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[Fitzcaraldo215]

For several months, I have been plagued by intermittent "stuttering" just on TV sound.  It is not truly stuttering, but short dropouts several times a second once it gets started.  Then it might disappear for several minutes, only to return for several minutes.  There are absolutely no sound problems with any other source up to 192k.  TV video quality is top notch with no problems, even during the audio stuttering.

PC is Win7 with an I7 processor and 16GB.  CPU during TV watching runs at 9-14%.

TV is from Comcast Cable Card in HD Homerun Prime.

Output is Mch to Dirac Live via WASAPI and from there to the Exasound G3 ASIO driver to an Exasound e28 DAC.

After many weeks of trial and error and head scratching, I might have found the issue.

In DSP studio, the setting was to upscale 48k to 96k.  TV audio input apparently is seen as 48k by JRiver.  Resetting that to "No Change" seems to have fixed it.   

[blgentry]

Output is Mch to Dirac Live via WASAPI and from there to the Exasound G3 ASIO driver to an Exasound e28 DAC.

I'm obviously not educated on something here.  What is your configuration that you have two devices with two different types of Windows sound drivers that are interconnected?

Brian.

[glynor]

FYI video is typically distributed at 48kHz.  If it wasn't using that sample rate on your tuner, then the audio and video would get badly out of sync.

Upsampling may require additional buffering, if you intended to do that on purpose (it sounds like not).

[Fitzcaraldo215]

I'm obviously not educated on something here.  What is your configuration that you have two devices with two different types of Windows sound drivers that are interconnected?

Brian.

Dirac Live software  is set as the Windows default sound output and also linked to explicitly as my output from JRiver via WASAPI.  In Dirac Live, I can then choose a link from the list Dirac provides to any other sound output device known to Windows using kernel streaming.  But, the Exasound is seen as a software driver, which communicates directly with the DAC hardware through USB.

So, it is JRiver software to Dirac software to Exasound driver to the DAC. It is conceptually just like daisy chaining the signal path through hardware boxes via wires, except it is all virtual in software except for the USB link to the DAC. It generally works fine, although there are occasional connection problems and hiccups.  And, it sounds really, really good.

BTW, there is also a plugin provided by Exasound to synchronize the volume controls in JRiver with the one in the DAC.  So, I can adjust volume in JRiver, JRemote or at the DAC (front panel or via a simple Harmony IR remote). They are all kept in synch.

[Fitzcaraldo215]

For several months, I have been plagued by intermittent "stuttering" just on TV sound.  It is not truly stuttering, but short dropouts several times a second once it gets started.  Then it might disappear for several minutes, only to return for several minutes.  There are absolutely no sound problems with any other source up to 192k.  TV video quality is top notch with no problems, even during the audio stuttering.

PC is Win7 with an I7 processor and 16GB.  CPU during TV watching runs at 9-14%.

TV is from Comcast Cable Card in HD Homerun Prime.

Output is Mch to Dirac Live via WASAPI and from there to the Exasound G3 ASIO driver to an Exasound e28 DAC.

After many weeks of trial and error and head scratching, I might have found the issue.

In DSP studio, the setting was to upscale 48k to 96k.  TV audio input apparently is seen as 48k by JRiver.  Resetting that to "No Change" seems to have fixed it.   

Well, I spoke too soon.  It's back to dropouts.  Changing the output sample rate scaling seemed to do the trick for awhile, but then it started again.  Strange that it can go away for 1/2 hour or more, then suddenly reappear, disappear, reappear, etc.    I have always though it might be Comcast, maybe plus  the variable video clock in JRiver which jumps around a fair bit with TV.  But, video quality is perfectly smooth, and lip synch generally fine.

Back to trial and error, unless someone has another idea.

[blgentry]

Since I'm not familiar with this setup, thank you for explaining it.  It still sounds rather complicated to me.  Especially having several different types of sound drivers working at the same time.  I have no evidence that this would be any kind of problem... it just seems like the kind of thing that *could* cause problems.

You might try simplifying the path in some way.  The only way I can think of is to go directly to the exasound, without Dirac in the middle.  That's just me doing generic troubleshooting though; I have no idea if it will help or not.

Brian.

[glynor]

Back to trial and error, unless someone has another idea.

