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Audio Out of Sync

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Message 1 of 67
5,516 Views

I have had X1 service for two days.  Today at approx. 5:00 p.m.  The audio was out of sync

with video, e.g. All reporter's lips were out of sync with their voice (words) .  Occurred on all

channels. Comcast phone tech support sent a refresh signal to my box and said everything

was working properly.  Of course they could not view the problem. The Cmcast phone

tech walked me through changing resolution and going from stereo to surround and

back, thinking this might jog my local signal. Did not work.

 

At approx. 8:00 p.m. CDT, audio and video were back in sync.  I Googled this problem,

there are several posts stating my problem.   This occurred infrequenly with my non-X1

box.  Any suggestions?

 

Also X1 picture is not as sharp as with my old non X1 box.  Very disappointed. 

 

Problem #3.  With the X1 box, now after entering channel number, I must press OK.

Whats up with that.  Never had to with my old non-X1 box.  After I entered a channel

no. it automatically switched rapidly.   Any suggestions?

 

 

66 REPLIES
Posted by
Service Expert

Message 2 of 67
5,487 Views

jayrubin wrote:

I have had X1 service for two days.  Today at approx. 5:00 p.m.  The audio was out of sync

with video, e.g. All reporter's lips were out of sync with their voice (words) .  Occurred on all

channels. Comcast phone tech support sent a refresh signal to my box and said everything

was working properly.  Of course they could not view the problem. The Cmcast phone

tech walked me through changing resolution and going from stereo to surround and

back, thinking this might jog my local signal. Did not work.

 

At approx. 8:00 p.m. CDT, audio and video were back in sync.  I Googled this problem,

there are several posts stating my problem.   This occurred infrequenly with my non-X1

box.  Any suggestions?

 

Also X1 picture is not as sharp as with my old non X1 box.  Very disappointed. 

 

Problem #3.  With the X1 box, now after entering channel number, I must press OK.

Whats up with that.  Never had to with my old non-X1 box.  After I entered a channel

no. it automatically switched rapidly.   Any suggestions?

 

 


1.  The Out-of-Synch was probably a "gltich" in the transmission...

2.  Look within your TVs settings to ensure they are optimized for HD viewing.  CHeck to ensure all of your connections are tight and reseat your HDMI cable at both the box and your TV.

3.  Pressing OK after selecting a channel is the normal op for X1....you are actually also entering search mode when entering numbers so the OK is required.

 




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Posted by
Regular Contributor

Message 3 of 67
5,470 Views

I am seeing an increase in audio sync issues in my market. Last night it was the Travel Channel, night before, it was my local news. It varies by channel, and when it happens on my home theater, it is also happening on my stand-alone TV's elsewhere. Comcast needs to get it together, audio sync issues are last decade's problem.

Posted by
Frequent Visitor

Message 4 of 67
5,429 Views

I have also been getting audio sync problems all of a sudden. Never had the issue before. I say it started a few weeks ago. It is so ANNOYING. Does not happen all the time but seems to be happening more and more now. It was very noticable this weekend why watching the commentators in football. I also noticed it on my recordings. I want to call tech support but the thought of explaining this problem over and over and over again to techs who can't help makes me dread it. I know for a fact the techs can't help. No it is not my TV, No it is not my HT system, Yes my cables are plugged in tight, yes I sent refresh signals.  It is Xfintiy. I'm guessing a firmware changed things and now it is all messed up. Can anyone help or suggest anything?

Posted by
Regular Contributor

Message 5 of 67
5,425 Views

jgalego wrote:

I have also been getting audio sync problems all of a sudden. Never had the issue before. I say it started a few weeks ago. It is so ANNOYING. Does not happen all the time but seems to be happening more and more now. It was very noticable this weekend why watching the commentators in football. I also noticed it on my recordings. I want to call tech support but the thought of explaining this problem over and over and over again to techs who can't help makes me dread it. I know for a fact the techs can't help. No it is not my TV, No it is not my HT system, Yes my cables are plugged in tight, yes I sent refresh signals.  It is Xfintiy. I'm guessing a firmware changed things and now it is all messed up. Can anyone help or suggest anything?


Yes, it is a waste of time calling it in, the front line techs are not trained to handle anything beyond basics. The best advice I have is keep making noise up here.

Posted by
Service Expert

Message 6 of 67
5,415 Views

Are you speaking of live entertainment or recordings? Is it from a major network channel?




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Posted by
Frequent Visitor

Message 7 of 67
5,400 Views

Yes, Yes and Yes. Again, it is not 100% of the time and sometimes it is way off and others it is slightly off. There is no real pattern. My problem is I'm a broken man when it comes to dealing with tech support. Several times I have made it to the engineer level for major prolems I have found. It is exhausting. The amount of "my time" I need to dedicate to just get to the right level/person is crazy.  

Posted by
Gold Problem Solver

Message 8 of 67
5,393 Views
For those having audio sync issues, it is very important that you check to see if there are any firmware updates for your TV.

That being said, I recently noticed the audio sync is slightly off on the local ABC channel here in the Twin Cities. It seems to happen on local and national feeds.
Posted by
Frequent Visitor

Message 9 of 67
5,388 Views

I understand the suggestions about updating firmware on a tv but that is not the issue here. Yes TV is an older model but the fact is it has been working fine for years and then all of a sudden it started happening. Again, we can all guess a firmware update to the X1 box was the change. Now, if Xfinity's solution is to upgrade firmware on a TV (which not all companies provide) then we are going to have big problems. Make your product work like it did before with the devices on the market. See, this is why I dread calling, I have to get through all the "silly" questions and solutions they will put me through. AHHHHHHH! lol

Posted by
Gold Problem Solver

Message 10 of 67
5,384 Views
Actually,

Other forum members have reported in the past that updating TV firmware helped with this issue...

