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Audio Out of Sync

Posted by
Gold Problem Solver

Message 51 of 67
512 Views

Sounds like you don't have X1 boxes or X1 service.

X1 boxes do not have the "Advanced" tab in the audio settings like legacy boxes do. Are you sure you are posting in the right place?



DigitalMechanix wrote:

We just got the cable box upgraded to HD and had the out of sync audio problem.

Technician came out and said it's a problem with the TV.

We have a new Sony so I  figured probably not.

Went into the settings on the cable box after he left to see what options were buried in there. Audio was set to Advanced with options. I changed it to Stereo. Options disappeared. I figured problem solved since the audio was in sync on all channels and stayed there... for a couple of hours. Then it started to go out of sync again. After some more research I found Sony had a firmware update that seemed to resolve the issue. Unfortunately it looks to be only about a 90% solution to the problem because the audio STILL goes out of sync though much less often than before. I've gone as far as I can with troubleshooting. Changing settings helped some.. updating the TV's firmware... better, but still not right. I've read a lot of complaints from others with the same audio sync problems on all different kinds of setups and all I can say at this point is to try the known workarounds and hope they help because i don't see Comcast in any hurry to change they way they deliver and process HD. The old boxes worked fine. Never out of sync. I'm back to blaming the new cable box as the root of the problem. They should work without headaches on everybodys system regardless of how you have your audio output set up.

Let me add that up until last night all the out of sync errors have been audio ahead video lagging.  When I tried watching a show on bravo on demand last night... the audio was lagging behind the video. As a Comcast customer I found it annoying. As a computer tech I found it to be another interesting glitch.

So to all who think it's a codec problem you're absolutely right. The question now is where the codec should be.  I think it should be in the cable box so it outputs a "standard signal" that's easily played on any hd tv. The fact that some tvs work out of the box and others work better after flashing their firmware proves it's a software not hardware issue. So what to do if your setup doesn't work after trying settings and tv updating.. or doesn't even have the option to try?

Unfortunately I'm going to have to say buy a tv that works with comcast out of the box and use it's output to your cool speaker setup. I haven't taken the time yet to look deep into it  but Samsung and LG may work better than others.

It would be good to look up feedback from people who love the comcast hd and have no sync issues to get a feel for what the better hardware is.

Sorry MrScott1 but my original conclusion stands.






 

Posted by
Frequent Visitor

Message 52 of 67
499 Views

Am I sure about posting in the right place? No good neighbor and apologies if it's not. Small cable box with a big blue button.

(Doing a google search for "comcast audio out of sync" gives the usual list of hundreds of webpages. At the top are these forums with threads going back to 2012. At the top of all that, is this one with page header: Audio Out of Sync - Xfinity Help and Support Forums. Click!  Missed the fine print  re X1.. but congrats to jayrubin for having the #1 google goto for this one.. and forgive an old guys eyesight. The first time I used an internet connected keyboard was 1976. )

In any case the basic principles are the same and we're all in the same boat as far as audio synch issues goes. Will Comcast fix it so their boxes all work right? I don't know. Assuming they don't.. can we find hardware that will work with what what they give us? Probably. Is it worth it to get a new tv? Depends on how annoying you find the out of sync. I'm done with it for now.

If anyone has a better solution I'm here to learn, but if you're like Brian May's wife... or Veruca Salt.. and you want it all and you want it NOW!?  I think you need a tv with the right software installed.

Posted by
Frequent Visitor

Message 53 of 67
455 Views

Do you know if people with 4K tv's hooked up to regular HD boxes are having no problems at all with these out of sync episodes? The more I study this, I'm coming to the conclusion that 4K sets may be able to read and piece together the messy output from these cable boxes like it was a Dr. Seuss book.  And as much as people with 1 year old 1080p tvs are going to hate it.. the best real world  fix for the out of sync audio may be to retire it to the bedroom or let the kids use it for games and get the extra processing power of a 4k for the living room.

 

Posted by
Service Expert

Message 54 of 67
444 Views

DigitalMechanix wrote:

Do you know if people with 4K tv's hooked up to regular HD boxes are having no problems at all with these out of sync episodes? The more I study this, I'm coming to the conclusion that 4K sets may be able to read and piece together the messy output from these cable boxes like it was a Dr. Seuss book.  And as much as people with 1 year old 1080p tvs are going to hate it.. the best real world  fix for the out of sync audio may be to retire it to the bedroom or let the kids use it for games and get the extra processing power of a 4k for the living room.


audio streams (mpeg) have a primary and failsafe sync to stay in sync. It is the TV's responsibility to read and display lipsync and is why flatscreens have audio lipsync adjustments. 

