Why do I have .SEC files? (YI 4K Action Camera) .SEC files are much lower in bit-rate which allows you to quickly preview videos on the app. Related articles Why do I have .SEC files? (YI 4K+ Action Camera) How do I download videos and photos from the app?(YI 4K Action Camera) What is the bitrate for each resolution? How much space does each minute of video take up accordingly? Which FOV viewing angle mode can be available under each video resolution in the camera? What is a .thm file?