A .ts file is a video stream file format that stores video data compressed with standard MPEG-2 video compression. It is used to store video content on DVDs and Blu-ray discs. The file format is similar to MP4, but it is divided into tiny chunks, each consisting of a small piece of video, followed by a bit of audio, and an optional caption. A single TS file consists of many such chunks. TS files were popular during the DVD era in the 1990s and 2000s, but nowadays, as technology keeps developing and multimedia formats like .MP4, .MOV, .M2TS, etc. have progressed, the TS video format is outdated.

It is important to note that a .ts file may also refer to a TypeScript file, which is a text file that contains TypeScript code. TypeScript is a superset of JavaScript, and any JavaScript code is a valid TypeScript code as well. TypeScript files use the .ts file extension and can be transpiled to any flavor of JavaScript code.

To open and play TS files, you can use popular media players like VideoLAN VLC media player, which is freely available. You can also convert TS files to other formats using various media players and video editors, including VideoLAN VLC media player and Corel VideoStudio.