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Source Code (algorithm) ucamdemo-rev2

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  • Source Code (algorithm) ucamdemo-rev2

    HI i'm working with an FPGA, This retrieves pictures from the uCamTTL in RAW format and then it display them in the uOLED128 via serial-PMMC firmware( Using the "Display Icon" instruction), Now i need to take Jpeg pictures from the camera and this is not a problem, the problem is when I want to display this picture into the uOLED, Could you share the algorithm that decompress or converts the JPEG packets into pixel information, like the ucamdemo-rev? what I need to do with those packets and how to reassemble them to create a picture.

  • #2


    uCamDemo uses windows to decode the JPEG.

    Can't really help, perheps if you find the algorithm on the web?
    Mark

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    • #3


      I'm very disappointed about that.
      This type of camera is made for embedded systems.
      This camera is sold as a jpeg camera but if we are on an embedded system you said that there is no way to make a jpeg picture !
      The solution should be in the data sheet.
      Please could you do something about that ? I must fix this asap because the raw transfert is too slow.

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      • #4


        JPEG is copyrighted, we cannot put the algorithm anywhere without breaching that copyright, but as we said, if you search the web you should be able to find it.

        The main reason we sell this camera is so that you can use the RAW option.

        And I'll let you in on a little secret, fetching a picture in RAW mode is about the same speed as fetching it in JPEG mode.

        This is because JPEG is packetised and the overheads in that, plus the overheads of the camera compressing the RAW picture mean that by the time everything has happened RAW (because it is sent immediately in one burst) is about the same speed.

        What speed are you transferring at and what do you need? Have you tried uppping the speed? What about lowing the resolution or color density?
        Mark

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        • #5


          I'm transferring at 57600 bauds for a relative speed/stability. It's impossible to up the speed.
          What I need is a powerfull video mode and it's just impossible in raw mode even in 80*60 8bpp.
          for example, with the ucamdemo, 40 sec to fetch a 640*480 8bbp picture in raw mode, 5 sec in 640*480 color JPEG and less if I raise the package size.
          If you can explain how can I do to have the same time in raw mode I would not need the JPEG mode anymore.

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          • #6


            Well, it's all about the speed. The 'packet turnaround' starts eating into the JPG transfer time, whereas the RAW speed just keeps going faster in a linear fashion.

            It's impossible to up the speed.
            Why do you say that? We've had the camera working at 600kbaud straight to a Goldelox display without issues.
            Mark

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