Mute video and boost volume

Muting keeps the picture exactly as it was

Muting does not touch the video at all. The file is rewritten with the picture copied stream for stream, and the sound track simply left out, so there is no loss of quality and it takes seconds even for a long video. The result stays in the same format as the original and is slightly smaller, by the size of the sound track, which is about 1 MB per minute at a typical 128 kbps.

Useful for clips with private conversations or background chatter, videos for a website that should autoplay (browsers only allow silent videos to start by themselves), and screen recordings that picked up a fan or notification sounds.

Making a quiet video louder

Switch to Volume to change the loudness instead. The picture is still copied untouched; only the sound is processed and encoded again. 100 percent keeps the original level, 200 percent, the default, doubles it, and up to 300 percent is possible. The preview player lets you hear the result before saving.

• Auto measures the loudest moment in the whole track and raises everything until that moment sits just below the maximum. It is the safest way to make a video as loud as it can be without distortion.
• Soft limiter, on by default, rounds off any peak that would go past the maximum instead of cutting it flat. Flat cut peaks are what makes boosted sound crackle.

Raising the volume also raises background noise and hiss. For speech recorded far from the microphone, clean the sound first: take it out with video to MP3, run it through the noise remover, and use the cleaned track.

Percent and decibels

Sound engineers measure loudness in decibels, where every 6 dB doubles the strength of the signal. 200 percent is about 6 dB louder and 300 percent about 9.5 dB; to the ear, a 10 dB rise sounds roughly twice as loud, so even 300 percent sounds less than three times as loud. Auto can go further, up to six times the original level, when a recording is very quiet and its loudest moment is far below the maximum.

Turning sound down

Values below 100 percent lower the volume, for a clip with a sudden loud noise or music that drowns out other videos in a playlist. 0 percent is silent but keeps a silent sound track in the file, which some editing programs and platforms expect; Mute removes the track altogether.

If something goes wrong

• The boosted sound crackles. The volume is too high for the loudest moments. Use Auto, or keep the soft limiter on and lower the percentage.
• Auto barely changes anything. The video already has one loud moment near the maximum, such as a clap or a door. Set the volume by hand and keep the soft limiter on.
• It says the video cannot be rewritten in its original container. Convert it to MP4 first with the video converter.