How to remove audio from a large video file
Quick answer
Use a tool that copies the video stream instead of re-encoding it: FFmpeg’s ffmpeg -i input.mp4 -c copy -an output.mp4 handles files of any size in seconds to minutes. Avoid online tools that upload the file, since large videos often exceed their limits and take a long time to send.
Why large files are a problem
A 4K phone recording or a long screen capture often reaches several gigabytes. Many online muting tools upload the whole file first and cap the size, so you wait for an upload that may fail. Video editors can open big files, but they export a new video, which re-encodes every frame and can take longer than the video itself.
The fast way is a stream copy: the tool copies the picture exactly as it is and leaves out the audio track. Nothing is re-encoded, so quality, resolution and frame rate stay the same and the work is mostly limited by how fast your disk can write.
Use FFmpeg for any size
FFmpeg is free and runs on Windows, macOS and Linux. The first command removes the audio from an MP4 or MOV. The second is for MKV files: it keeps every stream except audio, including subtitles.
ffmpeg -i input.mp4 -c copy -an output.mp4
ffmpeg -i input.mkv -map 0 -map -0:a -c copy output.mkv-c copy copies the streams without encoding, and -an drops the audio. Write the output to a new file name; FFmpeg cannot overwrite the file it is reading.
On Windows, open the folder that holds the video, type cmd in the File Explorer address bar and press Enter to get a command prompt in that folder. On a Mac, open Terminal and type cd followed by a space, then drag the folder into the window and press Return. Use quotes around file names that contain spaces.
Mute a large file in the browser
If you prefer not to use a command line, MuteVideo removes audio from MP4, MOV and M4V files up to 4 GB each directly in the browser. It rewrites the file on your device without loading it all into memory, so a phone video of a few gigabytes is usually done in seconds, plus the time to save the result. WebM, MKV and AVI files use a different engine with a lower limit of 500 MB on a desktop and 150 MB on a phone.
Built-in options for phone videos
- iPhone: open the video in Photos, tap Edit, tap the speaker icon and tap Done. The file never leaves the phone, so size is not an issue.
- Android: Google Photos and many phone gallery apps have a mute option in their video editor; the exact steps depend on the phone.
- VLC on a computer can also strip audio by editing a conversion profile, but its default profiles re-encode the video, which is slow for big files.
Before you start
- Free disk space: the muted copy is almost as big as the original, so you need about that much room again.
- Check the drive format: USB drives formatted as FAT32 cannot store a single file larger than 4 GB. Use exFAT or NTFS for bigger results.
- Keep the original until you have played the muted copy from start to end.
- Removing audio makes the file only slightly smaller. A typical audio track adds about 1 MB per minute, while 4K video can add hundreds of megabytes per minute.
Questions and answers
Will removing the audio make my large video much smaller?
Usually not by much. Audio is a small share of most video files, so the size drops only slightly. To make a file substantially smaller you need to compress the video, which is a separate step.
Does removing audio from a big file lower its quality?
Not with a stream copy. FFmpeg with -c copy, or a tool that rewrites the container, keeps the picture exactly as it was. Editors that export a new video re-encode it.
Is there a size limit?
FFmpeg has no practical limit beyond your disk space. The browser tool described above takes MP4 and MOV files up to 4 GB each, and WebM, MKV and AVI up to 500 MB on a desktop.