UHD5000 stuttering in 4K MKV with TrueHD Atmos?

Hi all,

I'm a new owner of Zidoo, and have just picked up the UHD5000. So far I really like what I've seen and it's a big step up from my old Nvidia Shield. One issue is bugging me though, and I'm hoping someone can help shed some light.

I have a bunch of 4K discs that I've ripped into MKV files with MakeMKV, and a good number of these have TrueHD 7.1 Atmos audio tracks. Unfortunately when I enable this track I'm seeing a stuttering picture (usually at scene/camera transition points), and sometimes a very short audio dropout at the same moment. Switching to a non-Atmos Dolby 5.1 track, or to DTS, solves the stuttering completely. For some reason this issue is significantly worse in some specific movies - for example Cars/Cars 2, and Angry Birds Movie (possibly because they have fairly constant music tracks in the background?). It's noticeable in other movies, but far less jarring.

I have ruled out my networking equipment etc by copying one of the movies to the local storage of the Zidoo, and the problem persists when playing it directly from there.

Any ideas, please? Is this a known issue? (I did search before posting here and didn't find much). Any hope for a fix?

Thanks!

 

Nope, not a known issue and it's not something I've ever seen. The vast majority of my library is 4K TrueHD Atmos, and most are ripped with MakeMKV.

Quite honestly, and without exaggeration, you should never ever see a single glitch when playing MKV files.

There was a judder issue early on, but only with DTS-X and that was progressively fixed in v1.0.35 and v1.0.40.

The only issue involving THD was an unrequired HDMI resync, but that wasn't specific to Atmos and was fixed in v1.0.26.

The only thing I can think of as far as the Zidoo is concerned is in Settings/Audio/Pass-Through Amp compatibility which should generally be <off>

What firmware version are you using?

 

Make sure the Zidoo is set to match frame rate.

 

Thanks for the replies. I'll cover the settings first:

- Settings/Audio/Pass-Through Amplifier Compatibility - switch is set to Off. In all my testing I did try this set to On at one point, and it didn't make a difference to the issue.

- Match frame rate is set to On. I have also tried locking the frame rate to 23Hz as I saw this suggested somewhere, but it didn't help.

I'm running the firmware that shipped on the box, which is 1.0.52. I believe this is the latest one available. Are there any newer/beta versions out there I could try?

DTS/DTS-X tracks work absolutely fine - this problem legitimately only happens with the TrueHD Atmos audio tracks.

The only other bit of debugging I've done since my original post is connecting the Zidoo directly to my TV via the HDMI cable supplied with the Zidoo (in case there was a problem with my sound system or the cables I was using), but this didn't help either.

I'm wondering at this point, based on your comments Markswift2003, whether this issue is isolated to just the UHD5000 model (or if not perhaps my unit has a fault)?

Thanks again,

 

Interesting that connecting the TV directly to the Zidoo doesn't help - does your TV support THD? Most don't, so in most cases the AC-3 compatibility track would be played, if present, and if not, it would downconvert to stereo PCM.

I know this doesn't help, but all the boxes share the same SOC so it's not really possible for such a problem to manifest on one model and not others. Also I would discount a faulty box on such an issue - if caused by the box, it would be in software, not hardware. A hardware fault would be less specific.

Can you post two EDIDs - one connected via the amp and one connected direct to the TV and I'll have a look and test it here - essentially that makes my box act the same as yours.

To Download EDID
================

Settings/Display/Custom EDID/Save EDID

Save to a USB stick or network location.

Change the file extension from .bin to .txt to upload to the forum

(The forum won't accept .bin files)

 

Thanks Markswift2003. My TV is an LG OLED G1 (UK model). As far as I know it does support THD - it certainly supports Atmos, and the "Dolby Atmos" logo appears in the top right corner when I play the THD movie directly from the Zidoo.

Posting two EDIDs as requested:

edid-tv.txt (OLED55G16LA)
edid-sound.txt (LG SN11RG) (upgrades are planned )

I really appreciate the help.

 

Nothing untoward in those EDIDs, and yes, you're right, the TV does support THD so that explains that...

