The flexibility of MKV is its greatest strength, but it also creates complexity. When you need to remove an unwanted audio track, merge two video files, or change the aspect ratio flag, you cannot simply "save as" in a standard video player. You need a dedicated to handle the heavy lifting.
To become a master of the MKV format, you need these four tools on your hard drive. Bookmark these: mkv tool mix
The problem: The audio is 1.5 seconds ahead of the video. The mix: ffmpeg -i input.mkv -itsoffset 1.5 -i input.mkv -map 0:v -map 1:a -c copy fixed.mkv (Note: This delays the audio track by 1.5 seconds.) The flexibility of MKV is its greatest strength,
Cut large files into smaller parts based on size or time, or merge multiple MKV files into one continuous video. To become a master of the MKV format,
When you load a video into a standard converter to "fix" it (e.g., to remove a subtitle track), the software typically decodes the video and re-encodes it into a new file. This process is time-consuming and, more importantly, degrades quality. It is akin to photocopying a photocopy.