Who decodes the sound?
| Setup | Passthrough | Who decodes |
|---|---|---|
| Stick → TV, TV speakers | Off | The streaming device |
| Stick → TV → soundbar (ARC or eARC) | On, if the TV passes the format on | The soundbar |
| Stick → AV receiver → TV | On | The receiver |
| Stick → TV → basic stereo soundbar | Off | The streaming device |
Passthrough only helps if the equipment at the end of the chain can decode the format. If nothing can, you get silence.
Formats that need decoding
- Dolby Digital (AC-3) and Dolby Digital Plus (E-AC-3): most streaming devices can decode them, and most soundbars and receivers too. See Dolby Digital in IPTV.
- DTS: many streaming devices only pass it through. Amazon’s specifications for the Fire TV Stick 4K Max (2nd gen), for example, list DTS and DTS-HD as passthrough, while Dolby Digital and Dolby Digital Plus are decoded. If neither the TV nor the sound system decodes DTS, a DTS track is silent.
- AAC and stereo: decoded by everything; passthrough doesn’t matter.
ARC and eARC
When a soundbar is connected to the TV rather than to the streaming device, the TV sends audio back to it over HDMI:
- ARC, the original audio return channel, carries compressed surround such as Dolby Digital.
- eARC, its enhanced successor, adds much more capacity. HDMI.org lists support for audio up to 192 kHz and 24-bit, uncompressed 5.1 and 7.1, and formats including Dolby TrueHD, Dolby Atmos, DTS-HD Master Audio and DTS:X.
Both the TV and the soundbar need eARC, connected through the HDMI ports labelled for it, for eARC formats to get through.
Setting it in a player
Most IPTV players have an audio output or passthrough option in their settings, sometimes per format. Device settings matter too: on Fire TV, see Firestick audio settings.
A sensible order when a channel is silent:
- Choose another audio track, usually a stereo one, from the playback menu.
- Turn passthrough off, so the device decodes the sound itself.
- If you have a capable soundbar or receiver, turn passthrough on and make sure the HDMI path supports the format.
For more fixes, see no sound on IPTV.