I encountered an issue when using Litchi on a Mini SE with the iOS app. Whenever I set the resolution and frame rate in the app to 1920x1080 60fps and record video, all saved videos are being actually recorded only with 48fps, while still having 60fps timestamps and metadata. Effectively this leads to having a 1.25x speed-up when playing the video. (48*1.25=60fps).
My workaround for this was to manually slowdown the video with FFMpeg (How to speed up / slow down a video – FFmpeg)
I consequently tried different recording frame rates and found that only 50fps is working as it should:
Configured frame rate 50fps, actual 50fps
Configured frame rate: 48fps, actual ~36fps
Configured frame rate 30fps, actual ~27fps.
Another observation I had is that setting the resolution via the DJI Fly app and then just using this in Litchi resulted in the correct result, however the 60fps in DJI Fly would result in 59.94 fps and 30pfs in 29.97. This is displayed in the Litchi UI and results in none of the options being selected (I assume because we have options for 60fps but 59.94 is not quite 60
The main problem isn’t the 60 vs 59.94, the difference is much bigger. As said there is a 20% difference in the frame rate, it’s clearly visible that the timings are off. The linked video is very informative though, thanks
I tested ALL (9) possible video sizes and framerates with a DJI Mini-1.
ALL these test were done on Android & iOS, both with DJI Fly & Litchi.
The results were the same for ALL 4x9 tests and NO deviations were found.
Perhaps there are issues with the video codecs/drivers on your PC?
Configuration:
DJI Mini SE
Firmware Version: 01.02.0002
Flight Controller Version: 03.04.14.15
Remote Controller Version: 01.00.0602
Litchi v2.13.2
macOS 12.3.1
perhaps there is a slight difference between the Mini1 and Mini SE?
I also have some sample videos, recordings of a stopwatch, with the 60, 48 and 30fps once can see clearly that the speed is off, i.e. the stopwatch counts up to 25 seconds in a 21 second long video file.
