WVTV (18-1) Audio Dropouts

[Mark Strube]

So I was watching Supernatural tonight... I have a consistent 95% signal on this station.

There were about 4 audio dropouts during the show (no video glitches). Towards the end, the audio went out of sync (not terribly, but very noticeably) and at the end, perhaps the last 5 seconds of the show, the video went into about 2 frames per second. And now during the ads after the show, and now into the news, the video keeps freezing up (no audio dropouts or visible artifacting during this) and the sound is totally outta synch.

I have a strong feeling this problem isn't on my side... :confused:

UPDATE:

I tuned away and then back again... the audio sync is restored. Is this a common bug among OTA receivers?

[SRW1000]

You're not alone.  I also had some noticeable audio dropouts during that show (so far, it's my favorite of the new season), and I think I noticed the same problem last week.  It's the only HD show I watch on WB18, so I don't know how common it might be.

As far a sync issues go, I've had the same problem from time to time.  It's been worse on some receivers (my Dish 811 was doing this constantly).  People have also reported that there are some issues between certain receivers and TVs.  It's one of the growing pains a new technology goes through.  Luckily, commercials offer the perfect opportunity to switch a receiver off and on, which has always cleared up the problem for me.

Scott

[Doug Mohr]

I don't watch supernatural, but there are sync issues on Just Legal and there were on Everwood last season. It just might be a WB thing, sort of like 36-1's ever present audio sync problems :rolleyes:

[Drummerboy]

Every morning lately I am having reception issues with 18-1.  I'm lucky if I get it a picture for a sustained period of time.  I am not able to determine when reception stabilizes but in the evening typically I have no reception issues.  Any similar experiences or explanations?

[Mark Strube]

Late last night and all morning I was having issues receiving 12-1 (I usually get 98-100 signal)... The signal would go to 100 and then jump all over the place. Later in the afternoon it went back to being absolutely perfect, and still is now. No idea.

EDIT: Nevermind. 12 is on the fritz again. I don't get it... not one issue till late last night.

EDIT2: Problem solved!! I simply unplugged the power from the antenna. My best guess is it was pulling in a bunch of multipath or something with the power on. Now I get solid 94-96 signal. Whoo!

EDIT3: NEVERMIND. :bang:

[Mark Strube]

I've managed to pinpoint TWO audio dropouts. I made a mental note while watching Gilmore Girls and Supernatural tonight of when two audio dropouts ocurred (there were a total of about 6). I was watching using my voom ota tuner and sherwood 5.1 receiver. I then went to my computer which was recording the digital TS stream from a pci capture card, and sure enough, on playback the errors were there as well. MPEG2Repair (a stream checking utility) reports no stream errors, and during the entire 2+ hour recording, TSReader (recording utility) reported no continuity errors. It's my experience that whenever there's an actual signal reception error (many of which I get on 12-1 for example) both of those report errors. Here's the files for everyone to inspect themselves... I would recommend using VLC Media Player to view these files.

The .TS files are the video sample, and the .TXT files are the error report by MPEG2Repair.

[right-click, save target as for the .TS files]

Clip one - glitch during Gilmore Girls:
test.ts
test.txt

Clip two - glitch during Supernatural:
test2.ts
test2.txt

Clip three - crackling during a WB promo:
test3.ts
test3.txt

I repeat - these errors I was able to confirm on BOTH my tv setup and my pc, and the pc, using two different methods of error checking, was able to find no signal errors... combine that with the fact that many others are reporting these audio dropouts... this is on WB18's side. I hope this helps them get the problem solved! (Just don't do any messing around during Smallville and I'll be happy. )

[Jimboy]

I'll check the ts streams on Wednesday.  What I would like to setup is a comparison record back at the station. Does your PC also have dolby digital decoding capability?

[Mark Strube]

The TS streams are in dolby digital 5.1, and my pc decodes the sound, however it just decodes it to a standard stereo sound card.

[Jimboy]

The TS streams are in dolby digital 5.1, and my pc decodes the sound, however it just decodes it to a standard stereo sound card.

Two things.....

1). What is the next program you plan on analyzing from WB18?
2). The ts samples...can you provide larger files? 100mb or more?

I plan on recording the decoded satellite feed audio before it gets into our encoding system. This will tell me if it comes from the WB that way.

Thanks.

[Mark Strube]

Sure I could provide larger sample files, but just curious as to why?

I guess I could analyze Related tonight, if that's okay.

[Jimboy]

Sure I could provide larger sample files, but just curious as to why?

I guess I could analyze Related tonight, if that's okay.

My analyzer takes a little longer to lock up just before the glitch happens. Typically it needs 15 seconds but I was able to hear the problem.
 
I'll record the satellite audio from Related tonight and Smallville on Thursday.

Our station in Nashville came up with these times for last nights problems.
They are recording satellite audio as well.

Times are based starting at 7pm.
The approximate times we experienced these problems are at 00:14:38, 00:31:23 and 01:04:36 into prime time.  These are the only problems we have found on last nights prime.

Do they roughly correlate to the times when you experienced the drops?

[caveman]

Just wanted to add that we had audio dropout issues (each dropout lasting about 1-2 seconds) on Gilmore Girls last night.  After about the third dropout, I switched the digital out from Dolby Digital to PCM and that helped.  I think it's kind of weird that dolby stereo signals experience no dropout while the surround signals do.

[Mark Strube]

Do they roughly correlate to the times when you experienced the drops?

I'm not sure, since I no longer have the .TS file, however I do know that there were more than 3 total audio dropouts.

[Mark Strube]

During tonight's Smallville, audio glitches:
7:15, 7:32, and 7:49 (during commercials)

Also, the feed went to SD for about a minute at 7:53.

[Jimboy]

During tonight's Smallville, audio glitches:
7:15, 7:32, and 7:49 (during commercials)

Also, the feed went to SD for about a minute at 7:53.

I watched also and heard drops at the same time. I'll check the tape tomorrow which will indicate if it was sent from WB that way.

The HD switcher is controlled by automation and we normally have very few problems with it. When the automation system needs to be restarted (due to problems) the HD switcher drops to SD. I called ASAP.