Scarnag, there's nothing to apologize for as this is an issue that no one seems to have a straight answer for, and it's unrelated to your video editing abilities.
Every search for the subject in forums has the replies with a number of "I think", "probably", "I guess", and suggestions that fault the user. I don't understand why there isn't an official answer to this, apart from suspecting there is no easy or straight answer, since it's an inherent problem of DJI's making.
For disclosure purposes I own a Mavic Pro and a Spark, and use an iPhone X or iPhone 7 (and less often an iPad Pro) with the controller. I also always use a cable to connect the Spark’
s controller to the device. Although I’m not a full-time professional editor, I’m a filmmaker and have edited since before going to film school in the 90’s, on everything from analog film flatbeds, to VHS “pro” decks, Betacam, DV, through to Avid, Premiere, and Final Cut, both pre-X and X (although I do miss FCP 7…)
The problem apparently starts with the fact that the device running the DJI4 app, which records the audio, records a variable rate clip, while the drone itself records at a fixed rate, which for the mavic can be chosen and for the spark it's fixed at NTSC's video standard of 29.97fps. I say "seems" because some of those clips vary slightly in their actual fps when played, but at any rate the SD files seem to be recorded at a fixed speed, while the device's file may fluctuate with the environment and performance variations of the device.
Then there's the fact that the audio on your device is recorded at a 44.100Hz sample rate - the standard of audio CDs, whereas the default for audio in FCP X is 48.000 - the same as most pro editing equipment.
That all means that you get variable sizes and durations in your device clips - the ones with audio - that are never the same as your SD higher resolution ones. So if you want audio on your SD clips you need to resample, convert, then manually sync on the timeline using editing software.
I think most people don’t care or mind since there’s so little evidence of that. I personally find that problem a hassle beyond belief. And it’s not just for “pro” uses”. I shoot long takes with tracking shots of me and friends, and I tend to talk a lot. Syncing that audio to the video is always a nightmare. It literally falls out of sync over and over again in the course of one long sentence (or paragraph equivalent.) So all that resampling and re-encoding still doesn’t fix the fact the lengths have to be rematched on FCP X (by changing the speed of the audio and dragging on the timeline) and then re-synced by hand, every time that it’s visible that the audio is out of sync. And the auto-sync function of FCPX doesn’t work with either the resampled clips or the original clips from the DJI app and the SD card.
To me, that issue is incredible frustrating. I’ve tried also using the app to re-download the SD footage from the drone, and all it does is exactly that, and you just and up with the two files on your device. I originally expected for the app to do the resampling and syncing on its own…
I guess most use the footage without the audio, or when needing the audio for “casual” purposes, they just use the often crappy footage from the device, which at least to me stays (mostly) in sync with the video and its crappy changing quality.
If anyone has a solution to this and/or a workflow that “works”, pun intended, I’d love to stand corrected on this issue. And most importantly, find a better way to reconcile the audio with the better quality SD video from my DJI drones.
PS- I apologize for the incredibly lengthy post...
