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baess

join:2011-01-28

1 edit

Audio not in sync with video

Anyone else noticing the audio not being in sync with the video?

In Chicagoland it happens on WGN (channel 9) pretty much all the time for the last month or so. Last night while watching ABC (channel 7) it happened there too.

It's just a millisecond or two but it's noticeable and very annoying.

edit: I need to look further in to this. I forgot that most of the time I am watching a DVR recording. Just added the DVR (regular, not Ultra) so maybe that is the issue.

Does anyone ever notice the audio not syncing up when watching a recorded program?



RootWyrm

join:2011-05-09

Well, it's more than a millisecond or so if you're noticing it (probably over 100ms) but.. have you tried watching WGN live as opposed to recorded? With HD broadcasts especially, it's usually something with the source being out of sync, rather than the viewing equipment.


baess

join:2011-01-28

said by RootWyrm:

Well, it's more than a millisecond or so if you're noticing it (probably over 100ms) but.. have you tried watching WGN live as opposed to recorded? With HD broadcasts especially, it's usually something with the source being out of sync, rather than the viewing equipment.

It's definitely related to a recorded program. WGN is fine live, terrible when watching a recorded show. Some other channels have it to some degree and others are fine (obviously I haven't gone through every channel live vs. recorded).

So based on that sample is it as you say coming from the source? I know there has been issues for a month or two with some of the local channels related to how they display.

Or is it my DVR?

Not sure what to do but it's ridiculous to watch TV this way.


RootWyrm

join:2011-05-09

It is the DVR then, yes. Here's the problem; HD splits the audio and video streams and does not sync the time codes between the two. Which means that the output device has no way to tell that this frame of audio goes with this frame of video. Which is why you really only see it with HD broadcasts.

So it's partly your DVR, partly technical limitation. If it gets worse over time (relative to how long you've had the DVR and/or how many shows you've recorded since last power cycle) then possibly a full power cycle - meaning disconnecting the power cord completely for at least 2 minutes - might resolve it.

Which exact DVR do you have? (Not really a settop guy, but I have some folks I can ask for more tips.)


baess

join:2011-01-28

3 edits

said by RootWyrm:

Which exact DVR do you have? (Not really a settop guy, but I have some folks I can ask for more tips.)

Cisco Explorer 8642HDC which was brand new when installed by WOW.

I don't have HD service but based on your explanation what I'm seeing must be somehow related to it.

I think "regular" WGN is being broadcast in HD but it's dumbed down for us without HD...or maybe I'm totally wrong.

Also see "1080i" displayed on the set top box, not sure if that has any effect.

Maybe when Dan is back he can figure out why it is happening.


RootWyrm

join:2011-05-09

Found some information myself, but it's not good news. The 8642HDC is an HD DVR, even when connected to non-HDTVs. The problem with audio/video sync however, is apparently a firmware issue affecting many people. The initial "fix" was another firmware with worse bugs.

So unfortunately, on this one, unless Dan knows a secret I don't (totally possible,) stuck waiting till Cisco decides to release a firmware update that fixes it.



WOW_Dan
Premium
join:2011-03-24
Naperville, IL
kudos:34
reply to baess

Formatting the hard drive on the DVR would be my first suggestion. This will of course erase all your recordings.

I believe the process is the same for the Cisco DVRs as it is for the SAs. Hold Pause on the remote until you get the message waiting indicator (envelope icon) on the front of the DVR. Press Page Down on the remote, and then press the "List" button 3 times. The screen should then display "hddf". Let it sit there, it will then format the hard drive and reboot itself. This could possibly help if the hard drive is what is causing the problem. If those steps don't work, let me know.
--
Dan Della Terza
WOW! Internet, Cable & Phone
Network Operations Center


baess

join:2011-01-28

After quite a bit of recording and watching it seems the problem is only related to local Channels (WGN and WLS to some extent). I think it has more to do with how those channels are being broadcast. Even when watching those channels live there is some disconnect between the audio and video.

I'm sure I didn't see the audio/video issue when I had the regular digital receiver, so somehow the HD DVR/Receiver is messing with the non HD channels that originate in HD.

If it was truly a hard drive problem I would think it would happen on every channel. And this was a brand new DVR so a bad hard drive seems unlikely.

Are you aware of a firmware issue as RootWyrm mentions?



WOW_Dan
Premium
join:2011-03-24
Naperville, IL
kudos:34

said by baess:

After quite a bit of recording and watching it seems the problem is only related to local Channels (WGN and WLS to some extent). I think it has more to do with how those channels are being broadcast. Even when watching those channels live there is some disconnect between the audio and video.

I'm sure I didn't see the audio/video issue when I had the regular digital receiver, so somehow the HD DVR/Receiver is messing with the non HD channels that originate in HD.

If it was truly a hard drive problem I would think it would happen on every channel. And this was a brand new DVR so a bad hard drive seems unlikely.

Are you aware of a firmware issue as RootWyrm mentions?

I'm not aware of any firmware issues, but I can do some more research. If you'd like to force a firmware upgrade to the box, (in the off chance something is bad with the version or it's somehow behind) you can unplug the box, hold down the power and select buttons, and then plug it back in while continuing to hold the buttons until you see a countdown start on the box. This will force it to re-download its firmware to ensure it's a good version and correctly loaded.
--
Dan Della Terza
WOW! Internet, Cable & Phone
Network Operations Center


RootWyrm

join:2011-05-09

said by WOW_Dan:

I'm not aware of any firmware issues, but I can do some more research. If you'd like to force a firmware upgrade to the box, (in the off chance something is bad with the version or it's somehow behind) you can unplug the box, hold down the power and select buttons, and then plug it back in while continuing to hold the buttons until you see a countdown start on the box. This will force it to re-download its firmware to ensure it's a good version and correctly loaded.

Dan;

The issue is apparently specific to the 8640HDC and 8642HDC. AVSForums seems to indicate that 3.1.092 or later on OS build 6.14.98.1sp may resolve the sync, though other breakage potential exists. If you have any contacts at Cox, they would be the folks to reach out to - they apparently have been pushing Cisco on a number of bugs with these units, and can identify which build resolves the sync issues without causing the HDD power off issues.

baess

join:2011-01-28
reply to WOW_Dan

I spoke with the lead tech in the area and he knew about this issue. Gave me a bit of a technical reason but essentially he thought it was provider related.

He felt it had been resolved (drop off in customer complaints) but I still see it.

He said a bad box was possible but seemed to agree that would probably give me problems on more channels than just the few I see. I did see it during the recording of Hatfields and McCoys on History so now I'm starting to wonder if it is more widespread.

So it could still be the provider (and also some of the larger drop off issues still being experienced), the firmware as RootWyrm mentions or a bad box.