I understand what you are saying but that thinking doesn't apply here because we are talking about HDMI and X1 boxes have a questionable history with HDMI. You can't rule out anything until the problem is fixed.
Posted by
Frequent Visitor

Message 11 of 67
5,368 Views

OK, I see why you say this and would normally agree. Why are my recordings out of sync? This is on all TVs in my house.

(yes I realized I forgot to mention this small piece of important info, sry)

Posted by
Regular Contributor

Message 12 of 67
5,358 Views

This is NOT a TV firmware issue.

Posted by
Frequent Visitor

Message 13 of 67
5,356 Views

I completey agree with MrScott1!!!!

Posted by
Gold Problem Solver

Message 14 of 67
5,346 Views

Now that you posted more helpful details, I agree. Based on the original information you posted, firmware was a possibility. I agree that it is not now.

I can assure you that updating TV firmware has helped other forum members with this issue.

Good luck resolving it.



jgalego wrote:

OK, I see why you say this and would normally agree. Why are my recordings out of sync? This is on all TVs in my house.

(yes I realized I forgot to mention this small piece of important info, sry)




Posted by
Contributor

Message 15 of 67
5,266 Views

My old SA 4250 HDC box died. Took it to the Xfinity store and was given an X1 non DVR box. My set up involves a Bluray Player, Apple TV , Cable Card device driving a Windows Media Center DVR and a Cable Box. All components connect to a Sony Hometheater Receiver via HDMI or Component. The Receiver handles all audio and sends the video via HDMI to a Panansonic 50in tv.

 

Aside from the new X1 box not having the setup capabilities of the old box like pass through it has a better picture. However after a few days , depending on the channel, the audio becomes out of sync with the video. This rarely ever happpended with the old box and never happens with my other equipment running through the same set up. Therefore the issue is an X1 problem unique to itself. Resetting it helps, hitting it from the office helps but over time it gets so annoying that I am convinced that any claims that issues is actually solved are false.

 

Some observations. Off Air HD channels from the networks through the x1 box DO NOT HAVE THE PROBLEM. SD Cable Networks that are not also shown in HD , do not seem to have the sysnc issue as badly. The channels with the greatest sync problem are those HD Cable Channels where local advertising is inserted often. Much of this is old low tech SD 4;3 stuff and looks awful on an hd tv. When the boxes had pass through these format changes would cause chirps and drop outs when they came on because the receiver had to rescale during the commercial.Only fix was to keep the box on 1080I and live with the obnoxious stretch look or be satisfied with half sized pictures with alll border black barred.

 

Hence i think this may be why they ended  pass through on the new boxes. So the X1 box is now handling all of these scaling issues and it may not be robust enought to handle repetitive format changes that happen when SD or even multi format commercials are inserted and they start to develop a lag issue. Just a theory but my observations suggest something in this area is going on.

Posted by
Service Expert

Message 16 of 67
5,238 Views

Strange.  I have three X1 DVRs, two XG2 companions, and one Xi3 companion.  None of them have an "audio out-f-sync issue",




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Posted by
Contributor

Message 17 of 67
5,223 Views

There is so much sync delay on my x1 today that it is not watchable on some channels. Also your cable system and mine may use different signal processing techniques prior to a signals arrival at the home. Google is my freind and i have tried every single piece of Internet Voodoo to solve the issue. I stand by my initial conclusions. X1 has sync issues none of my other devices have when routed identically through my setup. Nor did i have this issue with the older non X1 4250hdc, it is clearly variable by channel, worse on channels where there is local ad insertions, worse on HD cable channels and barely detectable on the local network stations.A simple channel surf bears this out. It is also not happening on my cable card device which is routed through the same Hometheater set up as the X1 cable box. Its is obviously anX1 issue.

 

There is a seroius flaw in the X1 system that they need to rectify. It not the superior experience as the advertising boasts. Multiple box resets are getting old and the front line staff telling me to rewire my setup which is built into a cabinet , or do another box swap, simply means they are not listenting to me and are reciting their solutions from rote.

Posted by
Gold Problem Solver

Message 18 of 67
5,219 Views

If your X1 box is resetting, that means it is struggling with deficient incoming and or outgoing signal levels.

You can either search this forum to learn how to rectify the problem or have Comcast a tech out to troubleshoot. Signal related issues are discussed quite often in this forum.

FYI, X1 boxes have entirely different signal requirements than legacy boxes do. Just because a legacy box worked for you is no guaranty an X1 box will work.



randyhouse wrote:

There is so much sync delay on my x1 today that it is not watchable on some channels. Also your cable system and mine may use different signal processing techniques prior to a signals arrival at the home. Google is my freind and i have tried every single piece of Internet Voodoo to solve the issue. I stand by my initial conclusions. X1 has sync issues none of my other devices have when routed identically through my setup. Nor did i have this issue with the older non X1 4250hdc, it is clearly variable by channel, worse on channels where there is local ad insertions, worse on HD cable channels and barely detectable on the local network stations.A simple channel surf bears this out. It is also not happening on my cable card device which is routed through the same Hometheater set up as the X1 cable box. Its is obviously anX1 issue.

 

There is a seroius flaw in the X1 system that they need to rectify. It not the superior experience as the advertising boasts. Multiple box resets are getting old and the front line staff telling me to rewire my setup which is built into a cabinet , or do another box swap, simply means they are not listenting to me and are reciting their solutions from rote.





