# Discussion of Bug: Audio and Video Sync



## precon1 (Jan 4, 2004)

Jason,

Have you ever had anyone complain about the 811 voice not always following the video. The audio delayed a little on the OTA signal?


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## Ron Barry (Dec 10, 2002)

From time to time I have seen reports. If I recall they are usually short lived and tracked back to a content delivery issue. Are you seeing this on a particular channel? How Often? Does channel channels fix the sync issue?


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## Jason Nipp (Jun 10, 2004)

Yes their has been many reports of issues with AV sync. In the majority of cases it was occuring on a Digital OTA not Sat Feed. 

Let me ask this, is it thru your TOSLINK /AV Receiver that you see the sync issue or is it on a audio patch to your Display? Most AV Receivers have a delay to adjust for AV sync. All of my receivers have this feature.


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## bhenge (Mar 2, 2005)

Jason Nipp said:


> Most AV Receivers have a delay to adjust for AV sync. All of my receivers have this feature.


Be careful using AV Sync because you can fix one channel and mess up all the others if you forget to adjust it back! BTW, I had a similar AV Sync issue on my local OTA (WRAL Raleigh) and called the OTA station tech guy and they took care of it on their end in about 10 minutes!


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## precon1 (Jan 4, 2004)

Thanks for everyones feedback. The only place that I hear a delay is with over air signal. The satellite feeds are great. I live in Portland, OR.. My wife complained during the Oscars. The audio from that OTA signal was very rich and I think 5.1 sound. I have a bose sound system. (Lifestyle 28) I don't know about an AV sync feature with it. However, I would not want to mess up anything with the satellite feeds.

Jason, in laymens terms what is TOS/Link A/V receiver? 

Sorry! I am new to all of this. 

Thanks,
Doug Walter
precon1


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## Ron Barry (Dec 10, 2002)

precon1 said:


> Thanks for everyones feedback. The only place that I hear a delay is with over air signal. The satellite feeds are great. I live in Portland, OR.. My wife complained during the Oscars. The audio from that OTA signal was very rich and I think 5.1 sound. I have a bose sound system. (Lifestyle 28) I don't know about an AV sync feature with it. However, I would not want to mess up anything with the satellite feeds.
> 
> Jason, in laymens terms what is TOS/Link A/V receiver?
> 
> ...


TOS/Link A/V Receiver is a receiver that has a digital connection available. You link the receiver using this digital cable. This can be through an optical cable or using a coax. Most modern receiver have this capability. THis is the only way to do 5.1 with a Dish Receiver.

As to the Oscars. I watched them using my 811 with OTA and I did not notice any delay what so ever. You might want to crack open your Receiver manual and see what adjustments you have available. My guess is that this might be a configuration issue. Have you watched some 5.1 SAT content?


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## Jason Nipp (Jun 10, 2004)

Welcome aboard precon. The cases I have seen with OTA channels can usually be rid of simply by tuning away and then returning or by doing a softboot. Anything that would require re-acquisition of that OTA channel frequency. In the many discussions on this topic I have had this is caused by error on the broadcaster side. PSIP

There has been a few occurrences of this happening on SHO-HD and HBOE-2, these were resolved after a problem was found at the uplink center.


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## tonyp56 (Apr 26, 2004)

I have seen this on Sat channels too. (Audio through the TV, and A/V receiver turned off. using the 811's optical out to A/V receiver and RCA audio cables from 811 to the DVI input on TV. But the sync problem is with the audio on my TV) The audio sync issues were accompanied by choppy video on the Sat channels, the picture would get choppy, then it would clear up but the audio would be out of sync, only happens on HD channels. Especially TNT-HD, don't know why, but that channel seemed to do it the most, though I've seen the same thing on the others as well.(even after P2.84) Only way to fix it, hold down power button for five seconds and reset the 811. It doesn't go away otherwise, I left my house one day after my 811 did this and I didn't reset my 811, just turned it off, came back two hours later and it was still out-of-sync, reset 811, and it was back to normal.


Please Note: Even on cloudy days, the transponders that the HD channels are on have signal in the mid 90's, so that isn't why my video gets choppy. I've also tested my signal strength when I am experiencing this, I leave it on TNT-HD for example and go to the menu and look at the signal strength for that channel and it is always in the 90's.(what ever channel you are on before doing a signal strength test the transponder that the channel is on is automatically the transponder it checks the signal for) Of course when I get heavy rains I lose signal, but when choppy video/audio sync issues happens my signal is good.


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## HTguy (May 7, 2002)

From DigitalTelevision.com:

SMPTE RFI on Lip Sync Issues
By Staff
Mar 11, 2005, 14:02

There is an increasing awareness, both in broadcasting engineering circles and in the viewing audience, that audio-video synchronization errors in broadcasting, usually seen as problems with lip-sync, are occurring more frequently than they used to and often with greater magnitude. The Society of Motion Picture and Television Engineers S22 Committee on Television Systems Technology has formed an Ad Hoc Group on Lip Sync Issues to review all aspects of this problem and make recommendations for solutions.

