Audio Dropout on TWC locals

[mr_yeti]

I've heard some mention about "audio problems" here, but I am wondering specifically what these are. I, for one, am experiencing semi-frequent dropouts on 504 (the worst), 512 (usually ok), and 710 (not a problem, really, since I'm not watching for the music). Has anyone done any checking into the source of these issues? I seriously doubt that each individual broadcaster is consistently having an identical problem to the others. I'm positive that this has to do with Time Warner's equipment. So, the real question is, what are they doing to fix it? If I'm watching the Super Bowl without audio this year -- well, I guess that might not be too bad, considering who'll be doing a lot of the talking.

[techboywi]

Isn't TWC getting all those signals over fiber? I assume they are using a T-1 from the stations control room to the nearest cable headend, any dropped packets would cause audio dropouts. If the fiber is bad, thats what'll happen

[mr_yeti]

These feeds were set up very recently to Time Warner. How could they possibly have bad wiring already? Really, though I can't think of another explanation. HBO HD comes in just fine -- never any audio problems at all. It's only the local feeds, and therefore the problem is at the local office.

It's just amazing to me that less than a month after they began offering these channels (and possibly the whole time, for all I know), the audio drops out due to a technical oversight on their part.

[kjnorman]

Originally posted by mr_yeti:
I, for one, am experiencing semi-frequent dropouts on 504 (the worst), 512 (usually ok), and 710 (not a problem, really, since I'm not watching for the music). Has anyone done any checking into the source of these issues?

These are the same issues as I have. 504 is worse, 512 is usually not an issue. 710 "pops" quite regularly and 721 and 731 I've never had a problem.

I was going to complain to TW, but have been too busy to do it. So I just fired off an email to them:

I have a complaint about the current performance of the sound that is feed through on your HDTV feeds.

The problem is surrounding occassional loss of sound that is typically no more than a 1/2 second or so in length, but it results in a very annoying pop though my sound system.

I have recently exchanged my Scientific Atlanta 3100HD cable box and I still get the same sound drops. I have also heard of other people (through contact at www.milwaukeeHDTV.org (http://www.milwaukeeHDTV.org))) have the same sound drops on the same channels - so I know this is not a local issue to me, but must be originating at the Timw Warner cable head end.

The channels that are plague with this are 504 (WTMJ-HD) which is the worst, 710 (PBS-HD) which is equally bad, and 512 (WISN-HD) which only suffers this occasionally.

Please request that your engineers investigate and cure this sound problem.

I would also appreciate, if one of your engineers could contact me so that I may relay your efforts to resolve this to the others on www.milwaukeeHDTV.org (http://www.milwaukeeHDTV.org) that share the same problem with your cable feeds.

Kerry Norman
Contributor to: <A HREF="http://www.MilwaukeeHDTV.org[/QUOTE" TARGET=_blank>]www.MilwaukeeHDTV.org</A>

[This message has been edited by kjnorman (edited 11-27-2002).]

[mr_yeti]

If you'd like, I could write them also. I am 100% so far when it comes to bugging them until something happens.

[P a u l]

As far a I know TW is taking our signal OTA and then sending it down the cable pipe. We do not have a fiber or T-1 feed to them. The only fiber feed we have at the present time is to Direct TV.

I too have sent an e-mail to TW addressing the loss in sound quality and level with no response. Basically if you use the analog outputs from the 3100HD box and flip back and forth between 12 and 512 you will notice a significant loss in sound level and quality. To me it sounds like about an 8dB loss in level!!!! That means they are only putting out around a third of what we are sending out. I didn't do the exact math, but sound like RF works in a "log" fashion.

I did not ask them this, but I'm wondering what Digital format they are using? Dolby digital would require a light pipe connection and I only see an RCA connection.

[Pat]

FYI, Dolby Digital does not require a fiber channel, and can be delivered by copper.

[kjnorman]

Well TW have emailed me back saying that they have forwarded my email to their top Head End engineer. Hopefully they are now aware of this and can fix it.

Kerry

[SugarRay]

I am having the same problems. Kerry - is there a certain person at TW that I should email. Hopefully if they are aware that it is not an isolated problem.

[kjnorman]

I just used the customer service email system on TW web site.