Posted by
Contributor

Message 19 of 67
5,210 Views

I am not having to reset my box as would occur with no picture. I am resetting it to reduce the sound lag issue per the Comcast telephone people's instructions when i call in. Picture is fine all channels are coming in. Its the audio delay. Since you brought it up, what exactly is the technical difference with X1.I am a retired  cable tv engineer so do not hold back on a detailed explanation. Is each channel an IP based stream as opposed to a discrete Qam broadcast? If so, why would my Apple Tv services not have a lag in their audio also. X1 seems for me to be more like marketing hype , simply more of modern looking guide and navigator than a new or better technology. It seems to be less robust worse at error correction than the older Qam boxes. Also, should i simply insist on a trouble call, whcih will no doubt involve another box swap?

Posted by
Service Expert

Message 20 of 67
5,202 Views

randyhouse wrote:

There is so much sync delay on my x1 today that it is not watchable on some channels. Also your cable system and mine may use different signal processing techniques prior to a signals arrival at the home. Google is my freind and i have tried every single piece of Internet Voodoo to solve the issue. I stand by my initial conclusions. X1 has sync issues none of my other devices have when routed identically through my setup. Nor did i have this issue with the older non X1 4250hdc, it is clearly variable by channel, worse on channels where there is local ad insertions, worse on HD cable channels and barely detectable on the local network stations.A simple channel surf bears this out. It is also not happening on my cable card device which is routed through the same Hometheater set up as the X1 cable box. Its is obviously anX1 issue.

 

There is a seroius flaw in the X1 system that they need to rectify. It not the superior experience as the advertising boasts. Multiple box resets are getting old and the front line staff telling me to rewire my setup which is built into a cabinet , or do another box swap, simply means they are not listenting to me and are reciting their solutions from rote.


you are posting in the X1 forum do you have the Cloud DVR enabled? If so use site xtv.comcast.net or on a smart device the xfinity TV app. watch the same 'show' and see if you have the same issue. This test doesn't use your home X1 set top boxes.




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Posted by
Contributor

Message 21 of 67
5,196 Views

i do not have the dvr service. simply a non dvr x1 box rng150n i believe. Large blue light, 

 

Posted by
Contributor

Message 22 of 67
5,194 Views

My dvr is a scratch built Windows Media Center PC and a Silicon Dust HD Homerun Prime cable card tuner. Cable Card is authorized by Comcast. Media Center connects to one of my Hometheater receiver's  HDMI inputs. Cable Card Tuner is hard wired to ethernet within the house so up to three devices can tune cable channels without having to rent another box. It is all legal.Kodi or media center extenders all work fine. Same with Iphone. I can A/B the picture from the Media Center and the X1 non DVR on the same Panasonic 50 in. TV. Only the X1 has the delay issues to the point they are intolerable. Like I said, X 1 seems to not be very robust and the delay factors appear to be unique to it.

Posted by
Service Expert

Message 23 of 67
5,171 Views

randyhouse wrote:

My old SA 4250 HDC box died. Took it to the Xfinity store and was given an X1 non DVR box. My set up involves a Bluray Player, Apple TV , Cable Card device driving a Windows Media Center DVR and a Cable Box. All components connect to a Sony Hometheater Receiver via HDMI or Component. The Receiver handles all audio and sends the video via HDMI to a Panansonic 50in tv.

 

Aside from the new X1 box not having the setup capabilities of the old box like pass through it has a better picture. However after a few days , depending on the channel, the audio becomes out of sync with the video. This rarely ever happpended with the old box and never happens with my other equipment running through the same set up. Therefore the issue is an X1 problem unique to itself. Resetting it helps, hitting it from the office helps but over time it gets so annoying that I am convinced that any claims that issues is actually solved are false.

 

Some observations. Off Air HD channels from the networks through the x1 box DO NOT HAVE THE PROBLEM. SD Cable Networks that are not also shown in HD , do not seem to have the sysnc issue as badly. The channels with the greatest sync problem are those HD Cable Channels where local advertising is inserted often. Much of this is old low tech SD 4;3 stuff and looks awful on an hd tv. When the boxes had pass through these format changes would cause chirps and drop outs when they came on because the receiver had to rescale during the commercial.Only fix was to keep the box on 1080I and live with the obnoxious stretch look or be satisfied with half sized pictures with alll border black barred.

 

Hence i think this may be why they ended  pass through on the new boxes. So the X1 box is now handling all of these scaling issues and it may not be robust enought to handle repetitive format changes that happen when SD or even multi format commercials are inserted and they start to develop a lag issue. Just a theory but my observations suggest something in this area is going on.


local channels (HD) will (I read on other sites) be in mpeg2 so as not to have to do transcoding, and that may be the difference. You didn't say which x1 non-DVR box you got nor if you have x1 service (with internet). If your guide is dark with white letters it is indeed x1. If multi-colored you may have an X2 that is actually in "DTA" mode. Would like to actually know what you have. 

 

Do you have access to the https://tv.xfinity.com site to view tv in your home?

