Summary:
Plex decodes AC3 5.1 but outputs stereo PCM on tvOS
Other apps on the same device output correct multichannel audio with identical system settings
Device chain
Apple TV 4K ==> HDMI ==> Denon AVR-X1700H
Apple TV settings: Audio ==> Auto
Content: File with AC3 5.1
Plex overlay shows: ac3_at (AudioToolbox)
Channels: 5.1 ==> 5.1
AVR reports: PCM 2.0 (only L/R active)
Test
Same file
Apple TV settings: Audio ==> Dolby Digital 5.1
AVR reports: Dolby Digital 5.1 (all channels active)
Conclusion
Plex decodes 5.1 but outputs 2 channel PCM via AVFoundation on tvOS
Test
Same file
Apple TV settings: Audio==> Auto
Infuse Pro works fine
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Is this a known issue with Plex on tvOS?
Is there a recommended configuration to ensure multichannel PCM output?
Is a fix planned?
