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Does flash need format and Can BT656 transfor 720P signal?

Eric Hou
Intellectual 530 points

Hi, all:

    I 'm using DM365 to do a decoder to decode 720P stream and display it, and I trying to add a display chip to format stream signal as VGA  format so it can connect to LCD displayer,  I  changed code to make DM365 output digital signal from VPBE to display chip in BT656 standard, But got a picture only 640 pixels in horizontal like picture below show, left part(640x720) shows the whole picture sended(1280x720), and right part are NULL memory I think and it shows random colour, I' m sure the source stream  is 720P because it also display through YPbPr and I can see it display perfect, As I know BT656 has it's owen feature like It can just Transfor 625 lines on vertical and 17xx on H with SYNC info but I don't really understand it, so It caused by BT656 or something else? any suggest will be appreciate

     another question is:  Does flash partation need format? We use our flash as 5 part: uboot,params,kernel,filesystem1,filesystem2,  and the first four are write by nand write with some formated image, and I want to use part5 to save some config file so I need to mount it to my own filesystem with special type, but it can only mount as jffs2 type correct write and save, and it can mount as yaffs but can't keep data correct when umounted, so why? does kernel has format part5 as jffs2 yet, How can I use yaffs on part5?

 

  • 0
    TI__Genius 14405 points

    Hello Eric,

    Some quick thoughts....

    First of all, you have to make sure whether the "additional display chip" is programmeed correctly. Are you positive that the entire picture is shrinked to exactly half the size and on the left half of the 720P screen (it doesn't seem so from the picture attached)? A lot of thing can happen here. Are you able to tell what exactly is happening to the right half?

    Also, I would feed the VPBE with buffer with a known pattern (remove the decoder from the picture) that help you to analzye what exactly is seen.

    I am assuming this is VID0 only? Please dump all the OSD registers if you need more help.

     

    I have to rely on the Linux experts regarding your 2nd question.

  • 0 in reply to Paul.Yin
    Intellectual 530 points

    Hello, paul:

          I need to say that when I send a  720x756 stream as the same set, I can got a perfect display on the displayer, and also I'm sure the picture I showed when display 720P is 640x720 on the left half, because when I set the register on the display chip as accept 640x720 it display the whole picture perfect, the right part display with random colour and some place near the left part displayed last picture in the memory,  Does someone use BT656 translate 720P stream before and what feature it has? why I can transfor 720x576 perfect but can't do the same on 720P, by the way, as I know, BT656 standrad just developed for transfor D1 at first, any information?

  • 0 in reply to Eric Hou
    TI__Genius 14405 points

    Eric,

    It would be more helpful if you could attach some more pictures (you can tar them together). I would like to see what exactly is happening on the right side of the screen.

    By "BT656" here, do you just mean Y/C interleaved or were you also referring to the timings? Since the max clock supported is 75mhz, you can only do 720P30 here. I don't think we have such project available on this particular device, but this should be doable. When BT656 first came out, it was mainly targeted for D1, but the Y/C intereaved output, embedded sync format can be used for any dimension.

    Please read my previous post, there were some more suggestions.