 

 




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Posted by
Service Expert

Message 24 of 67
5,165 Views

randyhouse wrote:

I am not having to reset my box as would occur with no picture. I am resetting it to reduce the sound lag issue per the Comcast telephone people's instructions when i call in. Picture is fine all channels are coming in. Its the audio delay. Since you brought it up, what exactly is the technical difference with X1.I am a retired  cable tv engineer so do not hold back on a detailed explanation. Is each channel an IP based stream as opposed to a discrete Qam broadcast? If so, why would my Apple Tv services not have a lag in their audio also. X1 seems for me to be more like marketing hype , simply more of modern looking guide and navigator than a new or better technology. It seems to be less robust worse at error correction than the older Qam boxes. Also, should i simply insist on a trouble call, whcih will no doubt involve another box swap?


randy sorry I missed that tech question. x1 with STB is all QAM, lots of rumors about IP but nothing from comcast. The current conversion to mpeg4 from mpeg2 is apparently first step toward all the features mpeg4 suppports like control stream adding ability for all kind of meta data (ATMOS, AFD, others I haven't yet memorized). It appears from reading elsewhere mpeg4 also supports more security demanded by the MPA etc. and comcast appears to be upgrading/transitioning to DoCSiS 3.1 for the same reason.  The local broadcast channels (again read elsewhere) are going to be in mpeg2 while others will be in mpeg4 for HD and mpeg2 for SD. based on that the same shows in SD and HD on the DVR wouild take up almost exactly the same amount of room. As you know the QAM has multi-channels in each QAM channel band. 

 

Hope I covered the items you wanted.




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Posted by
Contributor

Message 25 of 67
5,157 Views

Thanks for the response. So x1 and the older boxes are tuning the same Qam frequency? Makes sense from a bandwidth standpoint.I am having a service call on Tuesday. It seems that there are some "errors" occuring. Either it got worse or X1 is not as robust or I had the problem all along and the Comcast phone people were just doing the usual box swap from rote when i was told to swap out the 4250 hdc. Hopefully the service call fixes the problem. I will suggest to the tech that they look into the ad insertion issue. When an ad pops up in a differnent format, aspect ratio, or resolution, there seems to be some latency issues as whatever device tries to handle it , has to reset picture and the sound. If the right scaling was used at the head end,and on the inserted ads, no variations, no equipment in the home would be forced to compensate, if that makes sense?

Posted by
Service Expert

Message 26 of 67
5,147 Views

randyhouse wrote:

Thanks for the response. So x1 and the older boxes are tuning the same Qam frequency? Makes sense from a bandwidth standpoint.I am having a service call on Tuesday. It seems that there are some "errors" occuring. Either it got worse or X1 is not as robust or I had the problem all along and the Comcast phone people were just doing the usual box swap from rote when i was told to swap out the 4250 hdc. Hopefully the service call fixes the problem. I will suggest to the tech that they look into the ad insertion issue. When an ad pops up in a differnent format, aspect ratio, or resolution, there seems to be some latency issues as whatever device tries to handle it , has to reset picture and the sound. If the right scaling was used at the head end,and on the inserted ads, no variations, no equipment in the home would be forced to compensate, if that makes sense?


x1 STBs have a diagnostic system available. watching live TV press and hold exit for 3 seconds or so then quickly press DOWN DOWN 2 --- in a few seconds you will get a white popover screen from the firmware. Press OK and when UI updates press down to see your in-band channels with standard dbmv power levels and type of modulation. press down again to get errors if any on the streams. next 'down' will show you the set top box's DoCSiS info used for streaming and apps and contact with comcast servers. the smaller xi3/xiD devices use the DoCSiS of either an X1 DVR or X2 set top box. MoCA is last setting in list and is for the anyroom service and for Xi3/XiD device communication.

 

the change causing issues currently is transition from mpeg2 to mpeg4 and older STBs decoding capability. the last thing you are describing if on SD channels is probably AFD command processing.




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Posted by
Contributor

Message 27 of 67
5,137 Views

Guide Black with white letters. Channel logos are in color, box has both HDMI and Component Outputs. I have internet and phone via my own modem router combination. There is another non x1 box in the house, (old blue guide) plus a DTA.

Posted by
Contributor

Message 28 of 67
5,099 Views

Since my last post , I have had a service call.  I was able to A/B the Homerun Prime/ WMC picture with the one from the X1 and the Tech said he could clearly see the audio sync issue.The Tech then told me an X1 box cannot co exist with a cable card device. Of course if you look through the vents on the X1 you will see a Cable Card inside as you will with the older boxes. Some research indicates that the real Cable Card issue is that certain cable card devices, like older HDTivos, only will decode mpeg2 and cant handle the MPEG4 streams that Comcast is transitioning to. So if this is actualy their policy, the staff at the Xfinity store made a mistake swapping out my old SA 4250 hdc with an X1, because a Cable Card is clearly shown on my account. They should have sent me home with a Cisco non X1 older blue menu "legacy" box. Apparently these also cannot co-exist with X1 because of the X1 MOCA circuit .The older box's return signals apparently cause issues with the X1.For X1 there are supposed to be filters at the entry point to keep the the MOCA data from leaving the house back through the network or getting data from other homes and each X1 box must have a dedicated line back to the entry point of the house so that the MOCA delivered video from the DVR, which I do not subscribe to can stream to the non dvr X1 boxes elsewhere in the house.

 

So the tech checked signals, installed a filter , replaced a splitter , and isolated the X1 box so that it was directly fed from the street. Everything else in my house was out of the circuit. Twice the box froze on the loading channel logo. And the sound sync issues remained. 

 

The solution? The tech removed the more advanced X1 box and Installed an older legacy box of the type I should have been given in the first place. Has not dropped out and no sync issues.

