Troubleshooting
Why Your Video Has No Sound on Someone Else's Device
A file that plays perfectly for you and arrives silent for someone else almost always has an audio codec their player cannot read. Here is how to tell, and what to do.
2 min read · Published 12 September 2026
The video plays. The picture is fine. There is simply no sound, and only on their machine. This is a narrower problem than it feels, and it is almost always the audio codec.
A video file is a container holding separate picture and sound tracks, each encoded in its own format. A player that understands the container and the picture format can happily show the video while having no idea what to do with the audio, and most players fail silently rather than saying so.
The usual culprits
| Audio codec | Plays almost everywhere | Notes |
|---|---|---|
| AAC | Yes | The safe default for MP4 |
| MP3 | Yes | Old but universally understood |
| Opus | Mostly | Common in WebM; some older players refuse it |
| AC-3 or E-AC-3 | No | Broadcast and disc audio; often missing on phones and browsers |
| PCM or WAV inside video | Varies | Large, and some phone players skip it |
If a file was exported for broadcast, pulled off a disc, or produced by a camera aimed at that world, AC-3 is the likely answer. If it came from a screen recorder or a browser based tool, Opus is the likely answer.
Checking before you guess
Read the file. The file info tool on this site reports the audio codec alongside the video one, which turns the whole question into a single glance. If it says AAC and the sound is still missing on their device, the codec is not the problem and it is worth looking elsewhere.
- AAC or MP3 reported: the codec is fine, look at the other causes below
- AC-3, E-AC-3 or DTS reported: that is the cause, re-encode the audio
- No audio track reported at all: the sound was never in the file
- Two audio tracks reported: their player may be defaulting to the wrong one
A file with no audio track at all is a surprisingly common outcome of screen recording, where the capture was set to picture only, or where the app was never granted microphone permission. The recording looks successful the whole way through.
The other causes, in order of likelihood
- The track exists and is silent, because the wrong input was recorded. Check the waveform rather than the settings.
- The file has multiple audio tracks and their player picked a different one. Some exports include a second language or a commentary track.
- Their device is muted, or media volume specifically is down while ringer volume is not. Worth one polite question before re-encoding anything.
- A browser blocked autoplay with sound, which reads as a silent video until clicked.
The fix that always works
Re-encode the audio to AAC in an MP4 container, and leave the picture untouched by copying the video stream rather than re-encoding it. That keeps the visual quality exactly as it was, takes seconds rather than minutes, and produces a file that plays on essentially anything made in the last fifteen years.
If you regularly send files to people whose devices you do not control, exporting as MP4 with H.264 video and AAC audio from the start avoids the conversation entirely. It is not the most efficient combination available, and it is the most likely to simply work.
Common questions
Why does my video have sound on my computer but not on a phone?
Usually the audio codec. Your computer has decoders a phone does not, and AC-3 is the common offender. The picture plays because the video codec is understood; the sound is skipped because the audio codec is not.
How do I check what audio codec a video uses?
Read the file's details rather than opening it in a player. A file info tool reports the audio codec next to the video codec, which answers the question directly and takes a second.
What audio format works everywhere?
AAC inside an MP4 container. It is the default for online video for exactly this reason, and it plays on phones, browsers, smart televisions and desktop players without anything being installed.
Can I fix the audio without re-encoding the video?
Yes, and you should. Convert only the audio track and copy the video stream across untouched. The picture quality is preserved exactly, and the process takes seconds rather than the minutes a full re-encode would.