Kodi on Mi Box Android 6 - only stereo when passthrough disabled

by wint_rmute

I'm running Kodi 17.3 on an Mi box, with Android 6.

If I have audio passthrough enabled, I get 5.1 surround sound hitting my AV receiver, over HDMI. However the audio gradually drifts out of sync. (Suspect because 23.98 hz video doesn't match up to 60 hz display, even with 3:2 pulldown*)

If I turn audio passthrough to off, then Kodi only sends stereo audio out the HDMI to the receiver. Even though I have the speaker configuration in Kodi set to 5.1, and audio output mode set to "best match".

Am I doing something wrong? Can I fix this?

The Plex app seems OK about sending multi-channel audio over HDMI and it stays in sync.

Footnote:

  • Yes, I know, I should be matching the refresh rates, but I have a Hisense 65M7000 TV which runs at a fixed 60 hz at 1080p. You can send it 24hz signals, but it does internal 3:2 conversion to 60hz anyway. 2160p has a genuine 24hz mode, but then you're relying on the little android tv box to do the upscaling, which can struggle at times.
NedSc

I forget which combo of settings does this, but basically you want to enable Dolby Digital transcoding. Maybe. I can't remember if Android 6 on the Mi Box supports multichannel PCM, but I think it does. Basically, you don't want "real" passthrough, where the audio is untouched, but you do want a AC3/DD signal so that the multichannel audio signal is transmitted. This should, in theory, allow for the audio track to be sycned with the video, while still using a AC3/DD signal.

EDIT: oh, and be sure to enable "sync playback to display" or whatever it's called in v17.

Maybe. I never really understood the audio passthrough stuff that well, so take this with a big grain of salt.

jaymef

Have you tried spmc

pawdog

Turning off passthrough is the equivalent of turning off digital audio. That's how the system works. People with surround systems use passthrough. People without leave it off. I remember having the sync issue a while back but I'll have to get home to investigate what I did about it. I do remember it being my changing some setting that caused it. Don't remember what it was though.