 

So this is my take. Comcast is rolling out MPEG4 HD because it more compressed, and allows more HD channels in the same bandwidth. This saves them money and is a more efficient transport. In order to do this the X1 boxes must have the abiltity to decode both MPEG2 and MPEG4. The Mpeg2 compatibilty is " a legacy feature" that will eventually be phased out. Mpeg4 decoding however is more processor intensive and this what the box must handle. They also need to compete with the advanced whole house features of Direct TV and Tivo hence the MOCA feature. By hypeing X1, selling dedicated X1 installations, in effect a system upgrade occurs. Eventually a critical mass is reached. However it is obvious that the the existing wiring of ones house and legacy equipment plays a role in the quality of the X1 experience. (I pay extra for wiring insurance) It is also clear that front line Xfinity store and CSRs on the phone need a lot more training so that the wrong box does not go into the wrong house. But even more so it seems that the network itself is not quite ready for x1 or the boxes themselves are not as robust as the older ones and require a much tighter system from their Head end to my house for it to work properly. 

Posted by
Service Expert

Message 29 of 67
5,057 Views

randyhouse wrote:

Since my last post , I have had a service call.  I was able to A/B the Homerun Prime/ WMC picture with the one from the X1 and the Tech said he could clearly see the audio sync issue.The Tech then told me an X1 box cannot co exist with a cable card device. Of course if you look through the vents on the X1 you will see a Cable Card inside as you will with the older boxes. Some research indicates that the real Cable Card issue is that certain cable card devices, like older HDTivos, only will decode mpeg2 and cant handle the MPEG4 streams that Comcast is transitioning to. So if this is actualy their policy, the staff at the Xfinity store made a mistake swapping out my old SA 4250 hdc with an X1, because a Cable Card is clearly shown on my account. They should have sent me home with a Cisco non X1 older blue menu "legacy" box. Apparently these also cannot co-exist with X1 because of the X1 MOCA circuit .The older box's return signals apparently cause issues with the X1.For X1 there are supposed to be filters at the entry point to keep the the MOCA data from leaving the house back through the network or getting data from other homes and each X1 box must have a dedicated line back to the entry point of the house so that the MOCA delivered video from the DVR, which I do not subscribe to can stream to the non dvr X1 boxes elsewhere in the house.

 

So the tech checked signals, installed a filter , replaced a splitter , and isolated the X1 box so that it was directly fed from the street. Everything else in my house was out of the circuit. Twice the box froze on the loading channel logo. And the sound sync issues remained. 

 

The solution? The tech removed the more advanced X1 box and Installed an older legacy box of the type I should have been given in the first place. Has not dropped out and no sync issues.

 

So this is my take. Comcast is rolling out MPEG4 HD because it more compressed, and allows more HD channels in the same bandwidth. This saves them money and is a more efficient transport. In order to do this the X1 boxes must have the abiltity to decode both MPEG2 and MPEG4. The Mpeg2 compatibilty is " a legacy feature" that will eventually be phased out. Mpeg4 decoding however is more processor intensive and this what the box must handle. They also need to compete with the advanced whole house features of Direct TV and Tivo hence the MOCA feature. By hypeing X1, selling dedicated X1 installations, in effect a system upgrade occurs. Eventually a critical mass is reached. However it is obvious that the the existing wiring of ones house and legacy equipment plays a role in the quality of the X1 experience. (I pay extra for wiring insurance) It is also clear that front line Xfinity store and CSRs on the phone need a lot more training so that the wrong box does not go into the wrong house. But even more so it seems that the network itself is not quite ready for x1 or the boxes themselves are not as robust as the older ones and require a much tighter system from their Head end to my house for it to work properly. 


new formats (4k 8k UHD ATMOS etc) are on the way. mpeg2 cannot handle the newer format so must be updated. mpeg4 will only be used for HD and above service, mpeg2 will continue to be used for local broadcast channels and SD channels. Thats all the info I have on it.

 

re: cablecard it is much more likely that the device the card is inserted in needs to have a firmware update or the device replaced for an updated technology unit.




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Message 30 of 67
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Same issues here.  Video/audio sync issues on all tv's (all of which are one year old, so rather new sets and smartTVs).  One is on the large X1 set top and the others are on the small boxes.  The channels are random but I've noticed it a lot more within the past 2 weeks or so.  It's ridiculous.  I want to check with my mother who has had DirectTV for years and see if she ever encounters this frustrating issue.  It makes me want to pop in a DVD, and if I start doing that regularly, I guess I don't need cable anymore.  Fix the problems and stop raising my rates!

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Message 31 of 67
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jonathanruby wrote:

Same issues here.  Video/audio sync issues on all tv's (all of which are one year old, so rather new sets and smartTVs).  One is on the large X1 set top and the others are on the small boxes.  The channels are random but I've noticed it a lot more within the past 2 weeks or so.  It's ridiculous.  I want to check with my mother who has had DirectTV for years and see if she ever encounters this frustrating issue.  It makes me want to pop in a DVD, and if I start doing that regularly, I guess I don't need cable anymore.  Fix the problems and stop raising my rates!


Thank goodness I have never had an audio sync isssue with any of my six TV's; I can't think why some people have it, unless it is an issue with the Comcast headend/connection.




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Message 32 of 67
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mpeg has streams for audio, video, closed captions, control information (to keep it all in sync). The audio has 2 syncs one keeps it in a few milliseconds and the 'backup' failsafe keeps it within less than 1/2 second (resync).  If the sound/lip sync is off on broadcast channels on an actual XG1 or XG2 the TV should have an adjustment to +/- the audio to the picture to make the sync match. 

 

keep in mind that the sync process is done at the point a signal is encoded. In the past there have been firmware issues that caused a problem but they were fixed long ago.

 

will you try the tv sync and post back if that fixed the problem?




