Audio passthrough not always working

Help and Support Vero 4K / Vero 4K +
1

Hi,
I’m still having issues with passthough audio only working sometimes.
If I get no audio I stop and restart the video and after a couple of tries my receiver detects the stream and plays audio.

No audio
Https://paste.osmc.tv/ayalezigix

Audio working after stop and restart.
Https://paste.osmc.tv/urepovukuq

I’ve tried enabling lock HDMI HPD, and adjust display refresh rate to both always and start/stop with no difference.
I have a delay of 20 seconds to start video after refresh rate change to give my projector plenty of time, but the issue also occurs when watching on my TV which changes modes near instantly.

PCM audio works fine if I disable pass through but this gives me full dynamic range so not ideal for watching movies at night.

2

Try turning off ‘TrueHD capable receiver’. Your receiver doesn’t support that (it says).

4

Thanks but It certainly does support it.
The receiver is a Sony STR-DN1070.

I have the same issue with passthough regardless of the format.

If I stop and restart the video it will work the second (or third) time.

In the second log above the audio worked the last time I tried.

When it fails the receiver shoes “no stream”, when it works it shows the correct format and I hear audio.
I have no issues from other sources including playing the same disc in my blu ray player.connected to the same splitter and receiver input through an HDMI switch.

What would cause the Vero to say it isn’t supported?
Is it possible to override this?

5

Hi, I have a Sony STR-DN1080 here and from the logs I don’t think you connected your Vero4k(+) to the Sony AVR but an LKV device instead:

====================== EDID =================== wE0go885
Rx Manufacturer Name: LKV
Rx Product Code: 6664
Rx Serial Number: 20180206
Rx Product Name: 4K60Hz8CH
Manufacture Week: 1
Manufacture Year: 2018
Physical size(mm): 1600 x 900

A Sony looks like

====================== EDID =================== wE0go885
Rx Manufacturer Name: SNY
Rx Product Code: 045b
Rx Serial Number: 01010101

Please, tell us more information about your environment means how your TV, AVR and the Vero are connected to each other (including HDMI extender).

6

Yes, there is an HDMI splitter in the path with EDID set to 4k60 7.2 to send video directly to my projector as the Sony receiver fails to pass through 3D even though the specs claim support.

Passthrough audio on the Vero works one out of three times starting a video.
The Vero does pass through audio when connected directly to the receiver.
I am asking why it works via the splitter sometimes with no other changes.

I suspect that due some timing issue when switching modes sometimes the EDID for the projector comes through and blocks most of the audio formats.

FWIW if I play 3D from the Vero via the receiver I get a top/bottom playback at 1920x2205.
If I manually set the projector to 3D mode I lose display altogether.

Most of my issues are caused by trying to workaround this problem but I am otherwise happy with the receiver.

Using multichannel PCM audio is a good enough fall back but I do lose DRC, I’ve enabled auto volume on the receiver to reduce the dynamic range.
My Apple TV and PS5 only support PCM audio anyway.

I thought that setting passthrough audio would ignore EDID, is there a way to force passthrough?

7

Well obviously this splitter device is part of the problem. It tells the Vero that it can only handle these audio formats

====================== Audio Cap =================== k3dRrf31
CodingType MaxChannels SamplingFreq SampleSize
AC-3, 6 ch, 32/44.1/48 kHz, MaxBitRate 640kb/s
AAC, 6 ch, 44.1/48 kHz, MaxBitRate 480kb/s
DTS, 7 ch, 44.1/48/88.2/96 kHz, MaxBitRate 1536kb/s
PCM, 8 ch, 32/44.1/48/88.2/96/176.4/192 kHz, 16/20/24 bit
AC-3, 6 ch, 32/44.1/48 kHz, MaxBitRate 640kb/s
AAC, 6 ch, 44.1/48 kHz, MaxBitRate 480kb/s
DTS, 7 ch, 44.1/48/88.2/96 kHz, MaxBitRate 1536kb/s

not mentioning any HD type. This is why @grahamh told you not to specify DTS-HD and TrueHD as currently configured in Settings->System->Audio at the moment.
I have my doubts as to whether this splitter can really reliably process HD audio formats.

What you can try is to create a fake file `aud_cap` in `/home/osmc/.kodi/userdata`:
  1. connect the Vero with the LKV device (all other devices powered on) and copy the file /sys/devices/virtual/amhdmitx/amhdmitx0/aud_cap somewhere
  2. now connect the Vero directly with the Sony AVR (power on all other devices) and copy /sys/devices/virtual/amhdmitx/amhdmitx0/aud_cap to another place
  3. now compare the both files and merge all lines you find in the Sony-copy but not in the LKV-copy and place the result as file aud_cap in /home/osmc/.kodi/userdata

No guarantee whether this solves your issue but any feedback is welcome.
Unfortunately the idea above does not work.

Here an example how this file /sys/devices/virtual/amhdmitx/amhdmitx0/aud_cap looks with my Sony STR-DN1080 connected:

CodingType MaxChannels SamplingFreq SampleSize
PCM, 8 ch, 32/44.1/48/88.2/96/176.4/192 kHz, 16/20/24 bit
AC-3, 6 ch, 32/44.1/48 kHz, MaxBitRate 640kb/s
DTS, 6 ch, 32/44.1/48/88.2/96 kHz, MaxBitRate 1536kb/s
Dobly_Digital+/ATMOS, 8 ch, 44.1/48 kHz, AFCDepValue 0x1
MAT, 8 ch, 44.1/48/88.2/96/176.4/192 kHz, AFCDepValue 0x1
DTS-HD, 8 ch, 44.1/48/88.2/96/176.4/192 kHz, AFCDepValue 0x3
DTS-HD, 8 ch, 44.1/48/88.2/96/176.4/192 kHz, AFCDepValue 0x1
OneBitAudio, 6 ch, 44.1 kHz, MaxBitRate 0kb/s

But it would be better if you use a splitter device that correctly proclaims via hdmi the formats it supports and then even works fine with those formats.

