Problem with Dolby Atmos audio

[bouchnouk]

Hi,

I am getting an error when I try to demux a Dolby Atmos track. With MediaInfo, I see that the audio track is Dolby Atmos type.


On tsMuxer, I am getting an error on the opening of the file.

Then, the first audio track is discarded by tsMuxer.

I don't know if this a bug or if tsMuxer doesn't support Dolby Atmos yet. If this is the case, I apologize in advance.

Thank you.
John.Wick.Chapter.3.Parabellum.2019.UHD.BluRay.2160p.TrueHD.Atmos.7.1.HEVC.REMUX-FraMeSToR.meta.zip

[jcdr428]

@bouchnouk tsMuxer (and mpeg-ts generally) does not accept TrueHD without AC3 core.
The problem is mkvtoolnix removing the AC3 core from Blu-rays. You can recreate a core with eac3to before muxing into txMuxer.

[bouchnouk]

Thank you for the answer. Sorry, I didn't know that. I tried to find tsMuxer documentation in order to find an answer but I didn't find anything.

The solution you're giving seems complicated. Anyway, I will try to find eac3to.

Sorry for the "false alarm". By the way, thank you for the outstanding work your team is doing with tsMuxer.

[justdan96]

The documentation could probably be updated to reflect this information.

[bouchnouk]

I was not complaining about the documentation. However, your proposition seems very interesting in my humble opinion.

Thank you.

[jcdr428]

@justdan96 @bouchnouk actually as this is a very common request, there is an enhancement possible: tsMuxer could interleave the TrueHD frames with empty 32kbit ac3 frames so that the track can be muxed / read by an HDMV player.

[justdan96]

I've updated the documentation with the following commit - until an enhancement comes along: 9cb01b3

[bouchnouk]

@jcdr428 Would that have an impact on Atmos sound ? I mean, is it like Dolby Vision with 2 tracks : one for the video signal and the other one hidden contains the HDR information? I know that an Atmos signal needs 2 tracks. By emptying one track, do we lose something useful?

From a user perspective working on macOS, that would be a fantastic enhancement.

Best Regards.

[jcdr428]

@bouchnouk the ac3 track is needed only for compatibility reason, as reading TrueHD is not compulsory for Blu-ray players. Adding silence ac3 frames does not change anything to the TrueHD track. Indeed it would be better to transcode the TrueHD to obtain the ac3+thd -which eac3to already does- rather than having an empty track.

[bouchnouk]

@jcdr428 I understand. For macOS user, eac3to might be difficult to use. For the others, the use of eac3to should not be a problem. It's up to you to decide. But ,in my humble opinion, it seems an interesting enhancement.

Thank you.

[MarkerB]

I'd love to be able to have tsMuxer read Atmos tracks, but I don't see how what's been discussed in this thread could be right. I've read over and over again that TrueHD cannot have an AC3 core; that a core is only something DTS-HD has.

Maybe I'm just too thick to get this.

Like... What would the procedure be to create a tsMuxer-readble Atmos track, if I have a "coreless" TrueHD/Atmos track, and an AC3 track? I don't see that eac3to can do something like this. I only see that it can "extract" an AC3 core from TrueHD, but I think that's really just transcoding.

[MarkerB]

I guess I believed a lot of misinformed people about TrueHD not being able to have a core!

The following thread goes into specific detail of how to use eac3to to create a TrueHd/AC3 combo track: http://forum.doom9.org/showthread.php?t=163296

This seemed to work.

[jcdr428]

Fixed by be59064