlayStation 2. The Emotion Engine CPU was the state of the art processor developed by Toshiba and Sony but for a more general overview, check out the screenshot of the architecture above:

All the essential components besides the Emotion Engine are already present on the PS4, although they are obviously much more advanced now. PlayStation 4 features a 2 gigabit of SDRAM which is mostly used for managing background downloading and compressing shared videos, and an Audio DSP which is based on AMD’s TrueAudio technology. So the main challenge for the development team must have been to emulate the Emotion Engine CPU and make it compatible with the existing unified memory architecture. We can’t say what kind of challenges the development team must have come across to implement the emulation but we certainly think that the simplified x86 architecture must have helped matters.

The Emotion Engine uses a 128 bit SIMD and integer registers which can be easily handled by the x86 architecture given that 128 bit SMID instructions were already present on x86 way back in the late 1990s. Given that Sony uses its own custom graphics API which has evolved over the last many years and they have already done this kind of stuff before, it must have made things a bit easier. After all, the existing architecture needs to understand the draw function calls from the emulator to the PS4’s GPU. Since the Emotion Engine is being completed emulated by software, the solution possibly has less dependencies on the PS4’s on-board CPU processor.

Trophy Support Logic:

ps2 emulation on ps4 trophy support

The emulator also comes packed in with a smart logic for trophies implementation. Modern games are programmed with an event base model which means certain things should happen before the event is fired to initiate a trophy. The PlayStation 2 did not had a trophy system back then but the emulator intelligently reads the game’s state and based on some internal variables, a trigger event happens. The emulator reads the game’s state and continuously compares them with the bunch of trophies that come along with the game. The big question here is how does the emulator understand these states? Do developers/publishers need to modify the game or make Sony aware about this handshake functions before they are actually allowed for emulation? This will obviously bring in costing issues [possible patches] for publishers and whether it’s a worthwhile investment for them is a topic that is up for debate.

Emulator Benefits:

So how do emulated games look like when compared to the originals? As can be clearly seen in the video above, the software emulation is bringing in several improvements. First of all, the emulation is using a custom post processing anti-aliasing drastically smoothing the jagged edges. It seems that Sony has developed a very smart algorithm to achieve the same so it will be interesting to see how this will work in more complex games such as Metal Gear Solid 2: Sons of Liberty or Grand Theft Auto: San Andreas, if they are ever added to the library. The emulation is currently upscaling the resolution to 1080p but we are pretty sure that the native resolution the emulation is rendering the game at will differ from game to game.

Talking about frame rates, the emulator is currently outputting the games at 60 frames per second. However it does not end there, it seems that the emulator is also implementing a tri-linear texture filtering resulting into cleaner and crisper details on objects and characters, something that the native PS2 game clearly lacks. All of this sounds pretty encouraging but we would love to see how the emulator responds to games like Metal Gear Solid 3: Snake Eater, a game which suffered from serious frame rate drops during the jungle sections.

Closing Note:

This is certainly an interesting addition by Sony but there a lot of things that we still need to look at. The benefits of this feature will depend on the catalogue of games that Sony will bring in and that will depend on whether players actually want to play older games on the PlayStation 4, given the plethora of new titles that will be made available in the coming year and ahead. I also wanted to add a little note regarding how Sony’s marketing team is doing a rather poor job of showing off new features. The emulation feature was released in Star Wars bundle for the PS4 including four average quality games…and Sony made no effort in announcing that emulation is coming to the console. Couple that with poor marketing for Until Dawn and the upcoming Beyond Two Souls for the PS4, it seems that Sony is now becoming a fan of stealth updates and releases. Regardless, stay tuned for more analysis as Sony releases more information and PS2 emulated games and a possible support for PlayStation One games as well.

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  • YaCoVv

    Very interesting… I just hope it will support PS2 discs & not only Digital downloads.

    • XbotMK1

      I hope so but always hope for the best and expect the worst.

    • Maria Hernandez

      Yahoo CEO, Marissa Meyer has gone so far as to Support the practice “Work at home” that I have been doing since last year. In this year till now I have earned 66k dollars with my pc, despite the fact that I am a college student. Even newbies can make 39 an hour easily and the average goes up with time. Why not try this .. vvbb

    • Truth™

      It’s sony so it will probably be downgraded and you have to pay for it yet you will still defend it.

  • XbotMK1

    I don’t see how you think this might be a reaction to Microsoft’s announcement. It’s quite clear Sony has been working on this for a while because of the recent Star Wars bundle with PS2 games and it’s clear they’ve been working on it since the beginning of 2014 when fans requested it after PS Now launched according to Eurogamer and the patent.

    The reason why PS2 emulation might not be for disks could be because PS2 disks have been pirated for years, or the emulation system might not recognize all game disks. The original PS3 model was able to play PS2 games disks because it had PS2 hardware chips inside. But later PS3 models ditched the PS2 hardware and relied on emulation so not all PS2 game disks would work on newer PS3 hardware.

