Audio Sync - Only One Channel

#1

Had the new Quad for a 10 days or so now. It’s been working well. I have one ongoing issue with one of my channels though. It’s WOTV ABC 41.1. Signal strength is 100 and so is SNR, so I don’t think it is a signal quality issue. The problem is that the Audio and video on this one channel is almost always out of sync. Sometimes it will be off just a little, sometimes it will be a full second or more off. There are times when it is also in sync (but not very often). This happens on recordings and live tv.

This issue does not seem to arise on any of the other channels.

What might be the cause of this. Does anyone else experience this type of issue with just one channel? Is this something support can view in the logs? I have another ABC channel, but it is in another direction and I would need a different antenna if I am going to pick that one up. Seems unnecessary if this syncing issue could get resolved. Any ideas?

#2

You didn’t say what your tablo audio settings are. Or whether this happens on all playback devices or only one.

#3

I set it to Stereo just in case I want to listen on a computer. I mainly listen on Roku Ultras, but I am not tested the issue with any other device. I guess if I experience the issue in a recording, I could pull up that episode on my android phone and see if it appears there as well.

#4

If you plug the antenna directly into your TV, do you see the A/V sync issue there as well?

#5

So the problem persists on my computer and Android but that is likely because…

Yes, sync issues occur there as well, so it’s not a Tablo issue. I wasn’t convinced it was originally, but this confirms it.

Still curious if anyone has any ideas on what the issue might be. Is this problem symptomatic of a signal issue? The signal tests fine, but I’m not sure what else it could be.

#6

I can only guess.

Most U.S. stations broadcast SAP audio in their OTA signal. Almost all of my channels have multiple SAP audio channels. Typically SAP audio channel 1 is English 5.1 or stereo. Many devices just use the audio in channel 1. So I have no idea if their would be a sync issue if instead of standard English it was descriptive. Some device will display what it thinks is in the SAP audio stream or allow the device to select a different SAP audio stream

#7

I had some audio sync problems crop up as well and at first wondered if it was the Quad. But it’s not. In my case I was initially streaming to a Roku Premium+ stick. Since there was no audio sync problem direct from the antenna I tried a Fire TV 4K stick and the sync problem disappeared. I’ve not had sync problems on my iPhone 7+, iPad Pro, or Mac Safari Web App either. I’m not sure this proves my Roku has a sync problem or if it was just that particular broadcast channel at that given moment in time. I’m also going to try moving the Roku to a different TV.

#8

On Roku, if you’re seeing audio sync issues go to Options (Roku remote “*” button… and this needs to be done while watching live tv or a recording on your Tablo…) then go to Volume Mode… if it says “Leveling”, change it. You’ll hear the volume change. Now go ahead and put it back on Leveling (volume will change again) and hit the Options button again to get that screen overlay off.

This fixes my lip sync issues every time. It seems for some reason, Volume Leveling has an effect on lip sync eventually. I like Leveling so I like to keep it on, so if I have to do this once a week or once every 2 weeks I’m ok with that. This is a Roku issue, not a Tablo issue and I found it and the solution in the Roku forums.

Other players may have something similar, but it seems the audio and video are separate and the players… by manipulating the audio… cause the sync to diverge. Turning whatever manipulation off and on again seems to reset it.

#9

@yardbird Thank you for the tip on the Roku leveling. I do use the Leveling feature on my Roku’s so I will remember this if I start to experience the issue on multiple channels. Unfortunately, the issue only appeared on one channel for me, and this occurred even outside of the Tablo environment. If I connected the antenna directly to my TV, the audio sync issue still appeared with just that one station.

I’ve come to consider that it must be just an issue with that one channel. TV fool shows it as a 2-Edge signal in the Yellow zone. Even though my Signal Strength, SNR Quality, and Sym Quality are all up near 100% on that channel, I still think it is a reception issue.

Seeing it was an ABC affiliate, I had another ABC station that was in-range, it just happened to be in the exact opposite direction. Where my antenna was mounted (on my garage roof), it was pointing through my entire house, so I couldn’t pick it up that other ABC affiliate. This past weekend, I added a 2nd antenna in my attic pointed in that opposite direction. After combining the two antennas and finding the right combination with amplifiers, all channels come in strong (at least thus far anyway).

I switched all my ABC recordings to the new ABC channel and the lip sync issue is not a problem with this new channel. Seems to have solved my issue. Fingers crossed it continues to work. It took awhile to find the right solution with amplifiers and antenna pointing to avoid any severe multi-path interference.

#10

Maybe contact the broadcast engineer at the problem station and let them know…

#11

@Lysander If I didn’t find an alternative ABC station that worked, I would be much more aggressive in finding the solution. I wouldn’t mind contacting the broadcast engineer, but I don’t have their info or even know how to easily obtain it. The station is ABC WOTV Real Channel 20 (Virtual 41.1) in the Grand Rapids / Battle Creek / Kalamazoo MI market. Now that I have another ABC station with the exact same programming lineup, I just don’t care. That is, unless something happens with my 2 antenna setup and reception.

The metro area is probably close to 1 Million people within broadcast range, I would be surprised if everyone was experiencing the same audio sync issue. Surely someone would have complained?

#12

Yeah, everyone is thinking “someone must have complained already…” :sunglasses:

Here you go…

Ken Selvig
Chief Engineer
120 College Avenue, SE
Grand Rapids, MI 49503
616-456-8888 [phone]
616-456-9169 [fax]

TV Station Information

See Link at Bottom…

#13

@Lysander Thank you for the information. I shot off an email to Chief Engineer Selvig, we will see if anyone responds. It appears he is in charge or more than one station, my guess is I will never hear back. I could call, but I just imagine how many people I would need to speak to before I find my way to someone who could help (or actually get through to). If I get a reply, I will note it here just in case others run into a similar situation.

#14

Doug, I bet you get a reply. Techie people love to talk about what they do. In my experience you can talk to just about anyone in organization if you put in the effort to find them. The exception is AT&T who have the most uniformed people on earth…

#15

lol, it sounds like you are speaking from personal experience here. Not that I disagree.

I’ll post here if/when I get a reply and we will see what they say.