Interference in HDHomeRun recordings when downloading something at very high speed!

[mkanet]

I didnt have this problem before until I switched to Comcast Internet which gets sometimes above 22mbit/sec download speed. For some reason, during these fast downloads, my HDHomeRun recordings are affected adversely.

I dont have this problem downloading at 6-8mbit/sec using ATT DSL.

I'm connected to my Netgear switch at 1000Mbps Full Duplex. If I didnt know any better, I would think that I was connected at only 100mbit.

NOTE: I've disabled Vista's TCPIP "autotuning" feature which people have complained degrade performance.

Thanks in advance!

[GKusnick]

You're using the HDHR for QAM tuning, I assume? So the TV and the Internet are coming in over the same coax? Is it possible that Comcast is trading off bandwidth between the two, dropping packets from your TV signal in order to serve your download faster? (Just guessing here since I'm not a cable Internet user.)

If that's not the case, then the things I'd look at are possible contention between the HDHR and the router on the 100mbit side of your LAN (depending on your network topology), or some disk bandwidth bottleneck on your server (assuming the download and the HDHR recording are going to the same disk).

[paulbeers]

Originally Posted by mkanet

I didnt have this problem before until I switched to Comcast Internet which gets sometimes above 22mbit/sec download speed. For some reason, during these fast downloads, my HDHomeRun recordings are affected adversely.

I dont have this problem downloading at 6-8mbit/sec using ATT DSL.

I'm connected to my Netgear switch at 1000Mbps Full Duplex. If I didnt know any better, I would think that I was connected at only 100mbit.

NOTE: I've disabled Vista's TCPIP "autotuning" feature which people have complained degrade performance.

Thanks in advance!

Is the download and the HDHomeRun Recordings going to the same computer? Are they "saving" to the same drive?

Just wondering if it isn't the network but the computer itself?....

[mkanet]

Im using it for QAM. Internet and TV for Comcast are two completely different technologies. They don't have TV over TCP/IP like some providers do.

I have dedicated hard disks for downloads, OS, and SageTV recordings... all SATA. Nothing much to my network topology... Just HDHR and PC connected to the same network switch.

Originally Posted by GKusnick

You're using the HDHR for QAM tuning, I assume? So the TV and the Internet are coming in over the same coax? Is it possible that Comcast is trading off bandwidth between the two, dropping packets from your TV signal in order to serve your download faster? (Just guessing here since I'm not a cable Internet user.)

If that's not the case, then the things I'd look at are possible contention between the HDHR and the router on the 100mbit side of your LAN (depending on your network topology), or some disk bandwidth bottleneck on your server (assuming the download and the HDHR recording are going to the same disk).

[padre]

Originally Posted by mkanet

Im using it for QAM. Internet and TV for Comcast are two completely different technologies. They don't have TV over TCP/IP like some providers do.

I think what he was trying to get you to think about is, both the TV and Internet services share bandwidth over the coax - it's not like you have one coax coming in for Internet to the house, and a separate one for TV services. They both share the same pipe (Internet on comcast is actually a subchannel of a standard channel).

So, if they cranked up your ability to download via Internet, it COULD be affecting your overall maximum bandwidth coming across the cable and impacting your QAM signal. Weirder things have happened.

Also, are you using the latest version of Sage and HDHR drivers/firmware? If so, that could also be it - as they've changed how they record the QAM channels and I've seen stories of bandwidth impacts.

[mkanet]

Yes,I know what he's saying. I forgot to mention this is specific to my HDHR's. I dont have any problems recording/watch from my HD cableboxs while downloading at full speed.

Originally Posted by padre

I think what he was trying to get you to think about is, both the TV and Internet services share bandwidth over the coax - it's not like you have one coax coming in for Internet to the house, and a separate one for TV services. They both share the same pipe (Internet on comcast is actually a subchannel of a standard channel).

So, if they cranked up your ability to download via Internet, it COULD be affecting your overall maximum bandwidth coming across the cable and impacting your QAM signal. Weirder things have happened.