Although I kind of knew what the result would be, I tried both EDIDs and as expected, THD videos behaved themselves.

Next thing is to try one of your files - could you clip say a 1m portion from one that you get this issue with, confirm that the issue still exists with the clip and upload to something like Mega.nz etc.

I'd use MKVToolnix to do this.

 

FWIW, I have an LG G1 and I don't have this issue. I just checked again with Eric Clapton Lady in the Balcony in HDR10 and Dolby Atmos. It plays perfectly from as an MKV file.

 

Thanks for checking. Unfortunately I can't find a way to solve the issue with mine. I just watched 10 minutes of my Back to the Future 2 rip and as soon as the intro music started playing (the flight through the clouds) the stuttering started to happen. Kind of proves that background music is the trigger. Not sure what else to try I'm certain it's not my files - they don't stutter on my old trusty Nvidia Shield.

 

Don't discount the files so quickly - they may be fine, but there may be some weird incompatibility with the Zidoo going on...

Send me a test file you and let me test it here - I'm curious about this one!

 

I saw some of that too..but with the leaked firmware it is way way less. Perhaps I saw it once.

 

Hi,
I have similar problem with my UHD5000. It happens if your 7.1 audio is 96khz. It will work with 7.1 48 kHz.
If you are using only one main HDMI for both audio and video then turn off your your audio hdmi in settings. Also set DAC to off.
Finally it also depends on your AV amp. I have Marantz cinema 40.
This problem is common between uhd5000 and z9 pro. Unfortunately Zidoo support is useless
I hope this helps

 

Ok - it looks like you found a pretty odd bug here. Good catch!

So it's definitely the files that are causing the problem, and definitely something to do with the TrueHD soundtrack. But it's not universal because I couldn't replicate it on any of my TrueHD files.

But yours, yes, there is most definitely a sync issue between the video and TrueHD audio.

However, you file works perfectly on older 1619DR boxes - I tested a Z9X and a Dune and both played the file without a glitch.

So it's a bug in the new SOC (to add to the rest of 'em!!) so I'll add this to my bug report and pass the file to the devs.

Again, good catch!

 

Thanks Markswift2003! I'm glad that you were able to replicate the issue, and I appreciate you raising a bug report to the Devs.

In your experience what would be the best move here? Are Zidoo likely to provide a fix for this any time soon? I believe that this issue is not present in any of your TrueHD samples (as it isn't in some of mine), but it is present to varying degrees in quite a large number of mine, and definitely impacts my enjoyment of the box. Is it worth holding out for a fix, or should I return it and replace with a unit with the 1619DR SOC?

 

Personally I'd hold onto it as this will certainly be fixed. As to when, at the moment your guess is as good as mine, so it's up to you.

At the moment I use a Z9X (1619DR) in my cinema, exclusively with MKVs, and it's pretty much bomb proof - haven't had an issue with it for a good couple of years. At some point I will replace it with one of my Z9X Pros, but not until the firmware is a lot more stable.

 

Both of those seem weird bit rate for movie audio
ie
I checked a few atmos movies /dts hd and they were all 6/8 ch at 48.0khz ( Enders game, Exorcist, King Kong Pacific Rim and maybe 10 others)

Could you list a few movies with the 96 khz to check out

Only asking cause i see no issues with my Z9X Pro and that was even with a week of movies etc while "resting"with a cold/covid last week (besides a couple Forced Edid loses after closing one movie tv epi ( marks replicated and sent for fix )

Stutter to me ,when only playing the higher ress files like atmos ,seems to say its a Low HDMI speed issue ,ie an hdmi1.3/2 cable and not a higher speed HDMI cable
,or audio hgmi port isnt set to enhanced maybe( denon speak )

 

Every file I've checked that stutters is 48KHz.

 

It's nothing to do with the sampling rate.

 

Hi
could you set HDMI audio to "LPCM 2 Channel", to check if have this problem yet?

 

No, LPCM works fine - It only happens when output is a bitstream.

You can check this behaviour with the file I sent you.