[kjnorman]

Hi all,

I have received feedback from TW's Headend supervisor for Milwaukee. He has ask me not to post his email address (I'm sure he would never get any work done) and I'll respect this. Also, I'm not going to post his name, but he has confirmed that he have been reading these posts, so that if you have problems with TW sound of the HD channels please post here.

Below are excerts from his reply back to me.

I am the Headend Supervisor for the Milwaukee Division. I, along with my entire staff are responsible for all signal reception & propagation in our headends, as well as fiber distribution for the entire Division. In a sense, you have 'struck gold' in terms of reaching someone who can resolve the audio problems you and others are having with our HD channels.
Since you are clearly an early adopter of HD and contribute to milwaukeehdtv.org, I assume you are quite technically literate. Therefore I will treat you as such, unless you inform me otherwise in the future... I feel doing this gets everyone on the same field, so intermittent issues such as this can be resolved. Therefore it is on that level that I hope you will indulge me a bit!

With regard to your very detailed information, it is clear this issue needs to be investigated.... and it will be. However; based on your information, I can find no 'smoking gun' at this time.
PBS' HD feed is received directly from the channel 10 studios via fiber link and directly feeds our modulator in the digital headend. Channels 4 & 12 run through our digital 'groomer' (mux), via both fiber feed (4) and off-air antenna (12). Both 4 & 12 are on the same mux output and yet 4 is worse than 12. Channel 10 has audio problems and does not run through the mux. Therefore at this time, the only constant are the two modulators involved and the set top converters.

As a first step, I will have one of my technicians monitor the feed going into our modulators with an MPEG stream analyzer. With any luck we will see & capture the events causing the problems. I'll get back to you with whatever we do or do not find in a few days...

On one point of clarification: Does the audio drop out on the digital output or L & R line outputs of the set top converter (or both)? We have an HD TV setup with L & R outputs and have not noticed any problems during the short periods of time we have to monitor the channels.

Notes: As erroneously assumed by some in the .org group, packet loss is not the problem here. Packet loss would affect the video as well... Also, as reported in the group... various users are reporting loss of audio during commercials on our HD feeds. TW does not switch feeds. We merely combine them in order to manage the received signals and route them into our modulators. We don't change the format of the received signal either... If we receive 720i, we transmit 720i. If we receive 16x9, we transmit it... there is no translation from the providers format. That goes for Dolby digital as well. Hope this helps to clarify some issues floating around!


The analog audio vs digital audio is certainly one thing to try. For those of you with the sound popping, can you try disconnecting the digital audio cable from you amp and see if the analog L&R feed is devoid of the popping.

Cheers
Kerry

[Gregg Lengling]

Kerry you really have hit paydirt! Alas I am not a TWC customer (Directv here) and can't help any but good luck to your cable subscribing friends on the BBS here and keep us posted on the results...I'm sure TWC's management is very happy to have this group as a resource for troubleshooting.



------------------
Gregg R. Lengling
RCA P61310 61" 16x9
(Built in DTC100 w/Directv)
HiDTV Pro 2 computer reciever card
glengling@ameritech.net

[mr_yeti]

Outstanding. Sounds like they were unaware of the problem, and are monitoring it with (correct me if I'm wrong here) the analog audio signal. I wasn't aware I could use the analog outputs for the HD channels, not that I would want to.

Hopefully this issue gets resolved before the Super Bowl. I would hate to have sound issues when I am demonstrating the wonders of HD for a large group of people.

Nice work, Kerry!

[Gregg Lengling]

There really aren't analog audio signals...their cable-box (decoder) decodes the audio data stream and then outputs them to the analog stereo jacks on the back of the decoder rather than feeding it to a stereo with 5.1 decode capability. It could be that their is a bit or level problem with their data stream that works find with their decoders but not all stereo systems. So that is probably where the problem lies. I've got a feeling that the problem is also their on their boxes but they don't sit there for hours listening/watching for problems like a viewer would but just sample from time to time.
(700)

------------------
Gregg R. Lengling
RCA P61310 61" 16x9
(Built in DTC100 w/Directv)
HiDTV Pro 2 computer reciever card
glengling@ameritech.net

[P a u l]

Originally posted by Pat:
FYI, Dolby Digital does not require a fiber channel, and can be delivered by copper.