[Conejo]

1. Cable feed overload (unlikely)
2. HDHR LAN overload
3. Processor, buffer, bus or drive overload
4. Possible Netgear Gbit switch issue

1. Unless it's a signal level imbalance I don't see how this could be a CableTV topology issue. To check, can you view those same channels on another QAM device (HDTV or STB), while doing a major download and see if the signal breaks down?

What does your Cable Modem diagnostics list for Download db, snr db, and Upload db? If your Upload db is above 50 then that could be a problem.

2. How many HDHR tuners are active when you see the issue? You'd think a Transport Streams of 19.39Mb/s (8vsb ATSC), 27.7Mb/s (64QAM) or 38.8Mb/s (256QAM) per tuner would coexist nicely with a 22mbit internet connection on a 1000mbit pipe.

3. What does taskmanager say your Proc% and NIC% are?

4. I've had a lot of problems using off-the-shelf home router/switches when streaming video. Any known issues with your switch?
Previously, I've had to toss switches into my junk box because they'd lock up after a few hours of streamed HD, or had problems with the store and forward transitions between 100 and 1000 mbit connections.

I also just moved into a house where an electrician had wired all the cat5 cables color-paired across the 1-8 pins instead of using a 568A or 568B wire scheme and my switches didn't like using the unbalanced pairs. Rewiring 16 cable runs took a while.

[mkanet]

You might have missed my post above. It doesnt happen on my other HD cable boxes while downloading at full speed.

Also, my other HD tuners are pushing data through the USB bus (which are unaffected during full speed downloads).

However, there still appears to be a relation between the HDHR tuners and full speed internet download.

There's definitely a resource deficit somewhere. If I pull data from my other PC via TCP/IP at 100mbit/sec; oddly, HDHR's aren't affected.

My next test will be to download something at full speed from my other PC while using my HDHR's...

Anyway, this isn't a big deal, but it's frusterating not to know what's causing it!

All resources that I can see are comfortably utilized (CPU's, Memory, disks).

I'll post later if I find out what's causing this...

Thanks for trying to help anyway..

Originally Posted by Conejo

1. Cable feed overload (unlikely)
2. HDHR LAN overload
3. Processor, buffer, bus or drive overload
4. Possible Netgear Gbit switch issue

1. Unless it's a signal level imbalance I don't see how this could be a CableTV topology issue. To check, can you view those same channels on another QAM device (HDTV or STB), while doing a major download and see if the signal breaks down?

What does your Cable Modem diagnostics list for Download db, snr db, and Upload db? If your Upload db is above 50 then that could be a problem.

2. How many HDHR tuners are active when you see the issue? You'd think a Transport Streams of 19.39Mb/s (8vsb ATSC), 27.7Mb/s (64QAM) or 38.8Mb/s (256QAM) per tuner would coexist nicely with a 22mbit internet connection on a 1000mbit pipe.

3. What does taskmanager say your Proc% and NIC% are?

4. I've had a lot of problems using off-the-shelf home router/switches when streaming video. Any known issues with your switch?
Previously, I've had to toss switches into my junk box because they'd lock up after a few hours of streamed HD, or had problems with the store and forward transitions between 100 and 1000 mbit connections.

I also just moved into a house where an electrician had wired all the cat5 cables color-paired across the 1-8 pins instead of using a 568A or 568B wire scheme and my switches didn't like using the unbalanced pairs. Rewiring 16 cable runs took a while.

[paulbeers]

You could try throwing a cheap 100mb NIC card into your Sage box and just have your HDHomerun dedicated thru that port. Then you would take the network out of the equation since it appears that is your issue.

[Polypro]

Have you tried this tweak?