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Posted by
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Message 33 of 67
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Rustyben wrote:

mpeg has streams for audio, video, closed captions, control information (to keep it all in sync). The audio has 2 syncs one keeps it in a few milliseconds and the 'backup' failsafe keeps it within less than 1/2 second (resync).  If the sound/lip sync is off on broadcast channels on an actual XG1 or XG2 the TV should have an adjustment to +/- the audio to the picture to make the sync match. 

 

keep in mind that the sync process is done at the point a signal is encoded. In the past there have been firmware issues that caused a problem but they were fixed long ago.

 

will you try the tv sync and post back if that fixed the problem?


Adjusting some setting on the tv will not fix the problem, just mask it.

 

When is the signal encoded you are talking about? Supplier, comcast transmit, cable box?

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Message 34 of 67
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mvenanzi wrote:

Rustyben wrote:

mpeg has streams for audio, video, closed captions, control information (to keep it all in sync). The audio has 2 syncs one keeps it in a few milliseconds and the 'backup' failsafe keeps it within less than 1/2 second (resync).  If the sound/lip sync is off on broadcast channels on an actual XG1 or XG2 the TV should have an adjustment to +/- the audio to the picture to make the sync match. 

 

keep in mind that the sync process is done at the point a signal is encoded. In the past there have been firmware issues that caused a problem but they were fixed long ago.

 

will you try the tv sync and post back if that fixed the problem?


Adjusting some setting on the tv will not fix the problem, just mask it.

 

When is the signal encoded you are talking about? Supplier, comcast transmit, cable box?


adjustting the TV setting will adjust the permanent offset, it does not mask it. 

 

the sync is part of the encoding of mpeg, and is done at point of encoding or at a later point of transcoding. Since CC must also be done by the producer the point is usually done as part of final product output by the producer.




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Posted by
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Message 35 of 67
4,899 Views

Tread carefully on this comment Rusty and please provide your documentation to back this up.



Rustyben wrote:

mvenanzi wrote:

Rustyben wrote:

mpeg has streams for audio, video, closed captions, control information (to keep it all in sync). The audio has 2 syncs one keeps it in a few milliseconds and the 'backup' failsafe keeps it within less than 1/2 second (resync).  If the sound/lip sync is off on broadcast channels on an actual XG1 or XG2 the TV should have an adjustment to +/- the audio to the picture to make the sync match. 

 

keep in mind that the sync process is done at the point a signal is encoded. In the past there have been firmware issues that caused a problem but they were fixed long ago.

 

will you try the tv sync and post back if that fixed the problem?


Adjusting some setting on the tv will not fix the problem, just mask it.

 

When is the signal encoded you are talking about? Supplier, comcast transmit, cable box?


adjustting the TV setting will adjust the permanent offset, it does not mask it. 

 

the sync is part of the encoding of mpeg, and is done at point of encoding or at a later point of transcoding. Since CC must also be done by the producer the point is usually done as part of final product output by the producer.


 

Posted by
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Message 36 of 67
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Rustyben wrote:

mvenanzi wrote:

Rustyben wrote:

mpeg has streams for audio, video, closed captions, control information (to keep it all in sync). The audio has 2 syncs one keeps it in a few milliseconds and the 'backup' failsafe keeps it within less than 1/2 second (resync).  If the sound/lip sync is off on broadcast channels on an actual XG1 or XG2 the TV should have an adjustment to +/- the audio to the picture to make the sync match. 

 

keep in mind that the sync process is done at the point a signal is encoded. In the past there have been firmware issues that caused a problem but they were fixed long ago.

 

will you try the tv sync and post back if that fixed the problem?


Adjusting some setting on the tv will not fix the problem, just mask it.

 

When is the signal encoded you are talking about? Supplier, comcast transmit, cable box?


adjustting the TV setting will adjust the permanent offset, it does not mask it. 

 

the sync is part of the encoding of mpeg, and is done at point of encoding or at a later point of transcoding. Since CC must also be done by the producer the point is usually done as part of final product output by the producer.


Of course it masks it, it only happens on some channels and at some times. If we adjust are tvs (if we could) what happens when it stops happening or change to a channel that doesn't have the problem?

 

If the producer (or supplier) is creating the sync problem then we should all have the problem on the same channels at the same time. This doesn't seem to be the case from what I've read here

Posted by
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Message 37 of 67
4,874 Views

RickGr4 wrote:

Tread carefully on this comment Rusty and please provide your documentation to back this up.



Rustyben wrote:

mvenanzi wrote:

Rustyben wrote:

mpeg has streams for audio, video, closed captions, control information (to keep it all in sync). The audio has 2 syncs one keeps it in a few milliseconds and the 'backup' failsafe keeps it within less than 1/2 second (resync).  If the sound/lip sync is off on broadcast channels on an actual XG1 or XG2 the TV should have an adjustment to +/- the audio to the picture to make the sync match. 

 

keep in mind that the sync process is done at the point a signal is encoded. In the past there have been firmware issues that caused a problem but they were fixed long ago.

 

will you try the tv sync and post back if that fixed the problem?


Adjusting some setting on the tv will not fix the problem, just mask it.

 

When is the signal encoded you are talking about? Supplier, comcast transmit, cable box?


adjustting the TV setting will adjust the permanent offset, it does not mask it. 

 

the sync is part of the encoding of mpeg, and is done at point of encoding or at a later point of transcoding. Since CC must also be done by the producer the point is usually done as part of final product output by the producer. 


rick, you want me to tutor on what encoding is and the tech aspects of it? enjoy reading via google search.




