Menu

Hybrid Scanlines

Home Forums OSSC OSSC – Feature Requests Hybrid Scanlines

This topic contains 97 replies, has 18 voices, and was last updated by  PRC 5 months, 1 week ago.

Viewing 15 posts - 1 through 15 (of 98 total)
  • Author
    Posts
  • #19241

    rgdelato
    Participant

    The UltraHDMI and the Analogue Super NT have something they call “Hybrid Scanlines”, which seems to lighten sections of the scanline based on the surrounding pixels. Here’s an example picture from RetroRGB:

    http://retrorgb.com/images/UltraHDMI-HybridVSSimpleScanlines.jpg

    Is there any chance we could see something like this on the OSSC?

    #19250

    James-F
    Participant

    I think this kind of function requires a framebuffer.

    #19257

    BuckoA51
    Keymaster

    Not necessarily, if Scale2x can be done with just a line buffer, this might be possible too, though it depends how the effect works.

    Truth of the matter is though there’s not much space left on the OSSC now for big new features.

    #19264

    haloharry
    Participant

    Is there any plans of making v2 or 1.5 with lot more space.

    Or is it possible to move some files into the sdcard.

    #19392

    paulb_nl
    Participant

    Challenge accepted 😀

    I did some testing which uses a very simple way of creating hybrid scanlines so it can be used on the OSSC. What do you think about the results? I like how it has a CRT bloom like side effect.

    First is hybrid then normal scanlines.
    Mario 64 hybrid scanlines
    Mario 64 normal scanlines
    Mario Allstars hybrid scanlines
    Mario Allstars normal scanlines

    #19393

    James-F
    Participant

    Looks great!
    *please link to a bigger pictures.

    The completely white region should still have scanlines clearly visible, a more realistic look would be 2 rows white and 1 row black (240p in 720p).
    Real scanlines are quite uniform and visible at maximum luminance (white), they gradually get thinner on darker regions.
    On a properly calibrated CRT (100 Nit peak luminance) the white color is not overbloomed or ‘connected’ as in your example images.

    Here are some photos from my 29″ Sony Trinitron:
    http://www.mediafire.com/?ee9d7cq9ioq0i

    Mainly this one:
    http://www.mediafire.com/convkey/4081/n43hyh269zm4cz4zg.jpg

    A great option would be to have the white region and black region scanline strength adjusted independently.

    Great work!
    Now lets see how they look in 720 after you fix the white region scanlines. 🙂

    #19394

    Harrumph
    Participant

    Very nice proof-of-concept! But yeah I agree the darkening should not completely disappear in high luminance sections.

    #19433

    paulb_nl
    Participant

    The example given of the UltraHDMI also has the bright areas without scanlines so I tried to make it look like that in the images I posted. You can increase the scanline strength so that bright areas still have scanlines.

    I am using a simple comparison to increase the contrast between dark and bright scanline pixels so its not possible to have the dark areas use 2 scanline and bright areas use 1 scanlines for example. I should probably name this feature Scanline contrast.

    I have it running on the OSSC and added a Low and High setting. Here is a comparison on lineX3 with scanline strength set to 100% with contrast Off, Low and High:
    https://i.imgur.com/Qcv6qAO.png

    Here is a lineX3 capture of scanline strength 81% with contrast High:
    https://i.imgur.com/MV2MnHK.png

    #19436

    James-F
    Participant

    Now this is amazing!
    Hope to see this in v0.80.

    #19438

    BuckoA51
    Keymaster

    Did you have to remove any other features or does it all fit in the existing firmware?

    #19455

    paulb_nl
    Participant

    It all fits in the firmware. This feature uses very few resources. SoftCPU which contains the menu among other things is getting low on memory but this just adds 1 menu item in there. The processing is done on the FPGA which Quartus reports has around 54% of logic elements used.

    #19458

    Harrumph
    Participant

    Individually adjustable scanlines is in the FW improvement roadmap. I don’t know if Marqs already has some code for that.

    Hypothetically, could “scanline contrast” be merged with adjustable scanlines, or you think they are mutually exclusive?

    If they could be combined, that seems to me almost like the ultimate scanline “sculpting” feature! 🙂

    #19475

    paulb_nl
    Participant

    Yea I am fairly sure they can be combined. I’ll have to wait and see how Marqs changed the scanline code 🙂

    #19496

    Jeruro
    Participant

    Wow! can you share the firmware to test?

    #19504

    SRRAE
    Participant

    This looks very interesting. It will also help against the image looking so dark when you use heavy scanlines.

Viewing 15 posts - 1 through 15 (of 98 total)

You must be logged in to reply to this topic.