Audio & playback
No sound on an X video? Check the player, then the file
Short answer
On X, videos often start muted, so tap the video to unmute and check device volume. If it is silent in a desktop player too, the file has no audio stream, or the audio codec is unsupported. Export H.264 video with AAC audio in an MP4 file under X's limits (non-Premium accounts: up to 140 seconds and 512 MB) and check the file with ffprobe before posting.
Key takeaways
- Autoplay on X starts muted; tap to hear the sound.
- Check that the local file has an audio stream before uploading.
- X Help states non-Premium accounts can upload videos up to 140 seconds and 512 MB.
- Export H.264 with AAC in MP4 to avoid codec problems.
Find your case
| What you see | What it usually means | Do this |
|---|---|---|
| Silent until you tap the video | Muted autoplay | Tap to unmute; add captions for sound-off viewers (step 4) |
| Silent after tapping and on all devices | Audio stream missing in the file | Check with ffprobe (step 2) |
| Silent on one phone only | Device volume, silent mode or Bluetooth output | Check device settings (step 1) |
| Audio present locally but gone after posting | Unsupported audio codec | Re-encode with AAC (step 3) |
Fix it step by step
Check the player and the device
Tap the video, make sure the speaker is on, raise the volume and turn off silent mode. If you use Bluetooth, disconnect it and test the phone speaker.
Check the file
Run
ffprobe -hide_banner file.mp4. You need a Video stream and an Audio stream. No audio stream means the sound was never in the file.Export a standard file
H.264 video, AAC audio, MP4 container:
ffmpeg -i in.mov -c:v libx264 -pix_fmt yuv420p -c:a aac -b:a 128k -movflags +faststart out.mp4. Keep it within X's limits.Design for sound-off
X shows captions with a CC slider on the web, and many viewers watch without sound. Burned-in or uploaded captions let a muted video still make sense.
Quick sound check before you post
- Play the exported file from start to end with the sound on.
- Run ffprobe and confirm an Audio stream is listed.
- Check the first three seconds, where a missing intro track would be obvious.
- After posting, open the post on a second device and tap to unmute.
Frequently asked questions
Why is there no sound on my X video?
Autoplay is often muted, the device may be silent, or the file has no audio stream or an unsupported codec.
What are X's video limits?
X Help says non-Premium accounts can upload videos up to 140 seconds with a maximum file size of 512 MB.
What format should I upload to X?
MP4 with H.264 video and AAC audio is the safe choice for compatibility.
Sources
- X Help: Posting videos on X (official, checked 2026-10-06)
Reviewed 2026-10-06. Steps not attributed to a source are general video practice or computed above.