    This might only be for digital and might require a modified version of the game to be downloaded. But we will have to wait and see.

    • Starman

      stfu … because they said …and i quote..”we are good with the path we chose , not interested in emulating old games” but let’s charge for crappy , laggy streaming , how are you trying to defend this you idiot
      and that’s from the mouth of yoshida …fangirl

    • kevin

      Fanboys like you are sad and need to grow up. If ps now is a lag fest for you that’s on your crappy internet connection not ps now but of course fanboys such has yourself will try to blame it on anything.

    • Starman

      i use 300dwn and 300 up verizon fios son .. now stfu and go play knack …lol

    • kevin

      Yeah sure you do lol fanboys Crack me up

    • Michael Norris

      You are the reason i will never own anything Xbox.

    • Truth™

      And you are stupid enough to buy Sony too

    • Riggerto

      “Stfu”, “idiot”, “fangirl”…

      There is a difference between someone who enjoys something as their hobby and a person who has become paranoid, obsessive, all consumed by it.

      I think you may be the later.

      Chill out. It’s a plastic box under the tv. Both companies are after your money and don’t care about you as a person. Just relax and enjoy playing video games. Yes it’s fun to debate the merits of either brand but making it personal just makes you look like you have completely lost it.

    • Starman

      who cares what you think about my approach, still giving facts …

    • Riggerto

      Case in point.

    • Gamez Rule

      ♦”we are good with the path we chose , not interested in emulating old games”♦ …..Hmm PS2 games working on PS4 shows that Sony have been working on emulating older catalog games to work on this gen hardware?

    • Starman

      it doesn’t work … dummy , they’re working on it ..and hoping , so why do’t they show it …dummy…and why not the ps3 , you guys are just plain stupid ..period

    • Gamez Rule

      Not working & dummy..Ok then…

      PS4 Star Was includes a voucher containing four Star Wars PS2 Classic games that are working right now on PS4☺

      The above PS2 games already working on PS4 proves what I stated to be correct.. “Sony have been working on emulating older catalog games to work on this gen hardware”. So call people stupid all you like but truth is PS4 is playing older games right now with more to follow.

    • Michael Norris

      Starturd stfu Sony has had this emulator in the works for a few years.Sony wants to re release Ps2 titles with resolution and frame rate upgrade.

    • Truth™

      720P is not much of an upgrade when PC has been emulating at 1080P for years, fam

      That weak hardware is a joke

    • Tech junkie

      For a Sony fanboy you don’t know very much about how the ps3 played ps2 gamers.

    • Robert

      Completely different from Xbox One since they’ll get 2 free Xbox 360 games with gold thats compatible on Xbox One every month.
      Sony’s logic
      “Rent the games you already own” PS Now
      “Re-purchase the games you already own” Digital PS3 games

    • Truth™

      720P emulation. LOL

      No one is impressed, John Derp.

  • Starman

    what are you all talking about , we know how it works … it’s age old tech , never did this when ms/xb1 announced , now the the ps4 is doing (not real emu) but some other way to stream and charge money lol what a joke …..

    • Michael Norris

      You are still playing old games as well.Also the upgrades you get on 360 emulation is a slight boost in performance.

    • Truth™

      720P PS2 games.

      Where is the “power of the PS4”

      Oh wait it’s non existent. kek

  • irrational010

    What a stupid article. How does ps2 emulation work on ps4? Same way pcsx2 works on pc and has been working for many years. I myself have been playing ffxii on my pc at 1080p running 60fps and extreme antialiasing Its not easy but its not difficult either. A group of determined programmers reverse engineered ps2 architecture, and wrote a publicly available code that can run already compiled ps2 games on a windows or unix pc. Sony probably just copied the code and added some improvements given that ps4 is essiantelly a unix machine running on x86 hardware.

    • E.J457

      The PS2 emulators you can find on PC don’t work for every game and it runs like garbage so stop lying. They don’t have trophy support either.

      It is also illegal to distribute or copy an emulator with a bios to people who don’t own a PS2.

    • Starman

      then you have the wrong one dummy , mine work flawlessly , so who needs a ps4 , that can’t really do sht when you look at it .. but play unstable games

    • Truth™

      Nope. PCSX2 works great. Has a 95% Compatibility rate and it’s community have created texture packs for games to bring them up to 1080P standard instead of Sony’s 720P

      Weak console can’t even run PS2 games at 1080P. LOL

  • Starman

    “How Does PS2 Emulation Work On The PS4?”

    it doesn’t !!!!

    • E.J457

      You’re a special kind of stupid aren’t you?

