Tvp7002 dissatisfaction screen

Hi everyone,

   I according to the "8637.tvp7002_THS8200_VGA_YPbPr_settings" configuration tvp7002 capture with 1080p,but use different computer as a source of VGA appeared two kinds of circumstances,  tvp7002_no.png and tvp7002_yes.png. it didn't pass tvp7002 is normal in the screen. 

The register Settings are as follows:

 Comparison of the two TXT. Can i solve this problem by configure tvp7002 register ?

tvp7002_yes.txttvp7002_no.txt

1 Reply

  • Please refer to the datasheet to understand what these read only registers are telling you.

    The registers 0x23, 0x24 & 0x25 are insignificant and only indicate the low order bits of the auto level detection. Different sources (and even different cables) will result in different DC offset levels.

    Register 0x14 bit 5 indicates that the sources have different H-sync polarities. First, make sure that you are adjusting the TVP7002 timings to match the different source format.

    How are you re-displaying the image? What is your source, capture display signal path?

    For digitizing analog video your system firmware must do a lot of timing processing and signal analysis in order to be able to adapt to different sources. It is necessary to read the sync status registers and H/V length registers etc... then change capture parameters accordingly.

    Additionally your system also needs to actually analyze the digital video stream to determine the REAL active video start positions and adjust blanking start/stop positions to match.

    Finally the sampling phase needs to be adjusted to sample analog pixels at the optimal point.

    You can see this behavior in virtually any analog monitor currently on the market. There is usually a menu option called something like "auto set", "auto adjust". If you run this option you will see the displayed image jump around until the monitor has correctly detected where the analog image really is in the analog stream.

    Different sources often have different positions in the analog stream for the actual image. There are VESA standards for many video formats, but not every source correctly follows the standards. There are also many resolutions which are not VESA standards.

    BR,
    Steve

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