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can Prop (theoretically) output monochrome (or better) 480p/720p/1080i via comp — Parallax Forums

can Prop (theoretically) output monochrome (or better) 480p/720p/1080i via comp

MiamicanesMiamicanes Posts: 2
edited 2008-05-27 18:32 in Propeller 1
Does anybody know whether it's theoretically possible or impossible to use a Propeller to generate single-bit (black/white) monochrome video (or better) and output a signal that a HDTV would recognize as legit 480p/1080i/720p if it were sent via its Y/Pr/Pb component video inputs? If so, does anyone know where I can download a signal/timing diagram for free (as opposed to paying for a copy of EIA/CEA-770)?

Also, I'm looking for suggestions as to how I might go about rapidly switching between a component-video HD source and the Propeller during a horizontal retrace so I could effectively replace one or more entire scanlines with Propeller-generated video (kind of like how the C64 and other computers used to switch video modes mid-screen). Since I'll be in control of the Propeller, and the Prop can tri-state its outputs, all the switch chip really needs to be able to do is rapidly connect and disconnect 3 inputs from 3 outputs (tri-stating the outputs when disconnected).

Thanks!

Comments

  • RaymanRayman Posts: 14,355
    edited 2008-01-06 12:50
    I'd also like a 480p driver... I think it should be possible...
  • crgwbrcrgwbr Posts: 614
    edited 2008-01-06 19:28
    While 1080i component video would no doubt be sweet, has anyone actually pushed composite (480i) video to its limit yet? The Xbox Original used composite video output, and its graphics were significantly better than what I've seen a Prop do yet. I'm sure the Prop II will be capable of at least 480p HDTV generation, I just don't think that it is currently necessary. It is a neat idea for future development though.

    Regards,
    Craig

    P.S. What about DVI output?

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  • ColeyColey Posts: 1,110
    edited 2008-01-06 23:01
    DVI is just HDMI without the audio and copy protection iirc.

    It certainly would be an achievement if you could do it....

    Some information to help you along your way.


    attachment.php?attachmentid=51289

    480p would be the one to go for first if the prop can shove out 27 Mega Pixels per Second....

    COley

    Post Edited (Coley) : 1/6/2008 11:06:49 PM GMT
    620 x 421 - 87K
  • MiamicanesMiamicanes Posts: 2
    edited 2008-01-07 00:34
    >480p would be the one to go for first if the prop can shove out 27 Mega Pixels per Second....

    Remember, I haven't specified any hard horizontal resolution... and since component video is analog, there's nothing that says I have to change the value 640, 704, 720, 1280, or 1920 times between the start and finish of any given scanline. In all likelihood, I'd probably have a de-facto horizontal resolution of 256 or 320, so the effective resolutions of 480p, 720p, and 1080i would be 256x480, 256x720, or 256x1080 respectively. The bigger question is whether the prop is fast enough to set up and handle the start and finish of each scanline fast enough to keep them from jittering back and forth.

    If it could do 256 x 480 at 60 progressive frames per second, it could almost certainly do 256 x 1080 at 60 interlaced fields per second, too (the prop itself would be treating it as if it were 256 x 540 progressive frames/second, anyway... the actual field order would be set by the "real" video signal, and the Prop would just be "finishing the job" and replacing the last few scanlines of each field/frame. 720p is the acid test. 480p60 requires basically double the timing performance as interlaced NTSC; 540p60 is only ~25% faster than 480p60. 720p60, however, is roughly 50% faster than 480p60. That's why natively-720p TVs were almost nonexistent in the CRT realm. If you have a CRT design that can do 480p60, massaging it to do 540p60/1080i60 instead is a relatively cheap step up. Going all the way to 720p60 involves MUCH more expensive improvements.
  • ahangahang Posts: 2
    edited 2008-05-23 11:50
    Hi,

    I have this nice plasma panel within eyespot every evening. It has its "HDMI 3" plug at the front.
    I'm asking myself is this one would·be feasible:

    1 * Propeller +
    1 * ADV7520NK ( 5$) by AnalogDevices ( "RGB + Audio" -> HDMI converter ).
    1 *· Bluetooth module to send whatever one wants : remote audio, pictures, serial data)

    That would be a very interesting plug-in to such , or not?

    Do you think it would work?

    Yours

    Ahang

    ·
  • KamPuttyKamPutty Posts: 48
    edited 2008-05-23 15:57
    Ahang, et. al.,

    What does the ADV7520NK actually do? Does it take a rgb signal generated by the prop and up converts it to 1080? Is that right? A friend of mine asked the other day if the prop could gen text/images for hd...

    I was thinking a fun project would be a caller ID (or similar) project that connects to a HD tv...simple app, but lots of future potential!

