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How to encode AVI for 1440 fps.

Gavin Smith
Intellectual 515 points

Hi, 

Im interested in using the 1440fps 1bit mode on the Pico DLP 2 kit for the rending of high speed animations for some reserch work, and from the documentation, I deduce that the the 60hz VGA signal being sent to the projector is simply interpreted differently, with the first 24 bits for each pixel being interpreted as the on/off value for a pixel for each of the 24 sub frames.

Correct me if I'm wrong, but say the the first pixel was white, then the first 24 bits would be 111111111111111111111111 , so in 1440 fps monochrome mode , would this mean that the first pixel would be on for the 24 sub frames?

If this is correct, then how would I go about building an animation to display 1440 unique frames of animation?  Would I need to render a monochrome video at 640*480 and then write some software to take the value of each pixel for groups of 24 frames and create a new file with those values?

Many thanks

 

Gav

  • 0
    TI__Genius 9935 points

    Hello Gavin,

    You have it close. Do you have the App Note: "Using the DLP Pico 2.0 Kit for Structured Light Applications" ? You can download it by going to http://ti.com/mems and following the link under "MEMS Devices" "DLP Technology" "0.17 HVGA Chipset" "Applications Notes". Get "dlpa021.pdf".

    The App Note shows how the modes are set up, and how the bits are allocated. The mode you are talking about is an External Structured Light mode. The input will be 640x480 60Hz video, but you mus put your patterns in the upper left region of 480x320, because the picture will be clipped to this region.

    As for "stacking" the patterns, the 1440 Hz monochrome mode simply sequences through the 24 bit input for each 60 Hz frame in the order given in section 3.3. This is (as shown) B0... B7, R0... R7,G0...G7. This means that your first pattern in the sequence is encoded in each of the pixels, but using bit B0, only. The second pattern is also in all of the pixels, but using B1, only. And so on.  Each bit plane (B0, B1, etc) will be displayed for 0.680 ms. All 24 bit planes will be displayed over a 16.67 ms

    Each subseqent 60 Hz frame must be encoded in the same way with patterns in each bit plane. The resulting monochrome frame rate will be 1440 fps.

    Best regards,

    Pascal

  • 0 in reply to Pascal DLP
    Intellectual 515 points

    Hi Pascal,

    another question, if I wish to purchase a PICO2 proejctor, and I only wish to use it in 1440 fps mode, which from what I can see would be set via a I2C instrution, then I must either use a ardinio, or USB i2c card or some other interface? Theres no way of using this projector standalone without buying another product, and no internal dip switches for setting it up manually?

     

    cheers

     

    Gav

  • 0 in reply to Gavin Smith
    TI__Genius 9935 points

    Gavin,

    You are correct. There is no "stand-alone" way to configure the Pico Kit v2 for modes other than the default video mode.

    You will need to send commands to the Pico Kit v2 via I2C. There are 2 ways to connect to the Pico Kit I2C.

    1) Use the I2C which is in the HDMI input (normally used only for querying the EDID), but is accesible using (for example) a BeagleBoard (xM). The BB can be loaded with a Linux distribution (recommend Angstrom) and i2c-tools can be used (command: bus3-i2c) to communicate with the Pico Kit.

    2) I2C is available on the Auxiliary port on the side of the Pico Kit v2. This requires a USB-to-I2C interface (for example, DevaSys) and a small flex cable (DigiKey - see BOM).

    Refer to the document dlpu002A (DLP Pico Chipset v2 Programmer's Guide) which can be downloaded by following the 0.17 HVGA links from http://ti.com/mems, which will lead you to http://focus.ti.com/lit/ug/dlpu002a/dlpu002a.pdf.

    Best regards,

    Pascal