Z9X Pro Stuttering (Solved)

Now just need to convince the devs - I sent them the dragon clip and they said they couldn't reproduce - if you have another clip with less action (movement), that'd be a great help.

 

My opinion is that one lost frame under any circumstances is unacceptable

 

I also have the same problem with stuttering. I really hope that it will be fixed soon with the next software update.
Watching with Dolby Digital instead of Atmos is not a real solution

 

If anyone can provide a short clip where the stutter is blindingly obvious that would really help - as I keep banging on, if we can't replicate it, we can't fix it and all my THD content plays perfectly.

 

The problem is the stuttering isn't consistent, it seem to happen mostly in busy scenes though. But as Gandalf67 mentioned, it happens about every 15 to 20 minutes and is sometimes very subtle, even hard to see up to a point where one can doubt there even was a stutter.
In the file in the attachment the stutter isn't so subtle as you can see.

I agree Mark, any lost frame is one too much, gets one out of the story of the movie.

A video of what i see:
filemail.com/d/lqrdblqmrbeawsb

 

This is the same issue I've been experiencing since getting this device. The GoT clip shared triggers the problem for me, but it's inconsistent not happening at the same point or even at all some times. After a few loops definitely saw it though.

I think it's present in every TrueHD file I have, or at least many of them.

 

I have regular stutter (every tenth time) independent of file and quality after pausing. stutter is gone if I rewind some seconds. very strange

 

Thanks for sharing supermood. The more cases we get, the better we can pinpoint the problem

 

Yes, you can always see the stuttering in some films, but in this film snippet (see link below, right at the beginning between the 10th and 16th seconds) you can always see the stuttering when Atmos Track is switched on. When Dolby Digital is selected, no stuttering is seen.

You have to put the link together. I'm not allowed to post links here

https
://we.tl/
t-9yrC52vIOW

 

I tried your testfile, John. And it's stuttering just as you said

 

That's a great example, both the German and English TrueHD tracks cause consistent stutter on the Batmobile reveal

 

If it's any use I did a bit of testing various settings with the flash sample to see if anything changed.

• Pass-through Amp compatibility mode didn't help.
• Setting HDMI audio to LPCM 2 Channel stops the stutter, but you only get stereo
• HDMI audio off, with HD down mixing via optical still stutters.

I also tested the sample on a couple of other devices, it played stutter free on my PC, which to my surprise actually bitstreamed the THD/Atmos and an Apple TV 4k which decoded the THD to PCM fine and no stutter.

 

My experience of stuttering with Z9X --> HDFury Vertex2 --> Samsung QE75 is horrible. Actually no way to playback any MKV 4K movie smoothly. Recently I downgraded a personal video from 4K 60fps 5.1 to 30fps 5.1 and stuttering gone totally. It's a clue that dev should pay attention for next fw revision.
Same video MKV 4k 60fps played back in Zappiti One 4K shows no stuttering at all.

 

Yes but you're not mentioning that you use a 3Km radio link to play the files so it's very likely that this has nothing to do with the box and certainly nothing to do with the TrueHD Stutter we're trying to solve here.

 

And a very strange update - another user provided a short clip of LOTR which had a very clear TrueHD stutter during a long panning shot.

I replicated this repeatedly and sent to the devs but they couldn't replicate it on two different AVRs.

I then installed a Debugger to send them a log but the stutter was gone with that particular clip and now I can't replicate it at all either.

Other clips provided to me still show stutter however so I've been able to send a debug log to the devs of this happening with a TrueHD soundtrack and not happening with an AC3 soundtrack on the same clip.

Just recounting this to show how hard it is to replicate these issues sometimes - we still don't know what causes this and why the majority of users (me included) don't have this issue with their own TrueHD content.

 

Yes, but this is another example of stuttering issue by Z9X which is very critical at this moment, IMO.

 

In my case local playback passing through Vertex2, Denon AVR-X6200W or direct connected to USB-3/Sata port, Z9X shows stuttering when playing high bitrate contents. I've tried with several D-Atmos and TrueHD samplers and some of them got the same issue.

 

I just don't want to confuse the issue with local file and delivery variables.

High bitrates have no bearing - at the moment the only intrinsic issue causing stuttering (and by that I mean intrinsic to the box and firmware) seems to be a certain, as yet undetermined, method of encoding with TrueHD soundtracks.

Other anecdotal problems only muddy the waters.

 

OK, I agreed as most of mentioned files were remux samplers.

 

Just to add something to the whole Stutter issues

When i first got my Z9X Pro i swapped out the Z9X ,which included placing the 2 external Hdds on top of the Z9X Pro ,to match old setup

I did find playback unstable that first day

What seems to have fixed my Pro ,was to remove the Hdds off the top to allow better ventilation of the unit ,since i found both the unit and the HDDs were VERY hot

I was moving some stuff around in the cabinet shelf area last night ( first 30 plus day for summer ) and again noticed the Z9X Pro was VERY warm to the touch on top

Im beginning to wonder if some of the issues ppl are seeing is just due to overheating ie installed in tight postions no air flow items on top etc

Im also going to add some spacers under mine to open up air flow around it

But again,since i moved the HDDs off the top of the unit ,mine has been almost totally stutter free for all file types