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Structured light patterns over HDMI on 4500 at 120hz

Gavin Smith
Intellectual 515 points
Other Parts Discussed in Thread: DLPC350

Hi, 

We have been using the original lightcrafter 3000 to send structured light patterns to the projector over HDMI at 60z. 

We generating the video in realtime and its not a repeating loop, but a continuously changing feed.

We used a variety of modes, including monochrome and 1 bit color, so the 24bit color input video is then projected at 1440 fps video in either a string of Monochome frames or in a repeating color sequence, like RGBRGBRGBRGB etc.

We recently upgraded to the LC4500 as we were told we could get twice the frame rate and increased brightness.

The manual for the LC4500 is very different and does not seem to indicate a series of modes to do what we were doing before over HDMI. 

Can you please tell us how we configure the LC4500 to appear on the PC as a 120hz video display and how we select an option to achieve 2880 fps over hdmi in cycling color and monochrome.

many thanks

Gavin

  • 0
    TI__Expert 4720 points

    Hello Gavin,

    To setup the pattern sequence for such operations, please read section 3.3 Pattern Sequence Mode from the LightCrafter 4500 User's Guide (http://www.ti.com/lit/ug/dlpu011b/dlpu011b.pdf) for the details. Here is a brief summary though.

    1. Set operating mode to "Pattern Sequence"
    2. Set pattern source to "Video Port"
    3. Set the internal trigger time (i.e. the time between the beginning of each single pattern)
    4. Set the exposure time (i.e. how long the pattern is displayed)
    5. Add the individual patterns to the sequence (select color, bitdepth, bitplane, etc.)
      1. If you increment the "frame index", the controller will update its buffer with the latest video frame sent via HDMI.
    6. Send the sequence.

    By default the EDID on the LightCrafter 4500 can accept inputs of 60Hz. The EDID needs to be updated so that you can send video at 120Hz to the device. Please send me a friend request and I can assist you further.


    EDIT: The LightCrafter 4500 already accepts 120Hz video signals. No software or hardware modifications are necessary. The video source is responsible for the frame rate. Many computer graphics cards only output 60Hz, if 120Hz video is desired the graphics card must be upgraded.

    Best regards,

    Blair

  • 0 in reply to Blair Conner
    Intellectual 515 points

    Hi Blair , 

    Thanks for that . I sent you friend request . Can you  please send the edid details ASAP . thanks again .

  • 0 in reply to Gavin Smith
    Prodigy 10 points

    Hi,

    I am trying the same as gavin, so I re-use this thread instead of opening a new on.

    I am stuck trying to get 120 Hz HDMI to get a binary pattern sequence of 2880 Hz.

    I have a nvidia GeForce GTX 760. I select 912x1140, and when I try to customize the resolution, I have different options of color depth 32, 16, 8, and for the timing, which I set to automatic. 

    I suspect I have to chose 32, and to use the proper timing, but I do not know which to use. GTF, DMT, CVT, CVT reduced blak , or manual. With manual I can set different paramenters defined by number of pixels (active, front porch, sync width, total), and polarity.

    I would really appreciate some help about this.

    Thanks in advance.

    Miguel

  • 0 in reply to Miguel Preciado
    TI__Mastermind 30875 points

    Hello Miguel,

    CVT or CVT reduced blanking should be fine.

    I would also like to update to about the problems in the DLPC350 firmware not displaying native resolution 912x1140 @ 120Hz source properly; we are debugging the issue currently. As soon as we fix the issue we will post the solution on the web.

    Attached a snapshot of various timing parameters settings for 120Hz.

    Regards,
    Sanjeev

  • 0 in reply to Sanjeev
    Intellectual 580 points

    Does it possible to run LC4500 at 120Hz with video input  from HDMI?

    I have

    • Ubuntu 16.04
    • GeForce GTX TITAN X
    • NVidia latest drivers (v375)
    • LC4500 connected via HDMI port, configured in Pattern Sequence mode: (Source:  video port, Trigger mode vsync)
    • Second monitor connected via DVI

    but I see only option 60Hz in Ubuntu.

    LC4500 was determined in xorg.conf as 

    Section "Monitor"
    Identifier     "Monitor1"
    VendorName     "Unknown"
    ModelName      "DLP LCr 4500"
    HorizSync       49.7 - 70.1
    VertRefresh     59.8 - 59.9"
EndSection

  • 0 in reply to Nik Rog
    TI__Expert 3240 points
    Hello Nik,

    Yes, the DLPC350 supports 120Hz. I will refer back to Blair's original answer:

    "EDIT: The LightCrafter 4500 already accepts 120Hz video signals. No software or hardware modifications are necessary. The video source is responsible for the frame rate. Many computer graphics cards only output 60Hz, if 120Hz video is desired the graphics card must be upgraded."

    Typically the limiting factor is the data rate output of your computers video card.

    Let me know if that helps!

    Best,
    ~Danny W
  • 0 in reply to Danny White
    Intellectual 580 points

    Thank you Danny,

    Do you have any procedure of how to get this 120Hz? I've tried to  make it under Ubuntu 16.04x64  Windows 7 x64 with powerful NVidia GPU's but no luck.

  • 0 in reply to Nik Rog
    TI__Expert 3240 points

    Hi Nik,

    Can you give me some the specific information on you GPU? Also, in order to achieve 120 Hz the very specific settings that Sanjeev posted above must be set. These will be found in your GPU's advanced settings. These will likely need to be set while you are connected to the LightCrafter 4500.

    Can you expand on your preferred use case is? The LightCrafter 4500 can accept 24-bit RGB at 120 Hz, but there is a minimum exposure time of 8333 us (120 Hz) for an 8 bit pattern, as seen in the DLPC350 datasheet. This means you will not be able to display the remaining 16 bits before the data is updated. So if you can expand on how you are using the streaming mode we can possibly find a work around. For example we could try achieving  a similar pattern rate by display 2 8-bit pattern per 60 Hz frame rate. 

    I will continue to do some digging, but let me know if this information you are able to adjust your GPU's settings as seen in the image above or if this alternative can work for you. 

    Best,
    ~Danny W