Technical questions

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  • #24318
    BlueStinger
    Participant

    Hello, me again, with even more questions :

    Sampling phase : What is that about ? Is it like the sampling dots when using supersampling ? Or is it something different ? And if I don’t have a way to test my 480p content like I do with the 240p (with the test suite), how can I know which one is the best setting ? Is 180° a safe bet ? I have a sofmodded XBox, can I just use a checkerboard pattern to create a “480p test suite” for it ?

    Allow Supersampling X2 : I understand the principle of supersampling. But supersampling 480p from a 480p (for instance)… how does that even work ? Does it “look” to the nearest neighbor to approximate a “better pixel” ? I understand its purpose, but not how it works.

    Reverse LPF : After setting up my LPF options, the picture is more stable but slightly more blurry. When I set “reverse LPF” to 1, the picture becomes slightly sharper and I can see details I couldn’t see previously. Should “Reverse LPF” always be “OFF” (set to “0”) ? What exactly does this setting ? Is it a fine tuning of the LPF ? If so, why does it make the picture over-sharpened when pushed to the max ?

    A PS1 question now : I bought a RGsB SCART cable from RetroGamingCable, why is it that the OSSC always displays “RGBS” then ? There is a “Sync on green” sticker on the SCART and the AV2 auto-detect works with RGsB, so the OSSC knows it’s RGsB. So why displaying RGBS ?!

    And a resolution-related question : (I’m using PAL consoles) Why does the OSSC see “wrong resolution” when using PAL consoles ? Why does it say “525i” or “525p” when I’m using 480i/p content ? Is it because of the 50/60Hz difference ? Or something like that ?

    I don’t NEED to know the answers to these things, I just want to understand the OSSC as much as I can. There isn’t a lot of infos out there, or I’m too stupid to find them. In the meantime, what I have on screen is already gorgeous anyway (even though I think my Xbox could look a bit better, I have some ghosting issues… But it may be the cable). So, don’t feel bad if you don’t/can’t answer them.

    THANK YOU !

    #24322
    James-F
    Participant

    Oh no, it’s you again.. 🙂

    Sampling Phase will move the sampling position from 0 to 360 degrees, 360 deg is a width of a single pixel.
    Your goal is to sample only ONE pixel at a time without overlapping the next or previous pixel.
    This option is only useful in Optimized Mode, since in Generic Mode the sampling frequency is much greater than actual horizontal resolution of the console.
    Old LCD monitors with VGA only input would automatically adjust the phase clock.

    Here is an example of wrong sampling phase:
    phase1

    Here is sampling phase correctly adjusted:
    phase2

    Supersampling X2 will double the sampling rate of H.Samplerate setting, effectively lowering apparent horizontal pixel misalignment thus shimmer.
    So if H.Samplerate is 1630, the digitizer will sample 3260 times between horizontal sync pulses.
    Very useful with lower H.Samplerate settings like Line2x.
    Keep it on, I don’t see a reason to turn this off.

    Reverse LPF is just a sharpening filter meant for consoles that for some reason have excessive blurry/smeared image like the non-1chip Snes.
    0 = off, this will represent the true signal from your console.


    PS1 is only RGB+Sync.
    PS2 is RGsB ONLY in 480p progressive mode, otherwise like the PS1 RGB+Sync in 480i or 240p modes.
    RGsB means the sync signal is not separate from the RGB lines, but is combined on the Green channel.
    The cable is absolutely identical.


    NTSC uses 525 lines for the entire frame between vsync signals, that includes back and front porch, blanking and sync, the active (content) resolution is only 480 lines out of these 525.
    PAL uses total of 625 lines while only 576 are active.

    Now move along, you’re asking too much questions.

    #24323
    BlueStinger
    Participant

    Yeah, I know, but you guys are kind enough to answer them so you’re incentivise me to ask even more ! =)
    Thank you mate, I really appreciate it, there are a lot of good infos in your post !

    #24325
    nmalinoski
    Participant

    PS2 is RGsB ONLY in 480p progressive mode

    PS2 also uses RGsB for 720p and 1080i.

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