 

a quick test is to play the same content on a desk/laptop or smart device and compare.




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Posted by
Frequent Visitor

Message 55 of 67
430 Views

Thanks for the reply Rustyben. Although you didn't specifically answer my question re 4K tv sets you DID give us another piece of the puzzle. The tv is completely responsible for sync and the cable box isn't going to do anything about it.

With computers, video playback issues have pretty much 3 possible causes. Bad file. Bad, missing, or improperly configured codecs, or not enough computer power to handle the data load. My theory is that a lot of tvs don't have the most current mp4 codec installed. And that updating firmware.. installing the newest decoding instructions may fix it, but if your tv doesn't have the processing power and buffer to hold the pieces until they're all there and put them together fast.. you get audio sync errors. My guess is that 4k tvs don't have any problem at all if they have the right codec installed.

I perceive you have depth of knowledge so I ask you this.. Does my conclusion make sense and do you think 4K might be the best solution.

Posted by
Service Expert

Message 56 of 67
422 Views

DigitalMechanix wrote:

Thanks for the reply Rustyben. Although you didn't specifically answer my question re 4K tv sets you DID give us another piece of the puzzle. The tv is completely responsible for sync and the cable box isn't going to do anything about it.

With computers, video playback issues have pretty much 3 possible causes. Bad file. Bad, missing, or improperly configured codecs, or not enough computer power to handle the data load. My theory is that a lot of tvs don't have the most current mp4 codec installed. And that updating firmware.. installing the newest decoding instructions may fix it, but if your tv doesn't have the processing power and buffer to hold the pieces until they're all there and put them together fast.. you get audio sync errors. My guess is that 4k tvs don't have any problem at all if they have the right codec installed.

I perceive you have depth of knowledge so I ask you this.. Does my conclusion make sense and do you think 4K might be the best solution.


mpeg4 (and that comes with 720p60) is no real difference in processing power and should be no problem for any television. the stream is digital (as set on output) to the TV. The TV takes the video and recodes it to their flat panel's proprietary format for display. Video is sent to the video circuit for output. Lipsync depends on the path as to handling. Direct to TV is probably not going to be out of sync. If the digital output is used to a sound bar then there should be less issues with lipsync than a sound bar linked by just bluetooth from the TV (all IMHO).




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Was your question answered? Mark it as an accepted solution!solution Icon
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Posted by
Frequent Visitor

Message 57 of 67
414 Views

Gotcha about processing power. You'd think that a tv that can play back fat blu ray files with no problem should be able to do the same with cable. But with those.. the input is pretty much in order and steady flow. With cable i'm guessing the packets may not be in order and there could be a lag in time before all the pieces are there. Those would have to be held in memory until there's enough to do something with it and keep it straight.

Of all the technology we play with today.. you'd think cable tv would be the most fool proof. Should just plug it in and turn it on. No brainer.  The only way I'm going to know for sure is to just do the experiment and hook up a 4k to see what happens.  If it still lags, then it's a garbage in garbage out situation that comcast needs to fix.

Posted by
Regular Contributor

Message 58 of 67
402 Views

If we're going to re-introduce the home theatre processing stream into this conversation, then lets not forget to reintroduce the fact that Comcast's audio sync issue does not exist on every channel, nor is the delay the same on each channel it exists on, nor is the delay the same minute to minute, hour to hour, day to day.

 

If you have a home theater issue, the delay is identical on everything, and can usually be adjusted for with your AV device.

Posted by
Frequent Visitor

Message 59 of 67
380 Views

Right on MrScott1.  Audio sync errors can be (+) or (-)  Varies in timing and not on all channels. And I have HDMI direct to the tv with speakers connected out the back. 

Up until this past week  I didn't give a rats tail about the technical details of cable/hdtv... but we'll get it figured out.

File (data stream), codec, hardware... if 2 of those are known to be good, the problem has to be in whatever is the 3rd assuming you have a media player that works.

