DTS Passthrough not working

pipsen · February 23, 2018 at 11:14 AM

Hi,

here is my Setup: Raspberry PI3 with HiFiBerry Digi+ with optical cable to my Audio receiver.

Until last week, I had OpenELEC 8.0.4 running on my PI and I enabled Passthrough + DTS capable Receiver.

When I played an mkv File with DTS audio track, my receiver said: DTS

Now I installed LibreELEC 9.0 Alpha nightly build and configered in the same way.

Now my receiver says: Dolby Digital (seems to be a Downmixing).

Any ideas?

PS: I have a full system export of all files from both systems available. I attached both guisettings.xml files to compare.

Thank you!

**blueribb** · February 23, 2018 at 2:47 PM

Have you tried other versions of Libreelec ?

pipsen · February 23, 2018 at 2:49 PM

Quote from blueribb

Have you tried other versions of Libreelec ?

No... not yet. I need the new alpha version for Amazon Prime and Netflix Addon.
Older Versions are not possible for me.

**blueribb** · February 23, 2018 at 2:53 PM

I would at least try an older version to see if your DTS issue is resolved.

pipsen · February 23, 2018 at 5:42 PM

Okay, I tried with latest LibreELEC 8.3.2 release... same issue.

Due to it is still Kodi 17.3 Krytpon, its much more easy to compare settings (see attached image).

I changed the settings manually to have exactly the same settings -> Still no DTS passthrough.

Any ideas?

**blueribb** · February 23, 2018 at 7:55 PM

Did you attempt to get help here: HiFiBerry Digi – HiFiBerry

After all, you paid them for the hardware you're having issues with.

pipsen · February 23, 2018 at 8:22 PM

HiFiBerry Digi itself ist working fine.. otherwise it would not work with OpenELEC8. It seems to be a Software/Config thing..

**zomboided** · February 23, 2018 at 9:05 PM

I found this when I was setting up my RPi2 with HDMI -> TV -> passthrough via optical to amp. I don't have HifiBerry tho. I think everything worked for me on OE7, but not when I got to LE8. I ended up with this fix which might help you. I use SSH to get to the command line and then follow these instructions. If you're not using SSH, you'll need to work out how to access /flash in write mode.

mount -o remount,rw /flash

Edit /flash/config.txt with the following ( nano /flash/config.txt will do this for you)

# Fix DTS passthrough

hdmi_audio_config=0x200

hdmi_clock_change_limit=40

mount -o remount,ro /flash

In my notes, I seem to be questioning whether the final line should be =20 instead of =40, but I can't remember why I was dithering about this. I've been using 40 since whenever with no issues so maybe 40 is fine. If not, you can google around this see if it helps you make progress

**blueribb** · February 23, 2018 at 9:32 PM

I don't know if this thread will help or not:

optical out on raspberry pi 3 ?

pipsen · February 23, 2018 at 10:03 PM

Quote from zomboided

# Fix DTS passthrough

hdmi_audio_config=0x200

hdmi_clock_change_limit=40

mount -o remount,ro /flash

Did not help...

**kszaq** · February 23, 2018 at 10:05 PM

pipsen disable AC3 transcoding in Kodi options.

**mglae** · February 23, 2018 at 10:06 PM

Since Krypton the setting "Sync playback to display" forces audio resampling resulting in PCM or AC3 streams.

pipsen · February 23, 2018 at 10:15 PM

Code

23:10:47.210 T:1941939520  NOTICE: VideoPlayer::OpenFile: nfs://hostname/path/sample.mkv
23:10:47.211 T:1839186816  NOTICE: Creating InputStream
23:10:47.224 T:1839186816  NOTICE: Creating Demuxer
23:10:47.884 T:1839186816  NOTICE: Opening stream: 0 source: 256
23:10:47.884 T:1839186816  NOTICE: Creating video codec with codec id: 28
23:10:47.897 T:1839186816  NOTICE: Creating video thread
23:10:47.897 T:1738011520  NOTICE: running thread: video_thread
23:10:47.898 T:1839186816  NOTICE: Opening stream: 1 source: 256
23:10:47.898 T:1839186816  NOTICE: Finding audio codec for: 86020
23:10:47.898 T:1839186816  NOTICE: Creating audio thread
23:10:47.899 T:1476383616  NOTICE: running thread: CVideoPlayerAudio::Process()
23:10:47.899 T:1839186816  NOTICE: Opening stream: 3 source: 256
23:10:47.910 T:1476383616  NOTICE: Creating audio stream (codec id: 86020, channels: 6, sample rate: 48000, no pass-through)
23:10:48.032 T:1941939520  NOTICE: Display resolution ADJUST : 1920x1080 (1920x1080) @ 23.98 - Full Screen (57) (wight: 0.000)
23:10:48.157 T:1939338112  NOTICE: CAEEncoderFFmpeg::Initialize - AC3 encoder ready
23:10:48.167 T:1941939520  NOTICE: VideoPlayer: OnLostDisplay received
23:10:48.364 T:1941939520  NOTICE: VideoPlayer: OnResetDisplay received

Display More

Here is the logfile of a sample.file with DTS Sound:

Creating audio stream (codec id: 86020, channels: 6, sample rate: 48000, no pass-through)

why??

pipsen · February 24, 2018 at 9:00 PM

Quote from mglae

Since Krypton the setting "Sync playback to display" forces audio resampling resulting in PCM or AC3 streams.

Thank you !!!!! Awesome.. dts und AC3 passthrough working again

DTS Passthrough not working

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