[mythtv-users] Dolby Digital Signal indicator on Receiver

Bob Sully rcs at malibyte.net
Tue Apr 22 21:38:33 UTC 2008

Tim Fenn wrote:
> On Sun, 20 Apr 2008 23:22:47 -0700 (PDT) "Bob Sully" <rcs at malibyte.net>
> wrote:
>> A clarification:
>> With these settings:
>>  Audio output device = /dev/adsp
>>  Passthrough outputdevice = Alsa:iec958:{AES0 0x02}
>>  Enable AC3 to SPDIF passthrough check
>>  Enable DTS to SPDIF passthrough check
>>  iecset audio 0
>> Frequently, if I play an "analog" (e.g., recording made from the STB,
>> or analog live TV) FIRST, then I get sound.  However, if I then play a
>> recording with AC3/5.1 sound (which always works and sounds great,
>> with all of the speakers lit up on my receiver), then try to go back
>> and play an "analog" source -> no sound.  Going back to an AC3 source
>> works but I no longer have any analog sound.
>> Can someone clue me in as to how to solve this?
> Not really a solution, but I just set a button in lirc to toggle
> between the audio states:
> begin
>   button = a
>   prog = irexec
>   config = iecset audio 0 ; mythtvosd --bcastaddr=
> --template=alert --alert_text="iecset audio 0"
>   config = iecset audio 1 ; mythtvosd --bcastaddr=
> --template=alert --alert_text="iecset audio 1"
> end
> HTH,
> Tim


That's an excellent idea in the absence of an actual fix (in other words,
figuring out a way to simply pipe everything through s/pdif from the

The only problem is that I've had issues with lirc, and the remote I want
to use is a Harmony 550; getting this working hasn't been real high on my
priority list, as I've been using a small RF keyboard with my Mythbox
which has been working well.

I plan on getting the lirc issues taken care of down the line, but for
now I don't think I can do what you propose with a keyboard (e.g. having
a key toggle execution of a command, as irexec will do) - if I'm wrong,
please set me straight.

There MUST be a correct setting for my system which will allow me to get
to the point where the OP is (working sound via s/pdif for all sources).
I also use Amarok at times when I'm not running mythfrontend on this
machine, and for that I have to set the iec958 parameter to 1 also (even
though I've set the config to use 5.1 sound).

Thanks for your post...if I can't get it working the other way, your
method might be the only answer I have.

Bob Sully - Simi Valley, California, USA

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