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Can BT.656 transmission 1080P mode video?

puyol jiang
Intellectual 555 points

Hi,

         My platform is DM8168, now I want to use FPGA to generate a 1080P video source with out any decoder. As I know, DM8168 VIN[0]_A support 8 bit embedded sync input, BT.656 is a format for the input , but I have some questions:

      1. I know the PAL or NTSC data store format, but I do not know how the 1080P data store format, can anyone give me some help?

      2 If I use BT.656 transmission 1080P/60 video, the clock frequency will be 148.5MHz? or others?

Thanks.

puyol.

  • 0
    TI__Mastermind 20245 points

    Hi,

    BT656 requires double the pixel clock frequency for input clock so you will required 148.5*2 MHz but VIN port can support upto 165MHz so its not possible to driver 1080P60 with BT656 interface. You can at max drive only 1080P30.

    Regards,

    Hardik Shah

  • 0 in reply to HardikShah
    Intellectual 555 points

    Thanks HardikShah,

               What about the datastore format? BT.656 about 525 line have the following format:

    How about 1080P? I do not know the line format?

  • 0 in reply to HardikShah
    TI__Mastermind 43875 points

    You can capture 1080p with 16 bit. This should already be supported.

    BR,

    Steve

  • 0 in reply to Steve Clynes
    Intellectual 555 points

    Which format 16bit input use? BT.1120? others?

    Thanks.

    puyol.

  • 0 in reply to puyol jiang
    TI__Mastermind 43875 points

    I believe the drivers already support embedded sync (1120) but the hardware should also be able to support discrete syncs too. I am not sure about SW support at the moment though.

    The data format for 1120 is basically the same as 656 but the sync codes are duplicated across the 2 8 bit channels.

    BR,

    Steve

  • 0 in reply to Steve Clynes
    Intellectual 555 points

    That means the input format is embedde sync used? So, we can set the input format as 16 bit embedded sync, clocking is 148.5MHz.

    Another question, the sync codes are duplicated across the 2 8 bit channels means the SAV and EAV as follows:

    SAV/EAV

    FFFF 0000 0000 XYXY

    blanking data

    8080 1010 8080 1010 ......  In sum of 280 Bytes?

    active data

    .............. 

    BR

    puyol.

     

     

  • 0 in reply to puyol jiang
    TI__Mastermind 43875 points

    Yes, this is pretty much it.

    The only difference is that it is the number of active pixels which is most critical. The number of blanking samples will depend on exactly which format is being sent, but in most cases is actually ignored anyhow.

    Check the CEA specifications for the number of samples during active and blanking times to be 100% standards compliant.

    BR,

    Steve