8

Excellent, that’s the file I need to monitor to see what is happening.

As we speak, with the splitter still in line and nothing changed, I am watching Dr Strange 3D with perfect “DTS-HD HR” bitstreaming to the receiver.

I suspect that the splitter is incorporating the downstream EDID from the other sinks, this includes the receiver which is then connected to both my TV and projector.

9

As you can see, audio formats are also communicated to the Vero twice. Somehow these are not correct.

11

Other devices take notice of the audio caps in the EDID and don’t send HD audio if the receiver doesn’t support that. When playing from your Blu-ray, what format is reported on the receiver? I’m guessing it’s not HD.

Since Kodi doesn’t automatically send a supported audio format based on EDID, that’s why it has manual controls and why you should turn off HD audio (TrueHD and DTS-HD) in settings. Did you try that?

It might be better to research why 3-D video isn’t being passed through the Sony. Is it supposed to support 3-D? If so can you post logs with the vero connected to the Sony and Sony to PJ and you attempting to play a 3-D title. Or have we already been there?

13

Thanks, The 3D through the projector didn’t work with the Blu-ray player either.
I’ll post some logs of the Vero connected directly on 3D mode.

14

Watching the video as above with DTS-HD working aud_cap only shows.
CodingType MaxChannels SamplingFreq SampleSize
PCM, 2 ch, 32/44.1/48 kHz, 16/20/24 bit

So this would imply that it doesn’t matter what is detected and the output is forced regardless?

HD audio is supported and displayed as below when I set the splitter to copy mode which would be the same as connecting directly.
I have no reason to disable the HD modes as they are supported.

CodingType MaxChannels SamplingFreq SampleSize
PCM, 2 ch, 32/44.1/48 kHz, 16 bit
AC-3, 6 ch, 32/44.1/48 kHz, MaxBitRate 640kb/s
DTS, 6 ch, 32/44.1/48/88.2/96 kHz, MaxBitRate 1536kb/s
Dobly_Digital+/ATMOS, 8 ch, 44.1/48 kHz, AFCDepValue 0x1
DTS-HD, 8 ch, 44.1/48/88.2/96/176.4/192 kHz, AFCDepValue 0x0
MAT, 8 ch, 48/96/192 kHz, AFCDepValue 0x1
AC-3, 6 ch, 32/44.1/48 kHz, MaxBitRate 640kb/s
DTS, 6 ch, 32/44.1/48/88.2/96 kHz, MaxBitRate 1536kb/s
Dobly_Digital+/ATMOS, 8 ch, 44.1/48 kHz, AFCDepValue 0x1
DTS-HD, 8 ch, 44.1/48/88.2/96/176.4/192 kHz, AFCDepValue 0x0
MAT, 8 ch, 48/96/192 kHz, AFCDepValue 0x1

I think that the receiver is getting upset by the convoluted path, I don’t know why it is inconsistent though.

15

@grahamh So, obviously we get some audio format information twice. Is the code robust enough or does it create issues, then?

16

Hmm, yes that’s very odd.
I’ll do some testing in various splitter modes and with a direct connection to the AVR.
Obviously, the splitter complicates things but is a necessary evil to get 3D working.

I have configured the Vero to override the 2D and 3D video modes along with HDR and it seems that the audio output is forced in passthrough so the EDID mode of the splitter shouldn’t be a factor - it certainly was with the blu-ray player though.

I did have an issue when starting the movie tonight that even PCM audio, including the GUI sounds, was coming and going every couple of seconds.

I fixed this by changing the HDMI output of the receiver from the TV (which was off), to the projector (which was set to the other input).

There are so many factors here, but nothing works consistently. I’ll find a splitter mode and other settings which work and then come to watch something the next day and have issues again with the same settings.

Unfortunately, the obvious but most expensive solution is to get a different receiver.

17

As noted above, Kodi doesn’t care about the audio caps in the EDID. All it cares about are the audio settings. But we are looking at changing this so that it does do some things automatically. I’m not sure if that would help in this case!

2 Likes
18

But before you do that

19

Besides the requested logs, you can also play with the following 2 audio options; perhaps, this influences the timing of the STR-DN1070 with this splitter thing:

  • keep audio device alive (try ‘always’)
  • send low volume noise
20

Thanks, yes I’ve tried those two options.

The kicker is that everything works fine one day and then gives me issues the next, or works after restarting a video a couple of times.

I did find a thread from another user with a similar issue which was only resolved by replacing the receiver.

21

As @grahamh says, at the time of writing, we send audio based on the settings that the user makes and we don’t filter this in any way. So if you elect to send DTS TrueHD to a receiver that only accepts PCM on 2 channels, we’ll still do so. So while the audio capability parsing looks odd (with duplicates); it won’t impact anything there.

If the receiver is problematic when things are connected directly, maybe there is a firmware update available.

22

Why do you need a splitter if your AVR has two HDMI outs?

23

The AVR doesn’t pass through 3D, even though it should.

I use the splitter to have a second direct connection to the projector to support 3D, this goes to HDMI 2 on the projector which is an HDMI 1.4 input.

The other connection from the splitter goes to the AVR which is then connected to both the TV and HDMI 1 on the projector which is an HDMI 2.0 input to support 4k.