Kodi 16 - LE7 RPi2 with Behringer UCA202 passthrough problem static noise

Hi,

I have the following setup for default sound output:
RPi 2 with LE7 > HDMI output > TV > TV speakers

I have the following setup for passthrough sound output:
RPi 2 with LE7 > PiHut 7 port USB hub > Behringer UCA202 USB soundcard > optical output S/PDIF > Creative Labs DDTS-100 decoder > Creative Inspire T7700 speakers

My settings are the following:
System > Audio output > Audio output device = PI: HDMI
System > Audio output > Enable passthrough = true
System > Audio output > Passthrough output device = ALSA: USB Audio CODEC, S/PDIF
System > Audio output > Dolby Digital (AC3) capable receiver = true
System > Audio output > Dolby Digital (AC3) capable receiver > Enable Dolby Digital (AC3) transcoding = true
System > Audio output > DTS capable receiver = true
System > Audio output > other values are default ones
Video > Playback > Sync playback to display = false

Every component is working great on his own, but I cannot get passthrough to work properly for Dolby Digital/DTS audio streams, instead I only get static noise.
RPi 2 is working perfectly.
Creative Labs digital decoder and speakers work perfectly when fed with Dolby Digital/DTS audio streams by other devices over S/PDIF (e.g. Blu-ray player ).
The passthrough detection works: ACC/MP3 audio streams are sent to default audio output device (i.e. "PI: HDMI"), while AC3/DTS audio streams are forwarded to audio passthrough device (i.e. "ALSA: USB Audio CODEC, S/PDIF").
If instead of using "ALSA: USB Audio CODEC, S/PDIF" I use "PI: HDMI" as passthrough device, then AC3/DTS audio streams are forwarded to TV and decoded by the TV without problem.
I also tried changing S/PDIF cable, same problem.
So the problem seems to be the Behringer UCA202 USB soundcard support.

Here is a kodi.log for LE 7.0.1 with debug on and verbose info for both video and audio.

The debug log matches the following sequence:

• boot LE7 on RPi 2
• open movie with 2 audio streams (one AC3 stream, one DTS stream)
• movie starts playing using DTS audio stream but I get static noise
• after a few seconds, switch to AC3 audio stream but I also get static noise
• stop playing movie

Any idea on how to get passthrough working with Behringer UCA202?
I posted the same question on Kodi forum.

Thanks for your help

Hi,

There are only 2 options listed in "passtrough output device" menu:

• PI: HDMI
• ALSA: USB Audio CODEC, S/PDIF

The output of lsusb:

##############################################
#                 LibreELEC                  #
#            http://libreelec.tv             #
##############################################


LibreELEC (official) Version: 7.0.1
LibreELEC:~ # lsusb
Bus 001 Device 009: ID 1058:10b8 Western Digital Technologies, Inc. Elements Portable (WDBU6Y, WDBUZG)
Bus 001 Device 008: ID 1058:10b8 Western Digital Technologies, Inc. Elements Portable (WDBU6Y, WDBUZG)
Bus 001 Device 010: ID 13fd:3940 Initio Corporation
Bus 001 Device 007: ID 05e3:0608 Genesys Logic, Inc. Hub
Bus 001 Device 006: ID 05e3:0608 Genesys Logic, Inc. Hub
Bus 001 Device 005: ID 08bb:2902 Texas Instruments PCM2902 Audio Codec
Bus 001 Device 004: ID 046d:c52b Logitech, Inc. Unifying Receiver
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
LibreELEC:~ #

Beside the UCA202, I have 2 Western Digital hard disks connected to USB hub, as well as a Blu-ray drive.
The Logitech receiver for keyboard is connected directly to RPi 2.