Lip Sync with Fios STB (VMS4100)

[Mbpe300]

Hey Verizon,

I have a new Fios TV installation and there is an audio delay issue from the STB when Dolby Digital 5.1 (surround) Audio Format is selected.

Switching to LPCM (stereo) Audio Format fixing the issue but I did not sign for the TV service to hear the channels in stereo on my home theater setup and definitely not to watch them with annoying lip sync issues.

The delay happens in both HDMI and OPTICAL outputs from the STB.

Just to clarify, the audio stream is being sent with a delay and lagging the video stream, which means that the "Audio Delay" function that is common in the various devices can't help.

Please provide a solution and by solution I mean something serious and not the: "replug the power", "reconnect the cables", "try different cables", etc. 

[clem21]

Are you going Fios box to TV, then TV ARC to sounndbar or receiver? Did you try Fios box to soundbar or receiver then to TV? Do you get the delay going Fios directly to tv?

[Mbpe300]

I do get the delay when going directly from Fios to TV or Soundbar via hdmi or optical. Once switched to Stereo the delay is gone.

Also, there are other devices connected to the same TV + Soundbar and there is no audio delay issue with them so it's pretty much clear that the delay happens during DD processing in the STB or even higher upstream. 

Makes me wonder what audio format is reaching the STB from the ONT 🤔

[clem21]

Supposedly with the latest firmware update there should be a passthrough option in the audio menu. That may do the trick. Problem is the new Fios One boxes convert every signal to DD5.1 regardless of source unless you choose PCM in the service menu. That was why I tried very hard to get the passthrough back in the menu. I have to agree that is the source of the delay in your case, especially if it happens direct to the tv.

[Mbpe300]

What firmware version has the "passthrough" option?

[clem21]

Version 6.8 was supposed to have the passthrough restored as an option.

[Mbpe300]

How the passthrough can be enabled in that version then?

[clem21]

Not sure if it's in the audio menu, or service menu. Haven't gotten the update myself so I'm not sure where you can access it.

[Mbpe300]

How the update is done? Automatically or can be initiated manually?

[clem21]

The updates are initiated on Verizons end. They do them zone by zone until everyone is updated. You can check which version you have in the info in the menu.