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SnesPSP_TYL (ThunderYoyoLaxer)



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SnesPSP TYL V0.2 Online Help.

We have found that many people on the board where complaining about the options in the emulator
because they are difficult to use.

Actually because the PSP is a limited device (333 Mhz CPU),
we needed to allow fine tuning of each options for the rendering of a game or be able
to desactivate specific feature of the snes graphic hardware.
Future version may have even more features.

About Audio.
About Graphics modes.
About Graphics hacks.
About Frameskip.
About Speed limit.
About Video sync.
About Gamma correction.
About Save.
Misc.

About Audio.

In the emu, you can choose between 3 emulation mode :

  • Sound off => No emulation at all : this mode will allow you to completly desactivate the audio emulation.
    But this has a drawback, see A/ below.
  • Sound simulated / no output => Emulation is supported but no audio data generated : this mode is here for full Snes compatibility with games
    that need APU synchro.
  • Sound on => Full Audio Emulation : the APU is emulated and audio data is generated to the PSP speakers.

    A/ Some games use synchronization between the APU (Audio Processing Unit) and the CPU.
    These games will not work (ex. Axelay) if sound is turned off (emulation of sound chipset is required in such cases).

    B/ Some games accept to work but if you switch between the "no emulation" and "emulated" audio mode,
    you may have a lost of synchro between games and some games will refuse to continue if you put the audio back
    or put the audio off. The only solution for this is to run the game always in one mode or use the game saves (not emu states).
    At this point the console need to restart at the saved point and will restore the APU data correctly.

    THIS IS NOT A PROBLEM SPECIFIC to our emu, so if this happen, stop bitching about it and do like everybody else :
    dont switch your mode or use in-game saves.

    Now, we you choose to have sound output, you can selected the frequency.
    11 / 22 / 32 / 44 Khz
    The higher the frequency is, the better the sound output is, but of course, more PSP cpu is used
    to generate the sound, so the game frame rate is slowing down as a result.


    About Graphics modes.

    You have the choice between 5 graphics modes :

  • Approx. Software.
  • Accurate Software.
  • PSP Accelerated.
  • PSP Accelerated + Approx. Software.
  • PSP Accelerated + Accurate Software.

    First, Accurate software is the implementation used inside the original Snes9x with Z Buffer.
    It is the implementation you can find in all the other snes emu for the PSP.
    While it is the most accurate, it is also the slowest by a huge factor.

    Second, the Approx. mode is avoiding some rendering mode such as :
  • Add/Sub BG blending mode.
  • Dont use the Z buffer system of the Accurate mode.

    This result in a good speed up but user loose in rendering quality.

    PSP Accelerated supports all the graphics effects of the Snes in PSP hardware except mode7 and offset mode
    (special mode used for example to do the 'flag' effect on 'trigger' in Chrono Trigger's into).

    So when the PSP is not able to do it in hardware we have the 2 mixed modes :
  • PSP Accelerated + Approx Software.
  • PSP Accelerated + Accurate Software.

    These 2 modes are really usefull since they uses PSP hardware when possible and switch back
    to software mode when needed.

    However in some cases, it's better to use only Approx. Software when fine tuning, mostly for mode7 games.
    Good examples are FZero & Mario Kart.
    Good performance can be achieved by using Approx Software & some hacks in hack/debug menu.


    About Graphics hacks/debug mode.

    By going into the debug menu, you can even select more specific parameters.
    Like showing or not the BGs, etc...etc... Only for people knowing the Snes architecture.
    'Show rendering passes' can help you in fine tuning. The goal is to have to lowest rendering pass.
    To do this, use the various hacks and see by how much you can decrease the rendering passes number.


    About Frameskip.

    Then you can choose the frameskip.
    Basically this will help the emulator to run faster by skipping the (time consumming) process of drawing the snes screen (a frame).

    A game on the real snes hardware always run at 60 FPS (Frame per second) for NTSC games, 50 for PAL games.

    When emulating, we try to get as close as possible to the hardware but when the snes program
    is making an heavy usage of the graphic chipset feature of the Snes, it is very difficult
    for the emulator to fill 60/50 frames per second.
    In this case you can choose how the emu is going to skip the frames :

  • 0 : Render all the frames.
  • n (1 or more) : skip n frames after having 1 frame drawn on the screen.
  • Autoskip : this will allow the emu to choose for you automatically
    the closest skip to 60/50 fps. Now be aware that while it is convenient, in some cases it is not the best.
    When by manually settings frameskip to 0,1 or 2(small values) you achieve near 100% speed, we advice you
    to keep manual mode.

    A note about FPS then, when the emu display FPS, it displays 2 numbers :
  • upper is the number of FPS processed by the emu on the SNES side (should be 60/50 for NTCS/PAL when at fullspeed)
  • lower is the number of FPS processed by the emu on PSP side (number of frames drawn on the screen).


    About Speed limit.

    This feature will allow you to have the emulator do not going over 60/50 fps (NTSC/PAL games dependant).
    One example is mario which is going up to 105 fps without this option.
    In this case speed is too fast, so this option.


    About Video sync.

    Video Sync :
    This will force the emu to transfer the rendering buffer to the PSP LCD screen at 60 fps EXACTLY.
    If the game is running ALWAYS >60 FPS , instead of setting up speed limit, one should use VSync.
    In this case it will run exactly like the Snes. All scrolling will be perfectly smooth as a real Snes.

    In other cases, this option is not recommanded.
    One example would be a game running at 50 FPS.
    Then it would take around 1.2 FPS of the PSP time to render 1 frame of the Snes on the screen, but because VSync is enable it will wait
    for the next refresh of the screen and then you game will drop to 30 FPS.

    http://en.wikipedia.org/wiki/Vertical_blank_interrupt


    About Gamma correction.

    Gamma Correction : Look at this adress, they will explain in a better way than me.

    http://www.cgsd.com/papers/gamma_intro.html



    About save.


    Savestate from Y's uosnes9x and zsnes can be imported, most of the time it will work.
    if not, the only consequence is the game freezing, so just access the menu & reset snes or load another savestate.
    In the previous version we were autosaving the SRAM when going into sleep mode, it seems that is was corrupting some memory stick.
    Same also when battery goes too flat.

    So here is the new system :
    1/ We write to the memstick ONLY when battery is NOT low.
    2/ We do not write to the memstick when going to sleep mode.
    3/ We have an autosave feature:
    Crash or issue is something that will probably stick for a while on many emus.
    Some details of the PSP are not well understood yet and you never know if a bug remains or not.
    We have fixed lots of bugs, and this release should be a LOT MORE STABLE than the previous release.
    Still, we believe that an autosave feature (like Word or Excel) is a good thing.
    Basically you can decide how long is the timer, and then every x minute , the emu will automatically save into a
    special state for you.
    If the emu crash, if the emu does not wake up correctly or if you battery falls, then you are loosing only you last x minutes
    of game.


    Misc.

    Also the background of the emu goes RED when the battery is LOW. This will warn you that you cant access to the memstick anymore
    then go into sleep mode and wait to be able to charge your battery. Safe and clean.

    Advice/TIPS about battery life : running at 333Mhz of course eats a lot of power but one of the most power consumer is screen lighting.
    Try to lower the screen lighting if you know that you will not be able to charge your PSP for a few hours of game play.
    also, instead of running at 333 Mhz at full speed, use a frameskip of 1 and lower your cpu clock to 266.
    If you are in the metro or something, may be you dont need audio neither. This will save you CPU power and increase the emu performance.




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