Why your video has no sound in the browser and how to fix it
Updated: November 5, 2026
Few things are as puzzling: the video plays perfectly, but there’s no sound. On your computer it plays fine (in VLC, say), but not in the browser. The cause is almost always the audio format. Here’s how to find out and fix it in a minute, without losing any picture quality.
Cause 1: the audio is in a format browsers can’t play
Browsers play AAC, MP3 and Opus audio. Many downloaded videos, or those made with some programs, carry audio in AC3 (Dolby Digital), E-AC3, DTS or PCM: you see the picture but hear nothing. It’s very common with MKV files.
Cause 2: the video started on its own and is muted
If the video autoplayed, the browser muted it by rule. It’s not a bug: tap the speaker icon or turn up the volume in the player.
Cause 3: the file has no audio track or it’s mono on one side
Some screen or camera recordings are exported without audio, or with sound on only one channel. Check in a player like VLC (Tools → Codec Information).
How to fix it: convert only the audio to AAC
With ffmpeg (free), this command copies the picture as is and converts only the audio to AAC. It’s fast and the picture loses nothing:
ffmpeg -i video.mkv -c:v copy -c:a aac -b:a 192k -movflags +faststart video.mp4To check the audio format
If it says ac3, eac3, dts or pcm, use the command above. If it says aac, mp3 or opus, the problem is elsewhere (muted autoplay or volume).
ffprobe -v error -select_streams a -show_entries stream=codec_name,channels -of default=nw=1 video.mkvFrequently asked questions
Because VLC plays almost any audio format and browsers don’t. Convert the audio to AAC.