    • Starman

      so show it working and i wont say another word , the only stupid ones here are the ones believing it will work , it will end up a streaming service , mark my words

    • RollingSun2000

      Did you miss the part that the games included in the Star Wars PS4 bundle are emulated PS2 games?
      There is even a video floating around the net demonstrating it. Anyone with a PS4 (or a love of PS2 games) knows about it by now. (Digital Foundry).

  • Hermione Granger

    its not free and you cant use your disc… so its crap and not worth any attention.

    • E.J457

      So you don’t think letting people play their PS2 digital classic on their PS4 that they bought from the PSN store is good or worth attention?

    • Hermione Granger

      sony can give options, but i guess everyone have forgotten. when sony was talking about ps+ on the ps3. and said the famous words ‘playstations is about options’. thats why they had free online gaming and you pay for ps+ if you want free games and cloud saving… look at ps+ on the ps4 the onlie play is been put behind a paywall, talk about giving people options.. i guess it was all lies and bs to ease people into paying for psn… for the players, the biggest lie and bs ever….

      sony should offer the games the option to not pay if they have the disc.. and if you have no disc and want the digital then pay…

      but again sony aint about options, its all about greed, arrogance, lies and bs so they can flog all their customers for every penny possible…. remember they are…. ‘for the players’ and ‘greatness awaits’… sony = worst liars ever.. facts!..

  • Michael is pitiful.

  • ImOnaDrugCalledSheen

    “will depend on whether players actually want to play older games on the PlayStation 4”

    they dont, and neither do xbox owners regardless of how much the vocal minority try to rub it in every ones faces. The feature is not necessary, the overall majority of people bought new consoles to play new games not old ones.

    • Tech junkie

      Why do you say that? I love retro gaming and so do many others, they sell retro consoles. I use my Xbox as it was designed. It’s the center on my media experience, I like that I get to play my 360 games but maintain the level of connection I get with my Xbox One.

      I play games from Atari all the way to the latest gen all the time. Many are just like me. You might not play old games but many do.

    • Sandra Salgado

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    • Truth™

      720P PS2 emulation is a joke, fam. PS4 has no games so people bought into a meme console.

      Pathetic, really.

  • Rikarudo

    Never cared for BC.
    But if this doesn’t hurt the overall ps4 new games divisions over the world. Go ahead, make it for those who want it but like I said.
    Don’t care for this or for the X1 BC.

  • Mr Xrat

    Full disc emulation or don’t bother. I hope this doesn’t end up another version of the Xbone’s limp and overhyped limited emulation.

    • Starman

      i use disc and digital …dummy , wth are you even trying to say

    • Mr Xrat

      If you can’t work it out, you’re as dumb as I thought.

    • Truth™

      You bought a console with no games and 720P VR, rcottyg. You are in no postion to call xbots dumb with your constant meltdowns.

      Your meltdowns over 720P VR and 720P PS2 games have been hilarious to read over the past week along with your usual projection :^)

    • Truth™

      Another rscottyg meltdown over a feature done years ago on PC. And at a worse resolution too. PS4 can’t even play PS2 games at 1080P. 720P LOL

      1080P or death? Which is it?

  • Darren Kendrick

    I do enjoy reading the arguments that commence when either console adds a feature, too many awesome new games coming in the next 12 months on both consoles for me to care about BC and emulation, I did buy the xb1 a couple of months back though, now that some decent exclusive titles have hit and will hit, but have had ps4 since launch, I like that I bought the xb1 with gears ultimate, playing it through again with my mate was awesome, and they’ve given us 2,3 and the other one which isn’t 4 for free to play through … that’s awesome too, enjoy both of them man, that’s all they’re made for, money and fun.
    Why limit yourself.

  • Gamez Rule

    ♦”However, it seems that Sony will be taking a different approach regarding the business model of making their *older catalog* available for the PS4 by charging for digital downloads compared to the free model that Microsoft opted for”♦

    PS-Now is NOT for backward Comp- like being made out to be. PS-Now is to allow all types of devices to play PlayStaion Network games ( not just for PS4 gamers ) but a wide range of gamers right down to a TV set.

    Star Wars bundled with older PS2 games shows that PS-Now is not needed. And was people charged for those *older catalog games*…Nope they came as an extra lol.

  • Robert

    Sony probably copied and paste pcxs2 code from Github even though you play in 4K with the same features what PS4 using

    • Greetingsfriend

      Or they would build their own while looking at the documentation of the PS2 hardware and how it worked. Something PCSX2 doesn’t have.

  • Valkyrine

    So I have not heard whether it is only digital games being emulated or support physical games. Both would be cool since it would be hard to find some games.

  • Jaymz W Steward

    All ps3s have the ability to run ps2 and ps1 games. Sony changed a file extension in the newer ps3s to block them from running. The custom firmware on my “non backward compatible” ps3 fixed this issue : )


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