SMPTE is therefore issuing this Request for Information from interested companies or individuals, particularly relating to the following areas:

-Sources of differential audio-video delay in television production, post-production, and distribution.
-Audio-video delay issues through professional MPEG encoding and decoding systems.
-Differential audio-video delay arising in consumer receiver, decoding, and display devices.
-Out-of-service methods of measuring differential audio-video delay.
-In-service (during program) methods of measuring differential audio-video delay.
-Devices for correcting differential audio-video delay at different points in the broadcast chain.

It is noted that there is an ATSC Implementation Subcommittee Finding: "Relative Timing of Sound and Vision for Broadcast Operations" (see www.atsc.org/standards/is_191.pdf). There is also an ITU recommendation: ITU-R BT.1359-1, "Relative Timing of Sound and Vision for Broadcasting" (available from www.itu.int/publications/bookshop/index.html). These references are provided for information only and it is noted that some broadcasters have adopted target tolerances for synchronization errors that are smaller than those indicated by the ATSC and ITU.
SMPTE is particularly interested to hear from manufacturers with practical solutions or proposals for measurement and correction of audio-video synchronization errors, and those willing to participate in development of related standards.

Responses should be sent in the first instance, and as soon as possible, to the ad hoc group chair, Graham Jones of NAB at [email protected].

NAB Science and Technology www.nab.org/scitech
ATSC www.atsc.org
SMPTE www.smpte.org


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## khearrean (Mar 24, 2004)

I know I've seen this addressed before, but I can't seem to find the subject in the archives. The other night when watching 'American Idol' via Distant Network Fox Chicago on my 811, I noticed the voices were slightly out of sinc with the video....."annoying to say the least". Unfortunately I didn't change over to another station to see if was limited to Fox or not.
Has anyone else had this experience and is it the network, SAT or an 811 issue?

Ken


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## tampa8 (Mar 30, 2002)

"Unfortunately I didn't change over to another station to see if was limited to Fox or not"

:nono:


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## khearrean (Mar 24, 2004)

tampa8 said:


> "Unfortunately I didn't change over to another station to see if was limited to Fox or not"
> 
> :nono:


Yeah...I know, stupid on my part, but I figured it wouldn't be a good comparison since "Idol" was being broadcast live, so changing to another station which wasn't would not be an 'apples-to-apples' comparison..

Ken


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## Mark Lamutt (Mar 24, 2002)

There have been a lot of reports of audio sync problems with American Idol from a variety of sources around the country, affecting a variety of receivers. It's a source problem, not a specific receiver problem.


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## Jason Nipp (Jun 10, 2004)

New thread merged into an older thread. 

Reason, similar topic.


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## hawki (Mar 9, 2005)

I have had lip sync issues with only the Sat DD Audio channels. All other channels sync fine. When I first tune to a channel with DD the sync is fine ... over time (just minutes) it degrades badly and I usually change channels and then back to re-sync.
It got so annoying that I finally just set my audio on the 811 to Prologic only. I'm hoping P285 will help.


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## Jason Nipp (Jun 10, 2004)

hawki said:


> It got so annoying that I finally just set my audio on the 811 to Prologic only. I'm hoping P285 will help.


I reckon you mean PCM only? What I have learned is that the SPDIF header fix in this rev. has tested out real good and is looking to have resolved this issue for the most part. If there are any remaining incompatibilities, please list the receiver brand and model number in this thread. http://www.dbstalk.com/showthread.php?t=39882


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## jbryant789 (Apr 1, 2005)

This is starting to happen more often, but last night it was really getting on my nerves while I was trying to watch Eliza Duskku on Tru Calling. I had to turn off my receiver 4 times in order to get the a/v to sync. 

Has anyone else been having this problem?


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## ibglowin (Sep 10, 2002)

Make sure your doing either a soft or hard re-boot of your system at least every 3 to 4 days and both you and your 811 will be much happier. (Soft reboot= hold powerbutton in for 10 seconds and release. Hard reboot = pull the plug for 30 seonds and the plug back in and reboot)

Oh and by the way Welcome to DBSTalk.com! :welcome_s


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## khearrean (Mar 24, 2004)

jbryant789 said:


> This is starting to happen more often, but last night it was really getting on my nerves while I was trying to watch Eliza Duskku on Tru Calling. I had to turn off my receiver 4 times in order to get the a/v to sync.
> 
> Has anyone else been having this problem?


This has been a pretty constant problem for me....

Ken


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## precon1 (Jan 4, 2004)

This has been a constant problem for me as well. But, only with the over the air signals. The dish HD has been great.


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## ts937km (Jan 19, 2005)

I'm having the same problem in Louisville, KY. American Idol has always been fine. But I always have trouble with ABC, "Lost" in particular. I always end up switching back to the Satellite Locals because it is so bad...

I'm still at 284, fwiw.


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## dalucca (Feb 5, 2005)

jbryant789 said:


> This is starting to happen more often, but last night it was really getting on my nerves while I was trying to watch Eliza Duskku on Tru Calling. I had to turn off my receiver 4 times in order to get the a/v to sync.
> 
> Has anyone else been having this problem?


I will occasionally notice the issue and it is very annoying. Will start paying attention as to whether it is the local OTA or satellite feed


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