FWIW, the AC3 feed I get from the SPDIF Optical Out on my Time Warner cable boxes is often full of timecode breaks and other encoding errors that cause skipping and stuttering with other players.  Worse, it varies from channel to channel and even from program to program on the same channels.

I was convinced for the longest time that the issue was with my recorders, or my PVR application (which was SageTV at the time), until I went through the hassle of actually hooking up one of my cable boxes directly to my receiver and plugged in the optical audio cable and low-and-behold, even that had the same skips and stuttering.

But... Proving that MC's AC3 decoding is better than your average bear and that bitstreaming is often not all its cracked up to be, the same recordings that stutter badly when being bitstreamed or played back through VLC, play perfectly fine when I let MC decode the audio.

You might be looking at issues in the source stream, which are exacerbated by Dirac.  TV signals, particularly digital cable and satellite, are super-compressed and often very messy.

[Fitzcaraldo215]

Since I'm not familiar with this setup, thank you for explaining it.  It still sounds rather complicated to me.  Especially having several different types of sound drivers working at the same time.  I have no evidence that this would be any kind of problem... it just seems like the kind of thing that *could* cause problems.

You might try simplifying the path in some way.  The only way I can think of is to go directly to the exasound, without Dirac in the middle.  That's just me doing generic troubleshooting though; I have no idea if it will help or not.

Brian.

Thanks, Brian.  Yes, my audio signal path has a lot of software hops in it, although it is quite easy to set up.  And, it works great, except for TV audio.

I thought I had tried removing Dirac from the chain before, but you might be right.  I will try that again and give it a long term test.

[BryanC]

For several months, I have been plagued by intermittent "stuttering" just on TV sound.  It is not truly stuttering, but short dropouts several times a second once it gets started.  Then it might disappear for several minutes, only to return for several minutes.

I've been experiencing this same issue and was close to starting a topic on it this weekend. For me, the short dropouts start happening after ~20 minutes. Then I will use the fast forward button on my remote, and the sound will play fine again for another 20 minutes until I have to repeat the 'fix'. I don't have a complicated setup, just a simple usb tuner with MC doing the audio decoding.

I should mention this is on 21.0.6.

[RoderickGI]

It sounds like either a buffering or sync problem. Maybe the Video Clock is "hunting" to keep the signal smooth?
Does it happen with both Live and Recorded TV?

Anyway, could you set up a TV only Zone and give it more buffering, and see if that fixes the problem? I don't know if you could create a Zoneswitch rule that would automatically switch to a TV zone when playing both live and recorded TV, but if a TV Zone with more buffering and switching manually fixes the problem, maybe something could be worked out.

Just throwing out ideas and questions. I see a little bit of this problem on live and recorded TV, but once the media is playing correctly and I leave it alone, the problem usually goes away. It usually happens when I skip forward or back on the timeline.

[Fitzcaraldo215]

I've been experiencing this same issue and was close to starting a topic on it this weekend. For me, the short dropouts start happening after ~20 minutes. Then I will use the fast forward button on my remote, and the sound will play fine again for another 20 minutes until I have to repeat the 'fix'. I don't have a complicated setup, just a simple usb tuner with MC doing the audio decoding.

I should mention this is on 21.0.6.

Yes, that seems somewhat consistent with my experience.  It is fine for 20-30 minutes, then the dropouts start, on and off thereafter.  I have tried both 20.132 (plus a few earlier releases of 20) and 21.06 with the same problem. It seems that if I stop the video, make almost any setting change (like from 48k>96K to 48k>48k, a buffering change, etc.) it goes away for awhile after re selecting the station, then starts recurring again after another 20-30 minutes.  It might just be the stopping and restarting. 

I could be wrong, but I have had HD Homerun Prime/Cablecard set up for about a year.  I do not recall it doing that for about the first 6 months.  Of course, a regular Comcast box in my home does no such thing in the bedroom.

I have noticed the video clock "hunting" a fair bit, but I do not have that displayed all the time.  It might do the same thing when there are no audio problems.  But, again, video is perfectly smooth via HDMI and my GPU.  Not sure if that rules out Firewall/antivirus, but it would seem to.  Unfortunately, messing with that stuff is pretty hairy/scary for me.