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How can I determine the refresh rate of input video in HDMI-GR mode of ADV7441A?

By manipulating the read back parameters Block Length (BL) and Line count Field (LCF) information provided by STDI we can work out the vertical refresh rate as follows:

(Block Length x XTAL Period)/8 = T line of video

T line of video x LCF = T frame of video. 

(1 / T frame of video) = Refresh rate.

E.g for 720p60 BL readback ~ 5082. LCF ~ 750. XTAL Period = 1/28.63636MHz = 34.9ns

=> Tline of video = (5082 x 34.9ns) / 8 = 22.22us. 

T frame of video = 22.22us x 750 = 16.667ms

=> Refresh Rate = 60Hz

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