I said RCA...meaning the red and white outputs....not DD

[P a u l]

Originally posted by Pat:
FYI, Dolby Digital does not require a fiber channel, and can be delivered by copper.

I said analog...meaning the red and white RCA outputs....not DD. And yes I do know that DD does noit require fibre. We are sending you 5.1 and not a single fibre wire in the signal path.

[kjnorman]

I was unable to do any exhaustive testing last night but I was able to listing for about 1/2 hour during Leno.

I was able to tell some different between the analog L&R outputs and the digital. The L&R did not appear to suffer the sound "pops" as I described before. The L&R outputs are not as vivid in sonic clarity as the digital output, so this lack on dynamics make help mask the sound flaws. With a critcal audiophile ear though, I would say that the analog L&R do suffer with a base noise level and appear to slightly distort (like when an amp is being over driven). Now I must admit that my sound system is very revealing and with a normal TV you would never notice this. Overall it sounded acceptable (not great, but acceptable).

The digital signal, when it popped would not cause my amp (a Yamaha DSP-A1) to lose its lock - like I had previously thought, the amp's display never changed. It stayed on its digital input and does not momentarily switch to L&R. Of course, as the pop only happens for a small fraction of a second, perhaps it is too fast for the display to respond; I do not know.

Overall, its was hard to tell conclusively. I listened to both 504 and 710. The sound pops only happened in the first 10 minutes of my 1/2 hour test last night on both channels. During that time the digital feed clearly popped while the L&R feed appeared to slightly distort (difficult to tell it this as the analog equivalent of a "pop"). During the next 20 minutes I did not detect any significant sound flaws on either channel.

I'll try to monitor it over the coming week and see what happens.

I still do not believe it to be the box, as the digital sound on all other channels is okay. Clearly if the box was faulty then would this problem not be consistent accross all channels. I do believe that the cable box's D/A converter helps to mask any deficiency in the digital audio feed, that perhaps my Yamaha does not accept.

It would be helpful if those who have also said that they get the same type of sound pops, can test their analog L&R connections to determine the results.

Thanks
Kerry

[kjnorman]

Quick update:

Our headend engineer at TW still thinks that this may be a decoder box problem.

They are currently testing at the head end with a demo Pioneer HD decoder box, and have also been feeding back the sound issue problem with Scientific Atlanta to see if there is a firmware fix that can be done remotely.

I have not had any chance to really "watch" much TV in the last few days, but when I quickly tested about 20 minutes worth yesterday I did not experience any problems. Anyone still getting sound pops?

Kerry

[mr_yeti]

I've been pretty busy this week, but things should start settling down tonight. I'll do some watching and see if I still have problems.

May I assume that we're all using the coaxial digital outputs from our boxes?

[SugarRay]

I had audio 'pops' tonight on 710 and 504.

[kjnorman]

I've got some good news - hopefully.

Got feedback from our headend technican today:

I received a reply from SA regarding my inquiry of the audio problem. Based on a previous case in their database, the fix for the AC3 problem on HD boxes was an OS upgrade (set top operating system).
Low & behold... we are currently planning an upgrade for early morning Tuesday, December 10th. (Believe it or not, it was on the schedule already!) I still need to check if the OS as well as the Resident Application will be upgraded. Obviously I will petition for both. Will update you after the upgrade is completed.


It will be interesting to see if this fixes our problems post Tuesday.

Kerry

[mr_yeti]

That's great news!

I experienced significant problems with 710 last night, but fell asleep on the couch before I could check 504. 512 was pretty good.

[Gregg Lengling]

Even though I am not a TWC customer I am very happy to hear how well they have responded to the problem...located it and planned for the upgrade to the OS to take care of the problem. Pretty active service team down there...happy to see response of this caliber.

Gregg Lengling
Chief Engineer and President
Camel Communications, Inc.
Milwaukee, Wisconsin

[kjnorman]

Lastest from TW on the 3100HD update:

The firmware upgrade went off without a hitch this morning. I verified that the new Operating System (OS) version on the 3100HD is now 3.3s7. I had one of my techs monitor 504 for several hours this afternoon. Although he had not previously heard the problem, I described what to listen ( & watch) for. No audio issues were noticed. Hopefully the upgrade has fixed our issues with AC3 audio...

and

Just tuned to 710 and thought I heard an audio problem. Looking closely, there were several minor video 'jumps' as well. It could be the HD demo tape. It looked like highlights of a college game.
It would be interesting to have users note what video format is in use when sound problems are noticed. On channel 504 (upconverted SD), there were no sound problems for nearly 2 hours. On channel 710, (16x9) I thought there were some sound problems yet... it is quite hard to hear clearly in the noisy environment.
In any event, we will pull in whatever resources are needed to ID and fix this problem as we move forward.


