Save IPad videos and photos as MP4/Jpeg

In iOS 11, the photos and videos you take will no longer be encoded in the compatible formats you’re used to. Instead of JPG for images and MPEG-4 for video, they’ll use High-Efficiency Image Format (HEIF) and High-Efficiency Video Format (HEVC), respectively. Files in these newer formats are about half the size of JPG and MP4 files of similar quality.

Go to Settings > Camera > Format and select Most Compatible instead of High Efficiency.