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Viewing pixel in memory from CCDC with DM6437

Fabrizio
Intellectual 460 points
Other Parts Discussed in Thread: TVP5146

Hi,
I am working with evmdm6437. I am a beginner with Da Vinci,and for learn and understand I am doing practice with the samples delivered with dvsdk. Im working with sample named dm6437_evm_video_st_sample.pjt, contained in c:\dvsdk_1_01_00_15\psp_1_00_02_00pspdrivers\system\dm6437_evm\src\video\sample\loopback.
I have connected a NTSC camera and I try to watch frame video in memory filled with data from TVP5146 decoder. Dac D is connected to
a TV monitor. If I run application I see lines moving on TV monitor, I think that some data are flowing to dm6437 from decode, because
output is not the same. Signal VD, HD and PXCLK are moving too, but when I watch DDR2 memory at the address indicated by CcdallocFB[i]->frame.frameBufferPtr or VidAllocFB[i]
I don't see data changes. I run application for some second and halt processor, see my memory window, restart and so on. I have tried to see all memory buffer allocated in my application,
but I don't see any variation in data memory. I am mistaking anything. I have also verifyied that the addresses of frame video buffers used are present, one for time, in the VPFE register SDR_ADDR.
It is important for me learn how to see raw data in memory because in future I will try to connect a micron mt9v023 cmos sensor, with a custom board. How can I view in memory data from decoder or other device connected to vpfe?
Thank a lot

Fabrizio

  • 0
    TI__Mastermind 41665 points

    I think the wiki article on accessing pixels in a frame on DM643x may be of some help here, as it explains both how to get the pointer to the raw frame data and what format will be expected, there is also a small example modified from the loopback example that does some basic pixel modifications that should help to prove that you are actually working with the image data.

  • 0 in reply to Bernie Thompson TI
    Intellectual 460 points

    Thank You Bernie,

    I have read this your very interesting article and the sample code. I will try to run example. What do you think about get, after every call to FVID_exchange( ) completed, value of a fixed pixel and collect them in an array of n sample? I think that pixel value would change if I change my image source. I will tell you the result.

    Fabrizio

  • 0 in reply to Fabrizio
    TI__Mastermind 41665 points

    Fabrizio said:
    What do you think about get, after every call to FVID_exchange( ) completed, value of a fixed pixel and collect them in an array of n sample?

    My suspicion is either that the very top edge of your incoming image is not really changing if that is all you are looking at in a view memory window, or you are seeing a cache coherency issue where the data does not appear to change to you. In any case hopefully the example from the wiki will help you to see and modify the pixel data from your application, I can say for sure that the values change with that.

  • 0 in reply to Bernie Thompson TI
    Intellectual 460 points

    Hi Bernie,

    wiki example is running correctly, and I see data changing in memory. I have imported code contained in video_preview.c in psp_bios_vpss_loopback_sample.c with only one modification: function FVID_alloc( ) returned IOM_COMPLETED, but address of framebuffer was invalid. I have used instead FVID_allocBuffer( ) and all is correct. Another notation: if I don't perform image elaboration ( i have commented line of call to function process_image ) I see black and white image, but my camera is a color camera. Now I try to find why I have problem with original sample code.

    Thank

  • 0 in reply to Bernie Thompson TI
    Intellectual 460 points

    Hi,

    I had an hardware problem with my camera, and image was not really changing. Now I use my custom board with CMOS sensor MT9V023 and I am able to capture image and output it to a TV monitor with elaboration of frame pixel. Everything seems to working good.

    Thank you