bsaeed, sorry for the delay in response.
What I found was a combination of all stated above. To explain:
1st you need a good sd card, I use extreme U310 that will handle the processing speed of the video especially if you are shooting in 3.7 or 4K.
2nd, I found the camera settings play a major role as mavicDenver stated; try shooting in 3.7k at 24fps and soften you're settings in sharpness, contrast and saturation to -1-1-1 or at least -0-0-0 (depending on what you are shooting, the challenge in the shot posted was -90 degrees down and my speed- the camera with its settings trying to keep up with processing everything going on. Sometimes shooting in tripod mode will help greatly.
3rd, ND filters will also help a great deal by bumping down your shutter speed and reduce the amount of light, helping to give you smooth, cinematic footage.
4th, make sure your settings for export are correct. I don't know what editor you are using but they all basically work under the same concepts (and this is where everyone has their own opinion). I shoot in 3.7K at 24 or 30fps (depending on what I am shooting) (24 gives you a more cinematic look) and export at 1080p with the same frame rate (24/30) as the original. bitrate is never lower than 30,000 and most time 60,000 (not that the end product will keep 60000 but seems to be the sweetspot.
I would also suggest trying Dlog for video and RAW for photos (if you have lightroom) but if you do use Dlog I would lower the S-C-S to -2-2-2. Just play with the setting to see what you like. Most of the time decinelike works the best unless you plan to spend a lot of time in post-processing. Keep all settings on MANUAL so the settings wont change on you as the picture and light changes while your shooting. I also use custom white balance.
Last, when you think everything is perfect, it WILL glitch! is it the RC reception? camera? your settings or speed??? who the heck knows?!?! so when you capture footage, don't limit it to a specific shot and timeframe- shoot every angle, different styles and longer footage, you can always cut and trim, and when a shot just "glitches" you will find another shot that is perfect (40 minutes of footage finishes at 3-7 minutes).
I don't mean to assume you know nothing about this but you asked. Check out Continental Drone Aerial Photography on facebook and check out the latest video on the JD Monument, at the end of the video as I pull back through the gates something happened and no matter what I did it seems choppy for about 2-3 seconds...who knows but hope this long winded answer helps you!
