The reason why your action camera generates multiple files when shooting a video may be due to the following reason:
Video captured by an action camera is usually split into segments, and each segment is usually a few minutes in length, this is because the file system used by sports cameras (usually FAT32) has a limit on individual file sizes.
The FAT32 file system has a single file size limit of 4GB and if a sports camera captures video for too long, the individual file size may exceed this limit. For this reason, action cameras will often save longer video files in multiple smaller segments, each of which falls within the single file size limit.
You have to format the SD card before using it.
1)if the loop recording function is not turned on, the videos recorded with the resolution of 4K or 2.7K, 1080P, and 720P will be saved every 9 minutes, 25 minutes, and 37 minutes respectively till the SD card is full.
2) If the loop recording function turns on, you can do it with the resolution of 1080P or 720P and 10 minutes is one video. New videos will also cover the existing ones when the SD card is full.
In addition, segmentation helps to improve the reliability of video files. If something goes wrong with a sports camera during video captures, such as a battery drain or memory card error, segmentation ensures that only a small amount of video data will be lost.
action cameras will often time-stamp each video segment and save it as a file name for easy viewing and management. Each video segment can be combined into a complete video file when the user imports the video into a computer or other device.