[mythtv-users] ALSA, SPDIF, 5.1 output

[John P. Poet]

Okay, I figured out my problem.  I need to have "Audio output device" set to
"ALSA:iec958" and check "Enable AC3 to SPDIF passthrough".  I could have
sworn I tried this before without success, but it works now.

John
--

On Sat, 31 Jan 2004, John Poet wrote:

>
> I am using a pcHDTV card.  In general MythTV and this card work pretty
> well.
>
> The most annoying problem I have right now, is my ABC station.  It
> generally broadcasts in ac3 5.1.  All the other stations seem to
> broadcast in ac3 2.0.
>
> If the ABC station is the FIRST station I view after starting
> mythfrontend, I get sound, but it is messed up -- I only get audio out
> of the right front channel.  In this state, my pre-amp states that it is
> running in prologic mode.  This indicates to me that I don't have the
> ac3 pass-through configured correctly.
>
> I am using a SoundBlaster Live! card.  I have "Audio output device" set
> to "ALSA:default".  I do NOT have the "Enable AC3 to SPDIF passthrough"
> checked, because that just causes static to come out of the speakers --
> no matter what channel I am tuned to.
>
> If I try and tune to the ABC station after viewing another channel, I
> don't get any sound at all.  Mythfrontend reports these errors:
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~
> QDateTime::fromString: Parameter out of range
> QDateTime::fromString: Parameter out of range
> Video has changed: 1280 720 from: 1920 1088
> Audio has changed: 48000hz stereo
> ALSA lib pcm_hw.c:347:(snd_pcm_hw_hw_free) SNDRV_PCM_IOCTL_HW_FREE
> failed: File descriptor in bad state
> ALSA lib pcm_hw.c:324:(snd_pcm_hw_hw_params) SNDRV_PCM_IOCTL_HW_PARAMS
> failed: File descriptor in bad state
> Unable to set hw params for playback: File descriptor in bad state
> Error setting audio params: File descriptor in bad state
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~
>
> If I tune back to any other station, the audio plays just fine.  This
> indicates to me that the file descriptor does not stay in a bad state,
> it is only in a bad state for the ABC channel, with it's 5.1 format.
>
> If I check the "Enable AC3 to SPDIF passthrough", then I get static out
> the speakers, but I can change to/from the ABC channel without getting
> the above error messages.  I have tried setting "Audio output device" to
> /dev/adsp, but that just results in mythfrontend spitting out:
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~
> Error opening audio device (/dev/adsp):
> /dev/adsp: No such device
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~
>
> Can anyone who is using the pcHDTV card and "AC3 to SPDIF passthrough"
> via ALSA, tell me how they have it configured?
>
> Thanks,
>
> John
>
>
>
>