M2TS is a file extension used for video files that contain high-definition (HD) video content, typically recorded on Blu-ray Discs or AVCHD camcorders. M2TS files are essentially MPEG-2 Transport Stream files that store video, audio, and other data in a compressed format. These files usually have a .m2ts file extension and are typically used for storing and playing back high-quality video content, such as movies or home videos. They are supported by a variety of media players and video editing software.