It'll be a couple of days until I am able to properly evaluate this.

If you notice problems in the audio coming from the 3100HD box on any of the TW HD channels can you please note the channel, time and program and I will feed this back to our friendly engineer.

Cheers all!

Kerry

[mr_yeti]

I thought the sound actually got WORSE. 710 had some pretty nasty hiss and crackling, and the sound dropped out several times. I flipped through 504 when they were running SD stuff (I think it was local news), and there was no sound at all. I will do a more scientific and useful evaluation as time allows.

[kjnorman]

Well I only watched two things last night. HBO HD that had no sound issues but then it never did, and about 15 minutes of Leno with no sound issues.

It'll take some time to see if things have improved.

As to PBS, well, the quality of the demo tapes may be in question. We really need to test 710 when there is a scheduled HD program such as Tracks Ahead at 4pm or Smart Travels at 6:30pm. There is also a Jessye Norman (no relation) special at 9pm tomorrow. Finally it would be interesting to see if their SD widescreen programming has issues - eg Secrets of the Dead on Saturday at 7pm.

Kerry

[mr_yeti]

It was Tracks Ahead I was watching that had the crackling, actually.

Eventually, I just turned it off because the problem was so annoying. That and, well, trains.

Why always the trains? Or boats?

[SugarRay]

Had audio drops on 710 and 504 tonight.

[brewtownska]

I still experienced audio dropouts on 504 during the Wallflowers performance on Leno, and afterwards I checked out PBSHD on 710 and had lots of dropout on their loop (I think the gospel singers were on at that point).

I know earlier we were all told there was an upgrade done over the cable line to fix a known problem with the Scientific Atlanta 3100HD boxes, but does anyone know how to be SURE the upgrade took effect? I mean, does anyone know how to show the software or firmware versions...a code or some setting that will display that info. That would at least tell us if TWC's upgrade actually took effect.

Mike

------------------
**********
TWC 3100HD box on both
50" Toshiba 4:3 HDTV &
Sony 1272Q CRT Projector

[kjnorman]

I myself think it has improved. I do notice the occasional drop, but to me it is now more like a momentary hiss rather than the annoying pop. This is my experience at least on 504.

I will feedback the results to TW's engineer.

Kerry

[kjnorman]

Here is the latest:

Analyzer shows no problems with any of the packet timings. The next step is to get the Pioneer HD set top in a location where it can be closely monitored. I would like to set it up in my office, but it may take a week or so to make that happen... we are getting ready for next Thursday's channel lineup changes for the division. I will also re-open a ticket with SA so they can investigate further as well... Meanwhile, keep noting if the problem only occurs during 16x9 HD sessions.

Kerry Norman wrote:

I think the upgrade has improved the sound issue at least in my experience. I would not say it is cured, but I for one, have found 504 much better the couple of times I have had a chance to watch it. 710 still pops though and I find the 504 now seems to occassionally hiss rather than pop on my system. It is quite a low level noise, so you may not notice it if you are in a noisy environment, but if in a quiet living room, it does become apparent.

Others though I still dissenting about the drop outs. There are three others still claiming issues on http://www.milwaukeehdtv.org/ubb/Forum2/HTML/000210.html.

Anything come up on your mpeg analyzer?

I find it odd that this problem still only occurs with the local channels that seem to be fed by fiber (PBS 710 & WTMJ 504). WISN-DT is received OTA and to me atleast sounds fine.

Kerry

[Joseph S]

WISN-DT is received OTA and to me atleast sounds fine.

Not for me, the pops are still present on 504, 512, 710 and not 721 and 731. They are not correlated to drops on the OTA either.

[kjnorman]

I must say that I am still getting the sound issues on 504 and 710, so it looks like the firmware update on the 3100HD box did not help.

I am following up with the engineer at TW again to see if they have any new solutions out their.

Kerry

[kjnorman]

These sound issues may not be local to us. I have noticed a trend in the AVS forums with people mentioning digital sound issues on HD cable.

So i posted a poll there, to see how widespread this may be nationally.

Poll is here (http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=203221)

Kerry

[SLSCE]

I'm relieved to find out I'm not the only person with this audio problem. For me, the audio repeatedly drops out (for about 1/2 second) during the first 15 seconds of watching 504, 510, and 512. I am using the coaxial audio out. Also, the audio will ocassionlay drop out again for a split second during the first 20 minutes or so of watching theses channels. After about 20 minutes, the audio is generally perfect. Contrary to some comments I have read in this thread, channel 512 tends to be the most notorious channel for audio dropouts. Recently (Dec 29), I had a technician from TW come in and troubleshoot the problem. He had heard nothing of the audio dropout problems from his engineers (and he seemed extremely knowledgeable and even bragged about what good communication he has with the TW engineering crew). Anyways, after testing multiple cable boxes and component issues, he could find no solution to the problem. He did report the issue to TW, but again, mentioned that it seemed to be an aberation--no one had mentioned the problem before. Obviously, this seems to be a common problem. Any comments and questions and a solution are welcome. Thanks.

Has anyone heard of any new developments?

--------------
TV: Sony KP57WS500
Receiver: Sony STR-K740P
Cable Box: Scientific Atlanta 3100HD
Cable Provider: Time Warner

[Shpeel]

All,

I live in Cary, NC, which is near Raleigh. I have had TW HD for several months with an HD3100 STB and have been experiencing problems very similar to what you have been describing. Audio drops out for a second or two, usually more frequently when first switching to a new HD channel... almost as if it's buffering data. Then, at seemingly random intervals, the audio will continue to drop out. Sometimes I can make it through an hour without problems and then all of a sudden it will experience several drops in in a few minutes. More often than not, the video will also suffer. It will freeze, become pixelated, or even black out for a second. This is quiet annoying when you are watching a football or hockey game. :mad: This happens on the local channels as well as HBO.

I've written to my local TW tech support, so if I get a valid response, I'll pass it along. I just wanted to let you guys know that it could be a larger issue affecting all TW customers nation wide.

Shawn

[torgo]

I routinely get audio dropouts on the PBS HD channel (whatever the channel number is now) on TWC. Also, I would occasionally get dropout on HBOHD (of course, usually during the Sopranos.) The dropout only occurs via the digital audio, as when I switch to analog audio, the problem does not occur. I haven't watch the ABC or NBC feeds enough to make a judgement yet, but when I watched Leno the other night, it was fine.

[kjnorman]

I chatted with the TW chief headend engineer today on this, and they and Scientific Atlanta still do not have a resolution on the problem.

S.A. have asked for a 60 minute stream recording of one of the channels, so they can play it back in their lab. At the moment that is technically difficult for TW (We're not the only ones with no HD PVRs :o ) so they are trying to get a SA technical guy on the plane up here to experience this first hand.

So no joy at the moment but they are still trying.

[SLSCE]

I was just wondering if anyone experienced severe audio dropouts while viewing the Superbowl (512). The picture was terrific, but the sound consistently "popped" off and on. Usually, the pops would occur frequently for a short period of time (maybe a minute) and then the audio would be fine for the next ten minutes.

[kjnorman]

Generally I find ABC to be one of the better local stations on sound quality, though it is not always great.

Apart from some rear-front speaker mixing issues which were part of the ABC presentation I did not notice any serious flaws in the sound for the Superbowl (but then we had a very noise room of people...)

(FYI - I will be cancelling TWC soon, and so I will no longer be interfacing these sound problems to the TW headend engineer)

[mhz40]

SA is in town trying to capture the mpeg stream while the audio dropout problem occurs.
We monitored PBS's feed all afternoon (1-4 pm & 5-6 pm) and never caught an episode to capture. We will be monitoring ER and Leno tonight.
SA is leaving Friday afternoon. We will have use of the recorder through Monday or Tuesday, then they will want their $30,000 toy shipped back. In the meantime, any further feedback on this issue is appreciated on this thread, so we can try to capture this bug and get it into the lab for analysis.

Thanks
MHz