[Dune have acknowledged the problem] Dune Real Vision 4K Loss of audio on BD ISO

[Yarc]

Hi, recently noticed an audio problem with the Dune Real Vision when playing my backup Batman BD ISO images.  These images have been created using CloneBD and compressed down to 25GB.  I don't know if the problem I'm experiencing is with CloneBD, but don't think so because the same ISO's play fine with PowerDVD on my desktop.  So far, only noticed the problem with the Batman films (Batman Begins, The Dark Knight and The Dark Knight Rises) but not made an exhaustive test.

== The Problem ==

The issue is when the Batman films start (the first two were manufactured without the usual BD menus), often there is no audio and I can only get it by manually cycling through the audio tracks until I hear it.  If I then fast forward or reverse through the film the audio is lost and I have to cycle through the audio tracks to get it back.  Obviously the Dune player is able to play the audio but I don't understand why it's losing it.  I have the same issue with the 'Dark Knight Rises' ISO (this one was manufactured with a normal BD menu).  I get menu audio, but when the film starts it goes silent despite having selected the DTS multi-channel from the BD menu.

To be clear, when I create these compressed ISO images I only have the English audio tracks selected, so usually one or two tracks, one being the multi-channel DTS for example, the other being a stereo soundtrack.  I tend to prefer better visual quality over audio so select options in CloneBD to convert all audio to DTS with a bitrate of either 1472 or 1024 kbps so maybe this is the problem.  But, as said before, once I have manually cycled through all the audio channel options, eventually the multi-channel audio will come back.
 
If I just create a complete ISO backup of my Batman BD disks, I don't have the problem.  I've tried a few different things and one test I'm about to do is keep original audio and just compress the BD to 25GB to see if that works.  I suspect it will, and therefore think that for some reason, the Dune player is unable to select the correct audio track on some films.  I have tried several other BD backup images and they play fine and these have all been compressed, but I cannot now say what audio options I selected.  Some will have been converted to lower bit rates for sure, such as BladeRunner2049, but this plays without any issue and is a CloneBD backup.

I will carry on with various tests such as removing language tracks I don't need but keeping the source audio quality and see if this helps.  It's a time consuming thing, so welcome any helpful comments.

It may just be an issue with some BD's and I'll just have to live with this fact.

Cheers.

[Yarc]

I've just created a new backup ISO of The Dark Knight Rises, this time keeping the original source audio quality but selecting only the English tracks.  The image is compressed to 25GB but still has loss of audio when the film starts.  I doubt compressing the image has made any difference, it's more likely something to do with how the Dune player is selecting the audio track. This BD supports 8 languages but CloneBD sets them all to English.  I can see in PowerDVD all 8 languages are listed as English, and in this player it makes no difference whichever one I pick.

Interesting little glitch.  I'm now creating an MKV version which I'm sure will work, time will tell.

Should I report this to Dune?

Cheers,
Ray

[Yarc]

Just created an MKV version of "The Dark Knight Rises" encoded with H.265/HEVC and audio encoded as DTS 5.1 surround set at 1024kbps.  As expected this plays fine. 

This tells me the Dune Real Vision has no issues with the audio encoding from CloneBD and the issue is when playing some BD ISO files it does not always play the audio track for some reason!?

Is this is known issue?

[futeko.com]

Send details (all of the above) to Dune on support@dune-hd.com.

It's not something I've heard about before but it could be a bug particular to your ISOs as you describe.

[Yarc]

Ok, will do. It must be something strange with these Batman BD disks, so will be interesting to read what they say.  Thanks.

[Nice Monkey]

The Dune is turning out  to be extremely critical on cables. Swapped myself to the cable it came with in the box. In combination with UHD HDR video plus HD sound it may disappear and sound with side effects or drops. The sound will suffer first not the video strange enough.

My Zidoo players all work under those same conditions with my old cable.

Added this as a warning to my review.

[Yarc]

Ok, but I am using the supplied cable.  Not noticed loss of sound from other BD images yet but I have a few to go through.  I've sent a detailed report to Dune and apparently it's been forwarded to the correct department, so they are at least aware of something strange going on.

[Yarc]

I'm now in communication with Dune who quickly responded to my email.  They have asked for a sample ISO image showing the problem which I'm currently uploading to MEGA.

They also asked me to try the Alpha build 210625_1453_r17.dff but this made no difference.

In further testing I have found the problem seems to be when removing foreign language tracks, the Dune player then seems to get confused or at least sometimes.  However, I've just burned the same test ISO to a BD-25 disk and it plays fine in my Samsung BD player, so there is nothing wrong with the ISO image.

I'll post if there is any news.

[Yarc]

Today I received an e-mail from Dune saying the fix for the loss of audio will be in a future update.  A time could not be given, but I think this is very good service. I had a pleasant experience reporting the issue, from them asking for more information to their response today and all very quickly.  Many times in the past with other companies my experience has been somewhat different.