Posted by
Frequent Visitor

Message 60 of 67
361 Views

I think I've got this figured out.
Let's assume there are no problems in the wiring between the server and the cable box that are causing a signal loss.
Your stuff has been working fine. Now it's not. Why? What changed?
What changed is software. Data flow out of your cable box changed somehow. That's the file part. Let's assume it's good.
Your tv and cable box work fine. That's hardware.
What's left is codec. If the ENcoding part has changed.. and it has.. and will continue to.. we need to keep up with the DEcode part of codec. Firmware updates.
TVs aren't just television any more, they're computers and like computers you need to do your updates. With 4k I expect there will be a few of them as things develop.
Unfortunately for people with 1080p, new ones won't be coming because all the guys that write code are working on improving 4k and experimenting with 8k.
Rustyben said: [The TV takes the video and RECODES it to their flat panel's PROPRIETARY FORMAT for display.]
Each manufacturer has to have a code guy to write the stuff for their TVs because they're all different. If you don't have good decode software when the files change.. you get errors.
Updating my TV's firware helped a lot but didn't quite fix it.
I'm pretty much convinced now that upgrading to 4k will solve the problem.. not because we need the superior processing power (though it may help), but because we need the software.. codecs.
The better mp4 codecs (and better HDMI interface) could be the answer. Besides, we're going to need to get one eventually anyway.
If the audio sync doesn't get worse I can live with it until black friday.. plenty of time to figure out what's the good stuff.
If your out of sync is driving you nuts and you've updated firmware or can't do it at all. Try a 4k TV. Make sure it has the latest firmware. If it doesn't work better.. take it back to the store and complain to comcast. You had hardware and codec covered as well as you possibly could.

Posted by
Regular Contributor

Message 61 of 67
345 Views

I've said this in PM's, I'll say this here - when DirecTV was moving to MPEG4 they had audio sync issues for months. How did they fix it? The implemented some Dolby Digital feature (that I can no longer recall what it was) that needed to be implemented on their end. Problem went away. I'm virtually certain this is Comcast's issue as well.

 

I don't hold out much hope that Comcast will fix anytime soon. Back when, DirecTV cared about being the best (before ATT ate them up). Comcast has never given a hoot.

Posted by
Frequent Visitor

Message 62 of 67
335 Views

Thanks for the feedback MrScott1.  Exactly the kind of puzzle pieces I was hoping to get by popping in on the discussion. If you're right and that's the root cause of the problem.. not fixing it is pathetic. What would it take? Change some settings or apply and configure a software patch? We have no control over the file part of this.

I still want to test a 4k just to satisfy my curiosity but what you've just mentioned is very interesting and I'm going to look into it further.

Posted by
Regular Contributor

Message 63 of 67
320 Views

I went back and checked with some of my old DirecTV friends. What happened was DirecTV had to switch to a newer DD encoder at their head-end. I'm also informed that even that encoder is old news now, newer encoders are available. I find it hard, but not impossible, to imagine Comcast is using obsolete DD encoders at their head end.....

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Message 64 of 67
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Having huge audio sync problems. Never happened with my old box. This is definitely an X1 issue and not a TV firmware problem. Mine is up to date and experiencing horrible delays. It starts minimal and then becomes unwatchable. There's no reason this should happen. HDMI is digital and sends audio and video together. The box is playing with the incoming data streams and outputting to the HDMI unsynced. Whatever is happening inside the box is the problem. Comcast needs to own up and push out a fix or recall.
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Message 65 of 67
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DigitalMechanix wrote:

Do you know if people with 4K tv's hooked up to regular HD boxes are having no problems at all with these out of sync episodes? The more I study this, I'm coming to the conclusion that 4K sets may be able to read and piece together the messy output from these cable boxes like it was a Dr. Seuss book.  And as much as people with 1 year old 1080p tvs are going to hate it.. the best real world  fix for the out of sync audio may be to retire it to the bedroom or let the kids use it for games and get the extra processing power of a 4k for the living room.

 


Yes, I am having issues with my X1 and my Samsung un65ks8500 and the a/v is out of sync. I have an Onkyo tx-nr515 for a/v control via HDMI. The video is a quarter second or so ahead of the audio, I have adjusted all the tv and receiver settings for audio sync, but there's no way to get them to sync up. I have even tried going to the TV hub directly and no luck. I put my Tivo back in play and there is no a/v sync. It's definately an X1 DVR issue.

 

Also on some channels, like CBS, it get real bad judder with the X1 box. Shows like Modern Family and Blackish are all herky jerky. On my Tivo, no issues.

Posted by
Regular Contributor

Message 66 of 67
175 Views

Seeing this issue on many channels. Especially Showtime channels using Surround Sound with HDMI.

Posted by
Frequent Visitor

Message 67 of 67
95 Views

Excellent feedback good neighbor richfear! Thank you.  Good fast  4K hardware.

I think the latest firmware update for your TV is: MAR 23,2017 Upgrade File(USB type) ver. 1168.3, MULTI LANGUAGE

Assuming you have that installed.. still having synch problems would prove it's a Comast encode/decode issue. I read up on the workings of the head end and have to say I didn't realize how many levels of encoding are going on there. LOTS of places to have errors there as well as the cable boxes themselves.

Check your firmware version is really up to date and get back to us here so we can all complain loud and clear that we're getting ripped off by Comcast providing lousy out of synch programs.