What or device (VLC, Plex, TV, PC) are you using to watch it?
If the file won't play at all, your computer might lack the specific H264 or AAC decoders. Installing the K-Lite Codec Pack or using MPC-HC usually solves this.
ffmpeg -i input.mkv -c:v libx264 -crf 18 -c:a aac -b:a 128k output.mp4
If you meant something else by "fix," such as repairing a corrupted file, more specific steps or tools like video repair software might be required. Please provide more details for a more accurate and helpful response.
Drag and drop your Shot.Caller.2017.1080p.BluRay.H264.AAC file into the "Source files" window.
Sometimes the H264 video stream and the AAC audio stream separate slightly during playback.
Run the installer and select the "Advanced" profile to automatically overwrite corrupted system decoders.
