ADV7281-M Video issue

Question

abnormal normal 
 We developing a product using the ADV7281AWBCPZ-M. 
 We convert analog video input to MIPI and output it. 
 It is causing the phenomenon that the even and odd of the interlace are reversed. 
 This phenomenon occurs when the analog video input is turned on and off, and does not always occur. 
 Any advice would be appreciated. 
 Thanks

PoornimaSubramani · Accepted Answer

Hi, 
 Please refer below expert comments to get rid of the I2P artifacts, 
 There are two possible causes of these artifacts: Interlaced to Progressive conversion artifacts or 2D comb artifacts. 
 Interlaced to progressive conversion: 
 The I2P block of the ADV728x works by storing a few lines of video. e.g. lines 1, 3, 5 on an odd field. It will then interpolate between these lines to generate the missing lines e.g. it will interpolate for lines 2 and 4. 
 The I2P does contain a smoothing filter to minimize artifacts but some artifacts can still occur. 
 2D Comb: 
 The ADV7180/ADV7182/ADV728x video decoders are designed to be low cost analog to digital video decoders and as such they only have 2D comb YC separation filters. 
 2D comb filters are good at separating the luma and chroma information but artifacts such as the one you have highlighted are still possible. 
 Solutions : 
 1) Use a deinterlacer in your back end processor rather than using the I2P block of the ADV7280. The backend processor will have to store an odd frame of video in a buffer, then store an even frame of video and then stitch these two frames together to generate a progressive field. This will minimize interlaced to progressive errors but will add a delay to your system. 
 Be sure to introduce a line counter or similar software control to ensure that you do not get buffer overflows. 
 2) Modify some of the registers in the ADV7280 to try and minimize 2D comb this artifacts for your system. 
 Try reading the Chroma filter, Luma Filter, Chroma Transient Improvement, Digital Noise Reduction and Luma Peaking Filter, and Comb filter sections of the ADV728x hardware manual. You may get some improvement but you will never be totally able to remove 2D comb artifacts. 
 Note: The ADV7186 part can perform frame based deinterlacing which should avoid the artifacts that you see with the ADV7280 (the ADV7280 uses line based deinterlacing). 
 Note the tradeoff here is that the ADV7186 is more expensive and complex than the ADV7280. Also the frame based deinterlacing will generate a significant latency through the system. This is usually not desirable for automotive safety applications. 
 Kindly refer below post on how to modify the boundary box test pattern, 
 boundary box test pattern can't be complete display 
 In interlaced mode the boundary box test pattern top line appears on odd fields and bottom line appears on even fields. 
 In interlaced mode the first/last pixel on every second line in the odd and even fields are white to generate the white vertical lines. 
 In progressive mode the line interpolation algorithm doubles the size of the odd and even fields. Therefore the first frame could be doubled odd field that will only have the white line at its top. The next frame could be doubled even field that will only have the white line at its bottom. 
 Thanks, 
 Poornima)

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ADV7281-M Video issue