Decode DTS-HD MA core

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Brettermeier Offline
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Post: #1
Hi,

I have the following problem: I successfully made my raspberry (this is not a raspberry specific question, please read on) play DTS by overclocking. But now I have plenty of movies that only come with a DTS-HD MA track. It cannot decode those fast enough though, so I would like it to just software decode the DTS core track in it. Is there some way to tell xbmc to ignore the lossless part and just handle the core like a normal DTS track?

Another option would be to re-encode everything from awful DTS-HD MA into a good format like FLAC, but I'd rather not go this painful way.

Thanks!
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jjd-uk Offline
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Post: #2
Disable DTS-HD and only DTS is passed through.

Disable DTS and DTS core is decoded to multichannel LPCM.
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popcornmix Online
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Post: #3
On the PI DTS-HD should not be selectable, so you should always get the DTS core, and I'd expect that to play.

What distribution and what version are you using? Older versions did struggle with DTS, but this is largely resolved now.

Where is the file? Wired or wireless? NFS/SMB?
Post the mediainfo of the file. xbmc.log could provide some clues.
If you can produce a 200MB sample of the file (and confirm that sample still fails to play well), upload it and I'll test it.
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Brettermeier Offline
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Post: #4
Thank you for the information! I have DTS files that play perfectly... the DTS core is just a regular DTS stream, nothing special that takes longer to decode, right? I'm using raspbian with a custom 3.10.13 kernel, but the stock next branch behaved exactly the same. It's over nfs using ethernet, but as said, regular files with the exact same setup with DTS play fine.

I'm a little confused though, shouldn't a DTS-HD MA stream be decoded without falling back to its DTS core by default? That would seem more reasonable, at least for devices that have enough computational power?

I could provide a sample tomorrow!
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popcornmix Online
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Post: #5
(2013-10-23 20:22)Brettermeier Wrote:  I'm a little confused though, shouldn't a DTS-HD MA stream be decoded without falling back to its DTS core by default? That would seem more reasonable, at least for devices that have enough computational power?
My understanding is that ffmpeg doesn't support DTS-HD decode on any platform. E.g.
http://forum.xbmc.org/showthread.php?tid...pid1306134
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jjd-uk Offline
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Post: #6
That's right DTS-HD MA can't be decoded, it can only be passed through, if decoding XBMC can only decode the DTS core track.
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Brettermeier Offline
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Post: #7
Then is there any explanation as to why regular DTS files work more smoothly than DTS-HD MA files? Both software decoded to a stereo output?
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popcornmix Online
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Post: #8
(2013-10-23 22:57)Brettermeier Wrote:  Then is there any explanation as to why regular DTS files work more smoothly than DTS-HD MA files? Both software decoded to a stereo output?

Higher bitrate?
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Brettermeier Offline
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Post: #9
Oh, the DTS core can have a higher bitrate than a classical DTS stream? That would explain it, thank you! So I'll have to hope there is hardware DTS at some point, which turns this into an rpi specific question Wink
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jjd-uk Offline
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Post: #10
Normal DTS supports up to 1536kbps from memory, at the beginning of the DVD era some disc's would support this bitrate however these would tend to be DTS only soundtrack disc, I think Apollo 19 was an example. Over time it became more common to include both DTS and AC3 soundtracks, therefore it became the norm for DTS @ 768kbps to be used on DVD.

On Blu-Ray the DTS core is always at the max bitrate of 1536kbps.

For this reason DTS core from Blu Ray can still be far better than DTS from the equivalent DVD.

Perhaps use MediaInfo to see what bitrate the plain DTS files are.
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Brettermeier Offline
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Post: #11
Thanks and sorry for my late reply. This was an interesting hint, and surprisingly, all my files have 1536kbps. The DTS-only ones play fine, those with DTS-HD MA track cause problems since the raspberry cannot decode them fast enough.

Could the process of extracting the DTS core be so computationally intense? Any other hints?

Thanks!
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popcornmix Online
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Post: #12
If you produce a sample that fails to play (e.g. with mmg from http://www.bunkus.org/videotools/mkvtoolnix/), give me a link to it and I'll check if I can play it.
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