[MrDohnuts]

Hi guys

I've got XBMC outputting sound via my IEC958 (SPDIF) Output to my 5.1 amp.

AC3 works great but DTS is silent. I can see the DTS being decoded by XBMC (it recognises the source as DCA) but I just don't get any sound.

I installed mplayer at the desktop and the platey the same file without issue.

Where's the best place to start debugging this?

Thanks

[MrDohnuts]

Update:

So the problem turned out to be that my BOSE system is quite old and doesn't support DTS decoding, only regular Dolby Digital 5.1.

I downloaded a test clip which is encoded as Dolby Digital and as DTS. The regular DD clips plays fine, the DTS clip has no audio output at all. I experimented and noticed a few things:

1. My regular Xbox1 was has the same issue. However, if I disable the 'DTS compatible amp' option it re-samples the DTS down to regular DD5.1. This doesn't happen in the Linux version.
   
   
2. If I set the Linux build to use 'analog' instead of 'digital' it plays the DTS audio but down samples it to 2.1.
   

Does anyone know if the Linux version can be made to down sample the DTS to regular DD?

[spiff]

if there's an ac3 encoding plugin for alsa that could be used.

it's the xbox soundsystem that does it for us on xbox - in hw (xbox has hw ac3 encoding)

[MrDohnuts]

if there's an ac3 encoding plugin for alsa that could be used.

it's the xbox soundsystem that does it for us on xbox - in hw (xbox has hw ac3 encoding)

Hi Spiff

I just want to make sure I understand what you're saying:

LXBMC passes audio to ALSA for processing and then ALSA pushes it through the digital port (IEC958). I need to setup ALSA to downmix DTS to AC3 and I'm good to go - is that right?

The link below makes reference to a52encode as an ALSA plugin - does that sound like the sort of thing I should be looking at?

http://gentoo-wiki.com/HOWTO_Dolby_Digit...AC3,_SPDIF)

Thanks

[MrDohnuts]

Update 3:

After some more in depth testing I found the problem is actually down to either the bitrate or the variant of DTS being output.

Streams below 750 K/S decode fine, most sources encoded above that gives me no audio.

I'm still trying to figure out how to re-encode to AC3.

If anyone is interested I'll post a couple of audio samples so you can test your own amps.

[slash]

Hi guys,

I'm still trying to figure out how to configure Digital output to my amp with XBMC.
I have a SB Live ! 5.1 according to ALSA tools the digital output is hw:0,2 but I still don't know how add this in XBMC audio configuration (digital).
As soon as I get to work I will let you know the results with DB and DTS.

[BLKMGK]

To go from DTS audio to AC3 use eac3to. This is what I convert all of my HD video with and it handles DTS and other audio encoding very well.

[MrDohnuts]

To go from DTS audio to AC3 use eac3to. This is what I convert all of my HD video with and it handles DTS and other audio encoding very well.

Hi BLKMGK, that's a great tool - I use it too. However, I'm really looking for a real-time AC3 to DTS encoder. I've got about 50 HD MKV's with DTS audio and I really don't want to re-encode them all. Besides, I'll no doubt get a better amp one of these days and the high bitrate DTS will be nice to have.

I know that the real-time encoding is possible, becuase various media players on the Ubuntu desktop achieve this without incident. It's my lack of linux and in particular my understanding of how XBMC interfaces with ALSA that is letting me down

[spid]

Another solution is to change to Analog output, not ideal as you need to switch back to digital for optimal sound during AC3.. atleast it gives you audio..

It would be a good to have the "disable DTS" button in XBMC auto switch to analog audio during DTS instead of doing nothing.

But in the end, my solution was to get a new amp.

[MrDohnuts]

Another solution is to change to Analog output, not ideal as you need to switch back to digital for optimal sound during AC3.. atleast it gives you audio..

It would be a good to have the "disable DTS" button in XBMC auto switch to analog audio during DTS instead of doing nothing.

But in the end, my solution was to get a new amp.

Hey Spid, yeah I found that analogue work around to get stereo sound from the DTS track, it does get you out of a hole :-)

I think I might be getting a new amp too, though it's a shame to rip out my Bose lifestyle the sound is just stunning.

[madmunky]

Does anyone know if this is possible yet, I have a lot of DTS stuff and it would be nice to have it in AC3 rather than just Stereo so a realtime reencoder would be grate

[kernel]

I think I may be having the same problem, except my tuner decodes DTS (I just bought it about 2 years ago...before that I was using a tuner + audio decoder hardware). Have never had a problem. While I do have problems hearing no audio on what appears to be 5.1 DTS files, I have ripped non-HD DVD's to my HTPC and get no sound on some of them, most I do, however. On the other hand, most of mine are TV series DVD's like Magnum PI and original Battlestar Galactica which didn't really have 5.1 sound.

I have my audio set to Digital and even enabled play audio to all speakers. I can only get sound on these if I downmix to Stereo, which kind of defeats the point. All of my hardware is new within the last two years, so there should be no issues with DTS decoding. The tuner accepts optical and coax digital audio, as well as component ins. My video card is using component, so audio should be going through the sound card.

Not sure what's going on, but it sounds like the same problem.

[madmunky]

I've got the same problem, I thought my decoder didn't support DTS but its only a year old do I looked it up and it does support DTS.

I have it set to enable DTS support and also in XBMC and the sound card is set to IEC958 and AC3 plays fine.

[ianmen]

I'm having the same problem with my HTPC. Al audio formats play ok. Only DTS doesn't play at all. No error message. Has this anything to do with my Televison ? I connect my HTPC with my television with a HDMI cable.

[dottorthomas]

Hi guys, I think I have the same problem:

My pc is connected via HDMI to a Denon amplifier with DTS decoder, yesterday I tried some "mkv" and "m2ts" files and XBMC displayed an audio error (I don't exactly remember the text of the message).

My settings were:

- audio output: HDMI
- speaker configuration: 5.1
- Dolby Digital (AC3) capable receiver (on)
- DTS capable receiver (on)
- audio output device: HDMI

So, I switched "DTS capable receiver" off and now the audio works fine, but the sound is not digital, not as good as it could be.

I don't know where the problem could be, can anyone help me please?
Thank you!