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I am using Arch Linux and xbmc 9.11 and I can play MKV files with AC3 5.1 streams and they work correctly with the channels mapped properly according to test files I have run. When I play MKV streams with DTS 5.1 streams, the audio comes out the right speakers, but is accompanied by a very loud hissing that sounds like pink noise. I'm guessing that the audio is being decoded properly, but then is mixed with the raw output of the compressed digital stream, but that's pure speculation.

Interestingly, if I enable downmixing of all multichannel streams to stereo only, then the loud noise is gone and the audio is good, but only 2-channel. This would indicate to me that perhaps the software decoder has some problem with 6-channel DTS, but once it engages the downmixing algorithm, it works properly.

The debug log is here:
http://pastebin.com/f9062640

I am using an Audigy 1 soundcard (snd_emu10k1) with three mini din jacks each carrying two channels to my 6 speakers.

Thanks for any help anyone can provide. If this is already fixed in SVN, I can compile and try that. I searched the forums and couldn't find much about this. Most people are using external receivers and want to get digital passthrough working.

hi everyone...
i can confirm this problem. the same strange noisy sound when i'm trying to play files with dts audio stream. i'm using xbmc 9.11 on gentoo with a recent kernel and audigy1 soundcard on analog 5.1 speakers. ac3 works without problems for me too.

first i thought it could be a isssue in the system-wide ffmpeg, because gentoo compiles xbmc with external libs (i think this is default setting in xbmc-9.11.ebuild), but other media player (ie. vlc, mplayer, xine ) playing the same dts content without any problems...
thanks for any help.....

I'm glad to know that it's not just me. I believe that Arch Linux compiles with the built in ffmpeg (because the one in the Arch Repositories does not support VDPAU yet). Is this some sort of isolated issue with the interaction of the Audigy 1 sound card and XBMC? That seems unlikely considering that DTS output works fine in other applications that also use ffmpeg libs.

I'm still hoping someone knows something about this.

I added information to my first post about DTS when downmixing is enabled:


Does anyone else have the same issue?

ok, just going back to xbmc-9.04.1 (without changing anything else) and dts audio streams sound is fine. this is just a workaround, i know. so i`m guessing xbmc uses internal libs, no matter if you enable external libs or not (at least dts decoding/included (?) libdca).
could it be something like an interface change libdca to alsa i'm using alsa 1.0.20, most recent version is 1.0.22...maybe i try an alsa update tomorrow....

mailman, what alsa version do you use?

I'm using alsa 1.0.22, so it's not that.

hmm well i just upgraded to camelot on a spare hard drive in my really old dodgey pc and have no sound what so ever. But if i revert back to my old version of xbmc on another hard disk no problem what so ever....so i am sticking with that till it is fixed. Lucky i had a rollback plan.

I just relized that the i686 version of xbmc 9.11-8 on Arch Linux is compiled using --enable-external-libdts as well as external ffmpeg. When I changed the PKGBUILD to disable both of those options and recompiled, DTS worked as expected again. This looks like it's not a bug in xbmc after all.

Thanks for everyone looking into this!

sorry for my stupid question but where i enable the external-libdts?

i am abit new in xbmc things cant figure out how to fix my 5.1 audio