An IDX file is typically associated with subtitle files in the context of video playback. These files are commonly used to store index information or references to accompany other files, often in conjunction with video files and their corresponding subtitle tracks. IDX files are not standalone subtitle files but work in tandem with other related files, such as SUB or SRT files.

How to open an IDX file:

1. Subtitle Players:

2. Video Editing Software:

Programs that may open IDX files:

1. VLC Media Player:

2. MPC-HC (Media Player Classic – Home Cinema):

3. Subtitle Edit:

Various apps that use files with IDX extension: