InfiniTV4 audio clipping

[jziggity]

I will more than likely submit a support ticket on this, but I figured I would check here first. On at least one channel in particular, I am having excessive audio clipping issues. The sound drops out for about a half second, and it happens about every 15-30 seconds or so. The signal levels on this channel (HubHD) are all fine - Signal level is 1.5, SNR is 36.6, temperature is at 52 degrees. I have watched this channel in the past without this issue, but within the last month or so it seems like it is really bad. Every once in awhile the picture itself freezes for a few seconds as well, and then everything catches up again.

I have the internal PCI InfiniTV card. I also watched the non-HD version of the same channel, and there is no audio clipping, so it is not a network provider issue.

This problem is present both when watching the channel directly on the main HTPC and on extenders, so it is not an internal network issue. I just upgraded to the latest beta firmware today and that did not change anything. It is so bad the channel is just about unwatchable. And, I just noticed now, there are STILL lines of pixelation across the screen as well. Argh!! HDHomeRun is looking really good right about now. Any suggestions on things to try?

[adam1991]

Not the tuner card--all it does is pass the bits. It does zero processing of the bits.

Look to your provider.

[richard1980]

Just a shot in the dark, but check the DPC latency while the issue is occurring. I don't think that will affect the extenders (I could be wrong), but it could be what is causing the dropouts on the PC. Here are a couple of tools to use:

LatencyMon
DPC Latency Checker

You may also want to enable the High Precision Event Timer (HPET). To do this, first check BIOS to see if there is a setting to enable HPET. If there is, make sure it is enabled. Then in Windows, open an elevated command prompt and run the following command:

Code: Select all

%windir%\System32\bcdedit.exe /set useplatformclock true

Reboot and see if the problem persists.

If none of that helps, then I'd say Adam is correct and the problem is with your provider. I'm leaning in that direction anyway because of the extenders. But I don't know for sure that latency and timer resolution on the host PC doesn't somehow affect extenders.

[jziggity]

Hmmm, ok. I'm not really liking the results of LatencyMon. I don't really know what all of the numbers mean, but I'm guessing the far red end of the scale is not good. I know I can adjust overall system performance in my bios to reflect power savings, balanced, performance, etc. I'll try an adjustment there. I'm not aware of a bios setting that I have for HPET, but I'll check again. See below for the LatencyMon results.

I'm also very surprised that it is showing problem areas, given that I'm running an SSD for the OS drive, and the entire system itself was a brand new power machine in November of last year, so I would think it should (still) have no problems keeping up with this stuff, unless latency is affected by something else (other programs running)?

[JohnW248]

How are you getting audio from your PC to your viewing device? HDMI? Toslink?

If you're running HDMI to a receiver/tv set, you might want to look at your graphic card which will also be handling audio. If you are decoding on your host machine to local speakers then check your audio decoder/driver.

If you are running to an extender, you probably wouldn't see this since the pc would not be involved in decoding audio. You might also look through audio setting, it might just be that the channel changed encoding and something that was working before needs to be adjusted.

Right now it looks like there is a memory issue in handling audio.

[richard1980]

I don't really know what all of the numbers mean, but I'm guessing the far red end of the scale is not good.

Honestly, I don't either. I've never taken the time to learn, but I trust that the people that wrote those two tools know what they are talking about. They certainly know more than me on this subject.

I've actually used these tools in the past to diagnose audio dropouts that I had. IIRC, LatencyMon told me I had an issue with the graphics driver, so I changed that and the problem was solved. I've also seen issues with the NIC on a different motherboard, but I don't remember exactly what I did to resolve the issue. In any case, I think if you do whatever LatencyMon says you need to do, then you will probably solve the latency problem, and that could make the audio dropout issue go away.

[richard1980]

Right now it looks like there is a memory issue in handling audio.

Are you talking about the bottom bar? Any idea how to resolve that?

[JohnW248]

Right now it looks like there is a memory issue in handling audio.

Are you talking about the bottom bar? Any idea how to resolve that?

I don't know how Windows handles swap files with SSD, so if he wants to keep everything the same it would look like more RAM, otherwise I'd check how the audio is being decoded.....that's something that wouldn't be necessary if he was feeding a HDMI receiver/tv set where the decoding would happen at the end of the chain. But there just isn't enough information about the set-up to really figure out what's happening. Maybe his audio drivers got corrupted? Also it could be a HD problem if there is an issue with the buffer on playback, I would think video would be hit first with freezes and stalls, but something else to check. Again don't know the set-up, what the recording drive is, where it is, etc.

[erkotz]

I have the internal PCI InfiniTV card. I also watched the non-HD version of the same channel, and there is no audio clipping, so it is not a network provider issue.

This is an incorrect assumption. Generally the HD and SD channels, even though they show the same content, are completely different signal paths.

Not the tuner card--all it does is pass the bits. It does zero processing of the bits.

Look to your provider.

As others have mentioned, the InfiniTV is transferring bits and does no processing. If it's only one channel, most likely it's the content source. Do you have other devices in the house that can tune this channel? Do they experience the same issue?

[jziggity]

Ok, glad to see many suggestions since overnight. To answer the setup questions, I use almost exclusively extenders for watching/playback of TV. My Onkyo amp is magnifying the audio dropout by quite a bit, as that is how it is handling the brief hiccup. I can still hear it directly on the HTPC itself, but it is much shorter. My recording drive is a standard mechanical hard drive, one that I have not had issues with before. The OS is on an SSD. I have 16GB of RAM installed. Everything else audio related on my PC works just fine. The process that is throwing all of those hard page faults, per LatencyMon, is msmpeng.exe, which should be something related to Windows anti-malware? The only antivirus software I have installed is MS Security Essentials. Every so often ehrecvr.exe is also throwing some, but I'm watching LatencyMon and the hard page faults from that do not coincide with the audio drop outs.

All of my networks connections are gigabit - switch, router, NIC in the HTPC, and all cat6 cables. Extenders are connected via ethernet and typically work fine, although every once in awhile I do get "Network Error" issues where the video slows down dramatically. I run the network tuner on the extender (XBox 360) and that takes care of it right away. I do not have the HTPC connected in any way to any TV or amp - it just sits on a desk on its own.

Unfortunately I don't have any other cable boxes or other CableCard devices to test with. Another thing I didn't mention before, this audio clipping is part of the recording itself. If I back up live TV and play back the same segment again, it is still there, so it is not a one time thing, so to speak.

Graphics card wise on the HTPC, I am running a GeForce GTX 550Ti, and windows says the driver is up to date.

I haven't had time to monkey with anything in the Bios yet, so I'll try that next. Another odd feature - the video on this channel does occasionally lock up completely, hangs for a couple of seconds or so, and then moves on, all while the signal levels for the channel remain well within spec. Late last night it seemed like the issue got a lot better, with no changes made on my part, and then this afternoon it is back to the same frequency of occurrence again. Is it possible that weather conditions are affecting the cable company's equipment somehow?

Assuming that this is a TWC issue, I could describe the issue for them, but an easy million bucks says they will soundly blame it on my equipment, since I'm not using THEIR box, of course it must be MY stuff causing the issues.

[adam1991]

You are saying that "this audio clipping is part of the recording itself", which in the digital age means "it came from the content provider that way". You also say "this channel...locks up completely...for a couple of seconds...and then moves on, all the while the signal levels of the channel remain well within spec". It all comes down to, the cableco has a solid carrier in place, and what it's carrying is garbage.

Back in ye olden days, when NTSC analog came in out of the wall and something had to turn that to digital bits, that "something" would have been suspect. But as we've pointed out to you, the "recording" is nothing but a faithful storage of the digital bits the provider has already created and is simply sending to your house.

"Provider" could mean the cable company, or it could mean the content owner, or it could mean the guy in the middle who's being paid by the content owner to digitize it, or whatever.

Go get one of TWC's boxes and see if it happens on that. When it does, call them.

What channel is this, btw? We can all tune in and see if we get anything similar.

[jziggity]

Thank you everyone for the feedback. I am very much inclined to believe this is a TWC issue, given all of the reasons everyone has mentioned. I would like to go pick up a cable box from them just to test all of this, but I'm such a cheap-a$$ that the extra $10/month gives me pause. That, and the wrangling, arguing, and subsequent FCC complaint I filed against them the last time I returned my equipment leads me to believe they will completely F-up my package pricing if I make any equipment changes again.

The channel in question is The Hub HD. In my area (SE Wisconsin) it is on channel 1111. It is a kids/family channel, cartoons, movies and what not, and not one that I watch often, but my son likes it, and of course he doesn't care about the issues. He just watches it anyway.

I think people will enjoy the below image as well. On an evening walk through the neighborhood, I spotted the below power line configuration at an intersection about 2 blocks away from my house. There is construction there, so the line you see draped over the other lines is a temporary power line for street lighting during the construction. The power line is laying across the lower lines, which in our area are telephone and cable lines. I've got to think that can't be too good!!