Stuttering audio / video in Win7? Try this!

[texneus]

I've been fighting an occational video stutter on my new Win 7 SageTV install basically since I got it stable. Not an obnoxious stutter, but usually one about every 15-30 seconds, usually pretty subtle but still very visible on news crawls.

I finally found the answer...I had a DPC latency issue! What's DPC latency you ask? Good question, read here as it's a great explanation:

http://www.thesycon.de/deu/latency_check.shtml

To see if you have a problem, download the DPC Latency Checker from above and run. While I was researching this, it appears DPC Latency problems are very common on Windows 7. In my case, once I disabled EIST (in the BIOS) my SageTV box DPC "flatlined" and stays right around 100uS no matter what I do with it. AND playback is now completely and utterly smooth in SageTV.

I have read lots about A/V stutters here, but never saw this mentioned as a cause...

[Fuzzy]

Honestly, this really isn't as common a problem in audio video playback, because there is usually enough buffer in use to cover up any bad/slow hardware drivers. It is much more of a problem in DAW (Digital Audio Workstation) type setups, where you can't run with a high buffer, as it introduces too much audio latency between record and playback. As you've discovered, SpeedStep can have a detrimental effect on it, as each time the processor changes speeds, it can delay interrupt processing until it gets stable at the new speeds.

[QueOnda]

I converted to Win7 64bit and have some audio hickups. Used the DPC Latency Checker. Disabled my 1000mb lan card and showed that was the problem but is it really? I found that programs might also be a culprit. In disabling my Avast, utorrent and all other programs, seem a bit better.

I found a good read: http://forum.avast.com/index.php?topic=57589.0

Basically taking it up a notch to troubleshoot (see last post in page 4). I need to do this, I do some minor spikes (up to 591). Before I had above 1800.

If anyone has some other good sources or suggestings in trying to make this better. I wondering in shutting down some services. Or I remember in WinXPMCE you had to disable MCE part for it not to conflict with sagetv (or was that the other program b4 I came to sage).

NOTE: They say Win7 is better, not if this is a major PITA for DPC but I'm sure not the average user sees this.

[QueOnda]

Had a hardtime finding xperf, found a link and helped me out.

FYI:http://www.oamate.com/howto-install-...s-windows.html

[doncote0]

The main premise is that the network communication processing and audio processing is effectively shared due to Microsoft's throttling. By changing one registry entry and rebooting, a majority of issues go away due to this LAN/audio relationship.

Here are some good articles on it.

http://www.howtogeek.com/howto/windo...ows-vista-sp1/

http://support.microsoft.com/kb/948066

http://www.anandtech.com/show/2452/2

For Windows 7, the registry entry of concern can be found here:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile

[darcilicious]

Entirely non-SageTV related but I get audio stuttering occasionally when my HP TouchSmart 600xt gets too busy -- quite possibly to network-busy now that I think about it (it's my desktop and I watch a lot of HD video over the network...).

Thanks for posting this info, I'm going to have read up and see if this may be a fix for me

[doncote0]

You're welcome. I know many have said that non-integrated network interface cards have given them better performance over integrated. I wonder if this is related.

Maybe this setting is adjusted in the setup routines of some those devices (especially Intel).

[QueOnda]

Originally Posted by doncote0

For Windows 7, the registry entry of concern can be found here:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile

I don't see Multimedia under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\

[doncote0]

I believe that the throttling registry entry may only be for Intel chipsets. I checked the path on 4 different computers.

[gplasky]

Originally Posted by doncote0

I believe that it may only be for Intel chipsets. I checked the path on 4 different computers.

On a 790 Gigabyte AMD powered mb and chipset. Win 7 Ultimate 64bit. This does have WMC built-in and may have something to do with it.

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile]

Gerry

[doncote0]

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia

probably exists on Intel systems only.

I am also running Win7Ultimate 64 bit on multiple Intel systems and the reg entry is found on each one.

[gplasky]

Originally Posted by QueOnda

I don't see Multimedia under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\

Originally Posted by doncote0

I believe that the throttling registry entry may only be for Intel chipsets. I checked the path on 4 different computers.

Originally Posted by gplasky

On a 790 Gigabyte AMD powered mb and chipset. Win 7 Ultimate 64bit. This does have WMC built-in and may have something to do with it.

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile]

Gerry

Originally Posted by doncote0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia

probably exists on Intel systems only.

I am also running Win7Ultimate 64 bit on multiple Intel systems and the reg entry is found on each one.

I'm sorry-what am I missing? Intel systems as opposed to what? I mentioned that setting is also found on my AMD systems. 3 of them to be exact. Which is the same type system QueOnda has and where he said he can't find that setting in his registry. In Windows 7 it should be there.

Or are you saying Intel as opposed to Linux or Intel NIC as opposed to other NICS?

Gerry

[doncote0]

I saw that at the bottom of your answer you included the path to the registry entry. I assume now that it means you also found the entry on your AMD system.

My apologies, gplasky. I meant no disrespect, and didn't understand what you were trying to say.

It now seems that Windows 7 Ultimate (as well as Windows 7 Enterprise since it is the Enterprise version of the same OS) with WMC will have this entry regardless of the chipset.