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Discussion Starter · #1 ·
I have an MKV with a DTS-MA stream in it (at least MediaInfo indentifies it as such). I just have analog 5.1 speakers connected to the PC.


The file plays fine with mpc-hc and FFDShow (also without FFDShow) but on the info section of FFDShow it says:


Input description: 48000 Hz, 6 channels 1536 kbps dts (libdts)


...and not DTS-MA!


How do I know it is not playing the lossy DTS track instead of the HD audio? Is this even possible to output the decoded DTS-MA track to analog speakers?
 

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As of now there is no decoder for DTS-MA, just TrueHD. What you are getting is the DTS-MA core decoded which is better than the 640kbps on DVDs. What you can do is encode the DTS-MA track to FLAC to get bit perfect audio that can be decoded in ffdshow. This is only necesary for DTS-MA since TrueHD can be decoded.
 

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Discussion Starter · #3 ·
Thanks for that explanation. I went on to look into this a bit more and found a guide on how to encode the DTSHD-MA track to FLAC with eac3to. For anyone wanting to do the same it's here:
http://forums.guru3d.com/showthread.php?t=314683


I first had to extract the audio track with mkvextract to get a .dtshd file with the DTSHD-MA stream. Then I used eac3to to transcode it to flac. Finally with MKVtoolnix add the streams together.


The only problem I had was I didn't have the Arcsoft TMT program, so eac3to complained about it and used the libav encoder instead which only transcodes the core DTS track. After installing the trial version of TMT version 3 it couldn't find the decoder. I tried all kinds of solutions available everywhere (registering decoder manually, copying files to eac3to folder, add decoder folder to the path environmental variable), but to no avail. Then I just hunted down an older version of TMT (version 2.1.6.113) which worked immediately. I use Windows 7 x64 by the way.


By the way, the extracted DTSHD-MA stream was a 4.5 GB file. After transcoding, the FLAC file was merely 4GB. So I guess FLAC compresses better than DTSMA?


And the file I got from decoding with libav (without Arcsoft installed) was just about 300MB smaller... So the added quality to the lossy track in this case is less than 10 percent?

Well, tonight I'm going to watch the movie, I'll see if I hear any difference.
 
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