[RESOLVED] What happens to embedded AC3 in truehd?

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Re: What happens to embedded AC3 in truehd?

Post by admin » Sat May 18, 2019 12:48 pm

Sure, renols, it's highly desirable to be able to extract the embedded AC3 one way or another. I'll try to make it happen. Thank you for bringing this to light.

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Re: What happens to embedded AC3 in truehd?

Post by admin » Sat May 18, 2019 12:59 pm

OK, it's easy to output thd+ac3 from DGIndexNV. But is that what you want? How would you then get the embedded AC3?

I'm thinking to have an option saying whether you want .thd, .ac3 (embedded), or .thd+ac3 when demuxing TRUEHD tracks. What do you think?

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Re: What happens to embedded AC3 in truehd?

Post by renols » Sat May 18, 2019 1:08 pm

If all three options could be available it would be super.

The options I use personally is thd+ac3 or just ac3. Don't think I have ever used just thd.

But maybe someone would like that option.

If it is no big programming task for you to add all three options, that would make it most flexible, and people can choose whatever they want.

renols

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Re: What happens to embedded AC3 in truehd?

Post by admin » Sat May 18, 2019 1:10 pm

OK, but how do you use the thd+ac3 file that you get? We want to avoid needing EAC3TO for anything.

I could just always output thd+ac3 as the only option. That would be trivial to implement. The full options much more work.

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Re: What happens to embedded AC3 in truehd?

Post by renols » Sat May 18, 2019 1:22 pm

When I use the thd+ac3 file I always mux it with mkvtoolnix, which automatically seperates thd and ac3 to two seperate tracks in the mkv file.

But I also use the AC3 track alone sometimes. Which would mean having to use eac3to to extract the AC3 (embedded) stream.

If eac3to should be out of the equation for me thd+ac3 and ac3 (embedded) would be the two outputs I would need.

If thd+ac3 is the only option, I would have to use eac3to to extract the embedded ac3 sometimes. But if thd+ac3 is trivial to do, and ac3 or thd alone Means a lot of Work, I can easily live with just thd+ac3 output.

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Re: What happens to embedded AC3 in truehd?

Post by admin » Sat May 18, 2019 1:31 pm

Got it, thank you. I'll think it over.

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Re: What happens to embedded AC3 in truehd?

Post by admin » Fri May 24, 2019 11:24 am

OK, here is what I have working. When you demux a TrueHD stream it will always generate a file.thd that is stripped of the core AC3, and if there is an embedded AC3 it will generate a file.ac3 that contains the embedded AC3 by itself. I do not generate a .thd+ac3 file for an obscure technical reason (don't ask :lol:).

@renols

Then for your sample the following files are generated:

uhd_sample PID 1100 48000 8ch.thd
uhd_sample PID 1100 embedded.ac3

The contents are identical to what you get from EAC3TO when you do the appropriate commands.

Will this solution work for you? I like it because I do not have to add any new settings and associated processing. Presumably where you loaded the .thd+ac3 into mkvtoolnix, you can now just add both the separate streams.

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Re: What happens to embedded AC3 in truehd?

Post by renols » Fri May 24, 2019 12:19 pm

Sounds great.

I see no reason as to why it should not give the same result muxing the streams seperatly rather than adding the thd+ac3, since mkvmerge splits it in two streams anyway.

What you are suggesting should Work just fine I believe.

Thanks a lot.

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Re: What happens to embedded AC3 in truehd?

Post by admin » Fri May 24, 2019 12:31 pm

Great. Thank you, renols. I'll do some regression testing/refactoring and then make a slipstream.

It is thanks to users like yourself that we are able to make DGDecNV better and better. :salute:

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Re: [RESOLVED] What happens to embedded AC3 in truehd?

Post by admin » Sun May 26, 2019 12:36 pm

Released in slipstream 176. Let's see what I broke. :P

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