If the picture plays but there's no sound, or voices don't match lips, the cause is almost always how your device, TV or soundbar handles the audio format, not a problem with the service. Some channels use Dolby Digital (AC-3) or Dolby Digital Plus (E-AC-3) audio, which not every player or TV setting handles correctly.
Audio formats you may come across
| Format | Where you'll find it | If it's silent |
|---|---|---|
| AAC or MP2 (stereo) | Most live channels | Rarely a problem; check volume, mute and the HDMI cable |
| Dolby Digital (AC-3) | Some channels, many films | Set the device's audio output to PCM or Stereo |
| Dolby Digital Plus (E-AC-3) | Some HD channels, films and series | Turn Dolby Digital Plus off, or use PCM |
| DTS | Some films | Many TVs can't decode it; let the player decode it, or pick another track |
No sound on some channels
Change the player or audio decoder
Most IPTV apps include more than one internal player. Switch to another, or look for an option to use software audio decoding. In IPTV Smarters Pro, that's in Settings > Player Selection.
Check the audio output format
On your streaming device or TV, find the audio output or digital audio format setting. If it's set to pass Dolby audio straight through (“passthrough” or “bitstream”) but your TV or soundbar can't decode it, you get silence. Try PCM or Stereo, or Auto. On Fire TV, look in Settings > Display & Sounds > Audio.
Try another audio track
Some channels carry more than one audio track. Open the player's audio or language options during playback and select a different track.
Where to find the audio settings
Menu names change between software versions, but on most devices the audio format setting is here:
- Fire TV: Settings > Display & Sounds > Audio. Try setting Surround Sound to Stereo, or Dolby Digital Output to Dolby Digital Plus Off.
- Android TV and Google TV: Settings > Display & Sound (or Device Preferences > Display & Sound) > Advanced sound settings or Audio output. Try Auto, or turn surround formats off.
- Apple TV: Settings > Video and Audio > Audio Format. Choose Change Format and try Stereo.
- Samsung and LG TVs: in the sound settings, look for Digital Output Audio Format or Digital Sound Out and try PCM or Auto.
Change one setting at a time and test the same channel after each change, so you know what fixed it.
No sound on any channel
- Check the TV and the device aren't muted, and that other apps have sound.
- Unplug and re-seat the HDMI cable, or try another HDMI port.
- If you use a soundbar or receiver over HDMI ARC or eARC, check the TV's sound output is set to it, and try switching the soundbar off and on.
- Restart the device and the TV.
Sound cuts out for a moment when you change channel
When channels use different audio formats, a soundbar or receiver has to switch format each time, and the first second of sound can go missing. Setting the streaming device to a fixed output, such as PCM, stops the switching. On Apple TV, tvOS 26.4 added a Continuous Audio Connection option in Video and Audio for the same reason.
Audio out of sync
- Use the app's audio delay setting. Many players let you shift audio earlier or later during playback in small steps.
- Use the device's sync option. On Fire TV, Settings > Display & Sounds > Audio > AV Sync Tuning walks you through lining up sound and picture.
- Check soundbar and TV settings. TVs and soundbars have their own lip-sync or AV sync adjustment. Processing modes like “sports” or “cinema” can add delay.
- Match frame rate. Turning on frame-rate matching on your device (where available) can fix drifting sync.
- Change channel and back. If sync drifts during long viewing, restarting the stream resets it.
For other playback problems, see buffering and freezing or go back to the troubleshooting overview.
Sources
We checked the facts on this page that come from other organisations against these sources in October 2026.
- Apple releases tvOS 26.4 (MacRumors, March 2026)