[mythtv-users] AC3 passthrough not working

[Glenn Sommer]

Hey

I'm trying to get AC3 / DTS passthrough to work in MythTV 0.21-fixes.

This is what I've done sofar.

1. Tested the SPDIF output works using mplayer (mplayer -ac
hwa3c,hwdts -ao alsa:device=hw=0.1)

2. Configured MythtTV:
Audio output device = ALSA:default
Passthrough output device = ALSA:iec958( AES0 0x02 )
Max Audio Channels = Stereo
Upmix = Passive
Enable AC3 to SPDIF passthrough = checked box
Enable DTS to SPDIF passthrough = Checked box
Aggressive Sound Card = Not checked box
Use internal volume control = Not checked box

(All other channels NOT using AC3 or DTS are working fine over spdif)

aplay -L says:
mythtv at mediecenter ~ $ aplay -L
default:CARD=Intel
    HDA Intel, ALC888 Analog
    Default Audio Device
front:CARD=Intel,DEV=0
    HDA Intel, ALC888 Analog
    Front speakers
surround40:CARD=Intel,DEV=0
    HDA Intel, ALC888 Analog
    4.0 Surround output to Front and Rear speakers
surround41:CARD=Intel,DEV=0
    HDA Intel, ALC888 Analog
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Intel,DEV=0
    HDA Intel, ALC888 Analog
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Intel,DEV=0
    HDA Intel, ALC888 Analog
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Intel,DEV=0
    HDA Intel, ALC888 Analog
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
null
    Discard all samples (playback) or generate zero samples (capture)

aplay -l says:
mythtv at mediecenter ~ $ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Intel [HDA Intel], device 0: ALC888 Analog [ALC888 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: Intel [HDA Intel], device 1: ALC888 Digital [ALC888 Digital]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

3. I've ensured no /etc/asound.conf or ~/.asound.conf files exist!

When trying to watch something containing AC3, I shortly see my
receiver says Dolby Digital... By looking at my receiver - it seems
that it knows an AC3 stream is there, but it contains 0 channels (my
receiver shows the channels in use, and all channels are off when
using MythTV).

When using mplayer everything works as expected.

Clearly I must have missed something obivios here - I just cannot
figure out what?