    ~Kam (^8*
  • VIRANDVIRAND Posts: 656
    edited 2008-05-23 20:24
    I'm yet totally in the dark about the signal timing format of DVI,
    but it had crossed my mind to wonder if the Propeller or Propeller II
    are compatible with it, and/or whether the 15 pin VGA connector
    will be supported by video monitors for at least the next 5 years.
  • LawsonLawson Posts: 870
    edited 2008-05-24 04:40
    Miamicanes said...
    Does anybody know whether it's theoretically possible or impossible to use a Propeller to generate single-bit (black/white) monochrome video (or better) and output a signal that a HDTV would recognize as legit 480p/1080i/720p if it were sent via its Y/Pr/Pb component video inputs? If so, does anyone know where I can download a signal/timing diagram for free (as opposed to paying for a copy of EIA/CEA-770)?

    Also, I'm looking for suggestions as to how I might go about rapidly switching between a component-video HD source and the Propeller during a horizontal retrace so I could effectively replace one or more entire scanlines with Propeller-generated video (kind of like how the C64 and other computers used to switch video modes mid-screen). Since I'll be in control of the Propeller, and the Prop can tri-state its outputs, all the switch chip really needs to be able to do is rapidly connect and disconnect 3 inputs from 3 outputs (tri-stating the outputs when disconnected).

    Thanks!

    My limited understanding is that component video is similar to a VGA/RGB signal but in a Y/Pr/Pb color space. Sync is most likely a composite sync multiplexed onto the "Y" video signal. (basically the VGA H-sync and V-sync signals would need to make Y go to a minimum value when they are low and otherwise have no effect)

    DVI/HDMI use a completly differnet signaling system. They're both very high speed digital serial interfaces. (DVI can also include a full set of VGA signals.)

    Random Ramblings,
    Marty

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  • ahangahang Posts: 2
    edited 2008-05-27 08:26
    Hi,
    I took a look into the HDMI specification. Indeed, it allows a variety of resolutions.:

    640x480p @ 59.94/60Hz
    • 720x480p @ 59.94/60Hz
    • 720x576p @ 50Hz
    • 1280x720p @ 59.94/60Hz
    • 1920x1080i @ 59.94/60Hz
    • 720x480p @ 59.94/60Hz
    • 1280x720p @ 50Hz
    • 1920x1080i @ 50Hz
    • 720x576p @ 50Hz

    I'm rather worried about this one:

    "Pixel Encoding Requirements:
    Only pixel encodings of RGB 4:4:4, YCBCR 4:2:2, and YCBCR 4:4:4
    may be used on HDMI.
    All HDMI Sources and Sinks shall be capable of supporting RGB 4:4:4 pixel encoding."

    Any Idea how to do this?

    About the Controller Chip (ADV7520)I mentioned:


    It not only builds up the physical interface to HDMI plug converting RGB and Audio, it also catchs up the CEC (this is a on-wire command line of the HDMI). One should then be able to get commands from the TV-remote-controller and unse it for making a user interface for the propeller chip.

    http://www.analog.com/pr/ADV7520NK

    Anyway, I ordered somer samples of this chip from ADI and I'm going to try it out together with a propeller chip and a bluetooth module! Hopefully someone else also joining me!

    Yours

    Ahang
  • kerrywkerryw Posts: 61
    edited 2008-05-27 16:18
    I was just thinking about this yesterday. I was calibrating a new LCD television using DVE Essentials and the HD709 dvd. Then it hit me - wouldn't it be nice to have a little handheld device that generates greyscale images, color bars etc.? They make them, but they cost a lot. Getting grayscale, contrast, brightness, hue and color levels correct is a large portion of the calibration. All of these images are pretty straightforward to create. A box with a prop, HDMI and component out would be a great tool.

    Kerry

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  • Agent420Agent420 Posts: 439
    edited 2008-05-27 16:47
    I find this topic interesting from a Propeller performance perspective, but on the flip side it seems that an inexpensive FPGA might be a more potent solution to this particular task.·

    I'm new to the Prop, but it appears the included vga demos seem to be pushing the limits of the device for that type of application, if only in memory usage.
  • ColeyColey Posts: 1,110
    edited 2008-05-27 18:32
    The Prop is capable of doing 640*480 and even 720*576 with a standard composite signal.

    see here... www.youtube.com/watch?v=wdYU6J30k10

    The main challenge as Agent420 implied, is the limitations with RAM not with the power of the processor.

    The 'easiest' way is with the ADV7520 chip but you will still be left with the same colour/resolution limitations.

    Maybe PropII will be able to do this on chip...... (crosses fingers!)

    Regards,

    Coley tongue.gif

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