Audio pass through (AC3, DTS-HD, ...)

andrejb · Published in 2016-5-21 02:02:27

I can confirm that DD, DTS passthrough (i can test also DD+ if needed) work with default images.. just DTS-HD and DD TruHD does not work. This two formats are special, because they need some special HDMI handshake and maybe even hardware can be problem, because of no enough hdmi bandwidth (as with raspberry pi). I do not know the orangepi limitations. Some discussion about truhd and dts-hd on raspberry pi (http://openelec.tv/forum/124-ras ... lby-truehd?start=15)

manatouboji · Published in 2016-5-21 11:17:18

jernej replied at 2016-5-20 23:13
I know. In the mean time I pushed new code. However, it seems that there might not be need to do an ...

DTS-HD = DTS-HD MA

giaur500 · Published in 2016-5-21 18:37:16

jernej replied at 2016-5-20 23:31
One github user confirmed working passthrough on unmodified images. It works for most formats except ...

Jernej, any progress with vsync implementation? This is the only important feature I'm missing now

jernej · Published in 2016-5-22 23:05:59

giaur500 replied at 2016-5-21 11:37
Jernej, any progress with vsync implementation? This is the only important feature I'm missing now ...

This is off topic, take a look in main thread.

tomaszd · Published in 2016-5-26 21:57:05

I've tested audio passthrough using an image built today and a Denon AVR-1911 receiver (pretty old model, but does support every audio format I need) with PCM audio set to 2.0 in OpenELEC (5.1 disables all sound, no matter what mode I'm in).

Unfortunately, only Dolby Digital passthrough works, DTS passthrough definitely does not work. The PCM logo and HDMI Audio logos flash multiple times in the beginning, but it ultimately goes back to PCM audio, the DTS logo never appears on the receiver's screen.

Obviously DTS-HD MA and Dolby TrueHD don't work either (though I wish it would magically downgrade to DD/DTS, most of my movies are DTS-HD MA - is that even possible to do if a receiver does support these formats, but the source can't bitstream them?).

If you have any ideas how to fix DTS passthrough, patches to test, etc, I'm open for it.

jernej · Published in 2016-5-27 00:02:10

I actually have few ideas how to fix this, but because I don't have access to a AV receiver, I stopped working on it. I though that it won't take much, but I was wrong. So unless someone takes this over, it won't be fixed anytime soon, if ever.

tomaszd · Published in 2016-5-27 01:31:18

jernej replied at 2016-5-27 00:02
I actually have few ideas how to fix this, but because I don't have access to a AV receiver, I stopp ...

I know debugging by proxy is frustrating, but if you ever get inspiration to create a separate branch to implement your ideas, I'd be willing to test them out.

tester3 · Published in 2016-6-5 05:40:31

Edited by tester3 at 2016-6-5 21:13

I have built latest version of the openelec-7.0 branch. The video issues are gone so I have tested the passthrough. Here are my results:
Dolby Digital - OK
Dolby Digital Plus - OK
Dolby TrueHD - FAILED
DTS - OK
DTS-HD MA - FAILED

I have also Kodi on my PC and NAS QNAP TS-453mini, which is based on Intel J1900 and has one HDMI output. The NAS firmware allows to install Kodi right in the NAS and use it as multimedia player. The Kodi there shows version 16.0 and operation system Ubuntu 14.04.1 LTS. The PC is running Kodi 16.0 on Windows 7. Results for both are:
Dolby Digital - OK
Dolby Digital Plus - FAILED
Dolby TrueHD - FAILED
DTS - OK
DTS-HD MA - FAILED

I think that the passthrough support should be improved by the Kodi itself. The Kodi on my PC does not even allow to set receiver capabilities for the "FAILED" formats, it allows to check/uncheck DD and DTS only.

EDIT: I was wrong. Both the QNAP NAS and PC are capable to passthrough all the mentioned formats. One just needs to change default Audio output device in the System/Audio output menu. If anyone other encounters this problem,...
On the QNAP NAS:
- change "Playback/recording through the PulseAudio sound server" to "HDA Intel PCH"
On PC:
- change "DIRECTSOUND: default" to "WASAPI: default"

jernej · Published in 2016-6-5 16:14:16

Due to a lack of HDMI documentation and AV receiver it's hard to say anything. I still think that it's doable, just not in this moment.

tester3 · Published in 2016-6-5 21:24:57

I have just edited my previous post, I thought the HD formats were not properly implemented by Kodi yet but I was wrong.

You may check the links below if you are interested. The HDCP could be a serious problem (if it is true).

http://openelec.tv/forum/124-ras ... dolby-truehd#132220
http://forum.odroid.com/viewtopic.php?f=93&t=17288