Anandtech -

"HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile\NetworkThrottlingIndex

...defaults to 10 (for 10%) and can be adjusted to between 1 and 100, with the system requiring a reboot between adjustments. We did some quick testing with this key and were easily able to set it to 70%, which got us around 550Mbps of bandwidth through NTttcp, and we probably could have gone higher - especially on multi-core platforms."

http://www.anandtech.com/systems/sho...spx?i=3233&p=2



P

[simonen]

I had a similar problem using my linksys router so I dropped a switch between the server, 2 HD extenders and my HDHR. Hooked the switch to the router as well as all other misc. items and it solved the problem. So the majority of the traffic goes through the switch.

[mkanet]

Polypro, you hit the nail right on the head.

As soon as I turned off NetworkThrottlingIndex, downloads while streaming multimedia (HDHR TV streaming) went away immediately. I admit, I was skeptical at first; but, it stopped the problem dead in its tracks as soon as I applied the change and rebooted. This is A MUST for people with HDHR's and faster-than-DSL internet download capability.

I completely turned throttling off:
NetworkThrottlingIndex=0xffffffff

Thanks again,
Michael

Originally Posted by Polypro

Have you tried this tweak?

Anandtech -

"HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile\NetworkThrottlingIndex

...defaults to 10 (for 10%) and can be adjusted to between 1 and 100, with the system requiring a reboot between adjustments. We did some quick testing with this key and were easily able to set it to 70%, which got us around 550Mbps of bandwidth through NTttcp, and we probably could have gone higher - especially on multi-core platforms."

http://www.anandtech.com/systems/sho...spx?i=3233&p=2



P

[Sam]

Originally Posted by Polypro

Have you tried this tweak?

Is that a Vista only tweak? I have what may be a similar issue, but my Sage server is running on WinXP Pro.

I occasionally see severe studdering on my (wired) HD100, even when just playing a SD source. But I can never nail down a cause.

I also use a pair of powerline ethernet adapters to get a network signal into my exercise room to feed a MVP. It always used to be just fine, but lately also has studdering when the treadmill is running but has smooth playback as soon as the treadmill stops. Yet is always used to work just fine. Again, this is just with SD material and no transcoding.

The server is a quad-core with 4GB memory, and the media is on its own SATA II drive with 64k blocks. So I don't think the server is the bottleneck.

[evilpenguin]

Originally Posted by Sam

Is that a Vista only tweak? I have what may be a similar issue, but my Sage server is running on WinXP Pro.

I occasionally see severe studdering on my (wired) HD100, even when just playing a SD source. But I can never nail down a cause.

I also use a pair of powerline ethernet adapters to get a network signal into my exercise room to feed a MVP. It always used to be just fine, but lately also has studdering when the treadmill is running but has smooth playback as soon as the treadmill stops. Yet is always used to work just fine. Again, this is just with SD material and no transcoding.

The server is a quad-core with 4GB memory, and the media is on its own SATA II drive with 64k blocks. So I don't think the server is the bottleneck.

Your issue is most likely with the high current draw or electrical noise of the treadmill affecting the quality of the powerline connection so this really wouldn't help you.

You might try plugging the treadmill into a really nice surge protector and seeing if that helps at all.

edit: Fixed mistake where I said that this would help, as it won't.

[Polypro]

No prob, glad it worked. This, and disabling ReadyBoost/Superfetch makes Vista SP1 a great HTPC OS.

P

[Sam]

Originally Posted by evilpenguin

Your issue is most likely with the high current draw or electrical noise of the treadmill affecting the quality of the powerline connection

So it would seem, but this means I am not even getting SD speeds. The audio stuttering is near constant, on SD material. But more strange is that it used to be perfect until recently. Even with the treadmill running and the same powerline adapters.

[Conejo]

Powerline Ethernet Adapters can be a great convenience when they work. But because they use your home's AC wiring as the transport topology they are under constant noise interference produced by any device plugged into the same "AC Leg". The most prevalent of culprits for circuit noise are light dimmers, fluorescent lights, running Microwave Ovens, Hair Dryers or anything else with an AC motor. Placing a "Noise Filter" on the suspect plug-in electrical device can help reduce the noise interference it may be contributing.

You may want to run a local LAN speedtest to see how well your units are holding up.