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Posted by
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Message 38 of 67
4,872 Views

mvenanzi wrote:

Rustyben wrote:

mvenanzi wrote:

Rustyben wrote:

mpeg has streams for audio, video, closed captions, control information (to keep it all in sync). The audio has 2 syncs one keeps it in a few milliseconds and the 'backup' failsafe keeps it within less than 1/2 second (resync).  If the sound/lip sync is off on broadcast channels on an actual XG1 or XG2 the TV should have an adjustment to +/- the audio to the picture to make the sync match. 

 

keep in mind that the sync process is done at the point a signal is encoded. In the past there have been firmware issues that caused a problem but they were fixed long ago.

 

will you try the tv sync and post back if that fixed the problem?


Adjusting some setting on the tv will not fix the problem, just mask it.

 

When is the signal encoded you are talking about? Supplier, comcast transmit, cable box?


adjustting the TV setting will adjust the permanent offset, it does not mask it. 

 

the sync is part of the encoding of mpeg, and is done at point of encoding or at a later point of transcoding. Since CC must also be done by the producer the point is usually done as part of final product output by the producer.


Of course it masks it, it only happens on some channels and at some times. If we adjust are tvs (if we could) what happens when it stops happening or change to a channel that doesn't have the problem?

 

If the producer (or supplier) is creating the sync problem then we should all have the problem on the same channels at the same time. This doesn't seem to be the case from what I've read here


the TV manufactuers know there are many reasons to allow adjustments due to signal processing. Even the old NTSC TV sets had to have a video 'delay line' to allow processing of chroma (color information) before the video (black and white info) was mixed with the color signal. the sound processing a +/- to the video is just recognizing technology in use to be able to correctly matchup the processing. 

 

adjusting the timing of audio arrival is similar to adjusting the video to match a reference 'image' to allow proper settings of brightness, contrast, backlight-level, sharpness, gamma to get a balanced image reproduction of what the producers created for you to watch. 




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Posted by
Problem Solver

Message 39 of 67
4,860 Views

Rustyben wrote:

mvenanzi wrote:

Rustyben wrote:

adjustting the TV setting will adjust the permanent offset, it does not mask it. 

 

the sync is part of the encoding of mpeg, and is done at point of encoding or at a later point of transcoding. Since CC must also be done by the producer the point is usually done as part of final product output by the producer.


Of course it masks it, it only happens on some channels and at some times. If we adjust are tvs (if we could) what happens when it stops happening or change to a channel that doesn't have the problem?

 

If the producer (or supplier) is creating the sync problem then we should all have the problem on the same channels at the same time. This doesn't seem to be the case from what I've read here


the TV manufactuers know there are many reasons to allow adjustments due to signal processing. Even the old NTSC TV sets had to have a video 'delay line' to allow processing of chroma (color information) before the video (black and white info) was mixed with the color signal. the sound processing a +/- to the video is just recognizing technology in use to be able to correctly matchup the processing. 

 

adjusting the timing of audio arrival is similar to adjusting the video to match a reference 'image' to allow proper settings of brightness, contrast, backlight-level, sharpness, gamma to get a balanced image reproduction of what the producers created for you to watch. 


Adjusting audio sync using the tv setting will only be useful if it happened on all channels all the time, this is NOT the case here. This has been a occasional problem with comcast service for at least a few years based on forum history.

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Message 40 of 67
4,846 Views
The last two weeks have been the worst ever and is random per channel.
Setup is X1 DVR from March 2016.
Yamaha RX-A760
Toshiba 40"

While viewing a program (any HD channel) the sync starts off ok and drifts to point of ~1/2 sec lag of video behind audio. Turning off the X1 usually helps and makes the program watchable. Then over the next 40min it drifts off and becomes unbearable until X1 is reset.

A760 has video processing turned off.
TV is in Sports Mode at 1080P.
X1 is set to 1080P IIRC.

All efforts to reduce video processing have been implemented and the video lags at varying rates. It seems worse at night when perhaps more people are using more bandwidth.

What changed in the last 2 to 3 weeks?
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Message 41 of 67
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Posted by
Gold Problem Solver

Message 42 of 67
4,831 Views

The part of this that rusty seems to be missing is:

1. As others have said, any application of "sync adjustment" is global and effects all channels equally. This simply doesn't work.

2. With most audio sync issues, the audio is behind the video. In the case of X1, the audio is often ahead of the video. At least it is on ABC. A vast majority of today's AV products only allow sync adjustments when the audio is behind.

3. Then we bring in the "elephant in the room".  What is the audio system? TV speakers? Soundbar? 5.1 Audio Video system? How is everything connected???

4. It should be noted that I have 3 X1 boxes which are connected to external audio systems. The two systems I have which are connected fully HDMI with late model AV receivers don't give me any audio sync issues. The one system I have in my house that requires a TOSLINK digital audio connection is the one I notice the audio sync problems on.


Yes, there is a problem with X1 audio sync. I have a couple ideas where the problem might be. I notice it but I am not losing sleep over it. However I own some decent quality AV gear and that probably has something to do with why I do not have serious complaints about the audio sync issue...

Rusty is a bright guy and he certainly understands the technology, but I am very concerned that he has any "real world, field experience" with these issues. I am also wondering if he owns a TV and AV gear good enough to be in a position to reliably evaluate any of these concerns.

