Ancillary Data Error when chroma burst present in video signal

Hi,

This might be due to Interference with Ancillary data and Timing Misalignment.
Please check signal synchronization by ensuring the timing of the chroma burst and ancillary data are properly synchronized. 

Also kindly ensure with below things,

Hi Poornima,

Thank you for your answer. May I ask further question?

Video source is from TV Pattern Generator and it was checked on another device. Signal is ok.

Just for testing I switched to SAA7114 and ancillary data was stable.

ADV7180 VDP is ok and stable as I can check the image, but ADV7180 VBI slicer is not stable.

Register settings for VBI as follows:

Reg    data

0x03 = 8C; // VBI_EN

0x0e = 20; // access registers.  Table 103

0x62 = B5; // ADF_ENABLE, Byte type

0x61 = 00; // Disable auto GS. Because of wrong framing code when txt.

0x0e = 00;

Which registers I have to set to make VBI slicer works stable?

Hi,

  Could you please check by setting the 'VBI_EN' bit to 0 and this in turn should filter all video lines.

  And also try to configure the below mentioned registers,

Kindly refer our VBI expert comment at (+) ADV7180 VBI_EN - Q&A - Video - EngineerZone

Also refer VBI data decode section and it will describe about how to decode the VBI data in automatic & manual mode.

Thanks,

Poornima S

Hi,

Thank you for advise.

I checked result by setting  the 'VBI_EN' bit to 0 and nothing changed.

Also, registers that you mentioned below are not from ADV7180.

0x36 HS Position Control 3

0x37 Polarity

0x39 PAL Comb Control.

 > Kindly refer our VBI expert comment at (+) ADV7180 VBI_EN - Q&A - Video  > - EngineerZone <ez.analog.com/.../adv7180-

 > vbi_en/37873>

I also checked this expert comment and found that there is no any solutions to make VBI works stable.

I also tried to set VBI data in automatic & manual mode.

Nothing changed.

If I set Disable auto GemStar setting I can confirm right framing code. But as I can see in datasheet Gemstar is on line 23 to 25 and  286 to 288 in NTSC but no lines in PAL.

Does it mean that VBI doesn't count right vertical lines?

And when I worked on teletext I found that sometimes teletext decoded from line 12 to 15 as it should be but sometimes from line 11.

Should I give up and move to another product such as ADV7181C ?

Please advise.

Hi,

 Please try to configure 0x60 register as 0x08,

 Kindly refer VBI data recovery section at ADV7181C_Manual_RevC.pdf Here you can find more VBI details.

Below are the VBI data standards that can be decoded by the VDP for PAL input,
• Teletext System A or C or D ITU-BT-653
• Teletext System B/WST ITU-BT-653
• VPS (Video Programming System) ETSI EN 300 231 V 1.3.1
• VITC (Vertical Interval Time Codes)
• WSS (Wide Screen Signaling) BT.1119-1/ETSI.EN.300294
• CCAP (Closed Captioning)

Kindly note that, VDP decodes the VBI data on the incoming CVBS/YC or YUV data processed by the SDP core. The VDP cannot decode VBI data on the YUV data processed through the CP core. The decoded results are available as ancillary data in output 656 data stream. For low data rate VBI
standards like CC/WSS/CGMS user can read the decoded data bytes from I2C registers. 

Thanks,

Poornima

Hi.

Thank you for advise.

When I try to configure 0x60 register as 0x08, decoded anc data has no errors, but not all packets were decoded.

It means SDP skips some anc packets. What does bit 7 mean? It's a reserved bit.

Normaly I should set it to 0x88.

Again, if I turn off color burst and set picture to chess almost all packets were decoded and without error.

Maybe clamp level is good for Video but not good for VBI slicer?

As it sees color burst as clock run-in.

Please again advise. 

Regards.

Hi,

  Could you please crosscheck with below mentioned register,

Also note that, Setting 'BL_C_VBI' high blanks the Cr and Cb values of all VBI lines. This is done so any data that may arrive during VBI is not decoded as color and is output through Cr and Cb. As a result, it is possible to send VBI lines into the decoder and then output them through an encoder again, undistorted. Without this blanking, any color that is incorrectly decoded is encoded by the video encoder,
thus distorting the VBI lines.
Setting BL_C_VBI to 0 decodes and outputs color during VBI.
Setting BL_C_VBI to 1 (default) blanks Cr and Cb values during VBI.

Refer (2) How do we enable vertical blanking pass through? - Q&A - Video - EngineerZone

Thanks,

Poornima