Xbox compatibility issue with HDTV

NewHome Forums OSSC & OSSC Pro OSSC – Discussion and support Xbox compatibility issue with HDTV

Viewing 7 posts - 1 through 7 (of 7 total)
  • Author
    Posts
  • #39866
    TrantaLocked
    Participant

    I’m using an Xbox over component to the OSSC, then HDMI out directly to my Sharp 1080p HDTV.

    With the OSSC set to VESA 640×480, the full picture isn’t shown so that won’t work. Now for DTV 480p mode. In 480p passthrough mode, my TV doesn’t resize the image properly, so the picture appears zoomed in but at the correct proportions. In 480p line2x mode, if my TV thinks the picture is 1440×960 it shows me the entire picture but stretches it to widescreen. If I set the horizontal sample rate low enough so that my TV detects the picture as less than 1440×960 (like 1438×960), the picture gets sized much closer to 4:3, but slightly narrower at about a 1.28 ratio. So my TV will show 1438×960 at 1.28 but 1440×960 at 1.77. Obviously the goal is to see exactly 1.33 with a full view of the picture but I don’t know the best way to achieve that.

    The settings I have that give me a 1.33 image in DTV 480p line2x mode are as follows (TV detects as 1416×960):

    H. Sample rate: 841.95
    H. Synclength: 57
    H. Backporch: 60
    H. Active: 707
    V. Synclength: 6
    V. Backporch: 30
    V. Active: 480

    • This topic was modified 2 months, 1 week ago by TrantaLocked.
    #39871
    nmalinoski
    Participant

    DTV 480p is correct for the Xbox. The rest sounds like configuration issues on the display end.

    Now for DTV 480p mode. In 480p passthrough mode, my TV doesn’t resize the image properly, so the picture appears zoomed in but at the correct proportions.

    You need to toggle the aspect ratio on the display to a mode that disables overscan, like “1:1”, “native”, or something else.

    In 480p line2x mode, if my TV thinks the picture is 1440×960 it shows me the entire picture but stretches it to widescreen.

    You need to toggle the aspect ratio on the display to 4:3.

    If your display doesn’t let you toggle aspect ratio (rare, but happens), you’ll need to either add a video processor that can control aspect ratio (perhaps by pillarboxing) or use a different display.

    #39872
    TrantaLocked
    Participant

    Yeah that makes sense. My TV doesn’t allow user control to scale down to pillarbox or zoom out, only to upscale to wide/zoom in/panoramic. I don’t see overscan when I play direct over component to the TV or from the Xbox 360 @480p over HDMI to the TV, so I wonder what is making the TV mishandle the OSSC signal.

    Do my settings for achieving 4:3 make sense picture quality wise? I mean it doesn’t look bad to me, but is it technically worse than default sample settings to a TV that can properly display the picture?

    This setup with the OSSC direct to my TV was mainly for getting acquainted with the OSSC, but I still wanted to do my best to get optimal settings. I will probably use an upscaler in the end, either my DSC 301 or the mClassic (which I don’t have yet because Marseille’s internal processes are atrocious as they mishandled my order and shipping in multiple ways over the past three weeks).

    #39875
    Zacabeb
    Participant

    The optimal sample rate depends on whether each specific game runs at 640×480 or 720×480. In the former case, the optimal setting is 780 samples per line, and in the latter it’s the standard 858 samples per line (the picture is ever so slightly wider than 4:3 in that case).

    If you’re using Line2x mode with 480p and have Allow upsample2x enabled, the difference between those two sample rates gets less pronounced. Finding out whether a specific game runs at 640×480 or 720×480 requires some pixel peeping or detective work.

    Edit
    Here are the timings for square pixel 640×480 on the Xbox:

    H. samplerate: 780
    H. synclen: 58
    H. backporch: 59
    H. active: 640
    V. synclen: 6
    V. backporch: 32
    V. active: 240

    Take note if the picture appears shifted vertically. If so, reduce V. backporch to 31 or 30.

    • This reply was modified 2 months, 1 week ago by Zacabeb.
    • This reply was modified 2 months, 1 week ago by Zacabeb.
    #39902
    nmalinoski
    Participant

    Yeah that makes sense. My TV doesn’t allow user control to scale down to pillarbox or zoom out, only to upscale to wide/zoom in/panoramic. I don’t see overscan when I play direct over component to the TV or from the Xbox 360 @480p over HDMI to the TV, so I wonder what is making the TV mishandle the OSSC signal.

    Different input types are often handled differently by TVs; so your component input is likely doing different processing to what your HDMI inputs do. For example, I have an older Samsung LCD that will absolutely do 240p correctly over YPbPr component, but not over composite or HDMI (And probably not RGBHV, but I haven’t tested that one).

    I also have experience with a Panasonic plasma TV from about a decade and a half ago, which has an HDMI input, but it forces overscan on it; even though it has aspect ratio adjustments, disabling overscan didn’t appear possible. You might be having a similar issue, and I would suggest eventually getting a different display that would allow you to properly display inputs without overscan.

    #39996
    TrantaLocked
    Participant

    I just now realized that the TV also overscans on the 480p component output from my Xbox, something I missed in my initial tests. Now I see my TV does overscan most if not all 480p signals, while VGA 640×480 is rendered in full.

    Is the signal from an Xbox meant to be overscanned anyway? In Ninja Gaiden and while in the menu, at the top right is a gap between the menu and the right side of the screen that looks unintended to be seen by the player, and would be hidden if the TV overscans. Maybe there is an upside to it in terms of only seeing what the developer intended you to see?

    I’ve also realized Ninja Gaiden specifically feels bad when paired with typical HDTV input lag, and no external processor will fix that. Even if I achieve my TV’s lowest possible lag of 22ms, it doesn’t feel right in this game, so I’m probably just going to use my monitor with the OSSC (and maybe the mClassic) from the original Xbox. That will give me computer level responsiveness.

    #39998
    Zacabeb
    Participant

    Xbox games were indeed developed with overscan in mind. I think the title safe area was 80%.

    There are a few games where you might see some garbage along the edges of the picture without overscan (in OutRun 2006: Coast to Coast for instance, there’s a white border along the top and left edges in the menus).

Viewing 7 posts - 1 through 7 (of 7 total)
  • You must be logged in to reply to this topic.