: The specific track (video, audio, or subtitle) being referenced.

: The progress bar may be unclickable or snap back to the beginning. How to Rebuild an MKV Index

The Matroska specification uses the term for its indexing system. This element contains CuePoints , each referencing: CueTime : The absolute timestamp for a point in the video.

: The exact byte offset within the file where that data starts.

Files can suffer from "broken or missing index" errors due to interrupted downloads, software crashes during recording (like OBS), or poor muxing. Symptoms include:

For standard video files, Cues typically index every (I-frame) to ensure that when you click a point on a progress bar, the player can jump directly to a "complete" image rather than a partial one. Common Issues: Broken or Missing Indexes

In the context of multimedia, an (technically known as Cues ) is a metadata structure within a Matroska (.mkv) file that allows media players to seek instantly to specific timestamps. Without a functional index, a player might have to scan the entire file linearly to find a specific scene, leading to slow "scrubbing" or an inability to fast-forward. What is the MKV Index?

: Some players, like mpv , may explicitly report a "discarding broken index" warning.