AD9984 question

I am designing a VGA to HDMI board.for adapting 30 meters extension cable,  firstly input VGA signals into video amplifier LMH6739 3 channels and 74LVC1G125DCKRE4, turn out to AD9984,then adv7513 HDMI transmitter, the current problem:
1.Is ADV7850 better?
2. Can AD9984 or ADV7850 automatically adjust the vertical and the horizontal position ?
3. I use MCU to measured and estimate the frequency of horizontal and vertical sync to know the input video resolution,  is there any better method?