Open VLC Media Player and go to > Open Multiple Files . Click Add to select your Iron Man video file.

Note the exact millisecond delay that fixes the problem (displayed in the top-right corner of VLC). Method B: Permanent Fix in MKVToolNix

ffmpeg -i ironman.mp4 -i hindi.aac -map 0:v -map 0:a? -map 1:a -c copy -metadata:s:a:1 language=hin -disposition:s:a:1 default output.mp4

: In the "Tracks, chapters and tags" section below, you will see a list of all video, audio, and subtitle streams.

Streaming services handle audio tracks automatically through built-in menus, while local files require downloading external audio files and syncing them manually.

Within a few seconds, MKVToolNix will output a brand-new .mkv file containing both audio options without losing any video quality. Step 3: Troubleshooting Audio Sync Issues

At the bottom of the window, look at the field. Click the "Browse" button to choose where you want to save your new file. Make sure you give it a slightly different name than the original so you do not accidentally overwrite it (e.g., Iron Man (2008) Multi-Audio.mkv ). 4. Start the Process

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If the audio needs a permanent fix, open your file back up in MKVToolNix. Click on the Hindi audio track.

: Click Play . Right-click the video while it's playing, go to Audio > Audio Track , and select the new Hindi track. Method 2: Permanent Integration with MKVToolNix

: Select the Hindi track and set the "Language" property to Hindi (hin) . This allows your media player to recognize the language automatically.