I have my Air 3S set to shoot at 4K 60FPS.  After shooting, I transfer my files wirelessly to my Iphone which stores the images in iCloud.  When I look at the video quality, some of the clips are at 4K, but many are 1280 by 720.  They are recorded consecutively with the same image settings.  I am not using any Quick Shots or Master Shots.  I have already checked that those modes are also recording at 4K 60.  By contrast, my Mini 4 Pro records everything at 4K 60 and after downloading, the videos remain 4K 60.

What is going on with the Air 3S that it is not producing videos of consistent 4K resolution than what is set in DJI Fly.

Thanks,
Terry

Check if you have selected at download "Full size"...
Also check if the videos you see in other resolution is not Mastershots or Quickshots and in this mode is possible to have selected other resolution than Normal Video.

If these are files with the LRF extension, then this is simply a copy in reduced resolution of the original files. It is used for video editors to optimize its operation on a weak computer.

For best quality it seems best to remove the SD card and copy the files from it,  the app tend to mangle the content or the EXIF data.

Agreed ^^^ also using a sd card that is not fast enough could be the issue.

Thank you for all your advice, I really appreciate it.  I did finally discover the problem.  

I uploaded all my videos wirelessly to my iPhone using DJI Fly  It is then stored on my iCloud photos.  I would then download the images to my PC.   When this occurred, the full 4K images stored on the cloud were compressed to 1280 x 720.  I did not know this was happening.  The solution is to click on the three dots in the upper right hand corner in iCloud, and click on more download options.  It is there that you can choose to download full uncompressed videos.  When I did that, all my videos downloaded in 4K.  Now I need to redo three of my YouTube videos so they will take advantage of the full resolution.  What prompted the initial issue was that my YouTube videos were not of the quality they should have been, even after doing the correct exporting settings for maximum quality.

Hello Browntdb. We are genuinely sorry to hear about the inconvenience you have experienced with the video shooting footage quality of your DJI Air 3S. Your satisfaction is of utmost importance to us, and we are committed to resolving this matter for you. In order to provide you with an accurate and effective solution, we kindly request that you provide us with a video recording showing the comparison of the video footage. This will greatly assist us in understanding the specific issues you are encountering and enable us to offer you the best possible support and guidance.

You can provide us the video recording via Dropbox or Youtube. Your cooperation in providing this additional information is greatly appreciated, and it will allow us to address your concerns in a more precise and efficient manner. If you have any further questions or need additional assistance, please feel free to contact us. Thank you for choosing DJI.

DAFlys Posted at 1-14 01:23
For best quality it seems best to remove the SD card and copy the files from it,  the app tend to mangle the content or the EXIF data.

I get perfectly good results without removing the SD card. Same as for the Mini 4 Pro, you can just connect a USB-C cable directly to the PC. You do not have to turn the drone on, and two folders will open (Internal and SD card).  Just make sure to unmount both drives before removing the cable.  If you fail to do this, it may happen you wouldn't see both drives next time you connect (and will have to re-add the drive name to be able to see it).

fgange57 Posted at 1-16 03:20
I get perfectly good results without removing the SD card. Same as for the Mini 4 Pro, you can just connect a USB-C cable directly to the PC. You do not have to turn the drone on, and two folders will open (Internal and SD card).  Just make sure to unmount both drives before removing the cable.  If you fail to do this, it may happen you wouldn't see both drives next time you connect (and will have to re-add the drive name to be able to see it).

Thats basically the same as putting the SD card in a reader,  your just usiny the drone as the memory card reader.    My point was the app is what causes the problems.  

DAFlys Posted at 1-16 03:54
Thats basically the same as putting the SD card in a reader,  your just usiny the drone as the memory card reader.    My point was the app is what causes the problems.

I fully agree with you.  The sure thing to retain an undisturbed file is to either use a card reader or cable and download the files directly to the computer.