[mythtv-users] Exasperated: DD/DTS SPDIF works with everything *except* MythTV

Allen Edwards allen.p.edwards at gmail.com
Sun Dec 7 07:55:05 UTC 2008

On Sat, Dec 6, 2008 at 11:10 PM, Kingsley Turner <krt at krt.com.au> wrote:
> Allen Edwards wrote:
>> On Sat, Dec 6, 2008 at 3:21 PM, Steve Hodge <stevehodge at gmail.com> wrote:
>>> On Sun, Dec 7, 2008 at 6:26 AM, Kingsley Turner <krt at krt.com.au> wrote:
>>>> I have configured Myth to use
>>>>    "alsa:default" for audio,
>>>> and "ALSA:iec958:{AES0 0x02}" as the SPDIF output device.
>>>> Obviously the two checkboxes for sending AC3 and DTS sound out via SPDIF
>>>> are checked.
>>>> Mplayer works fine with: -ao alsa:device=iec958 hwac3
>>>> VLC works fine with: --spdif    (oh, *so* easy!)
>>> Have you tried just "alsa:iec958" in Myth?
>> Rename or delete asound.conf and .asoundrc.
>> Set the passthrough device to ALSA:iec958:{ AES0 0x02 }
>> Audio output device to ALSA:spdif.
>> If you are running Fedora, get rid of Pulse Audio (not
>> trivial apparently).
>> Turn on iec958 in alsamixer
> This is basically what I have already, except using ALSA:default instead
> of ALSA:spdif.
> I tried "ALSA:spdif", and got the same result.
> However I did notice that the digital sound (DD5.1 / playing DVD) seemed
> to be dropping in and out (according to the LED on the amp. anyway) and
> occasionally we'd get a split-second of sound before it dropped back to
> silence.  After changing back to ALSA:default I notice this is happening
> here also.  I'd guess it's not keeping up with the sound output or
> something, maybe some kind of buffering thing ??!  ("Agressive Sound
> card buffering" is turned OFF).
> thanks,
> -kt
> __________

Sorry, my reply was not complete:
Output ALSA:spdif
Passthrough device  ALSA:iec958:{ AES0 0x02 }
max Audio: Stereo (other setting is broken)
Upmix: Passive
Aggressive: unchecked
Internal Volume: I have it unchecked but I think it may work checked as well
Enable AC3 and DTS both checked.

Hopefully you didn't have max audio set to stereo and this will fix
your problem.

Good luck,


More information about the mythtv-users mailing list