Does removing the sound from a video reduce its quality?

Why the picture can stay untouched

• A video file holds separate streams. MDN describes a media container as "a file format that encapsulates one or more media streams (such as audio or video) along with metadata".
• Because the sound is its own stream, it can be left out without touching the picture stream.
• FFmpeg's documentation says its -an option can "skip inclusion of" audio streams, and that copy mode is streamcopy "with no decoding or encoding".
• Whether a given app does this is another matter. Some apps may convert the whole video again when you save. We did not test other apps.

What we tested

We ran our Remove audio tool on a 6-second, 1080p test video that we generated ourselves. It is a .mov file of 4.78 MB with H.264 video and AAC sound. We measured the file before and after with ffprobe and ffmpeg on 2026-10-13.

• Size: 4,781,120 bytes before and 4,654,073 bytes after, about 127 KB smaller. Six seconds of sound at 162 kbps would take about 122 KB.
• Picture data: 180 video packets and 4,651,099 bytes in both files. The MD5 hash of the video stream was the same in both: aec4e3ce2604cb555a6b1a30d1e7f1a5.
• Sound: the result has no audio stream at all. Our tool removes the track, rather than setting the volume to zero.
• Check: ffmpeg decoded the result without errors. It took about a tenth of a second.

What this does and does not show

It shows that, for this file, our tool left the video data unchanged. It does not show that other tools behave the same, or that every video does. We tested one MOV file. We did not test MP4 or WebM files, or large files.

How to check your own result

1. Remove the sound with Remove audio from video. It runs in your browser, and your video is not uploaded.
2. If you have ffprobe, run: ffprobe -v error -show_entries stream=codec_type -of csv=p=0 your-file.mov
3. It prints one line for each stream, such as video or audio. If the word audio does not appear, no sound track is left.

More plain answers are in all guides.