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ADV7180 Artifacts - Noise ?

Question asked by muzza on Sep 5, 2011
Latest reply on Oct 9, 2011 by muzza

Hi all,

 

I am getting weird artifacts from the ADV7180 video decoder. It is really bad with colour and grey scale bars test pattern. I get some with a single colour background video applied  (i.e. 75% red and 100 % white). With 100% black background, none. If I disconnect the video signal, so lock is lost, I get the default blue screen that the chip outputs, with no artifacts at all. This leads me to think that it is some sort of noise coupling through from the analog video source. I get the same results, with S-Video or composite, PAL or NTSC

 

My  chip setup for composite is

 

       //Composite Video Input

 

              {0x00, 0x04}, // Input Control            - (Select CVBS on AIN3, autodetect

                                  //                             PAL/NTSC/SECAM).

              {0x04, 0xD6}, // Extended Output Control  - (ITU-R BT.656 Rev4 output, SFL enabled,

                                  //                             blank Cr, Cb during VBI,

                                  //                             HS, VS, FIELD three-stated,

                                  //                             ITU-R BT.656-3 compatible).

              {0x17, 0x41}, // Shaping Filter Control 1 - (Auto select Y shaping filter,

                            //                             colour Shaping Filter 1).

 

 

              {0x31, 0x02}, // VS Field Control 1       - (Default).

              {0x3D, 0xA2}, // Manual Windows Control   - (Colour kill threshold 2).

              {0x3E, 0x6A},

              {0x3F, 0xA0},

              {0x0E, 0x80}, // ADI Control 1             -(Access main register space).

              {0x55, 0x81},

              {0x0E, 0x00},  // ADI Control 1             -(Access main register space).

 

Attached examples are frm_buf.bmp for 75 % red, and frm_buf2.bmp for colour bars.

 

 

Has anyone experienced this ?

 

Cheers

 

Mario Gencarelli

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