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Message 43 of 67
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I am sorry for the late response. Correct me if i am wrong. Since i have a media center PC with a homebrew DVr, a bluray player and Apple tv, plus a cable box, all sourced by HDMI, and only the cable box has sync issues, if I adjust the delay via the tv or home theater receiver, all of the other devices except the cable box will be out of sync. By fixing the cable, I would cause the other sources to lose sync. Not a viable fix in my book. So a sync problem can be source specific.The problem is in the X1 platform no doubt about it. After an hours work the tech simply installed  a legacy box and it went away. No delay adjustments were needed and all devices running into the common receiver and TV now work fine. I think there may an error correction  issue andor  lack of cpu  power and it builds up over time. This may be why an X1 box reset fixes the issue for a short period of time.

 

Since my last posts I had major pixelization on all channels, all TVS. Slow internet also. Service techs replaced drop, made new connectors. Problem persisted.A few days later, at my insistance, a sweep tech ran the problem down and fixed it somewhere in the system. Plant maintenance  fixed a high error rate. Coincidental or the original source of all the problems including X1?

Posted by
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Message 44 of 67
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randyhouse wrote:

I am sorry for the late response. Correct me if i am wrong. Since i have a media center PC with a homebrew DVr, a bluray player and Apple tv, plus a cable box, all sourced by HDMI, and only the cable box has sync issues, if I adjust the delay via the tv or home theater receiver, all of the other devices except the cable box will be out of sync. By fixing the cable, I would cause the other sources to lose sync. Not a viable fix in my book. So a sync problem can be source specific.The problem is in the X1 platform no doubt about it. After an hours work the tech simply installed  a legacy box and it went away. No delay adjustments were needed and all devices running into the common receiver and TV now work fine. I think there may an error correction  issue andor  lack of cpu  power and it builds up over time. This may be why an X1 box reset fixes the issue for a short period of time.

 

Since my last posts I had major pixelization on all channels, all TVS. Slow internet also. Service techs replaced drop, made new connectors. Problem persisted.A few days later, at my insistance, a sweep tech ran the problem down and fixed it somewhere in the system. Plant maintenance  fixed a high error rate. Coincidental or the original source of all the problems including X1?


if you have the cloud DVR enabled, play back a recording using a smart device or desk/laptop. Is it out of sync when playing back there too? Did you try a direct HDMI connection to the TV and with the TV sound 'up' is it out of sync there? Probably a good idea to narrow down at what point the mismatch begins happening.




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Posted by
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Message 45 of 67
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I am pretty sure this is an audio stream decode issue. I don't notice it when playing remote (to a computer), only when playing a show from a DVR (live or recorded).

I am set for surround sound. And it's worth noting that if I set the sound for stereo and the issue goes away.

Now I'm not sure why I just started noticing it in the last month or so. I swear it wasn't like this over the summer. I work for a video tech company and I'm pretty sensitive to audio video sync (I'll see two to three frames off). This is way beyond this.

I honestly don't remember this being the case before. Seems like a new thing. But even if it isn't, why are we still having these issues. Surround sound decode should be trivial now.

Oh, I have a X1 unit.
All devices connected to an AVR unit (which does have an audio offset, but as others have said it's not consistent on all channels). No Audi issues on Xbox one and 360 or Blu-ray player or popcorn hour. All play with perfect sync. Just not the Xfinity "advanced" set top box.

Joshua
Posted by
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Message 46 of 67
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Scimitar19 wrote:
I am pretty sure this is an audio stream decode issue. I don't notice it when playing remote (to a computer), only when playing a show from a DVR (live or recorded).

I am set for surround sound. And it's worth noting that if I set the sound for stereo and the issue goes away.

Now I'm not sure why I just started noticing it in the last month or so. I swear it wasn't like this over the summer. I work for a video tech company and I'm pretty sensitive to audio video sync (I'll see two to three frames off). This is way beyond this.

I honestly don't remember this being the case before. Seems like a new thing. But even if it isn't, why are we still having these issues. Surround sound decode should be trivial now.

Oh, I have a X1 unit.
All devices connected to an AVR unit (which does have an audio offset, but as others have said it's not consistent on all channels). No Audi issues on Xbox one and 360 or Blu-ray player or popcorn hour. All play with perfect sync. Just not the Xfinity "advanced" set top box.

Joshua

Since you are experiencing this issue and I am not with any of my six X1 boxes (one of which goes through my a/v receiver), it appears TO ME that the issue is equipment-related in some way.

 

There have been many threads started about this issue so it is real - I am concerned that Comcast can't fix the issue for every user because their equipment can't reproduce every user's configuration.

 

 




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Posted by
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Message 47 of 67
4,174 Views

Just to weigh in I have also noticed the "Lip Sync" issues on certain channels more Premium channels like HBO & STARZ. I'm using Arris x1 and Vizio 4251 sound bar with Surround

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Message 48 of 67
3,825 Views

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.

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 since you're just installing better decode instructions to make up for the mess that the cable box is sending out. 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? And you've swapped boxes and wires and whatever..

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. And it would be even better if comcast gave us boxes with the power and programming to just work plain and simple but that seems to not be the case.

Sorry MrScott1 but my original conclusion stands.

Posted by
Regular Contributor

Message 49 of 67
3,779 Views

Not so fast there. Not all of us run our audio through our TV. Might want to read more of this thread before you render your judgemenmt on your post #1

Posted by
Frequent Visitor

Message 50 of 67
3,746 Views

Hi there fellow unhappy comcast customer. I'm well aware that we don't all use the same hardware and what works on 1 guys setup may not work on another... and I've edited my post several times as I've been going thru troubleshooting, researching, and trying to resolve this issue.

I'm not one who normally posts anything online but the audio sync has really been tickin me off so this seemed like a good place to let others know what my experience has been so far and maybe get some helpful feedback.