I have not read all your letters but i can say this. It is the way these camcorders are recording to the sd cards that is your problem.. I have 6 Sony Digital camcorders bought back in the early 2000s and i loved them when they worked back in 2008. But in 2008 i reinstalled my Windows XP and i did not video editing for about a year then when i hooked my Sony FX7 to my pc it did nothing. And all my other Camcorders did nothing. I bought new fire wire cable still nothing. I went online and Sony says the drivers are still in my pc but maybe remove them then download them again. Did all that still nothing. I have bought 4 custom built pc's still nothing i went to BEST BUY hooked my 2 newest Cams- up nothing. Sony has truly removed the drivers for all camcorders bought after 2007. No other way this can be then that. So i bought new Canon Vixia G20 and when i try to record near the best video quietly it is jerky as hell no way would i want to watch that shit. But when i recorder lowest video looks great. So it is the way these camcorders are recording to the SD Card when you get to hi video. Thats my idea. Try the lower video setting . Which means your camcorder is not a true 4K camcorder. I also bought a Panasonic Digital camcorder must have been $9000 new i bought it off amazon last year it was all not found by my pc . I use to get the name of the camcorder and model of the camcorder would show up on my pc when i hooked them up not after 2008. So this is the shit they are pushing on us. JUNK.