mkvpropedit input.mkv --add-track-statistics-tags To fully regenerate cues (rarely needed):
mkvmerge -o output_indexed.mkv --cues "all" input.mkv ffmpeg -i input.mkv -c copy -movflags +faststart output_indexed.mkv Note: +faststart is primarily for MP4 but also helps MKV by reorganizing index data. 3. Using mkvpropedit – Fastest (modifies in place) If the file already has some index but is missing cues for certain tracks: index mkv